Antimicrobial Potential of Leaf, Seed Coat, and Bark Extracts of Sri Lankan Syzygium cumini (L.) Skeels: A Comparative Study

Abstract

Background and Objectives: Emergence of antimicrobial resistance emphasizes the requirement for new plant-derived bioactive compounds. Syzygium cumini (L.) Skeels (S. cumini) has been reported to possess various pharmacological properties; however, systematic comparison of different parts of the plant and extraction solvents under similar conditions is lacking. This study aimed to evaluate and compare the antifungal and antibacterial activities of extracts obtained from leaves, seed coats, and bark of the plant using ethanol, methanol, and water. Methods: The extracts were evaluated for antibacterial activity against Staphylococcus aureus, Escherichia coli, and Pseudomonas sp. Antifungal activity was evaluated using the agar well diffusion method against Mucor sp., Aspergillus niger, and Fusarium sp. through an in vitro bioassay. Zones of inhibition were measured and statistically analyzed. Results: Antimicrobial activities varied with plant parts and solvent. The ethanolic seed coat extract showed the maximum antibacterial activity against Staphylococcus aureus (27.56 ± 0.46 mm), while the aqueous bark extract showed the minimum antibacterial activity against Pseudomonas sp. (11.50 ± 0.66 mm). The leaf methanolic extract exhibited the highest antifungal activity against Fusarium sp. (15.87 ± 0.73 mm), whereas the bark aqueous extract exhibited the lowest antifungal activity against Aspergillus sp. (37.93 ± 0.80 mm). Seed coat extracts were more efficacious against bacteria, and leaf extracts were relatively more potent against fungi. Conclusion: This comparative study identified the most effective plant part–solvent combinations of S. cumini, supporting its potential as a naturally occurring source of antimicrobial agents for pharmaceutical and nutraceutical applications.