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Updated: May 28, 2026

Biosynthesis of a Flavonol from a Flavanone by Establishing a One-pot Bienzymatic Cascade
Published on: August 14, 2019
Antioxidant and structure-activity relationships of five tetraoxygenated xanthones from Swertia minor (Griscb.) Knobl
Chokkalingam Uvarani1, Kumarasamy Chandraprakash, Mathan Sankaran
1Department of Chemistry, School of Chemical Sciences, Bharathiar University, Coimbatore, Tamil Nadu, India.
Abstract:
Antioxidant activity-guided fractionations of chloroform extract of Swertia minor yielded five known tetraoxygenated xanthones (1-5), of which compound 3 was isolated for the first time from plant sources. Compounds 1-5 were identified with the aid of extensive NMR spectroscopic studies. A relationship between the structural features of 1-5 and their antioxidant activity was also determined. Among these bioactive isolates (1-5), compound 4 exhibited strong scavenging effect in DPPH (IC(50) = 10.31 µg mL(-1)), FRAP (8536.32 ± 34.1 Mmol Fe (II) g(-1)) and metal chelating (17.2 ± 0.88 mg EDTA g(-1)) assays. Compound 5 was potently active in secondary antioxidant assay (i.e. binding to metal ions strongly); however, its primary antioxidant capacity was found to be feeble.
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