Total phenolic, total flavonoid contents and antioxidant potential of Common Bean (Phaseolus vulgaris L.) in Vietnam

In this study, the antioxidant properties of total phenolics and flavonoids extracts from different parts (leaves, pods, and seeds) of common bean were evaluated. Specifically, the highest total phenolic content was recorded with methanol extracts of pods (95.41 [+ or -]1.18 mg GAE/g), whereas methanolic extract of seeds contained the lowest content of phenols (6.87 [+ or -] 1.45 mg GAE/g). The highest total flavonoid content was found in methanol extracts of leaves (44.59 [+ or -]2.15 mg RE/g). Meanwhile, the methanol extract of seeds and pods contained less flavonoid content (9.29 [+ or -] 1.65 mg RE/g and 3.64 [+ or -] 0.87 mg RE/g, respectively). The GC-MS analysis showed the presence of 29, 18 and 29 different plant compounds in methanol extracts of leaves, seeds and pods, respectively. The methanol extracts of leaves showed the highest antioxidant capacity with an inhibitory percentage of 48.74 [+ or -] 0.32% at a concentration of 100 [micro]g/mL and the [EC.sub.50] value of 137.4 [micro]g/mL. The methanol extracts of seed had the lowest antioxidant capacity with an inhibitory percentage of 13.99 [+ or -] 1.22% at a concentration of 100 [micro]g/mL and the [EC.sub.50] value of 486.2 [micro]g/mL. The results showed that the extract from leaves of common bean had the highest antioxidant activities as well as total contents of flavonoid in comparison with an extract from seeds and pods and the positive relationship between total flavonoids content and antioxidant activities in this plant. Keywords: common bean; phenolic contents; flavonoid contents; antioxidant activity