Investigation on extraction methods of garlic (Allium sativum L.) with activity against three strains of Vibrio causing disease in shrimp

Abstract

Garlic (Allium sativum L.) is a plant with potent antibacterial activity that has been known for a long time. In this study, we extracted different extracts from garlic such as essential oil, polysaccharide, 5% acetic acid extract, ethanol extract, fractional ethyl acetate extract, fractional ethanol extract and fractional water extract to find the garlic extract with the best antibacterial activity against Vibrio parahaemolyticus, Vibrio vulnificus and Vibrio cholera, all species causing white feces disease and acute hepatopancreatic necrosis disease in shrimp. The results showed that ethanol extract and essential oil had antibacterial activity in all three strains and garlic essential oil inhibited all 3 strains of Vibrio with the highest sterile ring diameter of 80 ± 0 mm by fumigation method. The MIC and MBC values of both ethanol extract and essential oil showed better resistance to V. vulnificus than to V. parahaemolyticus and V. cholera. The ethanol extract had MIC = 8.33 mg/ml and MBC = 12.50 mg/ml and the essential oil had MIC = 0.03 μl/100 μl and MBC = 0.05 μl/100 μl. The results of the time-kill curve showed that both the ethanol extract and the essential oil were able to kill all three strains of Vibrio only after 24 hours when added to the bacterial medium, while tetracycline only inhibited V. cholera, V. parahaemolyticus during the first 8 hours and 24 hours for V. vulnificus.