Bioactivity of 'Flemingin A' and other Natural Products from the leaves of Flemingia grahamiana

Abstract

Flemingia graharriiana (Wight & Arn.) is an erect herb or sub-shrub up to 1.8 m tall with deep (sometimes tuberous) roots and 3-foliate alternate leaves. It is distributed in Tropical Africa and occurs in open and wooded savanna, sometimes near water in riverine vegetation, on hillside, termite mounds and along roadsides (Gillett, et 01., 1971; Jansen, 2005). The powder from the fruits and inflorescence of the plant is one of the principal sources of a dye and cosmetic called 'Waras (or Wurrus, or black kamala), sold in India and Arabia (Cardillo, et 01., 1968; Jansen, 2005). The root decoction of the plant is used against diarrhoea and dysentery in Zimbabwe and Malawi. The plant is also used externally against skin diseases and internally as a purgative and against colds in India (Jansen, 2005). In our search for cancer chemopreventive agents from plants, we wish to report the antioxidant properties of a known chalcone, Flemingin A (1) and the cR-afa~cterization of a new chalcone with a 3,4-disubstituted-l-methylcyclohexene moiety (2) from the leaves of F. grahamiana. Also reported, for the first time from the genus Flemingia, is the known ~lnthra"quinone, emodin (3).