Nature of Pharma. Tech. / © 2013 GTRP-GRF group / www.gbtrp.com © 2014 GTRP Reserved. This is an Open Access article distributed under the terms of the Creative Commons Attribution License ((http://creativecommons.org/licenses/by-nd/3.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. http://www.gbtrp.com/journal/npt.htm Nature of Pharmaceutical Technology (2014) :4(2):1-6. Article ID : npt150814101 GC-MS analysis and antibacterial activity of Stem of Indigofera longeracemosa Boiv. Ex Baill. N. Subash and G. Raju Abstract: The aim of present study was to analyses and identified in bioactive components of Indigofera longeracemosa Boiv. Ex Baill.by Gas Chromatography - Mass Spectrometry (GC-MS) method and antibacterial activity of the hexane, chloroform and ethanol extract of I. longeracemosa. The results of Indigofera longerace- mosa stems were 21chemical components identified by GC-MS method. The major compounds of terpenoids con- stituents were 9-Octadecenoic acid (Z)-(14.44%), 13-Tetradece-11-yn-l-ol (11.23%), Pentafluoropropionic acid, octadecyl ester (8.97%). Plant extracts tested against three fish pathogens using agar disc diffusion method. The hexane extract showed maximum activity against Aeromonas hydrophila (3±0.2 mm) and Aeromonas sobria (9 ± 0.1) and no activity against Vibrio harveyi. The results of bioactive components and antimicrobial activity are dis- cussed. This plant may be used for treatment of several diseases caused by fish pathogenic microbes. This study recommends future research regarding the drug designs of this plant. Present Address Department of Zoology, Pioneer Kumaraswamy College, Nagercoil,Tamil Nadu– 629003,South India *Corresponding Authors e-mail to : rajumaran@yahoo.co.in Received: 13 June 2014 / Accepted: 12 July 2014 / Published Online: 15 August 2014 © Gayathri Publishers 2014 ISSN 2231 - 0436 OPEN ACCESS Citation : Subash, M. and *Raju,G. 2014. GC-MS analysis and antibacterial activity of stem of Indigofera longeracemosa Boiv. Ex Baill. Nature of Pharmaceutical Technology,4(2):1-6. Keywords: Indigofera longeracemosa, GC-MS, antimicrobial activity, Aeromonas hydrophila, Vibrio harveyi, Aeromonas hydrophila, Manuscript Type : Research Article Received Manuscript : Via Email Approved Letter : Received or Non Received Funding Source: Support or No Support Conflict of Interest : Nil Manuscript Full Responses: Authors Submission manuscripts info: nptjournal@yahoo.com © 2014 GTRP-GRF group 1. Introduction There is an increase in the research areas of newly development and prevention of fish diseases especially the role of flavonoids and phenolic acids as antioxidants moreover flavonoids and phenolic acids components play important roles in the control of different fish dis- eases (Raju et al., 2013). The clinical efficacy of many existing antibiotics is being threatened by the emergence of multidrug- resistant fish pathogens (Bandowet al., 2003).The genus of Indigofera belongs to the family Leguminosae. They are 750 species distributed throughout the tropical and subtropical regions of the world (Raju et al., 2013). A large number of the plants are claimed to possess the antibiotic prop- erties in the traditional system and are also used exten- sively by the tribal people worldwide. It is now believed that nature has given the cure of every disease in one way or another (Prashant Tiwariet al., 2011). Aqueous and hexane extracts Indigofera longeracemosa exhibit- ed good antibacterial properties against bacterial species of Escherichia coli, Klebsiella pneumoniae, Salmonel- la typhi, Vibrio parahaemolyticus, V.cholerae and gram – positive namely Bacillus subtilis and