Phytochemical characterization, thermal stability, antimutagenic, antifungal and antibacterial potential of O. sanctum against sewage water borne antibiotic-resistant bacteria

Abstract This study evaluated the phytochemical composition, antioxidant, antimutagenic, antifungal and antibacterial activities of O. sanctum leaf extracts, with particular focus on sewage water-borne antibiotic-resistant bacteria. Methanolic, ethyl acetate and hexane extracts were prepared and evaluated for phytochemical constituents, total phenolic and flavonoid contents and antioxidant activity. The methanolic extract (OsLME) showed the highest phenolic (43.15 ± 0.52 mg GAE g −1 ) and flavonoid (19.34 ± 0.36 mg RE g −1 ) contents and showed the highest antioxidant activity (89.12 ± 1.8 % inhibition at 4,000 μg mL −1 ). OsLME did not show mutagenic activity in the tested Salmonella typhimurium strains and showed antimutagenic activity against known mutagens. It also showed the highest antifungal activity against Candida albicans (22.11 ± 4.2 mm) and antibacterial activity against antibiotic-resistant bacteria, with the lowest MIC of 250 μg mL −1 against Pseudomonas aeruginosa . Thermal stability analysis showed a gradual reduction in bioactivity, particularly at 50 °C. The findings indicate that O. sanctum , especially its methanolic leaf extract, is a promising source of bioactive compounds with antioxidant and antimicrobial potential against antibiotic-resistant bacteria.