Abstract

A new compound (C<inf>20</inf>H<inf>18</inf>O<inf>9</inf>) was isolated from bambara groundnut seeds (Vigna subterranea (L.) Verdc.) and identified as a luteolin glycoside based on ¹H, ¹³C and 2D nuclear magnetic resonance spectroscopy data and previously reported data. This compound exhibited similar scavenging activity for DPPH radical to Trolox and had a higher inhibitory effect on superoxide anion radicals than gallic acid and Trolox. C<inf>20</inf>H<inf>18</inf>O<inf>9</inf> exhibited an inhibitory effect on DPPH and superoxide anion radicals, with IC<inf>50</inf> values of 2.25 ± 0.14 µg/mL and 9.8 ± 0.3 µg/mL, respectively. However, C<inf>20</inf>H<inf>18</inf>O<inf>9</inf> displayed low activities for FRAP and metal chelation. C<inf>20</inf>H<inf>18</inf>O<inf>9</inf> had a higher inhibitory effect on lipoxygenase (IC<inf>50</inf> = 2.16 ± 0.14 µg/mL) than nordihydroguaiaretic acid but had a lower inhibitory effect on xanthine oxidase than allopurinol. These results indicate that bambara groundnut seeds can be natural sources of antioxidants for humans and can serve as lipoxygenase inhibitor to reduce inflammation.