In Vitro Antifungal Activity of Okra (Abelmoschus esculentus L.) Leaf Extract against Different Plant Pathogenic Fungal Species

Abstract

The antifungal efficacy of Abelmoschus esculentus L. (Okra) leaf extracts was investigated across four distinct solvents (Ethanolic, Methanolic, Chloroform, and Water) against five significant fungal pathogens (Mucor sp., Rhizopus sp., Drechlera sp., Penicillium paxilli, and Aspergillus nigar). The Two-Way ANOVA confirmed that the choice of Extract Type was highly significant (P < 0.001), while the Pathogen Type was not statistically significant (P = 0.56137), clearly indicating that solvent polarity is the single most critical factor determining fungicidal activity. The intermediate-polarity Ethanolic and Methanolic extracts demonstrated superior, broad-spectrum potency, yielding inhibition rates between 94.54 % and 98.33 % across all fungal genera. This high efficacy is attributed to the optimal co-extraction of key semi-polar and lipophilic antifungal phytochemicals, such as phenolics and flavonoids, which exert their effect by targeting conserved fungal structures like the cell membrane and inhibiting essential metabolic processes. Conversely, the highly polar Water extract performed poorly (62.00 % to 76.00% inhibition) due to its inability to efficiently solubilize these highly active compounds, confirming that A. esculentus leaves are a source of potent, broad-spectrum natural fungicides best accessed via alcoholic solvents.