Evaluation of antioxidant activities of methanol extracts and cassane diterpenoids from Erythrophleum suaveolens [(Guill. et Perr.) Brenan] (Fabaceae)

Abstract

Erythrophleum suaveolens (Fabaceae), a medicinal plant from Cote d’Ivoire, was investigated for its antioxidant constituents. This led to the isolation of two cassane diterpenoid amides, 6a-hydroxy-nor-cassamide (1) and nor-cassamide (2), from the root barks. Their structures were established according to their spectroscopic analyzes (1D and 2D NMR, HR-ESIMS, IR). The antioxidant capacity of methanol extracts and isolated compounds were measured using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay and the Ferric Reducing Antioxidant Potential (FRAP). A significantly increased DPPH and FRAP activities were observed for all samples. But, the best activity was obtained with methanol crud extract of the root barks from E. suaveolens (ESER).