Free radicals scavenging and antioxidant activities of ethanol leaf extract of six nigerian ethnomedicinal plants: an in-vitro study

Many degenerative diseases are caused by oxidative stress, which is linked to excessive generation of pro-oxidants (free radicals) over antioxidants. Plants have been reported as cheap and rich source of natural compounds with notable bioactivities. This study was therefore designed to assess the free radicals scavenging and antioxidant activities of ethanol leaf extracts of six ethnomedicinal plants from Nigeria using in-vitro methods. This was done by conducting preliminary phytochemical screening, estimating total phenols and flavonoids contents, and determining free radical scavenging/antioxidant activities of the six plants extracts in different models, viz: DPPH radical scavenging, Nitric Oxide (NO) scavenging and Ferric reducing-antioxidant power assays. The results show that PGE and PMEhave highest (51.36±7.44mgGAE/g Extract) and lowest (35.42±5.91mgGAE/g Extract) phenols content respectively, while OGE and SAE have highest (49.71±4.50mg QE/g Extract) and lowest (27.16±5.34mg QE/g Extract) flavonoids contents respectively. All the six plants exhibited significant (p<0.05) antioxidant activity, but interestingly, PGE, GLE and OGE respectively produced highest DPPH scavenging (62.68%), NO scavenging (67.95%) and Ferric reducing (69.33%) activities, and thereforecan be exploited as important sources of antioxidant compounds. We therefore recommend for further isolation, characterization of active principles and testing in animal models, with a view to develop natural antioxidants that can used in management of oxidative stress-related disorders.