Bactericidal, Bacteriostatic, and Fungicidal Activities of Clausena anisata Fruit and Its Compounds, Stigmasteryl 3-Palmitate (a Phytosterol Ester) and Phellopterin (a Furanocoumarin), Against Some Clinical Pathogens

The emergence of antimicrobial resistance necessitates the exploration of novel therapeutic agents from natural sources. This study investigated the antimicrobial properties of Clausena anisata fruit ethanol extract (CAFE) and its isolated compounds against 11 bacterial and three fungal strains. The dried fruits were extracted with ethanol using a Soxhlet apparatus. The extract was partitioned and subjected to chromatography to isolate two compounds, which were characterized as stigmasteryl 3-palmitate (C-01) and phellopterin (C-02) using NMR spectroscopy and LC-MS analysis. CAFÉ demonstrated notable inhibition zones in agar well diffusion assays, with the strongest activity against Klebsiella pneumoniae (14.67 ± 2.08 mm) and Staphylococcus saprophyticus (13.67 ± 0.58 mm). Microbroth dilution assays revealed MIC values ranging from 0.0781 to 1.2500 mg/mL for CAFÉ and 0.0781 to 1.2500 mg/mL for stigmasteryl 3-palmitate and phellopterin, respectively. CAFE demonstrated bactericidal activity (MLC/MIC ≤ 4) against Pseudomonas aeruginosa, Proteus mirabilis, Salmonella typhimurium, K. pneumoniae, Streptococcus sanguis, S. saprophyticus, and Candida glabrata, while showing bacteriostatic activity (MLC/MIC > 4) against Candida albicans. Stigmasteryl 3-palmitate exhibited bactericidal activity against P. mirabilis, S. typhimurium, K. pneumoniae, and S. sanguis, with bacteriostatic effects against the other organisms. Phellopterin demonstrated primarily bacteriostatic activity except against S. saprophyticus. Both compounds showed potent fungicidal activity against Candida species. These findings highlight the therapeutic potential of C. anisata fruit and its constituents against typhoid fever, hospital-acquired pneumonia, and invasive candidiasis. This is the first report on the antibacterial and antifungal activities of C. anisata fruit, stigmasteryl 3-palmitate, and phellopterin.