Validation of ethnopharmacological findings of Aegle marmelos (L.) Correa through phytochemical screening and bioactivity assay

For centuries, medicinal plants have been integral to human health and well-being across the world. Aegle marmelos (Rutaceae), a medicinal plant indigenous to Nepal, holds substantial ethnomedicinal use among indigenous communities in South Asian countries. Present study aimed to explore the integration of contemporary scientific analysis of the phytochemical composition and bioactivity of A. marmelos leaf extracts harvested from Nepal with traditional ethnopharmacological knowledge. Leaf extracts of A. marmelos were subjected to phytochemical analysis utilizing mass spectrometry. The extracts underwent in vitro evaluation for antimicrobial, antidiabetic, antioxidant, and toxicity activities. Hexane fraction was found to possess volatile oils, polyphenols, and tannins, while other fractions were found to have alkaloids, terpenoids, coumarins, flavonoids, glycosides, saponins, and reducing sugars. Further analysis of the hexane fraction identified 21 compounds with over 90 % accuracy. The main phytoconstituents were 9,12,15-octadecatrienoic acid methyl ester (24.25 %), hexadecanoic acid (10.89 %), methylcyclohexane (8.39 %), methyl ester (4.26 %), and caryophyllene (4.10 %). The methanol extract exhibited significant antibacterial activity against Staphylococcus aureus and Escherichia coli. Additionally, the methanol extract demonstrated pronounced cytotoxic effects against brine shrimp, with an LC₅₀ value of 50.11 µg/mL. The 1,1-diphenyl-2-picryl hydrazyl assay revealed both methanol and acetone extract to have notable antioxidant activity, with IC₅₀ values of 90.63 ± 1.47 µg/mL and 89.93 ± 2.52 µg/mL, respectively. Remarkably, the acetone extract displayed superior antidiabetic activity compared to acarbose, with an IC₅₀ value of 13.50 ± 0.79 µg/mL. Our findings proves A. marmelos leaf extracts to harbor significant bioactive constituents, suggesting their potential as sources of natural compounds for applications in medicine and healthcare.