Antioxidant, xanthine oxidase and lipoxygenase inhibitory activities and phenolics of Bauhinia rufescens Lam. (Caesalpiniaceae)

Abstract

An aqueous acetone extract of the stem with the leaves of Bauhinia rufescens and its fractions were analysed for their antioxidant and enzyme-inhibitory activities, as well as their phytochemical composition. For measurement of the antioxidant activities, the 2,2-diphenyl-1-picrylhydrazyl, 2,2′-azinobis(3-ethylbenzoline-6-sulphonate) and the ferric-reducing methods were used. The results indicated that the aqueous acetone, its ethyl acetate and n-butanol fractions possessed considerable antioxidant activity. Further, the xanthine oxidase and lipoxygenase inhibitory assays showed that the n-butanol fraction possessed compounds that can inhibit both these enzymes. In the phytochemical analysis, the ethyl acetate and the n-butanol fractions of the aqueous acetone extract were screened by HPLC–MS for their phenolic content. The results indicated the presence of hyperoside, isoquercitrin, rutin quercetin, quercitrin, p-coumaric and ferulic acids in the non-hydrolysed fractions. In the hydrolysed fractions, kaempferol, p-coumaric and ferulic acids were identified.

Keywords:

• antioxidant activities
• flavonoids
• phenolics
• HPLC
• Bauhinia rufescens

Acknowledgements

This study was supported by the Agence Universitaire de la Francophonie (AUF), through the Doctoral Fellowship ‘EUGEN IONESCU’. The authors are also grateful to the International Atomic Energy Agency for its assistance through the technical cooperation project BKF 5002.