Phytochemical Characterization and Antifungal Potential of Opuntia ficus-indica Cladode Extracts Against Tomato Pathogens

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In the realm of sustainable and eco-friendly agriculture, current scientific research emphasizes the development of plant-based bioproducts to mitigate the agricultural footprint resulting from excessive fertilizer and pesticide use. This study investigates the cladodes of Opuntia ficus-indica to screen for bioactive compounds and assess their efficacy against fungal pathogens isolated from infected tomato fruits. Quantitative analysis of the methanolic extract revealed substantial concentrations of bioactive compounds: total polyphenols (86.6 mg GAEs/100 g FW), flavonoids (13.4 mg QEs/100 g FW), condensed tannins (8.9 mg TAEs/100 g FW), and carotenoids (0.9 mg β-CEs/100 g FW). Notably, the DPPH assay indicated that the cladode extract exhibited significant antioxidant potential at a concentration of 0.6 mg/mL. Seven fungal pathogens were isolated from infected tomato fruits and identified as belonging to the following genera: Rhizoctonia (EC2), Fusarium (EC1 and EC3), Alternaria (EC4), Mucor (EC5), Aspergillus (EC6), and Penicillium (EC7). At a concentration of 0.02% of the cladode hydroethanolic extract, the antifungal activity results demonstrated mycelial growth inhibition for Alternaria sp. (70.91%), Rhizoctonia solani EC2 (58.49%), Fusarium oxysporum EC3 (57.63%), and Fusarium solani EC1 (53.13%). Conversely, lower inhibitory activities were observed for Mucor sp. EC5 (31.08%), Aspergillus sp. EC6 (35.14%), and Penicillium sp. EC7 (28.38%). At a concentration of 0.04%, all cladode hydroethanolic extracts inhibited mycelial growth by more than 50%. Furthermore, the highest spore inhibition was attained with the 0.04% cladode hydroethanolic extract (exceeding 50%). Inhibition percentages of 83.02%, 85.96%, 87.76%, and 90.20% were recorded for Fusarium oxysporum EC3, Fusarium solani EC1, Rhizoctonia solani EC2, and Alternaria sp. EC4, respectively. Collectively, these findings suggest that Opuntia ficus-indica extract holds significant promise for application as a biopesticide against fungal pathogens affecting tomato fruits.