Isolation and identification of phase II enzyme inductors obtained from black Shawaya sorghum [Sorghum bicolor (L.) Moench] bran

The antioxidant capacity as oxygen radical absorbance capacity (ORAC) and in vitro chemopreventive effect of phytochemicals extracted, partitioned and isolated from the decorticated bran of black Shawaya sorghum (Sorghum bicolor L. Moench) was studied. The chemopreventive effect was evaluated as the induction effect of quinone reductase (QR) using murine hepatoma cells Hepa 1c1c7. The crude methanol extract with an antioxidant capacity of 3.7 μmol Trolox equivalent (TE)/mg was partitioned into 120 fractions with fast centrifugal partition chromatography (FCPC). Fractions with partition coefficients between 0.1 and 0.26 exerted more than 50% of the antioxidant activity of the original crude extract and contained the highest concentration of anthocyanins. No correlation was found for ferulic acid content and ORAC or chemoprevention. A derivative of 7-methoxyapigeninidin at a concentration of 1 μg/ml increased by 31% the QR activity while the original extract reached a maximum of 27% at 40 μg/ml.

► Bioactivity based screening from a methanolic extract of black Shawaya sorghum bran using FCPC. ► Strong correlation of antioxidant activity and anthocyanin concentration in FCPC fractions. ► Ferulic acid had higher induction of quinone reductase (QR) than raw methanolic extract. ► FCPC fractions with the highest concentration of ferulic acid did not have the highest QR induction. ► 7-methoxyapigenidin derivatives had the highest in vitro chemopreventive effects.