In Vitro Antibacterial Activity of Culinary Spices Aniseed, Star Anise and Cinnamon against Bacterial Pathogens of Fish

Antibacterial activity of crude extracts of culinary spices like Aniseed (Pimpinella anisum), Star anise (Illicum verum Hook fruit) and Cinnamon (Cinnamomum zeylanicum) against some of the common fish bacterial pathogens like Aeromonas hydrophila, Aeromonas salmonicida and Edwardsiella tarda were explored by finding minimum inhibitory concentration (MIC). A twofold serial dilution of compounds (100 μl) in sterile normal saline was prepared in 96-well microtitre plate and 50 μl overnight fresh bacterial cultures of one McFarland unit were added to each well. The plates were incubated overnight at 370C and bacterial growth was detected by adding 20 μl of p-iodonitrotetrazolium violet (INT) to each well and incubating for 30 min. The well that remained color less when there is no bacterial growth and that concentration was taken as MIC. A negative control was also maintained in which all wells with bacterial growth were found in red color. MIC values (mg/ml) for Pimpinella aisum against Aeromonas hydrophila, Aeromonas salmonicida and Edwardsiella tarda were 0.625, 0.15625 and 0.625; Illicum verum Hook fruit 0.15625, 0.078125 and 0.15625; Cinnamomum zeylanicum