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Endophytic fungi associated with medicinal plants are a rich source of bioactive compounds exhibiting diverse biological activities. This study investigated the antimicrobial, antibiofilm, antioxidant, and cytotoxic properties of ethyl acetate crude extracts (ECEs) from two endophytic fungi—Plectosphaerella sp. (ACR-12) and Stilbella aciculosa (ACR-15)—isolated from the rhizomes of Acorus calamus. The identity of these fungi was confirmed through morphological, microscopic, and molecular analyses (including ITS sequencing), and their sequences have been deposited in GenBank (PV082262 for S. aciculosa; PV082167 for Plectosphaerella sp.). GC-MS analysis revealed a range of bioactive metabolites, including erythro-9,10-dibromopentacosane from Plectosphaerella sp. and 1-nonadecene from S. aciculosa. Antimicrobial activity assessed via disc diffusion and microdilution assays showed significant inhibition against Escherichia coli (ATCC 25922), Staphylococcus aureus (ATCC 25923), Pseudomonas aeruginosa (ATCC 27853), Bacillus subtilis (ATCC 6633), Aspergillus niger (ATCC 16404), Fusarium oxysporum (ATCC 48112), and Candida albicans (ATCC 10231) with MIC values ranging from 3.125 to 50 μg/mL. Both ECEs exhibited antibiofilm activity against S. aureus (ATCC 25923) and P. aeruginosa (ATCC 27853), with S. aciculosa showing the highest inhibition (up to 67% at half the MIC). The DPPH assay indicated notable antioxidant activity for Plectosphaerella sp. (IC₅₀ = 59.37 μg/mL). Cytotoxicity testing against MCF-7 breast cancer cell lines (24-hour exposure) revealed IC₅₀ values of 95.39 μg/mL for ACR-12 and 32.58 μg/mL for ACR-15. These findings highlight the potential of A. calamus endophytes, particularly Plectosphaerella sp. and S. aciculosa, as promising sources of novel antimicrobial, antibiofilm, antioxidant, and cytotoxic agents, warranting further pharmaceutical exploration.
Keywords : Endophytes, Acorus calamus, Plectospharella, Stilbela aciculosa, antimicrobial, antibiofilm.
