Antioxidant related investigations on bark of Harungana madagascarensis from Eastern DR Congo

Abstract

Harungana(Harungana madagascarensis) is a commonly used medicinal plant in DRCongo. The aim of the study was to investigate potentials to develop an ethnomedicinal drug by evaluating the antioxidant activities and cytotoxicity of Harungana stem bark extract. A methanol(MeOH) extract and fractions of MeOH of Harungana stem bark were studied in vitro for total antioxidant activities by DPPH and ABTs and total phenol content was assessed with Folin‐Ciocalteau reagent. MTT and Griess reaction were used to test toxicity and nitric oxide(NO) production in RAW264.7 cells. We found no toxicity of ethyl acetate and aqueous extracts on RAW264.7. The methanol extract showed significant antioxidant activities(IC(50)22.89μg/mL and 20.37μg/mL in the DPPH and ABTs, respectively). The MeOH extract(100mg) yielded 271.96mg tannic acid‐equivalent phenolic content. Ethyl acetate and butanol extracts also expressed similar antioxidant effects as MeOH extract. Hexane and butanol extracts decreased NO production by RAW264.7 (IC(50)22.2 μg/mL). The present study provides an evidence that methanol, butanol and ethyl acetate extracts of Harungana stem bark are potential sources of natural antioxidants.