Asian Basic and Applied Research Journal

The raise of diabetes incidence in Nigeria prompts the search for therapeutic approaches. The aqueous extracts of 27 popular medicinal plants widely used in this country were tested for their in vitro ability to scavenge DPPH and nitric oxide (NO) radicals. Only seven extracts (A. senegalensis, B. ferruginea, D. ogea, K. ivorensis, K. senegalensis, T. bangwensis, and S. guineense) scavenged both. All these extracts produced greater antioxidant effect in the DPPH assay with lower EC50 values < 20 μg/ml. The presence of compounds with free labile hydrogen atoms is sufficient to produce good antioxidant effects in the DPPH assay, whereas NO scavenging requires the presence of compounds that can out-compete its reaction with oxygen to form nitrite ions. The most promising activities in terms of selectivity towards NO (SI_DPPH/NO > 0.4) were shown by the extracts of A. senegalensis, K. senegalensis and S. guineense. The extracts were dereplicated by HPLC-UV for known antioxidants. Caffeic acid, epicatechin, epigallocatechin, gallic acid, ellagic acid, quercitrin, rutin, vitexin, and vitexin rhamnoside were detected. It could therefore be proposed that extracts with specific NO such as A. senegalensis, K. senegalensis and S. guineense could be beneficial antioxidants in hyperglycaemic conditions.