Effect of phytochemical extract from Azadirachta indica leaves (neem) and its antifungal activities against Phytophtora and Alternaria

Abstract

The study evaluates the effects of phytochemical extracts of A. indica and their antifungal potential against Phytophthora spp. and Alternaria alternata. Phytochemical screening confirmed the presence of bioactive compounds such as flavonoids, tannins, alkaloids, saponins, and steroids. The antifungal activity was assessed using the agar well diffusion method. Ethanolic extracts of A. indica leaves exhibited the highest inhibition zones against both fungal pathogens, with a maximum of 16mm for Phytophthora spp. and 13mm for Alternaria alternata at 100 mg/ml. Comparatively, fluconazole showed similar inhibition zones, suggesting A. indica comparable efficacy. The MIC results indicated that ethanolic extracts, particularly from dried leaves, had the lowest MIC values of 3.96mg/ml for Phytophthora and 15.63mg/ml for Alternaria, highlighting their stronger antifungal potential compared to aqueous extracts. The findings from this study suggest that ethanol is a more effective solvent for extracting antifungal compounds and that shade drying A. indica leaves enhances their activity. These results support the potential of A. indica as a botanical fungicide, offering a natural alternative to synthetic fungicides for managing fungal plant diseases. Further studies are recommended to isolate the active compounds responsible for the antifungal effects and assess their field applicability.