PHYTOCHEMICAL AND ANTIFUNGAL ANALYSIS OF MAHOGANY LEAF EXTRACT AGAINST FUNGI IN SPOILT WATERMELON FRUITS

Watermelon is an important fruit vegetable cultivated globally for its diverse health and
nutritional benefits. However, its production is constrained by fungal pathogens causing
significant damages and crop yield losses. This study identified the fungi species in the spoilt
watermelon fruits and examined the efficacy of Mahogany leaf extracts (5, 10 and 15%
concentrations) against the fungi isolates. The fungi were isolated using ager plate method and
pure isolates were identified in accordance with a mycological atlas. Cold maceration technique
was used for the extraction of plant material while qualitative method was adopted to determine
the phytochemical constituents of the leaf extracts. In-vitro antifungal assay using food poisoned
technique was used to evaluate the effectiveness of the leaf extracts against the fungi isolates.
The results revealed the presence of three fungi species viz; Aspergillusniger,
Fusariumoxynoporum, and Penicilliumcitrinum. Among the pathogens, Aspergillusniger had
the highest percentage of occurrence (51.51%), followed by Fusarium oxynoporum (33.33%)
while Penicilliumcitrinum had the lowest (15.15%). The phytochemical screening showed the
presence of tannins, alkaloids, glycosides, flavonoids, balsams, steroids, and terpenoids in
Mahogany leaf extracts. The extracts significantly (p<0. 05) affected the mycelial growth of the
pathogens with 15% leading to the least mycelial growth, recording 24.3+0.7, 20.7+0.9 and
15.4+0.8 mm for Aspergillus niger,Penicillium citrinum and Fusarium oxynoporumcompared
to the control with 93.7+2.4, 91.3+1.6 and 95.3+1.2 mm respectively. The highest effect on
growth inhibition (%) was observed with 15% concentration on Fusarium oxynoporum (83.8%)
followed by Penicilliumcitrinum (77.2%) while the least was recorded with 5% concentration
on Aspergillusniger (40.9%). The results demonstrated the great potential of Mahogany (Khaya
senegalensis (Desr.)A. Juss.) leaf extracts as a natural and eco-friendly antifungal agent against
post-harvest fungal infestationin watermelon (Citrullus lanatus Thunb) fruits. They are thus
recommended to be incorporated in the control regime of these pathogens to prevent
contamination and to improve the quality of the fruits.