In vitro and In silico Approaches to Study the Bioactivity of Citrus limon Leaf Extracts

Aim: To study the bioactivity of Citrus limon leaf extracts through in vitro and in silico approaches. Methodology: In this study, the leaves of Citrus limon were subjected to solvent extraction using ethyl acetate and ethanol, and also the essential oil by hydro distillation method. Preliminary phytochemical screening of solvent extracts revealed the presence of alkaloids, flavanoids, anthocyanins, carbohydrates, triterpenoids, tannins and coumarins. The extracts and essential oil were then tested for the antibacterial, antioxidant and anticancer activity. Molecular docking studies were studied for the proteins namely tyrosine phosphatase, alkaline protease, and elastase of Pseudomonas aeruginosa whose protein structure retrieved from the PDB using discovery studio 2.0 version and inhibition was checked against all the three proteins. Results: The plant extract was found to inhibit the growth of Microvirga aerilata and Pseudomonas aeruginosa at 100 μg and 50 μg of essential oil and ethanol extract respectively. Cytotoxicity against HeLa cell lines by the crude extracts and essential oil appeared to be active at the concentration of 50 μg/mL and 100μg/mL respectively. GCMS studies on the essential oil revealed the presence of α-pinene, β-pinene, decanal, citral and α-terpineol. Molecular docking studies revealed that tyrosine phosphatase to interact better than the other two proteins.