Flavanones from Vernonia diffusa

Abstract

From the methanolic extract of the wood of Vernonia diffusa two flavanones were isolated and identified: hesperidin and a new flavanone, 3'-methylhesperetin (homoesperetin) and sucrose, which was identified as its acetyl derivative. The homoesperetin was identified as the aglicone obtained in the hydrolysis of the new natural flavanone glycoside, homoesperetin-7-O-rutinoside. From the dichloromethane extract, a mixture of sitosterol and stigmasterol was isolated together with a mixture of aliphatic acids. The new octaacetylhesperidin derivative was also prepared. Structural determination was made by ¹H and 13C-NMR spectrometric data including DEPT, ¹Hx¹H-COSY, and ¹Hx13C-COSY and NOEDIFF techniques.

Keywords

• Vernonia diffusa
• compositae
• homoesperetin
• flavanones