Seasonal impacts on antifungal activity and chemical composition of extracts from medicinal plants Turraea holstii and Clausena anisata

Curative dependence on season of harvest for medicinal plants is an alleged claim by traditional health practitioners. This study aimed to verify these claims by investigating antifungal activity and chemical profiles of two traditionally used medicinal plant species: Turraea holstii and Clausena anisata harvested in the rainy and dry seasons, with a view of establishing appropriate the season for optimal activity. The antifungal activities were determined by Broth micro-dilution method, while chemical profiling of the extracts from the plant materials was done by gas chromatography (GC). Results indicated that extracts of plant materials harvested in dry season showed enhanced antifungal activity as compared to extracts of plant materials harvested in the rainy season, highest potency being 0.39 mg/mL, observed on dichloromethane fractions of both T. holstii and C. anisata. The GC chromatograms showed a general increase in the number and amount of chemical species for extracts of plant materials harvested in dry season as compared to extracts of plant materials harvested in the rainy season. Thus, it is concluded that because the dry season produces the best curative activity, harvesting should focus on this season. Key words: Chemical profile, antifungal activity, extracts, seasonal impacts.