Fibroblast Growth Stimulation, DPPH Antioxidant Assay and Antimicrobial Activities of Funtumia elastica (Preuss) Stapf (Apocynaceae) Leaf Extracts

Abstract

Aims: To investigate the scientific basis for the wound-healing properties of Funtumia elastica (Apocynaceae) leaf extracts using relevant in vitro fibroblast growth stimulation, antimicrobial and DPPH-antioxidant assays. Place and Duration of Study: School of Health, Sports and Bioscience (Bioscience Laboratories), University of East London in the United Kingdom, between July 2007 and May 2010. Methodology: Methanolic extract of the leaves, and petroleum ether, ethyl acetate, n- butanol and aqueous fractions partitioned thereof were tested for antimicrobial activities against common wound pathogens (such as Staphylococcus spp, Pseudomonas aeroginosa and Escherichia coli). The Broth dilution method was used to determine the minimum inhibitory concentrations (MIC) of the extracts and fractions. The antioxidant activities were also determined using a 2, 2-diphenyl-1-picrylhydrazyl (DPPH) free radical assay; whilst the ability to stimulate fibroblast growth was investigated using the MTT (3- [4, 5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide) assay. Results: The n-butanol fraction exhibited the greatest overall activities. It stimulated the growth of fibroblast cells by 28%, and showed MIC range of 0.13 - 1.0 mg/mL against the Staphylococci species, P. aeruginosa, Bacillus subtilis and E. coli. The non-polar petroleum ether fraction exhibited MICs greater than 2.0 mg/mL against all the organisms. All the fractions exhibited antioxidant activities greater than or comparable to that of ascorbic acid. Conclusion: Collectively, the antioxidant activity, fibroblast growth stimulation and the antimicrobial activities demonstrated by F. elastica leaf extracts provide some evidence to support the use of the plant to manage wounds in African folklore medicine.