Antibacterial Activities of Spice Extracts Against Vibrio parahaemolyticus and Aeromonas sp.

This study evaluated the antibacterial activity of extracts from 12 spices; ginger (Zingiber officinale), fenugreek (Trigonella foenum-graecum), mustard (Brassica juncea), cumin (Cuminum cyminum), nutmeg (Myristica fragrans), black caraway (Nigella sativa), piper chilli (Piper chaba), cashew nut (Anacardium occidentale), cloves (Syzygium aromaticum), almond (Prunus dulcis), cinnamon (Cinnamomum verum), and ajwain (Trachyspermum ammi) against aquaculture pathogens Vibrio parahaemolyticus and Aeromonas sp., using hexane, ethyl acetate, ethanol, methanol, and water as solvents. Extracts were prepared by drying, grinding, solvent extraction with sonication and centrifugation, and tested via broth microdilution for inhibition percentages and minimum inhibitory concentrations (MICs). Water and ethanol extracts proved most effective, with 75-83% of spices inhibiting V. parahaemolyticus and Aeromonas sp. at tested concentrations; standout performers included nutmeg, cloves, cinnamon, and cashew nut, achieving 84-100% inhibition and MICs of 200-500 µg/mL, while mustard and fenugreek showed minimal activity.​ These results highlight polar solvents' superiority in extracting bioactive phenolics and terpenoids that disrupt Gram-negative bacterial membranes, offering eco-friendly alternatives to antibiotics amid rising resistance in Bangladesh aquaculture sector. The study successfully assessed spice extract efficacy against key pathogens and identified optimal spice-solvent combinations like water-extracted cloves and ethanol-extracted cinnamon for potent antibacterial action. Findings support sustainable disease management, reducing economic losses from vibriosis and ulcerative syndromes in fish and shrimp farming.

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