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. 2023 Dec 23;13(1):35. doi: 10.3390/antiox13010035

Table 5.

Different flavonoid chemical features contributing to the antioxidant activity of rice byproducts.

graphic file with name antioxidants-13-00035-i002.jpg

Compound C3′ C4′ C5′ C2-C3 C3 C4 C5 C7
Quercetin OH OH H Double bond OH C=O OH OH
Myricetin OH OH OH Double bond OH C=O OH OH
Apigenin H OH H Double bond H C=O OH OH
Catechin H OH OH - OH H OH OH
Rutin H OH OH Double bond O-R a C=O OH OH
Tricin OCH3 OH OCH3 Double bond H C=O OH OH
Luteolin OH OH H Double bond H C=O OH OH
Cyanidin-3-O-glucoside OH OH H Double bond O-R b H OH OH
Cyanidin-3-O-rutinoside OH OH H Double bond O-R a H OH OH
Cyanidin-3-O-galactoside OH OH H Double bond O-R c H OH OH
Peonidin-3-O-glucoside OCH3 OH H Double bond O-R b H OH OH

a: R = rutinose; b: R = glucose; c: R = galactose.