# Chemical and olfactory analysis of essential oils of Hedychium gardnerianum, Hedychium flavescens, Pittosporum senacia and Psidium cattleianum from Reunion Island

Marine Canton, Marina Thierry, Sylvain Antoniotti

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Marine Canton, Marina Thierry, Sylvain Antoniotti. Chemical and olfactory analysis of essential oils of Hedychium gardnerianum, Hedychium flavescens, Pittosporum senacia and Psidium cattleianum from Reunion Island. Journal of Essential Oil & Plant Composition, 2023, 1 (3), pp.298-311. 10.58985/jeopc.2023.v01i03.39 . hal-04293587

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Distributed under a Creative Commons CC BY 4.0 - Attribution - International License
1 Chemical and olfactory analysis of essential oils of *Hedychium gardnerianum*,

2 *Hedychium flavescens*, *Pittosporum senacia* and *Psidium cattleianum* from

3 Reunion Island

4 Marine Canton¹, Marina Thierry¹ and Sylvain Antoniotti¹,²,*

5 ¹ Université Côte d'Azur

6 Institut d'Innovation et de Partenariats Arômes Parfums Cosmétiques

7 Espace J.-L. Lions, 4 traverse Dupont, 06130 Grasse, France

8 ² Université Côte d'Azur, CNRS

9 Institut de Chimie de Nice

10 Parc Valrose, 06108 Nice cedex 2, France

11 *Correspondence: sylvain.antoniotti@univ-cotedazur.fr

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13 **ABSTRACT**

Four essential oils (EOs), rarely described in the literature, and never for 14 samples originating from Reunion Island, were studied by gas 15 chromatography with flame ionisation detector (GC-FID) and gas 16 chromatography coupled with mass spectrometry and olfactometry 17 (GC/MS-O). The chemical composition, as well as the main olfactory 18 properties, of the following four EOs were determined: longose 19 (*Hedychium gardnerianum*), yellow ginger (*Hedychium flavescens*), bois de 20 joli coeur (*Pittosporum senacia*), and Chinese guava (*Psidium cattleianum*). 21 The chemical compositions were found to be rich in mono- and 22 sesquiterpene hydrocarbons. The main components of *H. gardnerianum* 23 flowers EO was β-farnesene (12.1%), α-cadinol (9.7%) and α-farnesene 24 (7.1%). The composition of essential oil from *Hedychium flavescens* leaves is 25 reported for the first time with β- and α-pinene (47.8 and 18.7%, 26 respectively) as well as β-caryophyllene (17.5%) as the main compounds. 27 The main components of *P. senacia* leaves EO and *P. cattleianum* floral tops 28 EO was identified as nonane (36.2%) and β-caryophyllene (43.7%), 29 respectively. With such a chemical composition, herbal, citrus, green, pine 30 tree, and in some cases floral and woody odors were determined by 31 GC/MS-O. 32

**Keywords:** natural complex substance • chemical composition • natural 33 scent • olfactometry • joli coeur 34

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# INTRODUCTION

The genus *Hedychium* is part of the Zingiberaceae family and includes about 80 species distributed mainly in Asia. *H. gardnerianum* is a plant native to the Himalayas whose stem can be 2 meters long and its leaves 30 cm long. Its flowers can be pink or orange yellow [1-3]. It is considered an invasive plant on most of the Azores archipelago [1]. The rhizomes of the *Hedychium* species are known to be fleshy and aromatic. Some species are cultivated only to extract the fragrant essential oil from their rhizomes. Aerial parts of the *Hedychium* species can be used in the paper industry and its flowers as culinary ingredients [4]. The bloom of the *Hedychium* species is very brief and usually occurs during the monsoon. The chemical profile of *Hedychium sp*. EO is reported as complex and comprising monoterpene and sesquiterpene derivatives. The compounds α-pinene, β-pinene, eucalyptol, linalool and nerolidol, although quite ubiquitous, are described as markers of the genus *Hedychium* [4].

The genus *Pittosporum* belongs to the Pittosporaceae family and encompasses ca. 200 species [5]. Among these, *Pittosporum senacia* is a species found on Indian Ocean Islands. The chemical composition of EO from the whole plant from Mauritius was described in 2020 and 2021 by Jugreet et al. [5, 6]. In their most recent article, the distillation yield for *P. senacia* was found to be 0.77%. The chemical composition mainly comprised monoterpene hydrocarbons (up to 71.9%), and particularly β-myrcene (62.2%). Other compounds found were germacrene D (7.8%), limonene (3.4%), and β-
phellandrene (2.9%). In an earlier article from 1998, EO from the leaves of *P. senacia coursii*, endemic to Madagascar, was studied [7]. With a distillation yield of 0.67%, 95% of the chemical composition of the EO was determined by GC-FID and GC/MS. With monoterpene hydrocarbons accounting for only 20.4%, including β-myrcene (6.3%), α-terpinene (4.6%) and camphene (3%), the main compounds were found to be sesquiterpene hydrocarbons and derivatives (69.5%) such as α-cadinol (19%), α-muurolol (15.9%), and δ-cadinene (11.3%). In the same study, the antimicrobial activity of this EO against *Staphylococcus aureus* was shown to outperform streptomycin, while it was in the same order of magnitude as streptomycin against *Streptococcus faecalis* [7].

The genus *Psidium* belongs to the Myrtaceae family which contains ca. 5500 species [8, 9]. This genus is known for presenting rich essential oil bearing plants [9]. *Psidium cattleianum* is a species found in Oceania, Brazil, North America and the Caribbean [8]. The shrub is typically between 1 and 4 meters in height. The EO from the leaves of *P. cattleianum* has been described as having antifungal activities against *Candida spp.* and antibacterial activities against several strains such as *Staphylococcus aureus*, *Escherichia coli*, *Pseudomonas aeruginosa* in qualitative analyses with the antibiotic ampicillin as control [8].

The chemical composition of EO from *P. cattleianum* leaves has been studied with plants coming mainly from Brazil [8-12]. Older studies describe *P. cattleianum* EO harvested in Hawaii [13], Cuba [14], and California [15].
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As part of a project dedicated to the chemical and sensory evaluation of plants from Reunion Island for applications in perfumery, the chemical composition and olfactory properties of four essential oils (EOs) for which literature data are scarce or non-existent were studied. The four species, from the Zingiberaceae, Pittosporaceae, and Myrtaceae botanical families illustrated in Figure 1 are listed hereafter:

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- Longose (*Hedychium gardnerianum* Sheppard ex Ker-Gawl) – flowers,

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- Yellow ginger (*Hedychium flavescens* Carey ex Roscoe) – leaves,

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- Bois de joli coeur (*Pittosporum senacia* Putt.) – leaves,

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- Chinese guava (*Psidium cattleianum* Afzel. Ex Sabine) – floral tops.

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The aim of these studies was to determine the chemical composition of these essential oils and evaluate their olfactory profile for potential applications in perfumery.

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# MATERIAL AND METHODS

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## Plant materials

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*H. gardnerianum*, *H. flavescens*, *P. senacia* and *P. cattleianum* were collected in 2020 on Reunion Island, in the wild between 800 and 1300 meters of altitude and their essential oils were obtained from OLICA (19 Rue Fangourin, Saint-Leu 97424, La Réunion, FRANCE).

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The four pictures of the species in Figure 1 are licensed under the
Creative Commons Attribution-Share Alike 3.0 Unported license without
modification. Authors are (1) and (4) B. Navez, (2) Forest and Kim Starr, (3)
Change-ecorce.

<figure><img src="image_2.png" /><figcaption>Figure 1. The four species studied: (1) *H. gardnerianum*, flowers; (2) *H. flavescens*, leaves; (3) *P. senacia*, leaves; (4) *P. cattleianum*, floral tops.</figcaption></figure>

GC/MS-FID analyses

The analyses of the four EOs chemical composition were performed on
an Agilent GC 7820 chromatograph coupled to an Agilent 5977B electron
ionization mass spectrometer and equipped with a flame ionization detector.
The column used was Agilent HP5-MS capillary column (30 m x 0.25 mm i.d.,
film thickness 0.25 µm). The sample of EO was diluted to 1% v/v in ethyl
acetate. One microliter of the sample was injected with a split ratio of 1/10.
Carrier gas was helium with a flow rate of 1.2 mL/min. The temperatures of
injector and source was 250 °C and 230 °C, respectively. The oven temperature
117 was programmed to stay 4 min at 40°C, then to rise from 40 to 200°C with an increase of 2 °C/min and finally from 200 to 270 °C with an increase of 8 °C/min.
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119 For the MS, ionization energy was 70 eV and the range was from 35 to 350 m/z.
120 The FID detector was set at 270 °C with an air flow of 400 mL/min and a
121 hydrogen flow of 40 mL/min.

122 Characterization of the EOs

123 GC/MS was used for identification and GC-FID for quantification. The
124 identification of EO constituents was carried out by matching the retention
125 index (RI) determined against a series of C7-C40 alkanes as well as by matching
126 the EI-MS mass spectra obtained with various databases (NIST20, Wiley6n and
127 internal database).

128 GC/MS-O analyses

129 GC/MS-O analyses were performed on a Perkin Elmer Clarus 690
130 chromatograph coupled with a Perkin Elmer Clarus SQ8T mass selective
detector and equipped with a Perkin Elmer sniffing port. The column was a
131 Perkin Elmer Elite 5-MS (30m x 0.32mm i.d., film thickness 0.25µm). The sample
132 of EO was diluted to 10% v/v in ethyl acetate. One microliter of the sample was
133 injected with a split of 72 mL/min (inlet pressure: 23 psi). The split between the
134 MS and the Olfactometry detector was 1:7 (v/v). The oven temperature was
135 programmed to stay 2 min at 60 °C, to rise from 60 to 200 °C with an increase of
136 5 °C/min, then from 200 to 280 °C with an increase of 8 °C/min and finally held
137 at 280 °C for 5 min. The solvent delay was 5.5 min. Four panelists carried out
138
the GC/MS-O analysis in duplicate, on each of the four EOs. Compounds were
annotated by matching the EI-MS mass spectra obtained with databases
(NIST20).

## 142 RESULTS AND DISCUSSION

### 143 *Hedychium gardnerianum* and *Hedychium flavescens*

Essential oils obtained from the rhizomes of the two species *H. gardnerianum* and *H. flavescens* have been described in the literature [2-4, 16-18]. For example, Ray et al. (2018) studied 10 species of *Hedychium*, including *H. gardnerianum* and *H. flavescens*, cultivated under the same conditions in India [4]. After harvesting, the EO of each plant was collected from the rhizomes and analyzed by GC/MS and GC-FID. The distillation yield of *H. gardnerianum* and *H. flavescens* species was about 0.20%, which is lower than other species of the genus such as *H. thyrsiforme* (0.75%) and *H. gracile* (0.65%), and higher than others such as *H. flavum* (0.10%) and *H. greenii* (0.05%). The EO of *H. gardnerianum* was described as dark yellow and that of *H. flavescens* as dark brown. The chemical compositions of the two EOs were determined, accounting for 75.9% and 92.8% of oils of *H. gardnerianum* and *H. flavescens*, respectively. Both were composed mainly of monoterpene derivatives, mostly β-pinene and α-pinene (28.03% and 21.15% for *H. gardnerianum* and 29.76% and 13.17% for *H. flavescens*, respectively). Eucalyptol, one of the main compounds of *H. flavescens* (12.80%), was found in a much smaller fraction in *H. gardnerianum* (0.42%) [4].
The EO of *H. gardnerianum* flowers has been very little studied; to the best of our knowledge, only two papers published in 2002 and 2003 described the EO obtained from this part of the plant [1, 2] and EO extracted from the leaves of *H. flavescens* has never been described. Medeiros et al. (2003) studied the chemical composition of EO from *H. gardnerianum* flowers from three locations on San Miguel Island in the Azores [1]. The composition of these was determined using GC/MS analysis alone, accounting for 87%, 94% and 91% of the total EO from the three locations, respectively. Although they came from the same island, significant differences in the relative percentages of compounds were observed, although GC/MS alone can hardly provide reliable quantitative information.

The main compounds of the three EOs were monoterpene hydrocarbons with α-pinene (8.38-18.13%), β-pinene (5.06-11.99%), p-cymene (3.85-8.16%), γ-terpinene (3.15-14.43%) and the sesquiterpene derivatives α-cadinol (6.42-14.59%), β-caryophyllene (7.04-8.89%), δ-cadinene (4.89-8.76%) and τ-muurolol (2.64-5.86%). The chemical composition of EO from *H. gardnerianum* flowers from Fiji was studied by Smith et al. [2]. Up to 75% of its chemical composition was characterized by GC/MS-FID analyses. β-Caryophyllene (17.4%) and β-pinene (17.0%) were found to be the two main compounds.

*Hedychium gardnerianum* flowers EO analysis

The sample of *H. gardnerianum* flowers EO was found to be chemically very complex (Figure 2). As shown in Table 1, a hundred compounds were detected by monodimensional gas chromatography and those identified
accounted for more than 87% of the EO. The sample was mainly composed of sesquiterpene derivatives including β-farnesene (12.05%), α-cadinol (9.71%), α-farnesene (7.09%), τ-muurolol (5.89%) and δ-cadinene (5.83%). The monoterpene derivatives identified accounted for ca. 20% with α-pinene, β-pinene and humulene as main representatives (4.48%, 4.46% and 3.93%, respectively). The sample also contained diterpene derivatives including kaur-16-ene (2.42%).

Our results are in agreement with the article by Medeiros et al. (2003) concerning the study of the Eos of longose leaves and flowers (H. gardnerianum) from the island of San Miguel (Azores) [1]. In their study, the main compounds were α-pinene, β-pinene, p-cymene, γ-terpinene, β-caryophyllene, β-cadinene and α-cadinol. These compounds were all present in the sample studied herein. However, β-farnesene, the main compound in our sample, was identified to a much lesser extent (ca. 3%) in the study by Medeiros et al (2003). This could suggested a particular role of farnesene in plant defense particular to the Reunion Island territory for a compound known to be associated with insect attraction [19].

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<figure><img src="image_3.png" /><figcaption>Figure 2. Chromatogram of *Hedychium gardnerianum* flowers essential oil.</figcaption></figure>

<table><caption>**Table 1.** Chemical composition of *Hedychium gardnerianum* flowers essential oil.</caption><thead><tr><th>Peak #</th><th>RT (min)</th><th>Area %</th><th>Compound</th><th>Formula</th><th>RI</th><th>RI litt.</th></tr></thead><tbody><tr><td>1</td><td>17.625</td><td>4.48</td><td>α-pinene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>931</td><td>937</td></tr><tr><td>2</td><td>18.563</td><td>0.08</td><td>camphene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>945</td><td>952</td></tr><tr><td>3</td><td>20.344</td><td>0.15</td><td>sabinene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>971</td><td>974</td></tr><tr><td>4</td><td>20.493</td><td>4.46</td><td>β-pinene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>973</td><td>979</td></tr><tr><td>5</td><td>21.682</td><td>0.21</td><td>β-myrcene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>991</td><td>991</td></tr><tr><td>6</td><td>22.460</td><td>0.39</td><td>α-phellandrene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>1002</td><td>1005</td></tr><tr><td>7</td><td>22.853</td><td>0.04</td><td>3-carene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>1008</td><td>1011</td></tr><tr><td>8</td><td>23.339</td><td>0.24</td><td>α-terpinene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>1015</td><td>1017</td></tr><tr><td>9</td><td>23.892</td><td>1.46</td><td>p-cymene</td><td>C<sub>10</sub>H<sub>14</sub></td><td>1022</td><td>1025</td></tr><tr><td>10</td><td>24.175</td><td>0.52</td><td>limonene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>1026</td><td>1030</td></tr><tr><td>11</td><td>24.363</td><td>0.08</td><td>eucalyptol</td><td>C<sub>10</sub>H<sub>16</sub>O</td><td>1029</td><td>1032</td></tr><tr><td>12</td><td>25.000</td><td>0.23</td><td>(Z)-β-ocimene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>1038</td><td>1038</td></tr><tr><td>13</td><td>25.705</td><td>2.97</td><td>(E)-β-ocimene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>1048</td><td>1049</td></tr><tr><td>14</td><td>26.355</td><td>2.46</td><td>γ-terpinene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>1057</td><td>1060</td></tr><tr><td>15</td><td>28.431</td><td>0.09</td><td>terpinolene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>1086</td><td>1088</td></tr><tr><td>16</td><td>28.888</td><td>0.06</td><td>methyl benzoate</td><td>C<sub>8</sub>H<sub>8</sub>O<sub>2</sub></td><td>1093</td><td>1094</td></tr><tr><td>17</td><td>29.371</td><td>2.22</td><td>linalool</td><td>C<sub>10</sub>H<sub>18</sub>O</td><td>1100</td><td>1099</td></tr></tbody></table>
<table><thead><tr><th>Peak #</th><th>RT (min)</th><th>Area %</th><th>Compound</th><th>Formula</th><th>RI</th><th>RI litt.</th></tr></thead><tbody><tr><td>18</td><td>30.504</td><td>0.12</td><td>(E)-4.8-Dimethylnona-1,3,7-triene</td><td>C<sub>11</sub>H<sub>18</sub></td><td>1116</td><td>1116</td></tr><tr><td>19</td><td>31.954</td><td>0.01</td><td>sabinol</td><td>C<sub>10</sub>H<sub>16</sub>O</td><td>1137</td><td>1143</td></tr><tr><td>20</td><td>33.804</td><td>0.09</td><td>endo-borneol</td><td>C<sub>10</sub>H<sub>18</sub>O</td><td>1164</td><td>1167</td></tr><tr><td>21</td><td>34.654</td><td>0.10</td><td>terpinen-4-ol</td><td>C<sub>10</sub>H<sub>18</sub>O</td><td>1176</td><td>1177</td></tr><tr><td>22</td><td>35.662</td><td>0.11</td><td>methyl salicylate</td><td>C<sub>8</sub>H<sub>8</sub>O<sub>3</sub></td><td>1191</td><td>1192</td></tr><tr><td>23</td><td>41.904</td><td>0.06</td><td>bornyl acetate</td><td>C<sub>12</sub>H<sub>20</sub>O<sub>2</sub></td><td>1285</td><td>1285</td></tr><tr><td>24</td><td>41.921</td><td>0.06</td><td>2-undecanone</td><td>C<sub>11</sub>H<sub>20</sub>O<sub>2</sub></td><td>1285</td><td>1294</td></tr><tr><td>25</td><td>43.170</td><td>0.01</td><td>indole</td><td>C<sub>8</sub>H<sub>7</sub>N</td><td>1304</td><td>1295</td></tr><tr><td>26</td><td>45.202</td><td>0.05</td><td>δ-elemene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1336</td><td>1338</td></tr><tr><td>27</td><td>45.945</td><td>0.16</td><td>α-cubebene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1348</td><td>1351</td></tr><tr><td>28</td><td>47.567</td><td>0.19</td><td>α-copaene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1374</td><td>1376</td></tr><tr><td>29</td><td>48.614</td><td>0.21</td><td>β-elemene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1391</td><td>1391</td></tr><tr><td>30</td><td>49.628</td><td>0.04</td><td>α-gurjunene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1407</td><td>1409</td></tr><tr><td>31</td><td>50.219</td><td>1.38</td><td>β-caryophyllene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1417</td><td>1419</td></tr><tr><td>32</td><td>51.67</td><td>0.07</td><td>guaia-6,9-diene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1442</td><td>1443</td></tr><tr><td><b>33</b></td><td><b>52.281</b></td><td><b>3.93</b></td><td><b>humulene</b></td><td>C<sub>15</sub>H<sub>24</sub></td><td>1452</td><td>1454</td></tr><tr><td><b>34</b></td><td><b>52.640</b></td><td><b>12.05</b></td><td><b>(6E)-β-farnesene</b></td><td>C<sub>15</sub>H<sub>24</sub></td><td>1458</td><td>1457</td></tr><tr><td>35</td><td>52.848</td><td>0.01</td><td>allo-aromadendrene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1462</td><td>1461</td></tr><tr><td>36</td><td>53.484</td><td>0.18</td><td>γ-gurjunene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1472</td><td>1473</td></tr><tr><td>37</td><td>53.680</td><td>0.45</td><td>γ-muurolene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1476</td><td>1477</td></tr><tr><td>38</td><td>53.914</td><td>0.96</td><td>germacrene D</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1480</td><td>1481</td></tr><tr><td>39</td><td>54.061</td><td>0.21</td><td>α-curcumene</td><td>C<sub>15</sub>H<sub>22</sub></td><td>1482</td><td>1483</td></tr><tr><td>40</td><td>54.537</td><td>0.17</td><td>Bicyclosesquiphellandrene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1490</td><td>1489</td></tr><tr><td>41</td><td>54.822</td><td>1.67</td><td>bicyclogermacrene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1495</td><td>1495</td></tr></tbody></table>
<table><thead><tr><th>Peak #</th><th>RT (min)</th><th>Area %</th><th>Compound</th><th>Formula</th><th>RI</th><th>RI litt.</th></tr></thead><tbody><tr><td>42</td><td>55.070</td><td>1.05</td><td>α-muurolene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1499</td><td>1499</td></tr><tr><td>43</td><td>55.461</td><td>0.43</td><td>β-cadinene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1506</td><td>1518</td></tr><tr><td>44</td><td>55.646</td><td>7.09</td><td>(3E,6E)α-farnesene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1509</td><td>1508</td></tr><tr><td>45</td><td>55.848</td><td>1.03</td><td>γ-cadinene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1513</td><td>1513</td></tr><tr><td>46</td><td>56.449</td><td>5.83</td><td>δ-cadinene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1523</td><td>1524</td></tr><tr><td>47</td><td>56.891</td><td>0.09</td><td>cadina-1,4-diene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1531</td><td>1532</td></tr><tr><td>48</td><td>57.186</td><td>0.24</td><td>α-cadinene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1536</td><td>1538</td></tr><tr><td>49</td><td>57.476</td><td>0.12</td><td>α-calacorene</td><td>C<sub>15</sub>H<sub>20</sub></td><td>1542</td><td>1542</td></tr><tr><td>50</td><td>57.897</td><td>3.00</td><td>elemol</td><td>C<sub>15</sub>H<sub>26</sub>O</td><td>1549</td><td>1549</td></tr><tr><td>51</td><td>58.246</td><td>0.18</td><td>204 161 121 105 93 69</td><td>-</td><td>1555</td><td>-</td></tr><tr><td>52</td><td>58.548</td><td>0.14</td><td>204 161 121 109 93 41</td><td>-</td><td>1561</td><td>-</td></tr><tr><td>53</td><td>58.767</td><td>2.11</td><td>(E)-nerolidol</td><td>C<sub>15</sub>H<sub>26</sub>O</td><td>1564</td><td>1564</td></tr><tr><td>54</td><td>59.140</td><td>0.59</td><td>202 69 41 79 93 109 55</td><td>-</td><td>1571</td><td>-</td></tr><tr><td>55</td><td>59.372</td><td>4.33</td><td>222 161 119 105 91 81</td><td>-</td><td>1575</td><td>-</td></tr><tr><td>56</td><td>59.444</td><td>0.55</td><td>spathulenol</td><td>C<sub>15</sub>H<sub>24</sub>O</td><td>1576</td><td>1576</td></tr><tr><td>57</td><td>59.735</td><td>0.75</td><td>caryophyllene oxide</td><td>C<sub>15</sub>H<sub>24</sub>O</td><td>1582</td><td>1581</td></tr><tr><td>58</td><td>60.000</td><td>0.19</td><td>204 161 119 105 91 81</td><td>-</td><td>1586</td><td>-</td></tr><tr><td>59</td><td>60.332</td><td>0.18</td><td>202 159 97 83 69 55</td><td>-</td><td>1592</td><td>-</td></tr><tr><td>60</td><td>60.622</td><td>1.41</td><td>220 121 107 93 88 67</td><td>-</td><td>1597</td><td>-</td></tr><tr><td>61</td><td>60.851</td><td>0.26</td><td>204 122 107 93 81 69</td><td>-</td><td>1602</td><td>-</td></tr><tr><td>62</td><td>61.179</td><td>1.46</td><td>humulene oxide</td><td>C<sub>15</sub>H<sub>24</sub>O</td><td>1608</td><td>1604</td></tr><tr><td>63</td><td>61.358</td><td>0.55</td><td>222 179 105 91 69 41</td><td>-</td><td>1611</td><td>-</td></tr><tr><td>64</td><td>62.25</td><td>1.35</td><td>220 119 93 81 67 41</td><td>-</td><td>1628</td><td>-</td></tr><tr><td>65</td><td>62.413</td><td>0.97</td><td>γ-eudesmol</td><td>C<sub>15</sub>H<sub>26</sub>O</td><td>1631</td><td>1631</td></tr><tr><td>66</td><td>63.024</td><td>5.89</td><td>τ-muurolol</td><td>C<sub>15</sub>H<sub>26</sub>O</td><td>1642</td><td>1642</td></tr><tr><td>67</td><td>63.225</td><td>0.84</td><td>204 161 119 105 95</td><td>-</td><td>1646</td><td>-</td></tr></tbody></table>
<table><thead><tr><th>Peak #</th><th>RT (min)</th><th>Area %</th><th>Compound</th><th>Formula</th><th>RI</th><th>RI litt.</th></tr></thead><tbody><tr><td>68</td><td>63.411</td><td>0.67</td><td>β-eudesmol</td><td>C<sub>15</sub>H<sub>26</sub>O</td><td>1649</td><td>1649</td></tr><tr><td><b>69</b></td><td><b>63.749</b></td><td><b>9.71</b></td><td><b>α-cadinol</b></td><td>C<sub>15</sub>H<sub>26</sub>O</td><td>1655</td><td>1653</td></tr><tr><td>70</td><td>64.460</td><td>0.16</td><td>200 157 142 123 93 69</td><td>-</td><td>1669</td><td>-</td></tr><tr><td>71</td><td>64.929</td><td>0.10</td><td>cadalene</td><td>C<sub>15</sub>H<sub>18</sub></td><td>1677</td><td>1674</td></tr><tr><td>72</td><td>65.504</td><td>0.38</td><td>204 161 119 105 84 81</td><td>-</td><td>1688</td><td>-</td></tr><tr><td>73</td><td>66.212</td><td>0.12</td><td>220 177 159 131 117</td><td>-</td><td>1701</td><td>-</td></tr><tr><td>74</td><td>67.089</td><td>0.06</td><td>220 187 159 145 131</td><td>-</td><td>1719</td><td>-</td></tr><tr><td>75</td><td>68.005</td><td>0.21</td><td>oplopanone</td><td>C<sub>15</sub>H<sub>26</sub>O<sub>2</sub></td><td>1736</td><td>1730</td></tr><tr><td>76</td><td>70.851</td><td>0.06</td><td>1-octadecene</td><td>C<sub>18</sub>H<sub>36</sub></td><td>1792</td><td>1793</td></tr><tr><td>77</td><td>71.662</td><td>0.07</td><td>147 119 91 77 69 55</td><td>-</td><td>1808</td><td>-</td></tr><tr><td>78</td><td>72.253</td><td>0.10</td><td>187 159 119 107 93 77</td><td>-</td><td>1821</td><td>-</td></tr><tr><td>79</td><td>74.520</td><td>0.79</td><td>benzyl salicylate</td><td>C<sub>14</sub>H<sub>12</sub>O<sub>3</sub></td><td>1867</td><td>1869</td></tr><tr><td>80</td><td>80.459</td><td>0.06</td><td>97 91 83 69 57 55</td><td>-</td><td>1993</td><td>-</td></tr><tr><td>81</td><td>81.149</td><td>0.05</td><td>(8β.13β)-kaur-16-ene</td><td>C<sub>20</sub>H<sub>32</sub></td><td>2008</td><td>2012</td></tr><tr><td><b>82</b></td><td><b>82.173</b></td><td><b>2.42</b></td><td><b>kaur-16-ene</b></td><td>C<sub>20</sub>H<sub>32</sub></td><td>2032</td><td>2041</td></tr><tr><td>83</td><td>85.762</td><td>0.11</td><td>Coronarin E</td><td>C<sub>20</sub>H<sub>28</sub>O</td><td>2123</td><td>2136</td></tr><tr><td>84</td><td>87.726</td><td>0.03</td><td>207 91 83 77 69 57</td><td>-</td><td>2194</td><td>-</td></tr><tr><td>85</td><td>89.042</td><td>0.04</td><td>298 146 123 91 77</td><td>-</td><td>2259</td><td>-</td></tr><tr><td>86</td><td>89.229</td><td>0.04</td><td>281 109 96 81 67 55</td><td>-</td><td>2269</td><td>-</td></tr><tr><td>87</td><td>89.325</td><td>0.26</td><td>9-tricosene</td><td>C<sub>23</sub>H<sub>46</sub></td><td>2274</td><td>2278</td></tr><tr><td>88</td><td>89.806</td><td>0.15</td><td>324 99 85 71 57 43</td><td>-</td><td>2299</td><td>-</td></tr><tr><td>89</td><td>90.032</td><td>0.34</td><td>298 174 146 131 109</td><td>-</td><td>2313</td><td>-</td></tr><tr><td>90</td><td>90.719</td><td>0.03</td><td>207 151 81 69 55 40</td><td>-</td><td>2358</td><td>-</td></tr><tr><td>91</td><td>90.956</td><td>0.52</td><td>314 190 162 95 81 55</td><td>-</td><td>2373</td><td>-</td></tr><tr><td>92</td><td>92.293</td><td>0.05</td><td>283 109 95 82 67 55</td><td>-</td><td>2470</td><td>-</td></tr><tr><td>93</td><td>92.346</td><td>0.16</td><td>281 111 97 83 69 57</td><td>-</td><td>2475</td><td>-</td></tr></tbody></table>
<table><thead><tr><th>Peak #</th><th>RT (min)</th><th>Area %</th><th>Compound</th><th>Formula</th><th>RI</th><th>RI litt.</th></tr></thead><tbody><tr><td>94</td><td>92.402</td><td>0.19</td><td>290 108 95 79 67 55</td><td>-</td><td>2479</td><td>-</td></tr><tr><td>95</td><td>92.658</td><td>0.04</td><td>327 113 99 85 71 57</td><td>-</td><td>2498</td><td>-</td></tr><tr><td colspan="4">Total identified</td><td>87.43</td><td></td><td></td></tr><tr><td colspan="4"></td><td>%</td><td></td><td></td></tr><tr><td colspan="4">Monoterpenes / Monoterpenoid s</td><td>20.28</td><td></td><td></td></tr><tr><td colspan="4"></td><td>%</td><td></td><td></td></tr><tr><td colspan="4">Sesquiterpenes / Sequiterpenoid s</td><td>63.21</td><td></td><td></td></tr><tr><td colspan="4"></td><td>%</td><td></td><td></td></tr></tbody></table>

RT: retention time; RI: retention indices; RI litt. from NIST 2020 database. NI:

Not identified (12.55%). Bold: main compounds.

## Hedychium flavescens leaves EO analysis

The EO sample of *H. flavescens* leaves was found to be relatively simple and to contain mainly three compounds: β-pinene (47.81%), α-pinene (18.74%) and β-caryophyllene (17.47%), which together accounted for 84.02% of the sample (Figure 3). As shown in Table 2, in total, 96.26% of the EO was identified. In addition of these three compounds, monoterpene and sesquiterpene derivatives were found in smaller proportions such as the monoterpene hydrocarbons D-limonene (0.60%), β-myrcene (0.16%), γ-terpinene (0.05%) and sesquiterpene hydrocarbons bicyclogermacrene (2.65%), germacrene B (1.29%) and β-cadinene (1.14%).
<figure><img src="image_4.png" /><figcaption>Figure 3. Chromatogram of *Hedychium flavescens* leaves essential oil.</figcaption></figure>

<table><caption>**Table 2.** Chemical composition of *Hedychium flavescens* leaves essential oil.</caption><thead><tr><th>Peak #</th><th>RT (min)</th><th>Area %</th><th>Compound</th><th>Formula</th><th>RI</th><th>RI litt.</th></tr></thead><tbody><tr><td>1</td><td>17.625</td><td>18.74</td><td>α-pinene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>931</td><td>937</td></tr><tr><td>2</td><td>18.553</td><td>0.04</td><td>camphene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>945</td><td>952</td></tr><tr><td>3</td><td>20.553</td><td>47.81</td><td>β-pinene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>974</td><td>979</td></tr><tr><td>4</td><td>21.715</td><td>0.16</td><td>β-myrcene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>991</td><td>991</td></tr><tr><td>5</td><td>23.562</td><td>0.05</td><td>α-terpinene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>1018</td><td>1017</td></tr><tr><td>6</td><td>24.093</td><td>0.02</td><td>p-cymene</td><td>C<sub>10</sub>H<sub>14</sub></td><td>1025</td><td>1025</td></tr><tr><td>7</td><td>24.183</td><td>0.60</td><td>limonene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>1026</td><td>1030</td></tr><tr><td>8</td><td>24.352</td><td>0.42</td><td>eucalyptol</td><td>C<sub>10</sub>H<sub>18</sub>O</td><td>1029</td><td>1032</td></tr><tr><td>9</td><td>25.113</td><td>0.05</td><td>(Z)-β-ocimene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>1040</td><td>1038</td></tr><tr><td>10</td><td>25.799</td><td>0.05</td><td>(E)-β-ocimene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>1049</td><td>1049</td></tr><tr><td>11</td><td>26.391</td><td>0.05</td><td>γ-terpinene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>1058</td><td>1060</td></tr><tr><td>12</td><td>28.483</td><td>0.03</td><td>α-terpinolene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>1087</td><td>1088</td></tr><tr><td>13</td><td>29.398</td><td>0.02</td><td>linalool</td><td>C<sub>10</sub>H<sub>18</sub>O</td><td>1100</td><td>1099</td></tr><tr><td>14</td><td>31.920</td><td>0.01</td><td>pinocarveol</td><td>C<sub>10</sub>H<sub>16</sub>O</td><td>1137</td><td>1138</td></tr><tr><td>15</td><td>34.619</td><td>0.02</td><td>terpinen-4-ol</td><td>C<sub>10</sub>H<sub>18</sub>O</td><td>1176</td><td>1177</td></tr><tr><td>16</td><td>35.661</td><td>0.03</td><td>1-dodecene</td><td>C<sub>12</sub>H<sub>24</sub></td><td>1191</td><td>1190</td></tr></tbody></table>
<table><thead><tr><th>Peak #</th><th>RT (min)</th><th>Area %</th><th>Compound</th><th>Formula</th><th>RI</th><th>RI litt.</th></tr></thead><tbody><tr><td>17</td><td>45.195</td><td>0.90</td><td>δ-elemene</td><td>C<sub>10</sub>H<sub>18</sub>O</td><td>1336</td><td>1338</td></tr><tr><td>18</td><td>47.567</td><td>0.02</td><td>α-copaene</td><td>C<sub>11</sub>H<sub>18</sub></td><td>1374</td><td>1376</td></tr><tr><td>19</td><td>48.606</td><td>0.24</td><td>β-elemene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1391</td><td>1391</td></tr><tr><td>20</td><td>49.650</td><td>0.06</td><td>β-maaliene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1408</td><td>1398</td></tr><tr><td><b>21</b></td><td><b>50.269</b></td><td><b>17.47</b></td><td><b>β-caryophyllene</b></td><td>C<sub>15</sub>H<sub>24</sub></td><td>1418</td><td>1419</td></tr><tr><td>22</td><td>51.215</td><td>0.33</td><td>γ-elemene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1434</td><td>1434</td></tr><tr><td>23</td><td>51.673</td><td>0.66</td><td>guaiacol</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1442</td><td>1443</td></tr><tr><td>24</td><td>51.996</td><td>1.19</td><td>204 161 133 119 105</td><td>-</td><td>1447</td><td>-</td></tr><tr><td>25</td><td>52.257</td><td>1.20</td><td>humulene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1452</td><td>1454</td></tr><tr><td>26</td><td>52.658</td><td>0.27</td><td>(3E,6E)-α-farnesene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1458</td><td>1457</td></tr><tr><td>27</td><td>52.683</td><td>0.27</td><td>allo-aromadendrene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1459</td><td>1461</td></tr><tr><td>28</td><td>53.430</td><td>0.12</td><td>204 161 121 105 93 55</td><td>-</td><td>1471</td><td>-</td></tr><tr><td>29</td><td>53.659</td><td>0.08</td><td>204 161 133 119 105</td><td>-</td><td>1475</td><td>-</td></tr><tr><td>30</td><td>53.902</td><td>0.55</td><td>germacrene D</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1479</td><td>1481</td></tr><tr><td>31</td><td>54.202</td><td>0.02</td><td>204 189 147 122 108</td><td>-</td><td>1484</td><td>-</td></tr><tr><td>32</td><td>54.369</td><td>0.08</td><td>β-selinene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1487</td><td>1486</td></tr><tr><td>33</td><td>54.521</td><td>0.14</td><td>204 189 161 104 91</td><td>-</td><td>1490</td><td>-</td></tr><tr><td><b>34</b></td><td><b>54.818</b></td><td><b>2.65</b></td><td><b>bicyclogermacrene</b></td><td>C<sub>15</sub>H<sub>24</sub></td><td>1495</td><td>1495</td></tr><tr><td>35</td><td>55.057</td><td>0.02</td><td>161 136 105 95 91 53</td><td>-</td><td>1499</td><td>-</td></tr><tr><td>36</td><td>55.298</td><td>0.45</td><td>204 147 107 93 81 67</td><td>-</td><td>1503</td><td>-</td></tr><tr><td>37</td><td>55.454</td><td>1.14</td><td>β-cadinene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1506</td><td>1518</td></tr><tr><td>38</td><td>56.277</td><td>0.89</td><td>204 161 136 121 105</td><td>-</td><td>1520</td><td>-</td></tr><tr><td>39</td><td>56.647</td><td>0.02</td><td>122 119 107 91 77</td><td>-</td><td>1527</td><td>-</td></tr><tr><td>40</td><td>57.524</td><td>0.03</td><td>α-calacorene</td><td>C<sub>15</sub>H<sub>20</sub></td><td>1542</td><td>1542</td></tr><tr><td>41</td><td>58.010</td><td>0.02</td><td>106 91 79 41</td><td>-</td><td>1551</td><td>-</td></tr><tr><td>42</td><td>58.235</td><td>1.29</td><td>germacrene B</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1555</td><td>1557</td></tr></tbody></table>
<table><thead><tr><th>Peak #</th><th>RT (min)</th><th>Area %</th><th>Compound</th><th>Formula</th><th>RI</th><th>RI litt.</th></tr></thead><tbody><tr><td>43</td><td>59.428</td><td>0.07</td><td>spathulenol</td><td>C<sub>15</sub>H<sub>24</sub>O</td><td>1576</td><td>1576</td></tr><tr><td>44</td><td>59.706</td><td>0.49</td><td>caryophyllene oxyde</td><td>C<sub>15</sub>H<sub>24</sub>O</td><td>1581</td><td>1581</td></tr><tr><td>45</td><td>59.987</td><td>0.44</td><td>204 161 119 105 91 81</td><td>-</td><td>1586</td><td>-</td></tr><tr><td>46</td><td>60.843</td><td>0.08</td><td>161 105 93 81 77 67</td><td>-</td><td>1601</td><td>-</td></tr><tr><td>47</td><td>61.360</td><td>0.18</td><td>204 179 161 119 105</td><td>-</td><td>1610</td><td>-</td></tr><tr><td>48</td><td>62.099</td><td>0.07</td><td>204 161 119 105 91</td><td>-</td><td>1624</td><td>-</td></tr><tr><td>49</td><td>62.309</td><td>0.43</td><td>isospathulenol</td><td>C<sub>15</sub>H<sub>24</sub>O</td><td>1627</td><td>1638</td></tr><tr><td>50</td><td>63.668</td><td>0.01</td><td>204 161 121 91 81</td><td>-</td><td>1651</td><td>-</td></tr><tr><td colspan="4">Total identified</td><td colspan="3">96.26 %</td></tr><tr><td colspan="4">Monoterpenes / Monoterpenoid s</td><td colspan="3">68.08 %</td></tr><tr><td colspan="4">Sesquiterpenes / Sequiterpenoid s</td><td colspan="3">28.16 %</td></tr></tbody></table>

RT: retention time; RI: retention indices; RI litt. from NIST 2020 database. NI:

Not identified (3.72%). Bold: main compounds.

To our knowledge, the chemical composition of the EO obtained solely from the leaves of *H. flavescens* have not been published so far. In the most recent article on the EO of *H. flavescens* rhizomes, 78.05% of a sample obtained from a plant grown in India could be identified.[4] The main compounds described were β-pinene (24.77%) and α-pinene (11.17%), both present in large proportions in our sample (47.81 and 18.74%, respectively), together with β-caryophyllene and bicyclogermacrene.
## *Pittosporum senacia* leaves EO analysis

The relatively simple composition of the EO from *Pittosporum senacia* leaves was determined for more than 99% of the total EO (Figure 4). As presented in Figure 4. Chromatogram of *Pittosporum senacia* leaves essential oil.

**Table 3**, its chemical profile essentially contained four compounds: the C9 linear alkane hydrocarbon nonane (36.24%) and three monoterpene derivatives, β-pinene (25.11%), β-myrcene (19.19%) and α-pinene (7.36%), which together accounted for 87.9%. Moreover, the chemical profile included monoterpene derivatives such as limonene (1.46%), (Z)- and (E)-β-ocimene (0.01% and 0.09%, respectively), sesquiterpene derivatives like germacrene D (3.68%), humulene (0.40%), as well as other alkanes like decane (0.09%) and undecane (0.56%).

<figure><img src="image_5.png" /><figcaption>Figure 4. Chromatogram of *Pittosporum senacia* leaves essential oil.</figcaption></figure>

<table><caption>**Table 3.** Chemical composition of *Pittosporum senacia* leaves essential oil.</caption><thead><tr><th>Peak #</th><th>RT (min)</th><th>Area %</th><th>Compound</th><th>Formula</th><th>RI</th><th>RI litt.</th></tr></thead><tbody><tr><td>1</td><td>15.492</td><td>36.24</td><td>nonane</td><td>C<sub>9</sub>H<sub>20</sub></td><td>900</td><td>900</td></tr></tbody></table>
<table><thead><tr><th>Peak #</th><th>RT (min)</th><th>Area %</th><th>Compound</th><th>Formula</th><th>RI</th><th>RI litt.</th></tr></thead><tbody><tr><td>2</td><td>17.233</td><td>0.03</td><td>α-thujene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>925</td><td>929</td></tr><tr><td>3</td><td>17.578</td><td>7.36</td><td>α-pinene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>930</td><td>937</td></tr><tr><td>4</td><td>18.984</td><td>0.06</td><td>camphene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>951</td><td>952</td></tr><tr><td>5</td><td>20.464</td><td>25.11</td><td>β-pinene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>973</td><td>979</td></tr><tr><td>6</td><td>21.675</td><td>19.19</td><td>β-myrcene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>991</td><td>991</td></tr><tr><td>7</td><td>22.628</td><td>0.09</td><td>decane</td><td>C<sub>10</sub>H<sub>22</sub></td><td>1004</td><td>1000</td></tr><tr><td>8</td><td>22.843</td><td>0.05</td><td>α-phellandrene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>1008</td><td>1005</td></tr><tr><td>9</td><td>23.605</td><td>0.07</td><td>α-terpinene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>1018</td><td>1017</td></tr><tr><td>10</td><td>24.131</td><td>0.06</td><td>p-cymene</td><td>C<sub>10</sub>H<sub>14</sub></td><td>1026</td><td>1025</td></tr><tr><td>11</td><td>24.183</td><td>1.46</td><td>limonene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>1026</td><td>1030</td></tr><tr><td>12</td><td>25.145</td><td>0.01</td><td>(Z)-β-ocimene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>1040</td><td>1038</td></tr><tr><td>13</td><td>25.818</td><td>0.09</td><td>(E)-β-ocimene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>1050</td><td>1049</td></tr><tr><td>14</td><td>26.414</td><td>0.22</td><td>γ-terpinene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>1058</td><td>1060</td></tr><tr><td>15</td><td>28.474</td><td>0.08</td><td>terpinolene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>1087</td><td>1088</td></tr><tr><td>16</td><td>29.383</td><td>0.56</td><td>undecane</td><td>C<sub>11</sub>H<sub>24</sub></td><td>1100</td><td>1100</td></tr><tr><td>17</td><td>30.518</td><td>0.04</td><td>(E)-4,8-dimethylnona-1,3,7-triene</td><td>C<sub>11</sub>H<sub>18</sub></td><td>1116</td><td>1116</td></tr><tr><td>18</td><td>35.662</td><td>0.05</td><td>1-dodecene</td><td>C<sub>12</sub>H<sub>24</sub></td><td>1191</td><td>1190</td></tr><tr><td>19</td><td>36.632</td><td>0.05</td><td>decanal</td><td>C<sub>10</sub>H<sub>20</sub>O</td><td>1205</td><td>1206</td></tr><tr><td>20</td><td>45.180</td><td>0.81</td><td>δ-elemene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1336</td><td>1338</td></tr><tr><td>21</td><td>45.941</td><td>0.03</td><td>α-cubebene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1348</td><td>1351</td></tr><tr><td>22</td><td>47.279</td><td>0.05</td><td>α-ylangene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1370</td><td>1372</td></tr><tr><td>23</td><td>47.557</td><td>0.12</td><td>α-copaene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1374</td><td>1376</td></tr><tr><td>24</td><td>48.602</td><td>0.56</td><td>β-elemene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1391</td><td>1391</td></tr><tr><td>25</td><td>50.222</td><td>0.48</td><td>β-caryophyllene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1417</td><td>1419</td></tr><tr><td>26</td><td>50.795</td><td>0.15</td><td>β-copaene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1427</td><td>1432</td></tr></tbody></table>
<table><thead><tr><th>Peak #</th><th>RT (min)</th><th>Area %</th><th>Compound</th><th>Formula</th><th>RI</th><th>RI litt.</th></tr></thead><tbody><tr><td>27</td><td>51.134</td><td>0.15</td><td>γ-elemene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1433</td><td>1434</td></tr><tr><td>28</td><td>51.405</td><td>0.05</td><td>α-guaiene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1437</td><td>1439</td></tr><tr><td>29</td><td>51.682</td><td>0.10</td><td>guaia-6,9-diene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1442</td><td>1443</td></tr><tr><td>30</td><td>52.006</td><td>0.20</td><td>161 133 105 91 79 69</td><td>-</td><td>1447</td><td>-</td></tr><tr><td>31</td><td>52.242</td><td>0.40</td><td>humulene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1451</td><td>1454</td></tr><tr><td>32</td><td>52.842</td><td>0.03</td><td>cis-muurola-4(15),5-diene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1461</td><td>1463</td></tr><tr><td><b>33</b></td><td><b>53.910</b></td><td><b>3.68</b></td><td><b>germacrene D</b></td><td>C<sub>15</sub>H<sub>24</sub></td><td>1479</td><td>1481</td></tr><tr><td>34</td><td>54.213</td><td>0.03</td><td>β-selinene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1485</td><td>1486</td></tr><tr><td>35</td><td>54.519</td><td>0.06</td><td>161 105 91 44</td><td>-</td><td>1490</td><td>-</td></tr><tr><td>36</td><td>54.720</td><td>0.07</td><td>161 105 91</td><td>-</td><td>1493</td><td>-</td></tr><tr><td>37</td><td>55.057</td><td>0.06</td><td>α-muurolene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1499</td><td>1499</td></tr><tr><td>38</td><td>55.304</td><td>0.21</td><td>α-elemene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1503</td><td>1462</td></tr><tr><td>39</td><td>55.834</td><td>0.11</td><td>γ-cadinene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1512</td><td>1513</td></tr><tr><td>40</td><td>56.407</td><td>0.39</td><td>cadina-1(10),4-diene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1523</td><td>1524</td></tr><tr><td>41</td><td>56.650</td><td>0.03</td><td>122 43</td><td>-</td><td>1527</td><td>-</td></tr><tr><td>42</td><td>58.244</td><td>0.65</td><td>germacrene B</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1555</td><td>1557</td></tr><tr><td>43</td><td>60.289</td><td>0.10</td><td>1-hexadecene</td><td>C<sub>16</sub>H<sub>32</sub></td><td>1591</td><td>1592</td></tr><tr><td>44</td><td>61.085</td><td>0.04</td><td>rosifoliol</td><td>C<sub>15</sub>H<sub>26</sub>O</td><td>1606</td><td>1600</td></tr><tr><td>45</td><td>63.633</td><td>0.09</td><td>τ-muurolol</td><td>C<sub>15</sub>H<sub>26</sub>O</td><td>1653</td><td>1642</td></tr><tr><td>46</td><td>70.847</td><td>0.03</td><td>1-octadecene</td><td>C<sub>18</sub>H<sub>36</sub></td><td>1792</td><td>1793</td></tr></tbody><tfoot><tr><td colspan="3"><b>Total identified</b></td><td>99.09 %</td><td></td><td></td><td></td></tr><tr><td colspan="3"><b>Monoterpenes / Monoterpenoid s</b></td><td>53.78 %</td><td></td><td></td><td></td></tr><tr><td colspan="3"><b>Sesquiterpenes / Sequiterpenoid s</b></td><td>8.19 %</td><td></td><td></td><td></td></tr></tfoot></table>
RT: retention time; RI: retention indices; RI litt. from NIST 2020 database.

NI: Not identified (0.41%). Bold: main compounds.

Many of the metabolites present in the study by B. S. Jugreet et al. published in 2021 on the EO of *P. senacia* (whole plant) from Mauritius [5], were also identified in our sample such as β-myrcene, germacrene D, α-muurolene, limonene, α-pinene, α-thujene, p-cymene, β-ocimene, β-elemene, β-caryophyllene, and humulene. The alkanes nonane, decane, and undecane were not reported in the article by B. S. Jugreet et al. However, some alkanes, including nonane, have already been identified in the EO of the genus *Pittosporum*, such as in an endemic species of the Philippines, *P. resiniferum* [20]. Interestingly, nonane, a compound described as insect attractant, [21] was found in 36.24% in our sample.

## *Psidium cattleianum* floral tops EO analysis

In the most recent study, a distillation yield of 0.83% was reported for EO from *P. cattleianum* leaves [8]. A total of 68 compounds were observed within the oil, 60 of which could be identified. β-Caryophyllene was the main compound found in 14.7%, followed by eucalyptol (11.7%) and γ-muurolene (5.6%). The second most recent paper, published in 2019, describes the EO of the leaves of *P. cattleianum*. The EO was mainly composed of sesquiterpene and monoterpene derivatives (47.8% and 28.7%, respectively). A total of 46 compounds were identified with β-caryophyllene (23.4%), caryophyllene oxide (11.4%) and α-pinene (11.3%) as the main compounds [9]. Our results are in
agreement with this study (Figure 5), whose main compounds described were β-caryophyllene and α-pinene at 23.42% and 11.31%, respectively, caryophyllene oxide being present in 1.67%. Indeed, the chemical profile of the EO sample from *P. cattleianum* floral tops was identified at 88.41%. As shown in Table 4, nearly 70% of the composition was consisting in sesquiterpene derivatives including the main compound, β-caryophyllene, present at 43.68% In addition, fifteen monoterpene derivatives have been observed and identified. The four main monoterpenes were β-myrcene (4.67%), α-pinene (4.50%), (Z)-β-ocimene (3.23%) and terpinolene (2.98%).

<figure><img src="image_6.png" /><figcaption>Figure 5. Chromatogram of *Psidium cattleianum* leaves essential oil.</figcaption></figure>

<table><caption>**Table 4.** Chemical composition of *Psidium cattleianum* leaves essential oil.</caption><thead><tr><th>Peak #</th><th>RT (min)</th><th>Area %</th><th>Compound</th><th>Formula</th><th>RI</th><th>RI litt.</th></tr></thead><tbody><tr><td>1</td><td>16.610</td><td>0.03</td><td>5,5-Dimethyl-1-vinylbicyclo[2,1,1]hexane</td><td>C<sub>10</sub>H<sub>16</sub></td><td>916</td><td>921</td></tr></tbody></table>
<table><thead><tr><th>Peak #</th><th>RT (min)</th><th>Area %</th><th>Compound</th><th>Formula</th><th>RI</th><th>RI litt.</th></tr></thead><tbody><tr><td>2</td><td>17.214</td><td>0.15</td><td>α-thujene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>925</td><td>929</td></tr><tr><td>3</td><td>17.611</td><td>4.50</td><td>α-pinene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>931</td><td>937</td></tr><tr><td>4</td><td>18.920</td><td>0.01</td><td>camphene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>950</td><td>952</td></tr><tr><td>5</td><td>20.475</td><td>0.19</td><td>β-pinene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>973</td><td>979</td></tr><tr><td>6</td><td>21.677</td><td>4.67</td><td>β-myrcene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>991</td><td>991</td></tr><tr><td>7</td><td>22.467</td><td>0.24</td><td>α-phellandrene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>1002</td><td>1005</td></tr><tr><td>8</td><td>22.864</td><td>0.14</td><td>3-carene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>1008</td><td>1011</td></tr><tr><td>9</td><td>23.360</td><td>0.12</td><td>4-carene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>1015</td><td>1009</td></tr><tr><td>10</td><td>23.901</td><td>0.19</td><td>p-cymene</td><td>C<sub>10</sub>H<sub>14</sub></td><td>1022</td><td>1025</td></tr><tr><td>11</td><td>24.181</td><td>1.07</td><td>limonene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>1026</td><td>1030</td></tr><tr><td>12</td><td>24.984</td><td>3.23</td><td>(Z)-β-ocimene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>1038</td><td>1038</td></tr><tr><td>13</td><td>25.710</td><td>0.56</td><td>(E)-β-ocimene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>1048</td><td>1049</td></tr><tr><td>14</td><td>26.346</td><td>0.63</td><td>γ-terpinene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>1057</td><td>1060</td></tr><tr><td>15</td><td>28.421</td><td>2.98</td><td>terpinolene</td><td>C<sub>10</sub>H<sub>16</sub></td><td>1086</td><td>1088</td></tr><tr><td>16</td><td>40.039</td><td>0.23</td><td>linalyl acetate</td><td>C<sub>12</sub>H<sub>20</sub>O<sub>2</sub></td><td>1257</td><td>1257</td></tr><tr><td>17</td><td>45.984</td><td>0.27</td><td>161 136 121 105 93 67</td><td>-</td><td>1349</td><td>-</td></tr><tr><td>18</td><td>47.293</td><td>0.44</td><td>α-ylangene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1370</td><td>1372</td></tr><tr><td>19</td><td>47.581</td><td>1.18</td><td>α-copaene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1374</td><td>1376</td></tr><tr><td>20</td><td>48.127</td><td>0.07</td><td>α-bourbornene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1383</td><td>1384</td></tr><tr><td>21</td><td>48.598</td><td>0.12</td><td>204 121 108 93 81 55</td><td>-</td><td>1391</td><td>-</td></tr><tr><td>22</td><td>49.495</td><td>0.03</td><td>tetradecene</td><td>C<sub>14</sub>H<sub>28</sub></td><td>1405</td><td>1392</td></tr><tr><td>23</td><td>49.641</td><td>0.03</td><td>204 189 161 119 105</td><td>-</td><td>1408</td><td>-</td></tr><tr><td>24</td><td>50.374</td><td>43.68</td><td>β-caryophyllene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1420</td><td>1419</td></tr><tr><td>25</td><td>50.818</td><td>0.42</td><td>γ-elemene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1427</td><td>1434</td></tr><tr><td>26</td><td>51.387</td><td>0.07</td><td>aromadendrene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1437</td><td>1440</td></tr><tr><td>27</td><td>51.672</td><td>0.10</td><td>204 161 133 119 105 91</td><td>-</td><td>1442</td><td>-</td></tr></tbody></table>
<table><thead><tr><th>Peak #</th><th>RT (min)</th><th>Area %</th><th>Compound</th><th>Formula</th><th>RI</th><th>RI litt.</th></tr></thead><tbody><tr><td>28</td><td>52.009</td><td>0.16</td><td>204 161 119 105 91 79</td><td>-</td><td>1447</td><td>-</td></tr><tr><td>29</td><td>52.278</td><td>6.49</td><td>humulene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1452</td><td>1454</td></tr><tr><td>30</td><td>52.709</td><td>0.18</td><td>9-epi-caryophyllene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1459</td><td>1466</td></tr><tr><td>31</td><td>53.640</td><td>2.32</td><td>γ-muurolene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1475</td><td>1477</td></tr><tr><td>32</td><td>53.874</td><td>0.50</td><td>α-amorphene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1479</td><td>1482</td></tr><tr><td>33</td><td>54.197</td><td>1.27</td><td>β-selinene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1484</td><td>1486</td></tr><tr><td>34</td><td>54.307</td><td>0.29</td><td>204 133 119 107 93 79</td><td>-</td><td>1486</td><td>-</td></tr><tr><td>35</td><td>54.517</td><td>0.25</td><td>204 189 161 133 91</td><td>-</td><td>1490</td><td>-</td></tr><tr><td>36</td><td>54.727</td><td>1.70</td><td>204 161 133 119 105 93</td><td>-</td><td>1493</td><td>-</td></tr><tr><td>37</td><td>55.059</td><td>0.34</td><td>α-muurolene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1499</td><td>1499</td></tr><tr><td>38</td><td>55.454</td><td>0.51</td><td>204 161 134 119 105</td><td>-</td><td>1506</td><td>-</td></tr><tr><td>39</td><td>55.575</td><td>0.26</td><td>122 109 93 79 69</td><td>-</td><td>1508</td><td>-</td></tr><tr><td>40</td><td>55.837</td><td>0.87</td><td>β-bisabolene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1513</td><td>1509</td></tr><tr><td>41</td><td>56.175</td><td>0.88</td><td>γ-cadinene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1519</td><td>1513</td></tr><tr><td>42</td><td>56.401</td><td>2.38</td><td>cadina-1(10),4-diene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1523</td><td>1524</td></tr><tr><td>43</td><td>57.015</td><td>2.35</td><td>204 189 161 133 105 91</td><td>-</td><td>1533</td><td>-</td></tr><tr><td>44</td><td>57.184</td><td>0.74</td><td>204 189 161 133 105</td><td>-</td><td>1536</td><td>-</td></tr><tr><td>45</td><td>57.385</td><td>2.06</td><td>selina-3,7(11)-diene</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1540</td><td>1542</td></tr><tr><td>46</td><td>57.987</td><td>0.11</td><td>161 109 95 91 79 69</td><td>-</td><td>1551</td><td>-</td></tr><tr><td>47</td><td>58.238</td><td>1.84</td><td>germacrene B</td><td>C<sub>15</sub>H<sub>24</sub></td><td>1555</td><td>1557</td></tr><tr><td>48</td><td>58.604</td><td>0.17</td><td>204 189 133 119 105</td><td>-</td><td>1562</td><td>-</td></tr><tr><td>49</td><td>58.749</td><td>0.33</td><td>nerolidol</td><td>C<sub>15</sub>H<sub>26</sub>O</td><td>1564</td><td>1564</td></tr><tr><td>50</td><td>58.978</td><td>0.19</td><td>204 161 123 111 69 55</td><td>-</td><td>1568</td><td>-</td></tr><tr><td>51</td><td>59.701</td><td>1.67</td><td>caryophyllene oxyde</td><td>C<sub>15</sub>H<sub>24</sub>O</td><td>1581</td><td>1581</td></tr><tr><td>52</td><td>60.284</td><td>0.44</td><td>204 161 119 105 91 79</td><td>-</td><td>1591</td><td>-</td></tr><tr><td>53</td><td>60.593</td><td>0.07</td><td>204 161 119 107 93 79</td><td>-</td><td>1597</td><td>-</td></tr></tbody></table>
<table><thead><tr><th>Peak #</th><th>RT (min)</th><th>Area %</th><th>Compound</th><th>Formula</th><th>RI</th><th>RI litt.</th></tr></thead><tbody><tr><td>54</td><td>60.746</td><td>0.10</td><td>161 133 121 93 82 77</td><td>-</td><td>1600</td><td>-</td></tr><tr><td>55</td><td>60.956</td><td>0.09</td><td>204 161 133 119 105 95</td><td>-</td><td>1603</td><td>-</td></tr><tr><td>56</td><td>61.162</td><td>0.17</td><td>147 138 109 96 93 67</td><td>-</td><td>1607</td><td>-</td></tr><tr><td>57</td><td>61.623</td><td>0.29</td><td>202 187 131 123 91</td><td>-</td><td>1616</td><td>-</td></tr><tr><td>58</td><td>62.084</td><td>0.71</td><td>204 161 119 105 91</td><td>-</td><td>1624</td><td>-</td></tr><tr><td>59</td><td>62.221</td><td>0.78</td><td>204 161 119 105 91</td><td>-</td><td>1627</td><td>-</td></tr><tr><td>60</td><td>62.424</td><td>0.54</td><td>204 179 161 119 105</td><td>-</td><td>1631</td><td>-</td></tr><tr><td>61</td><td>62.642</td><td>0.14</td><td>159 136 107 91 79 69</td><td>-</td><td>1635</td><td>-</td></tr><tr><td>62</td><td>62.969</td><td>1.09</td><td>τ-cadinol</td><td>C<sub>15</sub>H<sub>26</sub>O</td><td>1641</td><td>1640</td></tr><tr><td>63</td><td>63.198</td><td>0.36</td><td>204 161 119 105 93</td><td>-</td><td>1645</td><td>-</td></tr><tr><td>64</td><td>63.489</td><td>0.41</td><td>202 187 121 105 91</td><td>-</td><td>1651</td><td>-</td></tr><tr><td>65</td><td>63.630</td><td>0.87</td><td>τ-muurolol</td><td>C<sub>15</sub>H<sub>26</sub>O</td><td>1653</td><td>1642</td></tr><tr><td>66</td><td>64.190</td><td>0.20</td><td>204 189 161 133 107</td><td>-</td><td>1664</td><td>-</td></tr><tr><td>67</td><td>65.113</td><td>0.06</td><td>126 119 111 77 55</td><td>-</td><td>1681</td><td>-</td></tr><tr><td>68</td><td>65.807</td><td>0.49</td><td>eudesm-7(11)-en-4-ol</td><td>C<sub>15</sub>H<sub>26</sub>O</td><td>1694</td><td>1692</td></tr></tbody><tfoot><tr><td colspan="3">Total identified</td><td>88.41 %</td><td colspan="3"></td></tr><tr><td colspan="3">Monoterpenes / Monoterpenoids</td><td>18.70 %</td><td colspan="3"></td></tr><tr><td colspan="3">Sesquiterpenes / Sequiterpenoids</td><td>69.99 %</td><td colspan="3"></td></tr></tfoot></table>

RT: retention time; RI: retention indices; RI litt. from NIST 2020 database.

NI: Not identified (11.61%). Bold: main compounds.

285

286

## Olfactory analysis

287

Olfactory evaluation of the four essential oils was performed by a panel of 4 persons by GC/MS-O analysis. The objective was to obtain an overview of

288
the main contributors to the overall scent of each EO which was found to be generally woody, a family of olfactory properties highly priced in modern perfumery.

In Table 5, the main aroma-active compounds and their odor properties are presented.

<table><caption>**Table 5.** Overview of the main contributors of the four EOs.</caption><thead><tr><th></th><th>RT (min)</th><th>RI<sub>apolar</sub></th><th>Annotated compound</th><th>Scent description</th></tr></thead><tbody><tr><td rowspan="3"><i>H. gardnerianum</i>,<br>flowers EO</td><td>9.55</td><td>1144</td><td>Sabinol*</td><td>Floral</td></tr><tr><td>17.23</td><td>N.D.</td><td>Unknown**</td><td>Woody</td></tr><tr><td>22.48</td><td>16.94</td><td>Unknown</td><td>Floral</td></tr><tr><td rowspan="2"><i>H. flavescens</i>,<br>leaves, EO</td><td>8.55</td><td>1093</td><td>Terpinolene</td><td>Woody</td></tr><tr><td>17.35</td><td>1512</td><td><i>trans-α-bisabolene</i></td><td>Woody, rose</td></tr><tr><td rowspan="2"><i>P. senacia</i>,<br>leaves, EO</td><td>6.61</td><td>N.D.</td><td>β-pinene</td><td>Pine, Green</td></tr><tr><td>8.53</td><td>1092</td><td>Terpinolene</td><td>Woody</td></tr><tr><td rowspan="3"><i>P. cattleianum</i>,<br>floral tops,<br>EO</td><td>6.42</td><td>979</td><td>β-pinene</td><td>Pine, Green</td></tr><tr><td>8.26</td><td>1078</td><td>Unknown**</td><td>Woody</td></tr><tr><td>11.80</td><td>1261</td><td>Unknown</td><td>Citrus, spicy</td></tr></tbody></table>

*Hedychium gardnerianum* flowers EO presented three characteristic areas, a woody area identified by 2 panelists out of 4, and two floral area for 2 panelists out of 4.

GC/MS-O analysis of EO from *Hedychium flavescens* leaves revealed a main contributor with a fresh, woody and green scent which was annotated as

<footnote>*Tentative assignation. **No peak detectable.</footnote>
γ-elemene. The presence of woody, earthy, and green area was highlighted by 5 panelists out of 5, floral and rose area by 4 panelists out of 5 and mint, herbal, and citrus area by 2 panelists out of 5.

Main aroma-active compounds of *Pittosporum senacia* leaves EO were annotated as β-myrcene with a green, woody and spicy scent and as terpinolene with a moss and woody scent. The GC/MS-O analysis revealed herbal, and pine tree area for 5 panelists out of 5 as well as floral and citrus area for 5 panelists out of 5.

Finally, *Psidium cattleianum* floral tops EO showed three characteristic scents with β-myrcene and two unknown compounds, eluting at 8.9 min and 13.25 min, respectively, both with floral scent. In addition of these markers, pine tree scent was found by 4 panelists out of 4, woody, and earthy area by 4 panelists out of 4, floral area by 2 panelists out of 4, and citrus with mossy/earthy area by 2 panelists out of 4. In addition to these main contributors, others smaller contributors as linalool, with floral and fresh scent, was detected in each of the four EOs GC/MS-O analyses.

## CONCLUSION

In general, the chemical composition of an EO varies according to many factors such as the year of harvest, the geographical area, the climate, the storage of the raw material, the duration of storage of the plant before extraction, the extraction process [22]. Two EOs from the same species may
therefore have a different chemical composition. Nevertheless, the chemical
profile and chemical markers may be specific to a given plant or chemotype.

The analysis and authentication tasks can be sometimes complicated by
conformity or adulteration issues [23, 24].

In this context, the main goal of our work was to characterize for the first
time the EOs of the four species harvested on Réunion Island and to compare
their chemical profiles with those described in the literature with samples
collected in other locations. We used two complementary analyses, gas
chromatography coupled with mass spectrometry (GC/MS) and with flame
ionization detector (GC-FID), to obtain the most complete description.

Additionally, an olfactory analysis was performed on these four EOs by gas
chromatography coupled with mass spectrometry and olfactometry (GC/MS-
O). The chemical composition of each essential oil was identified in more than
87.43% for *H. garderianum* flowers, 96.26% for *H. flavescens* leaves, 99.09% for *P.*
*senacia* leaves and 88.41% for *P. cattleianum* floral tops.

The chemical composition of *H. gardnerianum* EO, mostly composed of
mono- and sesquiterpene hydrocarbons of low complexity, was found to be
consistent with other EOs within natural variability due to differences in their
geographical origin (islands from Atlantic, Pacific, and Indian oceans). The
sample was mainly composed of sesquiterpene derivatives including β-
farnesene (12.05%), α-cadinol (9.71%), α-farnesene (7.09%), τ-muurolol (5.89%)
and δ-cadinene (5.83%). The monoterpene derivatives identified accounted for about 20% (mostly α-pinene, β-pinene and humulene).

For the EO from *H. flavescens* leaves, our study provided the first description of its chemical composition, which appeared to be rather simple and to contain mostly hydrocarbons. The main compounds were found to be β-pinene (47.81%), α-pinene (18.74%) and β-caryophyllene (17.47%), which together accounted for 84.02% of the sample.

For the *P. senacia*, while β-myrcene was found to be an important constituent of the EO, as was the case for material from Madagascar and Mauritius, which are geographically close to French Reunion, the composition was different but consistent, and the striking difference was the presence of nonane. The oil primarily contained nonane (36.24%), β-pinene (25.11%), β-myrcene (19.19%) and α-pinene (7.36%), together accounting for 87.9% of the composition.

Lastly, the composition of the *P. cattleianum* EO was very consistent with other studies, with 70% sesquiterpene derivatives including the main compound, β-caryophyllene, present at 43.68%.

With these compositions mostly based on mono- and sesquiterpene hydrocarbons, it came as no surprise that the panelists described the scent of these EOs as herbal, citrus, green, pine tree, and in some cases floral and woody.
With these results in hand, these endemic essential oils from Reunion could receive in the future further attention for applications in fragrance and cosmetic products. Future work could include the determination of odor impact molecules by aroma extract dilution analysis based on the GC-O studies presented herein.

## AUTHOR CONTRIBUTIONS

CONCEPTUALIZATION, M.C AND S.A.; METHODOLOGY, M.C AND S.A.;

INVESTIGATION, M.C, M.T. AND S.A.; RESOURCES, S.A.; DATA

CURATION, M.C, M.T. AND S.A.; WRITING – ORIGINAL DRAFT

PREPARATION, M.C AND S.A.; WRITING – REVIEW & EDITING, M.C, M.T.

AND S.A.; SUPERVISION, S.A.; PROJECT ADMINISTRATION, M.C, M.T.

AND S.A.

## ACKNOWLEDGEMENTS

This work was supported by Université Côte d'Azur, CNRS and Technopole de la Réunion in the framework of the Insola Scent project (Sophie Afchain). We are grateful to Charlotte Richard and Julie Abdalla for contributing to the olfactory evaluation during GC-O analyses and Dr. Catherine Buchanan for proofreading.

## CONFLICTS OF INTEREST

The authors declare no conflict of interest.
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