Flavonoid glycoside constituents of the leaves of Solanum melongena collected in Thua Thien Hue and their anti-inflammatory activity

Abstract

Solanum melongena is a member of Solanum genus that widely cultivated as fruit vegetable in Vietnam. According to Vietnamese traditional medicine, the fruits and whole plants are used to treat toothache, turgescence, pruritus, and haemorrhoids. As part of our project to study the chemical composition and bioactivity of Solanum genus in Vietnam, five flavonoid glycosides including kaempferol-3-O-β-D-glucopyranoside (1), isovitexin (2), kaempferol 3-O-β-D-glucoside-7-O-α-L-rhamnoside (3), kaempferol 3-O-β-D-sophoroside-7-O-α-L-rhamnoside (4), and kaempferol 3-O-β-D-sophoroside (5) were isolated from the methanol extract of the leaves of Solanum melongena growing in Thua Thien Hue province, by using various chromatography methods. Their chemical structures were determined by detailed analysis of 1D- and 2D-NMR and HR-ESI-MS data as well as comparison with the literature. Compounds (2) and (5) were isolated from Solanum melongena for the first time while compounds (3) and (4) were the first isolated from the Solanum genus. Besides, compounds 2-4 showed weak anti-inflammatory activities against NO production in RAW 264.7 macrophage line with IC₅₀ values ranging from 54.28 to 91.37 µg/ml.