Volume 12. Issue 11. Pages 1673-1820. 2017
ISSN 1934-578X (printed); ISSN 1555-9475 (online)
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Natural Product Communications

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EDITORSPROFESSOR ALEJANDRO F. BARRERO
Department of Organic Chemistry, University of Granada,Campus de Fuente Nueva, s/n, 18071, Granada, Spainafbarre@ugr.es
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Department STEBICEF,
University of Palermo, Viale delle Scienze,
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G.B. Elyakov Pacific Institute of Bioorganic Chemistry,Far Eastern Branch, Russian Academy of Sciences,Pr. 100-letya Vladivostoka 159, 690022,
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NPC

2017
Vol. 12
No. 111793 - 1796

Natural Product Communications

Evaluation of Anti-glycation Activities of Phlorotannins in Humanand Bovine Serum Albumin-methylglyoxal Models
Shingo Sugiuraa,f, Yuya Minamib, Ryosuke Taniguchia,f, Reiji Tanakaa,d,f, Hideo Miyakea,d,f,
Tetsushi Moric,d,f, Mitsuyoshi Uedae,f and Toshiyuki Shibataa,d,f*aGraduate School of Bioresources, Mie University, 1577 Kurimamachiya-cho, Tsu, Mie 514-8507, Japan
Faculty of Bioresources, Mie University, 1577 Kurimamachiya-cho, Tsu, Mie 514-8507, Japanc
Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology,
2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japand
Seaweed Biorefinery Research Center, Mie University, 1577 Kurimamachiya-cho, Tsu, Mie 514-8507, Japane
Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake, Sakyo-ku, Kyoto 606-8502, Japanf
Japan Science and Technology Agency, CREST, 4-1-8 Hon-cho, Kawaguchi, Saitama 332-0012, Japanbshibata@bio.mie-u.ac.jp
Received: June 29th, 2017; Accepted: August 22nd, 2017

In this study, the anti-glycation activities of phlorotannins contained in the Japanese Lessoniaceae (Ecklonia cava, Eck. kurome, Eck. stolonifera, Eisenia
arborea, and Eis. bicyclis) were tested using serum albumin-methlglyoxal (MGO) models. In the human serum albumin (HSA)-MGO model and the bovine
serum albumin (BSA)-MGO model, the concentrations of crude phlorotannins at 50% inhibition (IC50) of fluorescent advanced glycation end products (AGEs)
formation was in the range of 0.45 to 0.53 mg/mL and 0.43 to 0.53 mg/mL, respectively. Among the purified phlorotannins, phlorofucofuroeckol A with the
benzobisbenzofuran skeleton had the highest inhibitory activities (IC50: 4.8 x 102 µM in HSA-MGO model and 4.1 x 102 µM in BSA-MGO model) against
fluorescent AGEs formation, and showed about 13 times the inhibition in the HSA-MGO model, and about 20 times the inhibition in the BSA-MGO model,
with respect to aminoguanidine hydrochloride, which was used as a positive control. In the test on MGO-scavenging activity using HPLC analysis, it showedthat eckol and its simple dimers (dieckol and 8,8´-bieckol) had higher scavenging rate than aminoguanidine hydrochloride. In addition, it was revealed byliquid chromatography-electrospray ionization-mass spectrometry that eckol reacted with MGO and formed two adducts with it. These results strongly suggestthat phlorotannins are novel and effective anti-glycation substances derived from natural plants.
Keywords: Advanced glycation end products, Anti-glycation, Eckol, Methylglyoxal, Phlorotannins, Phlorofucofuroeckol A, Lessoniaceae, Liquid
chromatography-electrospray ionization-mass spectrometry.

In vivo, reducing sugars react nonenzymatically with lysine andarginine residues of proteins, and cause irreversible denaturation ofproteins. This reaction is called a glycation reaction of proteins(glycation), which leads to the production of advanced glycation
end products (AGEs) after the formation of sugar metabolic
intermediates such as glyoxal, methylglyoxal (MGO), and 3deoxyglucosone [1]. It has been pointed out that AGEs play key
roles in the development of diabetic complications [2,3,4],
atherosclerosis [2,4], osteoporosis [5], and aging [6]. From thisscientific background, studies regarding the development ofcompounds, and the search for natural products, having an
inhibitory effect on AGEs formation are conducted competitively.
Among sugar metabolic intermediates, MGO of α-dicarbonylcompound is well known for the following facts: (1) MGO is morereactive with proteins than glucose [7], (2) the precursor of AGEs invascular endothelial cells is MGO [8,9], and (3) the blood level of
MGO in type I diabetics is about 6 times higher than in healthy
subjects [10]. Therefore, AGEs formation pathway via MGO can be
regarded as one of the most significant pathways in the AGEs
formation pathways.
In a study of patients with chronic renal failure, the relationshipbetween the increase in oxidative stress and the promotion of theglycation reaction of proteins is clarified. It has been reported thatplant foodstuffs rich in antioxidants exhibit excellent anti-glycation
activity [11-13]. Therefore, it is highly possible that antioxidants(e.g. polyphenols) derived from plants act as anti-glycation

HO

a

OH

OH

OH

O
O

HO

c

OH

HO

OH

O

HO

d

OH

e

O

OH

HO

HO

OH

O

OH

OH

O
O

OH

OH

O

HO

O
OH

O
O

HO

OH
OH

O

OH

OH

OH

O

OH

OH

O

OH

O
O

OH

OH

OH

HO

O

O

O

OH

HO

HO

OH

O

O

OH

HO

O

O

OH

O

OH

b

OH

HO

OH

O
OH

Figure 1: Chemical structures of eckols isolated from the Japanese Lessoniaceae. a:eckol, b: fucofuroeckol A, c: phlorofucofuroeckol A, d: dieckol, e: 8,8´-bieckol.

substances. Phlorotannins are polyphenols which occur only inbrown algae and have a structure in which phloroglucinol is simply
polymerized [14].
In the preceding reports [15,16], we isolated phloroglucinol andeckols (eckol, fucofuroeckol A, phlorofucofuroeckol A, dieckol,
and 8,8´-bieckol) from the brown alga Eisenia bicyclis (Figure 1)
and revealed that they have superior antioxidant properties
compared to catechins, ascorbic acid, and resveratrol. In this study,
we extracted and isolated phlorotannins from several species of the1794 Natural Product Communications Vol. 12 (11) 2017

Japanese Lessoniaceae (Laminariales, Phaeophyceae) including
Ecklonia cava, Eck. kurome, Eck. stolonifera, Eisenia arborea, andEis. bicyclis, and evaluated their inhibitory activities against the
production of fluorescent AGEs in the serum albumin-MGO
models. Furthermore, the measurement of the MGO scavenging
activity of phlorotannins was also carried out using HPLC andliquid chromatography-electrospray ionization-mass spectrometry(LC/ESI/MS).
Table 1: IC50 values of crude phlorotannins from Lessoniaceae against fluorescent
AGEs formation.
Algae

Specific area of origin

Eck. cava
Eck. kurome
Eck. kurome
Cultured Eck. kurome
Eck. stolonifera
Eis. arborea
Eis. bicyclis

Mie
Fukuoka
Kumamoto
Kumamoto
Yamaguchi
Mie
Fukuoka

HSA-MGO(mg/mL)
0.53
0.45
0.53
0.46
0.52
0.46
0.45

BSA-MGO(mg/mL)
0.51
0.46
0.50
0.46
0.47
0.53
0.43

All the data are expressed as the mean of three independent measurements. The IC50
values of aminoguanidine hydrochloride were 0.70 mg/mL in the HSA-MGO modeland 0.90 mg/mL in the BSA-MGO model.
Table 2: IC50 values of phloroglucinol and isolated phlorotannins against fluorescent
AGEs formation.
Compounds
Phloroglucinol
Eckol
Fucofuroeckol A
Phlorofucofuroeckol A
Dieckol
8,8´-Bieckol

HSA-MGO (µM)
3.9 x 103
1.3 x 103
5.5 x 1024.8 x 102
6.9 x 102
6.3 x 102

Sugiura et al.

serum albumin in a concentration-dependent manner in both serum
albumin-MGO models. Calculation of the IC50 value showed that
fucofuroeckol A, phlorofucofuroeckol A, dieckol, and 8,8´-bieckol
had the most effective activities out of all of the tested compounds,
and the range of values were 4.8 x 102 to 6.9 x 102 µM in the HSAMGO model and 4.1 x 102 to 7.4 x 102 µM in the BSA-MGO model(Table 2). In particular, phlorofucofuroeckol A showed the highest
inhibitory activity of fluorescent AGEs formation in both models
and the IC50 values were 4.8 x 102 µM and 4.1 x 102 µM,
respectively (Table 2). In comparison of the IC50 values,
phlorofucofuroeckol A showed anti-glycation activity about 13
times greater in the HSA-MGO model, and about 20 times greaterin the BSA-MGO model, with respect to aminoguanidinehydrochloride. MGO is known to be formed by the degradation andoxidation of Amadori products in the middle stage of protein
glycation [21]. Therefore, the test using the albumin-MGO model
evaluates the anti-glycation activity of the target sample in thismiddle stage. From the data obtained in the present study, it wassuggested that phlorotannins from Eisenia and Ecklonia species,
especially phlorofucofuroeckol A, may exert excellent inhibition of
AGEs formation in the middle stage of protein glycation.

BSA-MGO (µM)
2.4 x 103
1.6 x 103
7.4 x 1024.1 x 102
7.4 x 102
6.9 x 102

All the data are expressed as the mean of three independent measurements. The IC50
values of aminoguanidine hydrochloride were 6.4 x 103 µM in the HSA-MGO modeland 8.1 x 103 µM in the BSA-MGO model.

In both human serum albumin (HSA)-MGO and bovine serum
albumin (BSA)-MGO models, all samples tested in this study
inhibited the formation of fluorescent AGEs in a dose-dependent
manner. The concentrations (IC50) of crude phlorotannins at 50%
inhibition of fluorescent AGEs formation were calculated andshown in Table 1. In the HSA-MGO model, the IC50 values of thecrude phlorotannins were in the range of 0.45 to 0.53 mg/mL.
Among the tested samples, crude phlorotannins prepared from Eck.
kurome, Eis. bicyclis, Eis. arborea, and cultured Eck. kurome
showed effective inhibitory activities of fluorescent AGEs
formation, and their activities were about 1.6 times higher than thatof aminoguanidine hydrochloride used as a positive control. In the
BSA-MGO model, the crude phlorotannins of Eis. bicyclis
exhibited the highest inhibitory activity against fluorescent AGEs
formation, and its IC50 value was 0.43 mg/mL. Since the IC50 valueof aminoguanidine hydrochloride was 0.90 mg/mL in the model, it
was revealed that crude phlorotannins prepared from Eis. bicyclis
had about 2.1 times the inhibitory activity. In another study using
brown algae rich in phlorotannins, Liu et al. [17] prepared a 70%
acetone extract (phlorotannins rich fraction) from brown alga Fucus
vesiculosus and reported its inhibitory activity on the formation offluorescent AGEs in the BSA-MGO model. As a result ofcomparing data with the IC50 values described in the report, it was
found that the anti-glycation activity of crude phlorotannins from
Lessoniaceae are equivalent to that of a 70% acetone extract fromF. vesiculosus.
To further analyze the inhibitory activity of phlorotannins against
fluorescent AGEs formation in serum albumin-MGO models, a test
was carried out using phloroglucinol and five kinds of purified
eckols (eckol, fucofuroeckol A, phlorofucofuroeckol A, dieckol,
and 8,8´-bieckol). These phlorotannins are common compounds
contained within the Japanese Lessoniaceae [14,18-20].
Phloroglucinol and the purified eckols inhibited the glycation of

Figure 2: MGO scavenging activities of isolated phlorotannins, phloroglucinol, andaminoguanidine hydrochloride. All the data are expressed as the mean of three
independent measurements.

In addition to involvement in the formation of AGEs in vivo, MGO
causes inactivation of superoxide dismutase and increases
production of reactive oxygen species [22,23]. Consequently,
scavenging of MGO is considered to possibly result in a reductionof both glycation stress and oxidative stress. As a result ofexperimentation at a concentration of 1 mg/mL, each crude
phlorotannins from the Lessoniaceae scavenged MGO over time,
and the scavenging rate was in the range from 75.2% to 86.7% after
120 min of incubation (data not shown). The MGO-scavenging
activities of phloroglucinol and five kinds of purified eckols were
measured, and the obtained data are shown in Figure 2. Differencesin MGO-scavenging activities were observed in the tested eckols
depending on the presence or absence of the benzobisbenzofuranskeleton in their molecules. After 30 min of incubation, eckol andsimple dimers of eckol (dieckol and 8,8´-bieckol) showed higher
MGO-scavenging activities (90.5%, 93.6%, and 91.8%,
respectively) as compared to aminoguanidine hydrochloride(84.4%) (Figure 2). In contrast, the MGO-scavenging activity ofphlorofucofuroeckol A, which was the highest in inhibiting
fluorescent AGEs formation, showed the lowest value of 64.6%(Figure 2). The scavenging activity of fucofuroeckol A, having abenzobisbenzofuran skeleton in its molecule similar tophlorofucofuroeckol A, was also lower than that of aminoguanidinehydrochloride. Phloroglucinol exhibited a scavenging activity justbelow that of eckol, and its proportion was 86.0%. Using
LC/ESI/MSn analysis, Liu et al. [17] reported that phloroglucinol
reacts with reactive carbonyls (glyoxal and MGO) and forms
phloroglucinol-carbonyl adducts. In analogy with phloroglucinol,

Anti-glycation activities of phlorotannins in albumin-methylglyoxal models

Natural Product Communications Vol. 12 (11) 2017 1795the formation of NƐ-carboxymethyl-lysine, a kind of AGEs, in vitro
test. The evidence obtained in the previous and present studies
suggest that phlorotannins may prevent or ameliorate chronic
diseases (e.g. diabetes and atherosclerosis) in which AGEs are
involved, as novel anti-glycation substances from natural products.
Experimental
Materials: The brown algae Eisenia bicyclis (Kjellman) Setchell,
Eis. arborea Areschong, Ecklonia cava Kjellman, Eck. kurome
Okamura, and Eck. stolonifera Okamura, approximately 90-120 cm
in length, were collected from the coasts of the Itoshima peninsula(33°37´N, 130°10´E) in Fukuoka prefecture, Itsuwa (32°54´N,
130°13´E) in Kumamoto prefecture, Sakishima peninsula (34°14´N,
136°50´E) in Mie prefecture, and Kawatana (34°9´N, 130°53´E) in
Yamaguchi prefecture, Japan, in 2015. The cultured Eck. kurome
was purchased from the Fisheries Cooperative Association of
Amakusa in Kumamoto prefecture, Japan, in 2015. The algae used
for the extraction of phlorotannins were washed with filteredseawater, air-dried, and pulverized. The algal powders were stored
at -30°C until use.

Figure 3: Detection and analysis of eckol-MGO adducts using LC/ESI/MS. a: total ion
chromatograms of eckol and eckol-MGO reaction solution. The peak of eckol was
detected in total ion chromatogram with a retention time of 10.3 min. b: MS spectra ofeckol-MGO adducts, c: SIM chromatograms of eckol-MGO adducts.

eckol and the dimers, having MGO-scavenging activity, may
possibly form adducts with MGO. In fact, an analysis of eckol and
MGO reaction solution suggested that there were two kinds ofeckol-MGO adducts (Figure 3). In the negative mode of
LC/ESI/MS measurement, the reaction solution of eckol-MGO wasanalyzed. The first eckol-MGO adduct eluted at 10.5 min (peak i)(Figure 3a), which gave rise to m/z 443 [M-H]- (Figure 3b). This
yielded a product ion at m/z 371 that was consistent with eckol
moiety. Therefore, this adduct was identified as an adduct of one
eckol molecule and one MGO molecule. The second adduct eluted
at 11.7 min (peak ii) (Figure 3a) and had m/z 515 [M-H]- (Figure3b). Fragment ions at m/z 443 and 371 result from the eliminationof one molecule of MGO and two molecules of MGO molecules,
respectively. This was consistent with an adduct composed of one
eckol molecule and two MGO molecules. As a result of
measurement using the selected ion monitoring (SIM) mode of themass spectrometer, chromatograms showing each of the two
adducts were obtained (Figure 3c). These results suggest that the
scavenging activity of MGO may partially contribute to the antiglycation activity of eckol and its dimers (dieckol and 8,8´-bieckol).
To our knowledge, this is the first study to evaluate the antiglycation activities of phlorotannins in human and bovine serum
albumin-MGO models. Recently, Corona et al. [24] evaluated thebioavailability of phlorotannins extracted from Ascophyllum
nodosum in healthy subjects. In that literature, it was reported thatthree types of low molecular phlorotannins (hydroxytrifuhalol A,
7-hydroxyeckol, and dimer of phloroglucinol) were detected as
metabolites in both samples of plasma and urine. Okada et al. [25]clarified that eckol and dieckol isolated from the Eis. bicyclis inhibit

Extraction and purification of phlorotannins: Extraction ofphlorotannins from algal powder was prepared according to themethod described in the previous report [20]. Phlorotannins werepartially purified by silica column chromatography (1.5 cm i.d. x
150 cm) using Wakogel C-300 HG (Wako Pure Chemical) with amobile phase of CHCl3:MeOH:water (80:20:2, v/v) according to themethod described in the previous reports [15,16]. Further
purification of phlorotannins was carried out using preparative
HPLC with an Inertsil ODS-3 column (10 mm i.d. x 250 mm, GL
Science) [16]. Each of the obtained phlorotannins (eckol,
fucofuroeckol A, phlorofucofuroeckol A, dieckol, and 8,8´-bieckol)
was confirmed to have a purity of 98% or more by threedimensional HPLC (SPD-M10AV, Shimadzu) with an Inertsil
ODS-3 column (4.6 mm i.d. x 250 mm, GL Science) [16]. The
purified phlorotannins were stored at -30°C until use.
Serum albumin-MGO assay: The antiglycation assay ofphlorotannins in the serum albumin-MGO model was performed
according to the method of Liu et al. [17] with slight modification.
Sample, MGO (60 mM), and albumin (HSA or BSA, 20 mg/mL)
solutions were prepared separately by dissolving in 100 mM
phosphate buffer (pH 7.4). The measurement was carried out using
a 96-well black plate (FLUOTRAC600, Greiner) and a 96-well
microplate reader (Infinite 200, Tecan). The sample solution (50µL), MGO solution (50 µL), and albumin solution (50 µL) wereadded to the wells in the plate. Sodium azide was added to eachwell to a final concentration of 0.2 mg/mL. Measurement was
carried out with fluorescence intensity at an excitation of 340 nm
and an emission of 420 nm, and the obtained value was taken as acontrol value. After incubation at 37°C for 7 days, the fluorescenceintensities of each well were measured under the same measurement
conditions. For blank wells, phosphate buffer was used instead ofsample solution. Aminoguanidine hydrochloride was used as apositive control. The inhibition rate (%) of fluorescent AGEs
formation was calculated using the following formula:
Inhibition rate (%) = [1 - (fluorescence intensity of sample after incubation for 7 days fluorescence intensity of control of sample) / (fluorescence intensity of blank after
incubation for 7 days - fluorescence intensity of control of blank)].

The IC50 value was calculated from the logarithmic function
obtained by plotting the inhibitory rate of fluorescent AGEs
formation against the sample concentration.

1796 Natural Product Communications Vol. 12 (11) 2017

MGO-scavenging assay: The MGO-scavenging activity ofphlorotannins was carried out using a modification of the method of
Liu et al [17]. Five mM MGO and 20 mM o-phenylenediamine
were prepared using 100 mM phosphate buffer (pH 7.4). The crude
phlorotannins extracted from each brown algae was dissolved in thephosphate buffer to a concentration of 1 mg/mL. Purified
phlorotannins, phloroglucinol, and aminoguanidine hydrochloride
were dissolved in the phosphate buffer to a concentration of 5 mM
each. Each sample solution (25 μL) and a MGO solution (25 μL)
were mixed and incubated at 37°C. In the test using crude
phlorotannins, incubation was carried out for 5, 10, 20, 40, 60, and
120 min, respectively. In the test using purified phlorotannins,
incubation was carried out for 5, 10, 15, 20, 25 and 30 min,respectively. After incubation, o-phenylenediamine solution (5 μL)
was added to the mixture and maintained at 25°C for 30 min to be
derivatized. For the blank test, the phosphate buffer was usedinstead of a sample solution. The amount of 1-methylquinoxaline
produced by the reaction of o-phenylenediamine and MGO

Sugiura et al.

remaining in the mixture, was quantified using HPLC (LC2000Plus, JASCO) with LUNA Phenyl-hexyl column (4.6 mm i.d.
x 150 mm, Phenomenex). Elution was performed at a flow rate of 1
mL/min with 50% MeOH as a mobile phase. The UV detector was
set at 315 nm.
Detection and identification of Eckol-MGO adduct using
LC/ESI/MS: Eckol and MGO were dissolved in ultrapure water to aconcentration of 5 mM each. The eckol solution (300 µL) and the
MGO solution (300 µL) were mixed and incubated at 37°C for 2
hours. Detection and identification of eckol-MGO adducts were
performed using LC/ESI/MS (Agilent 6120, Agilent). The conditionof LC/ESI/MS was utilized for the analysis condition ofphlorotannins reported in the preceding study [20]. The m/z was set
from 50 to 1000.
Acknowledgments - This work was financially supported by theJapan Science and Technology Agency, CREST.

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Natural Product Communications Vol. 12 (11) 2017
Published online (www.naturalproduct.us)Highly Cytotoxic Xanthones from Cratoxylum cochinchinense Collected in Myanmar
Zaw Min Thu, Hnin Thanda Aung, Myint Myint Sein, Marcello Maggiolini, Rosamaria Lappano and Giovanni Vidari
Chemical Constituents of Sinningia hatschbachii
Magali S. Amorim, Alessandra F. Serain, Marcos José Salvador and Maria Élida A. Stefanello
Two Dibenzoquinones from the Fungus Acremonium cavaraeanum
Qiao Xu, Miao-Miao Zhang, Shu-Zhen Yan, Lu-Fen Cao, Qiang Li, Jie Lin and Shuang-Lin Chen
Phenolic Derivatives from Periplaneta americana
Yong-Ming Yan, Hong-Jie Zhu, Bin Xiang, Jing-Jing Qi and Yong-Xian Cheng
Caffeic Acid Esters Affect Intracellular Oxidation and Vitality of Yeast Saccharomyces cerevisiae Cells
Tanja Petelinc, Manca Medved, Tomaž Polak and Polona Jamnik
A Phenylpropanoid and Biflavonoids from the Needles of Cephalotaxus harringtonia var. harringtonia
Anju Mendiratta (Nee Chugh), Rameshwar Dayal, John P. Bartley and Graham Smith
Copper(II) Sulfate Stimulates Scopoletin Production in Cell Suspension Cultures of Angelica archangelica
Tomáš Siatka, Jakub Chlebek and Anna Hošťálková
Resveratrol Demonstrated Higher Antiproliferative and Antiangiogenic Efficacy Compared with Oxyresveratrol on
Head and Neck Squamous Cell Carcinoma Cell Lines
Napaporn Sintuyanon, Waranyoo Phoolcharoen, Prasit Pavasant and Sireerat Sooampon
Self-Nanoemulsifying System in the Accumulation of Resveratrol and N-Acetylcysteine in the Epidermis and Dermis
Sonia Laneri, Antonia Sacchi, Andrea Fratter, Walter Bertin, Alessia Bino, Silvia Vertuani and Stefano Manfredini
A Comprehensive LC-MS and Isolation Study of Cicada Slough as a Crude Drug
Hiroki Matsumoto, Katsuhiro Konno and Kohei Kazuma
Evaluation of Anti-glycation Activities of Phlorotannins in Human and Bovine Serum Albumin-methylglyoxal Models
Shingo Sugiura, Yuya Minami, Ryosuke Taniguchi, Reiji Tanaka, Hideo Miyake, Tetsushi Mori, Mitsuyoshi Ueda and Toshiyuki Shibata
Antibacterial and Antioxidant Activities of Leaf Extracts from Juglans sinensis, and its Phenolic Compositions
Kook-Il Han, Eui-Gil Jung, Bharat Bhusan Patnaik, Chang-Il Hong, Young-Jun Kim, Seunghyeon Jung and Man-Deuk Han
Phytochemical Analysis and Antimicrobial Activity of Origanum dictamnus Traditional Herbal Tea (decoction)
Myrto Varsani, Konstantia Graikou, Aristea Velegraki and Ioanna Chinou
Comparative Analysis of Phenolic Compounds in Seven Hypericum Species and Their Antioxidant Properties
Gordana Zdunic, Dejan Godjevac, Katarina Savikin and Silvana Petrovic
Evaluation of Phenolic Compounds in Cistus creticus Bee Pollen from Greece. Antioxidant and Antimicrobial Properties
Emmanuel Atsalakis, Ioanna Chinou, Maria Makropoulou, Sofia Karabournioti and Konstantia Graikou

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Structural Basis for Great Protein-Binding Potential of Flavonoids: A Case Study of Quercetin
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Natural Product Communications
2017
Volume 12, Number 11
Contents
Polyphenols: Occurrence, Roles and Benefits(Guest Editor: Marina Stefova)
Original Paper
New Primula-type Flavones from Exudates of Selected Dionysia spp. (Primulaceae)
Wolfgang Hinterdobler, Karin M. Valant-Vetschera and Lothar Brecker
Methoxyflavones from Marcetia taxifolia as HIV-1 Reverse Transcriptase Inhibitors
Joseph T Ortega, María Luisa Serrano, Alírica I Suárez, Jani Baptista, Flor H Pujo and Héctor R Rangel
Developing a Validated HPLC Method for the Phytochemical Analysis of Antihyperuricemic Phenylethanoid Glycosides
and Flavonoids in Lippia nodiflora
Lee-Chuen Cheng, Vikneswaran Murugaiyah and Kit-Lam Chan
Fruits of Rosa brunonii – A Source of Antioxidant Phenolic Compounds
Muhammad Ishaque, Yamin BiBi, Karin M. Valant–Vetschera, Johann Schinnerl and Markus Bacher
Hypolaetin-7-O--D-xyloside from Juniperus communis Fruits Inhibits Melanogenesis on Zebrafish Pigmentation
Eun Ju Jeong, Jonghwan Jegal, Ki Wung Chung, Sang Gyun Noh, Hae Young Chung, Youn Hee Nam, Tong Ho Kang,
Su-Nam Kim and Min Hye Yang
Antioxidant Activity and Upregulation of Antioxidant Enzymes of Phenolic Glycosides from Aquilaria crassna Leaves
Chonlakan Supasuteekul, Narawat Nuamnaichati, Supachoke Mangmool, Kittisak Likhitwitayawuid, Parkpoom Tengamnuay,
Waraporn Putalun and Boonchoo Sritularak
Quantitative Analysis of Various B-ring Unsubstituted and Substituted Flavonoids in Ten Australian Species of Eucalyptus
Isha Saraf, Karen J. Marsh, Sanjay Vir, William J. Foley and Inder Pal Singh
Anti-proliferative Activities of Two Flavonols with Unsubstituted B-ring from the Leaves of Platanus acerifolia
Hui-Feng Chen, Ri-Zhen Huang, Bo Zuo, Lan-Ju Ji, Zhi-Jian Mo and Zhi-Xin Liao
Inhibition of Lipoxygenase and Peroxidase Reaction by Some Flavonols and Flavones: The Structure-Activity RelationshipZbigniew Sroka, Alina Sowa and Andrzej DryśQuercetin-3-O-glucoside Improves Glucose Tolerance in Rats and Decreases Intestinal Sugar Uptake in Caco-2 Cells
Denys Torres-Villarreal, Alberto Camacho, Fermín I. Milagro, Rocío Ortiz-Lopez and Ana Laura de la Garza
UFLC-MS-IT-TOF and Bioassay Guided Isolation of Flavonoids as Xanthine Oxidase Inhibitors from Diospyros dumetorum
Zhen-Tao Deng, Tong-Hua Yang, Xiao-Yan Huang, Xing-Long Chen, Jian-Gang Zhang, Xue-Mei Zhang, Ji-Jun Chen andChang-An Geng
Chemical Constituents of Aglaia odorata Leaves and Their Anti-inflammatory Effects
Mai Efdi, Antoni Pardede, Akinori Kakumu, Hirokazu Hara, Syafrizayanti, Dessy Arisanti, Masayuki Ninomiya and Mamoru Koketsu
Two New Carboxyethylflavanones from the Heartwood of Dalbergia tonkinensis and Their Antimicrobial Activities
Ninh The Son, Kenichi Harada, Nguyen Manh Cuong and Yoshiyasu Fukuyama
Inhibitory Mechanism of Taxifolin against α-Glucosidase Based on Spectrofluorimetry and Molecular Docking
Jiang Liu, Xiansheng Wang, Sheng Geng, Benguo Liu and Guizhao Liang
Proliferation Effects on Hair Growth of Compounds Isolated from the Bark of Dalbergia oliveri
Seon Ju Park, Nguyen Xuan Nhiem, Bui Huu Tai, Hoang Le Tuan Anh, Seok Hyun Oh, Jong-Hyuk Sung, Nanyoung Kim,
Guijae Yoo, Jun Hyung Park, Hee Jae Kwak, Pham Thanh Loan, Seung Hyun Kim and Phan Van Kiem
A New C-methyl Isoflavone and Other Compounds from the Roots of Amphiblemma monticola (Melastomataceae)
Fabrice S. T. Ndjateu, Mathieu Tene, Pierre Tane and Muhammad I. Choudhary
Daidzein Production and HeLa Cytotoxicity of Bituminaria bituminosa Hairy Root Cultures
Francesca D’Angiolillo, Cecilia Noccioli, Barbara Ruffoni, Roberto Scarpato, Luisa Pistelli and Laura Pistelli
Biotransformation of 4-Chromanol, 4-Flavanol, Xanthydrol, and their Analogs by Tissue Cultured Cells
Masahiko Nagaki, You Kikuchi, Shingo Maekawa, Takumi Kidachi, Kazushige Honda and Yukiyasu Chounan
Biotransformation of Daidzein to Diadzein-7-Glucoside and Its Anti-allergic Activity
Yuya Fujitaka, Kei Shimoda, Minami Araki, Shouta Doi, Tsubasa Ono, Hatsuyuki Hamada and Hiroki Hamada
Phenolics from the Fruits of Maclura pomifera
Zushang Su, Ping Wang, Wei Yuan, Greg Grant and Shiyou Li
Broad Spectrum Antimicrobial Activity of Licochalcones A and E against MDR (Multidrug Resistant) Strains of Clinical Origin
Jung-Eun Kim, Goo Yoon, Jung-Hyun Shim and Seung-Sik Cho
DNA Topoisomerase I Inhibitory Activity of Quinochalcone C-glycosides from the Florets of Carthamus tinctorius
Shi-Jun Yue, Wen-Xiao Wang, Cheng Qu, Lan-Ting Xin, Yu-Ping Tang, Jin-Ao Duan and Chang-Yun Wang
A New Glycoside and in vitro Evalution of α-Glucosidase Inhibitory Activity of Constituents of the Mangrove Lumnitzera racemosa
Nguyen H. Phuong, Nguyen T. L. Thuy, Nguyen T. Duc, Nguyen T. A. Tuyet, Nguyen T. T. Mai and Nguyen K. P. Phung
Salicylic Glycosides in Salix mucronata with Antioxidant and Antiinflammatory Activities
Amila A. Dissanayake, Chuan-Rui Zhang, Mohamed K. A. Gaber and Muraleedharan G. Nair
Continued inside backcover

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