Ethnopharmacological survey and in vitro evaluation of wound-healing plants used in South-western Nigeria.

ETHNOPHARMACOLOGICAL RELEVANCE Traditional healers in Nigeria employ a range of plant preparations as wound healing agents. Despite the use of local plants in wound healing, there is only scant literature on the wound healing properties of these plants to support the continued therapeutic application of these herbal remedies. AIM OF THE STUDY To document plants commonly used to treat wounds in South-western Nigeria and to test the scientific basis of such claims using relevant in vitro tests. MATERIALS AND METHODS Structured questionnaires were used to determine which plant preparations are in common use, via interviews with Yoruba traditional healers. Aqueous and ethanolic extracts of the nine most common plants cited by the healers were collected, identified and tested using relevant in vitro wound healing assays. Minimum inhibitory concentrations (MIC) were determined against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Bacillus subtilis. Antioxidant activity was measured by DPPH assay and fibroblast proliferation determined by neutral red assay. RESULTS A total of 20 traditional healers from South-western Nigeria were involved in the study. Thirty-six plant species were recorded with their local names and parts used in the traditional wound healing preparations. Ethanolic extracts of nine species most frequently cited by the healers exhibited strong antioxidant activities (3.8-31.3 μg/ml) comparable to ascorbic acid (7.3 μg/ml). Crude extracts of the selected plants also inhibited the growth of bacteria with MIC values 0.3-7.6 mg/ml. Ethanol extracts of Bridelia ferruginea Benth. (1-30 μg/ml) and Parkia biglobosa Jacq. (15-30 μg/ml) influenced the proliferation of dermal fibroblasts significantly (p<0.05). Extracts from the remaining seven plants either had no effect on fibroblast proliferation or were cytotoxic. CONCLUSION Traditional use of many wound-healing plants from Nigeria can be rationalised by activity determined in relevant in vitro investigations of ethanol and aqueous extracts. These results support the traditional selection of these plants in South-western Nigeria for wound healing.