Abstract:
The activities of leaf extracts of two Nigerian edible vegetables (Gongronema latifolium and Vernonia amygdalina) used in traditional medicine for the treatment of various infectious diseases, were evaluated in vitro for potential antibacterial activity and in vivo for efficacy of diabetic wound healing activity, the former was screened by agar well diffusion method while the later was carried out using the excision wound model in alloxan induced diabetic rats. The pattern of inhibition and the rate of wound area relative varied with the plant extract, the combination ratio and the organisms tested. Both aqueous and ethanolic extracts of these plants leaves were tested against Escherichia coli, Staphylococcus aureus, Pseudomonas aeroginosa and Streptococus pyogenes, with the ethanolic extracts had significant antibacterial activity on the test isolates. The minimum inhibitory concentration (MIC) of both extracts ranged between 50mg/ml to 100mg/ml for aqueous extract and 6.25mg/ml to 12.5mg/ml for ethanolic extract. The combinations of the leaf extracts exhibited a higher zone of inhibition on the test bacterial species (16mm to 24mm) than any of the individual plant extracts (12mm to 16mm). For in vivo activity, wound surface area (WSA) and bacterial colony count (BCC) were used to measure the outcomes at different day interval. Results showed a significant reduction in wound contraction and bacterial colony count in extracts treated groups compared to control group. The wound size in animals of the treated group were significantly reduced (P<0.05) when compared with the control groups. Extract treated animals exhibited 90% reduction in the wound area when compared to controls which was 20%. Our present study revealed that the potency of the ethanol extract based on the zones of inhibition, MIC values, significant wound healing and accelerated wound closure promotes the great therapeutic potentials of these plants which might be used as adjunct in the treatment of diabetic wounds and associated infections. Topical application of G. latifolium and V. amygdalina singly and combined could be helpful in diabetics, in order to improve the wound healing process avoiding possible adverse effects from systemic medication. Further identification of the active constituents is suggested to exploit them in evaluating efficacy and safety in vivo against organisms implicated in diabetic wounds in humans.
