# Rice Secondary Metabolites: Structures, Roles, Biosynthesis, and Metabolic Regulation
## 2 Structural Diversity and Roles of Rice Secondary Metabolites
### Flavonoids and Their Biological Functions
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Name** & **Rice Part Used for Isolation** & \
\begin{tabular}{c} **Biological Activity and** \\ **Function** \\ \end{tabular} & **Ref.** \\ \hline \hline \multirow{6}{*}{Tricin \(4^{d}\)-\(O\)-\(\beta\)-\(D\)-xylopyranoside (**82**) &
\begin{tabular}{c} Cytotoxicity and apoptosis \\ induction in multiple tumor \\ \end{tabular} } \\  & & & cells \\ \cline{1-1}
7-\(O\)-\(\beta\)-\(D\)-glucopyranoside (**59**) & Leaves & - & [53] \\ Tricin \(4^{d}\)-\(O\)-(_three_\(\beta\)-guanacylglycerol) ether & Leaves & - & [53] \\
7-\(O\)-\(\beta\)-\(D\)-glucopyranoside (**60**) & Leaves & - & [53] \\ Tricin \(4^{d}\)-\(O\)-(_orth_\(\beta\)-guanacylglycerol) ether & Leaves & - & [53] \\
7-\(O\)-\(\beta\)-\(D\)-glucopyranoside (**61**) & Leaves & - & [53] \\ Tricin \(4^{d}\)-\(O\)-(_three_\(\beta\)-guanacylglycerol) ether & Leaves & - & [53] \\
7-\(O\)-\(\beta\)-\(D\)-glucopyranoside (**62**) & Leaves & - & [53] \\ Tricin \(4^{d}\)-\(O\)-(_orth_\(\beta\)-guanacylglycerol) ether & Leaves & - & [53] \\
9-\(O\)-\(\beta\)-\(D\)-glucopyranoside (**63**) & Leaves & - & [53] \\ Tricin \(4^{d}\)-\(O\)-(_thm_\(\beta\)-\(4\)-hydroxyphenyl[glycerol) ether (64) & Leaves & - & [53] \\ Tricin \(7^{d}\)-\(O\)-trutinoside (**65**) & Grains of brown rice & - & [53] \\ \hline Flavo & Flavo & & \\ \cline{1-1} Brassicin (**66**) & Grains of transgenic _ japonica_ & Radical scavenging activity & [39] \\ Brassicin-\(4^{d}\)-\(O\)-\(\beta\)-D-glucopyranoside (**67**) & Grains of transgenic _ japonica_ & Radical scavenging activity & [39] \\ Isorthamenti-\(4^{d}\)-\(O\)-\(\beta\)-D-glucopyranoside (**68**) & Grains of transgenic _ japonica_ & Radical scavenging activity & [39] \\ Isorthamenti-\(7^{d}\)-\(O\)-\(\beta\)-\(D\)-colloboside (**69**) & Grains of transgenic _ japonica_ & Radical scavenging activity & [39] \\ Kaempfer (**70**) & Husk and bran & - & [24] \\ Myricetin (**71**) & Rice flour & - & [57] \\ Quercetin (**72**) & Rice flour & - & [57] \\ Quercetin 3-\(O\)-glucose (**73**) & Rice flour & - & [57] \\ Quercetin 3-\(O\)-galactoside = Hyperoside (**74**) & Rice flour & - & [57] \\ Quercetin 3-\(O\)-ratios = Rutin (**75**) & Rice flour & - & [57] \\ Syntegine 3-\(O\)-\(\beta\)-D-glucopyranoside (**76**) & Leaves & - & [53] \\ Synfingetin 3-\(O\)-rutinoside (**77**) & Leaves & - & [53] \\ \hline Flavanones & & & \\ Hesperidin (**78**) & Rice flour & - & [57] \\ Naringenin (**79**) & Leaves & - & [42] \\  & - & Antifungal activity & [43,44] \\  & Rice flour & - & [57] \\  & Rice fungal pathogen & - & [44,45] \\ Naringenin 7-\(O\)-\(\beta\)-\(D\)-xylopyranoside (**80**) & Rice fungal pathogen & - & [45] \\ Sakurantein (**81**) & Leaves & Antifungal activity & [43,44] \\  & Leaves & & \\  & Leaves & & activities & [58] \\  & Leaves & Anti-_Heliochxter pylori_ activity & [49] \\  & - & Antiphenylosomal activities & [50] \\  & - & Antioxidant activity & [42] \\  & - & Anti-inflammatory activity & [47] \\  & - & Anti-mutagenic activity & [48] \\  & - & Induction of adipogenesiseness in & \\  & - & 3T3-I.1 cells & [46] \\ Sakurantein \(4^{d}\)-\(O\)-\(\beta\)-\(D\)-xylopyranoside (**82**) & Rice fungal pathogen & - & [51] \\ Sternbin (**83**) & Rice fungal pathogen & - & [45] \\ \hline Flavanonolds & & & \\ \cline{1-1}
3-\(O\)-Methyltaxifolin (**84**) & Grains of transgenic _ japonica_ & Radical scavenging activity & [39] \\
3-\(O\)-Methyltaxifolin-\(7^{d}\)-\(O\)-\(\beta\)-D-glucopyranoside (**85**) & Grains of transgenic _ japonica_ & Radical scavenging activity & [39] \\
3-\(O\)-Methyltaxifolin-\(4^{d}\)-\(O\)-\(\beta\)-D-glucopyranoside (**86**) & Grains of transgenic _ japonica_ & Radical scavenging activity & [39] \\
3-\(O\)-Methyltaxifolin-\(5^{d}\)-\(O\)-\(\beta\)-D-glucopyranoside (**87**) & Grains of transgenic _ japonica_ & Radical scavenging activity & [39] \\ \hline Flavanods & & & \\ Calculation (**88**) & Rice flour & - & [57] \\ Epicatechin (**89**) & Rice flour & - & [57] \\ \hline Anthocyanins & & & \\ Cyanidin (**90**) &
\begin{tabular}{c} Bran \\ Black rice kernels \\ \end{tabular} & Antioxidant activity & [52] \\ Cyanidin 3-\(O\)-gentiobioside (**91**) & Bran & - & [60] \\  & - & Inhibitory activity on & \\  & - & tunicamycin-induced retinal & [32] \\ Cyanidin 3-\(O\)-glucose (**92**) & Bran & - & [60] \\  & & Inhibitory activity on & \\  & & tunicamycin-induced retinal & [32] \\  & & damage & \\ \hline \hline \end{tabular}
\end{table}