INDIAN JOURNAL OF APPLIED MICROBIOLOGY Copyright  2013 Indian Association of Applied Microbiologists, Chennai, India Volume 16 Number 1 January-June 2013, pp.21-29. Preliminary screening of Curcuma longa (Linn) extract against Penaeus monodon (Fab) Pathogenic Vibrio sp. *N. Chandrakala 1 , P. Sasikala 1 , P. Sankar Ganesh 2 , M. Prabakaran 3 and G. Sampath Kumar 4 1 Dept of Zoology, Kunthavai Naachiyar Govt. Arts College (W) Autonomous, Thanjavur - 613 007, Tamilnadu, India. 2 Department of Biotechnology, Periyar Maniammai University, Thanjavur - 613 403, Tamilnadu, India. 3 Sri Gowri Biotech Research Academy, Thanjavur - 613 001, Tamilnadu, India. 4 Department of Botany, Dr.Ambedkar Govt. Arts College, Chennai, India Abstract: Fish and fishery products are one of the important items of healthy food. Aquaforming is a profitable business gaining much attention all over the world. India is one of the leading countries in aquaculture practicing with a special focus on shrimp production. The plants which are rich in secondary metabolic products with pharmacological value are termed as medicinal plants. An attempt was made to study the bioactive compounds present in Curcuma longa (Turmeric) by Gas Chromatography Mass Spectrum (GC-MS) analysis and to assay these compounds for in vitro antagonistic activity against Vibrio sp isolated from diseased Penaeusmonodon. Based on active principle, molecular weight, molecular formula and retention time observed in GC-MS analysis, five compound including 3ethyl 3-methylheptane, undecane, Heptadecane 9 hexyl, Diethylphthalate and Dibutyl phthalate were isolated. The antibacterial activity revealed that the n-butyl extract showed the maximum zone of inhibition against Vibrio harveyi (NL) 10.1± 0.1mm and Vibrio harveyi (L) 10.1± 0.1mm. Key words: Shrimp, Vibrio sp., Bioactive compound, GC-MS analysis, Antivibrio. *Author for Correspondence. E-mail: nc_kala@hotmail.com