Shorea macrophylla (Engkabang) phytochemical fruit extract exhibits antimicrobial susceptibility against Salmonella enterica and Citrobacter freundii

Abstract

Bacterial infections are a major concern in aquaculture, and although antibiotics are commonly used for treatment, they may lead to toxicity and environmental risks. In search of safer alternatives, this study explores the antibacterial potential of natural compounds from the fruit of Shorea macrophylla (Engkabang), a native species known for its bioactive phytochemicals. The objective was to evaluate the antibacterial activity of engkabang fruit extracts against five aquaculture-relevant bacteria: Pseudomonas koreensis, Citrobacter freundii, Enterobacter hormaechei, Salmonella enterica, and Bacillus subtilis. Using the disc diffusion method, extracts were tested at concentrations of 20 mg/disc, 10 mg/disc, and 2 mg/disc with hexane, isopropanol, and acetone as solvents. Notably, C. freundii showed inhibition zones at all concentrations with isopropanol and hexane extracts, while S. enterica exhibited inhibition zones at all concentrations with isopropanol and acetone extracts. These results indicate significant antibacterial activity, highlighting engkabang fruit extract as a promising natural alternative to antibiotics in aquaculture.