# Phytochemicals and Antioxidant Properties of Edible Flowers
## 3 Antioxidant Activity of Edible Flowers  
Chemical reactions that involve electron transfer between electron-rich molecules to an oxidizing agent, which undergoes reduction, is called oxidation [102]. The oxidizing agents, or simply oxidants, are usually forms of free radicals that have unpaired elec \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Flower** & **Total Tocopherol** & **\(\alpha\)-Tocopherol** & **Reference** \\  & **(mg/100 g DW)** & **(\% of Total)** & **Reference** \\ \hline _Calendula officinalis_ L. & 60.9 & 93 & [77] \\ _Viola \(\times\) vittrockiana_ (yellow) & 24.9 & 89 & [72] \\ _Moritga oleifera Lam._ & & & \\ (Quinhamel) & 21.0 & 90 & [78] \\ _Moritga oleifera Lam._ (Bissau) & 19.9 & 87 & [78] \\ _Viola \(\times\) vittrockiana_ (white) & 11.3 & 77 & [72] \\ _Urtica leptophila_ & 11.1 & 63 & [70] \\ _Camella japonica_ & 10.9 & 85 & [72] \\ _Latacto canadensis L._ & 9.7 & 63 & [82] \\ _Rosa damascene_/ _R. gallica_ & 9.3 & 88 & [77] \\ _Dahlia mignon_ & 7.3 & 60 & [77] \\ _Aloe vera_ & 4.7 & - & [83] \\ _Borago officinalis_ L. & 3.2 & 69 & [79] \\ _Iuglans Regia_ L. & 2.9 & 7 & [81] \\ _Centaure c cyanus_ L. & 2.4 & 52 & [79] \\ _Amarantthus caudatus_ L. & 2.0 & 24 & [80] \\ _Centaure c cyanus_ L. & 1.3 & 78 & [84] \\ _Viola \(\times\) vittrockiana_ (white) & 1.1 & 63 & [72] \\ _Centaure c cyanus_ L. & 0.8 & 65 & [77] \\ _Narcissus poeticus_ L. & 1.5 1 & - & [85] \\ _Cynara cardunculus_ & 0.6 1 & - & [86] \\ \hline \hline \end{tabular} \({}^{\dagger}\)Only \(\alpha\)-tocopherol.  
\end{table} 
Table 10: Total tocopherol content of several edible flowers from recent studies. \begin{table}
\begin{tabular}{c c} \hline \hline
**Terpene** & **Flower** \\ \hline \multirow{2}{*}{Linalol} & _Jasminum samba_ L. (59\%) a, _Cananga adornata_ (29\%) b, _Lavandula hybrid_ \\  & (37\%) c, _Crocus sativus_ (26\%) d \\ \hline \multirow{2}{*}{\(\alpha\)-Pinene} & _Hypericum lydium_ Boiss (71\%) e, _Myrtus communus_ var. italica L. (18\%) f, _Chrysanthemum coronarium_ (15\%) \& _Pranges ferulacen_ (21\%) h \\ \hline \multirow{2}{*}{1,8-Cineole} & _Myrtus communus_ var. italica L. (13\%) f, _Santolina rossarinfilolia_ (13\%) i, _Cocota quizcos_ (8\%) \({}^{\dagger}\)), _Crocus sativus_ (44\%) d \\ \hline \multirow{2}{*}{Eugenol} & _Myrtus communus_ var. italica L. (10\%) f, _Eugenia carophyllata_ (80\%) k \\ \hline \multirow{2}{*}{Camphor} & _Chrysanthemum fos_ (11\%) 1, _Chrysanthemum coronarium_ (29\%) \& _Santolina rossarinfilolia_ (80\%) i, _Rosmarinus officinalis_ (36\%) m \\ \hline \multirow{2}{*}{Camphene} & _Prangos ferulacen_ (12\%) h, _Cistus ladanifer_ (6\%) n \\ \hline \hline a, [88] b, [89] c, [90] d, [91] e, [92] f, [93] g, [94] h, [95] i, [96] j, [97] k, [98] l, [99] m, [100] n, [101]. \\ \hline \end{tabular}
\end{table} 
Table 11: Major terpen detected in some edible flowers’ essential oils. trons such as hydroxyl, alkoxyl and reactive oxygen species [3]. These oxidants are very reactive and attack other molecules. The mechanism by which these oxidants (free radicals) usually work involves three main steps: (a) initiation (the number of free radicals increases); (b) propagation (the total number of radicals remains constant and the reaction spreads); and (c) termination (the number of free radicals decreases) [102]. Antioxidants are compounds that prevent the oxidation of systems, and edible flowers contain numerous such compounds. There are two main classes of antioxidants: those that actively inhibit oxidation reactions (primary antioxidants) and those that inhibit oxidation indirectly by mechanisms such as oxygen scavenging, binding pro-oxidants, etc. [103]. Phenolic compounds present in edible flowers may act both as primary antioxidants and secondary antioxidants. Two mechanisms are available for the action of primary antioxidants: the hydrogen-atom transfer (an antioxidant compound quenches free-radical species by donating hydrogen atoms) and the single-electron transfer (an antioxidant transfers a single electron to aid in the reduction of potential target compounds) [102].