# Phytochemicals and Antioxidant Properties of Edible Flowers
## 2 Phytochemicals
### Phenolic Compounds
#### 2.1.1 Total Phenolic Content  
The most common and simple method for the estimation of total phenolic content (TPC) is the colorimetrical assay based on Folin-Ciocalteu reagent. However, this method usually overestimates the TPC of samples since all the compounds with an active hydroxyl group(s) may react with the reagent and give a positive result [11; 12]. Such compounds, apart from the phenolics, include reducing sugars, ascorbic acid and others. Despite that, this method is the most commonly used, and therefore is the same method used for the extracts of edible flowers. The TPC of more than 200 edible flowers, expressed as mg gallic acid equivalents (GAE) per g in dry weight (DW) or fresh weight (FW), are presented in Tables 1 and 2 [13; 14; 15; 16; 17; 18; 19; 20; 21]. In studies where TPC was expressed in DW, the highest values were reported for _Rosa rugosa_ (312 mg GAE/g DW), _Carpobrotus edulis_ (299 mg GAE/g DW), _Rosa chinensis_ (285 mg GAE/g DW) and _Rhododend sinsii_ [PERSON] (250 mg GAE/g DW), while the lowest were reported for _Agare salimana_ and _Aloe vera_ (4.6 mg GAE/g DW). In studies where TPC was expressed in FW, the highest values were reported for _Rosa hybrid_ (35.8 mg GAE/g FW) and  
Figure 2: Potential health benefits linked with edible flowers. _Limonium situation_ (34.2 mg GAE/g FW), while the lowest were reported for _Iris japonica_ (0.6 mg GAE/g FW) and _Lilium candidum_ L. (0.9 mg GAE/g FW). The results in Tables 1 and 2, also revealed the main problem of TPC estimation through Folin-Ciocalteu reagent. This method is highly affected by the raw material, extraction method and duration of reaction for color development. Therefore, in some cases, almost identical results were obtained for the same flower, such as _Matricaria recuitia_ (26.5 mg GAE/g DW [20] and 26.4 mg GAE/g DW [18]); in other cases, a small difference occurred, such as _Siratia grosvenorii_ (12.8 mg GAE/g DW [20] and 22.2 mg GAE/g DW [18]); but completely different values may also be reported, such as _Lavandula angustifolia_ Mill. (36.9 mg GAE/g DW [18] and 7.4 mg GAE/g DW [16]) and _Tropaeolum majus_ (62.7 mg GAE/g DW [18] and 11.8 mg GAE/g DW [16]). \begin{table}
\begin{tabular}{c c c c c} \hline
**Flower** & **TPC** & **Flower** & **TPC** & **Flower** & **TPC** \\ \hline _Agave salminua_ & 4.6 \({}^{\text{d}}\) & _Dianthus carophyllus_ & 30.8 \({}^{\text{a}}\) & _Myostis sylvatica_ & 64.0 \({}^{\text{a}}\) \\ _Aglaia odorata_ & 55.5 \({}^{\text{a}}\) & _Dianthus_ L. & 15.9 \({}^{\text{b}}\) & _Myrtillocatus geometrizans_ & 28.7 \({}^{\text{d}}\) \\ _Albizzia julibrisin_ & 14.2 \({}^{\text{a}}\) & _Epipremutum aureus_ & 12.9 \({}^{\text{a}}\) & _Nelumbo nucifera_ & 54.5 \({}^{\text{a}}\) \\ _Allium schoneoprasum_ L. & 7.2 \({}^{\text{b}}\) & _Eriobtruja japonica_ & 21.6 \({}^{\text{a}}\) & _Nymphae stellata_ & 69.6 \({}^{\text{a}}\) \\ _Aloe vera_ & 4.6 \({}^{\text{d}}\) & _Erythrina americana_ & 7.8 \({}^{\text{d}}\) & _Oroxylum indicum_ & 46.0 \({}^{\text{a}}\) \\ _Amygdala persica_ & 51.2 \({}^{\text{a}}\) & _Florists chrysanthemum_ & 32.5 \({}^{\text{a}}\) & _Osmanthhus fragrans_ & 134.0 \({}^{\text{a}}\) \\ _Armeniaca mume_ & 54.6 \({}^{\text{a}}\) & _Florists chrysanthemum_ (white) & 23.2 \({}^{\text{a}}\) & _Osmanthhus fragrans_ ([PERSON].) & 68.2 \({}^{\text{c}}\) \\ _Bauhinia variegata_ & 48.0 \({}^{\text{a}}\) & _Gombrema globosa_ & 11.1 \({}^{\text{a}}\) & _Paeonia laciflora Pall._ & 222.0 \({}^{\text{c}}\) \\ _Begonia tuberhbridia_ [PERSON]. & 33.0 \({}^{\text{b}}\) & _Gombrema globosa_ [PERSON].