Evaluation of Cymbopogon citratus (lemongrass) leaf extract: phytochemical screening, antimicrobial activities, cytotoxicity, antioxidant properties, and toxicological assessment.

Abstract

This study evaluates the phytochemical composition, antimicrobial activity, cytotoxicity, antioxidant potential, and toxicity profile of Cymbopogon citratus (lemongrass) leaf extract. The extract demonstrated antimicrobial activity with inhibition zones ranging from 14.33 ± 0.67 mm to 30.67 ± 0.88 mm for concentrations of 25-200 mg/mL against Escherichia coli, Staphylococcus aureus, and Aspergillus niger, while Salmonella Typhi and Pseudomonas aeruginosa were resistant. Minimum inhibitory concentration (MIC) values were 50 mg/mL for E. coli and S. aureus, and 25 mg/mL for A. niger. Cytotoxicity testing in Drosophila melanogaster showed low toxicity, with an LC₅₀ of 1050 mg/10 g diet. Antioxidant assays revealed significant reductions in malondialdehyde (MDA) levels and increased glutathione-S-transferase (GST), catalase (CAT), superoxide dismutase (SOD), and thiol levels (p < 0.05). Acute toxicity testing in Swiss albino rats at 5000 mg/kg showed no mortality. Sub-chronic toxicity testing (28 days, 250-1000 mg/kg) revealed no significant changes in body or organ weights; however, elevated alanine transaminase (ALT) and aspartate transaminase (AST) levels at 250 mg/kg indicated mild hepatotoxicity. Kidney function parameters remained stable, and hematological analysis showed enhanced erythropoiesis and immune function. These results confirm the therapeutic potential of C. citratus but underscore the importance of dose control to prevent hepatotoxic effects, as indicated by elevated ALT and AST levels. Limitations in advanced phytochemical profiling and histopathological validation highlight the need for future studies to refine clinical applications.