A New Isoflavanol from the Fruits of Kotschya strigosa (Fabaceae)

The phytochemical investigation of the MeOH extract from fruits of Kotschya strigosa using repeated normal and reversed‐phase column chromatography and Sephadex LH‐20 chromatography led to the isolation and characterization of a new isoflavanol, named kotstrigoisoflavanol (1), together with three known compounds, diosmetin (2), β‐sitosterol (3), and the 3‐O‐β‐d‐glucopyranoside of β‐sitosterol (4). The antioxidant activity of crude extract, 1, and 2 was determined using the 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH˙) method. The crude extract (IC50 61.7 ± 0.2 μg/ml) and 2 (IC50 70.2 ± 0.1 μg/ml) showed moderate antioxidant activities, while 1 was weakly active (IC50 153.1 ± 0.1 μg/ml), as compared with the standard reference l‐ascorbic acid (IC50 21.9 ± 0.0 μg/ml).