Exploring Phytoconstituents of Neem Leaf Extract and its Potential Antimicrobial and in Vitro Anticancer Activities

Considering the growing interest in exploring the biologically active chemicals of the neem (Azadirachta indica A. Juss) plant, this current study was designed to explore and characterize the probable phytoconstituents of the methanolic extract of neem leaves using GC-MS analysis. The antibacterial activity of the extract was studied against Agrobacterium tumefaciens, Serratia marcescens, and Acinetobacter johnsonii and its antifungal activity against Rhizoctonia solani, Penicillium italicum, and Fusarium oxysporium. Further, the cytotoxicity was assessed against PC-3, MCF-7, and Caco-2 cancer cell lines, compared with the normal Vero cells, where IC50 and selectivity index for each cell line were calculated. The GC-MS analysis of the methanolic neem leaf extract revealed the presence of diverse components, more than 50% of which belong to steroids, phytosterols, and fatty acids, with γ-sitosterol being the predominant component. When tested against several bacterial and fungal strains, neem extract showed high antibacterial potential against A. johnsonii and S. marcescens and high antifungal activity against F. oxysporium. The extract also exposed a considerable antiproliferative activity against the PC-3 cancer cell line with good IC50 and selectivity index (IC50 = 98.2 μg/ml, SI = 5.88). These findings suggest that the neem leaf extract is rich in biologically active phytochemicals and possesses significant antimicrobial and in vitro anticancer properties.