Bioactive potential of secondary metabolites of rhizospheric fungus Penicillium citrinum isolate-ABRF3

A strain of Penicillium citrinum isolate-ABRF3 collected from the Achanakmar Biosphere, India, was examined for its bioactive potential. Under optimized conditions, secondary metabolites were extracted from the fungus using the solvent extraction method, and all fractions were assessed for antioxidant, antimicrobial, anti-aging, and antiproliferative activity. The highest antioxidant activity was shown by Penicillium citrinum ethanolic extract, i.e., 80%, 79%, 77%, and 75% when assessed by 2,2-diphenyl 1-picrylhydrazyl, Ferric reducing power, Phosphomolybdenum, and 2, 2’-azino-bis3-ethylbenzthiazoline-6-sulfonic assays, respectively. A maximum inhibition zone of 17.18 ± 1.3 mm was observed against pathogenic bacteria Staphylococcus aureus in the ethyl acetate column fraction compared with standard antibiotics. Ethyl acetate column fraction demonstrated meaningful anti-aging activity against Yeast mutant strain, BY4742, along with methanol and chloroform column fraction depicted a substantial DNA fragmentation and antiproliferative action against a set of mammalian cancer cell lines. The Gas Chromatography with Mass Spectroscopy and Nuclear Magnetic Resonance analysis identified (E)-9-Octadecenoic acid ethyl ester as a significant secondary metabolite in the extract. In silico molecular docking was performed for identified metabolite (E)-9-Octadecenoic acid ethyl ester to ascertain its putative role in extract bioactivity, with various anti-aging and anticancer targets.