Phytochemical Profiling, Quantitative Assessment, and Antimicrobial Potential of Premna tomentosa Leaf Extract

The present study explores the phytochemical composition and antimicrobial properties of Premna tomentosa leaf extracts using different solvents: methanol, chloroform, ethyl acetate, and petroleum ether. The phytochemical analysis revealed that methanol was the most effective solvent, extracting the highest concentrations of alkaloids (450 mg/g equivalent), flavonoids (650 mg/g equivalent), phenols (550 mg/g equivalent), and tannins (500 mg/g equivalent). Chloroform also showed considerable efficacy, particularly in extracting flavonoids (650 mg/g equivalent) and alkaloids (400 mg/g equivalent). The antimicrobial activity of the extracts was tested against four bacterial strains (Pseudomonas fluorescens, Escherichia coli, Staphylococcus aureus, and Bacillus subtilis) and three fungal strains (Fusarium oxysporum, Sclerotium rolfsii, and Phytophthora infestans). The methanol extract exhibited the highest antibacterial activity, with zones of inhibition measuring 12 mm against Pseudomonas fluorescens, 9 mm against E. coli, 6 mm against Staphylococcus aureus, and 5 mm against Bacillus subtilis. The chloroform extract also showed significant antibacterial effects, with inhibition zones ranging from 5 mm to 7 mm across different bacterial strains. For antifungal activity, the methanol extract again demonstrated the highest efficacy, with 60% inhibition against both Fusarium oxysporum and Phytophthora infestans, and 50% inhibition against Sclerotium rolfsii. Chloroform and ethyl acetate extracts showed moderate antifungal activity, while petroleum ether extract was the least effective. The study underscores the potential of Premna tomentosa for developing natural antimicrobial agents and highlights the importance of solvent selection in maximizing the extraction of these compounds.