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 (DPPḢ) 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).