In vitro Anti-Bacterial Effect of Piper betle Leaf Extracts on Aeromonas spp. and Streptococcus agalactiae which Cause Hemorrhagic Disease in Tilapia

Abstract

    The use of antibiotics for treating fish diseases has several advantages but raises the concerns about antibiotic residues in fishery products and increases antibiotic resistance of pathogenic bacteria as well. Herbs have been increasingly demonstrated their important role in the pharmaceutical industry as a biosafety solution, an alternative to synthetic chemical drugs. The present study aimed to examine the efficiency of leaf extraction from Piper betle by five different solvents (distilled water,methanol 80%, ethanol 96%, n-hexan andaceton 100%), and evaluate the anti-bacterial effects of the extract on Aeromonas spp. and Streptococcus agalactiae which cause hemorrhagic disease in tilapia. The results showed that the extraction efficiency varied from 4,00% (n-hexan solvent) to 19,67% (ethanol 96% solvent). At the concentration of 100 mg/ml, all these extracts showed good antibacterial activity against Aeromonas spp. and Streptococcus agalactiae. For Aeromonas spp., the inhibition zone varied from 15,00 mm (distilled water solvent - DW) to 28,00 mm (ethanol 96% solvent). The inhibition zones of Streptococcus agalactiaewere varied from 17,67 mm (DW solvent) to 31,67 mm (ethanol 96% solvent). The ethanol-extract solution showed highest anti-Tác dụng ức chế vi khuẩn in vitro của cao khô dịch chiết lá trầu không (Piper betle) đối với vi khuẩn Aeromonas spp. và Streptococcus agalactiae gây bệnh xuất huyết trên cá rô phi 870 bacterial effect. This extract remained the anti-bacterial activity to Aeromonas spp.and Streptococcus agalactiae at concentration 0,39mg/ml and 0,78 mg/ml, respectively.