Bioactive Secondary Metabolites from the Locally Isolated Terrestrial Fungus, Penicillium sp. SAM16‑EGY

Background: Penicillium is a diverse genus occurring worldwide; its species are of major importance in the natural environment as decomposer of organic materials as well as food and drug production. Objective: Chromatographic isolation and identification of its bioactive secondary metabolites and their evaluation as antimicrobial agents. Materials and Methods: Disc agar plate method has been recognized to assess the antimicrobial activities. The antioxidant activity was determined using phosphomolybdenum method. The fungus strain SAM16‑EGY was isolated from soil and was molecularly identified as Penicillium sp. SAM16‑EGY using 18S ribosomal ribonucleic acid technique (acc. no., KP125952). Results: Seven compounds namely 3‑O‑docosyl‑4‑benzoyloxy methyl‑3‑oxobicyclo (4.1.0) heptane‑1,5,6,7 tetrol (3‑O‑docosyl‑3‑debenzol rotepoxide) (1), (4bE, 6Z, 8E, 9aS, 10S)‑1,4‑dihydroxy‑9a, 10‑dihydro‑10,12‑epoxy‑5‑methylbenzo[a] azulen‑12‑one (2), 7α,9β,15β‑triacetoxy‑3‑β‑hydroxy jatropha‑5E, 11E‑diene (3), sesquiterpene I diol dihexoside malonate ester (4), piperogalone (5), (5R, 8Z, 11Z)‑5 β‑(6’‑O‑malonyl‑β‑glucopyranozyloxy‑6‑hyd roxy tetradeca‑8, 11‑dienoic acid (6), and n‑trcosanyl‑n‑octaced‑9‑enoate (7) were isolated and identified from this fungus. Their structures were determined on the basis of proton nuclear magnetic resonance and carbon‑13 nuclear magnetic resonance spectroscopy. Compounds 1, 2, 4, and 5 exhibited antimicrobial activities against Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans only, whereas compound 3 exerted higher antimicrobial activity against S. aureus (9 mm), P. aeruginosa (9 mm), C. albicans (11 mm), and Aspergillus niger (13 mm) as compared to the other compounds. In the phosphomolybdenum assay, compound 5 showed high total antioxidant capacity value of 608.59 mg ascorbic acid equivalent/g compound, followed by compound 2 (443.66 mg) and compound 1 (332.16 mg). Conclusion: The isolated compounds showed promising antimicrobial and antioxidant activities.