S641 Document heading Phytochemical and bio - efficacy studies on methanolic flower extracts of Peltophorum pterocarpum (DC.) Baker ex Heyne. Vinod Kumar Nathan 1 , Johnson Marimuthu Antonisamy 2* , Wesely Edward Gnanaraj 3 , Kavitha Marappampalayam Subramanian 1 1 Centre for Biotechnology, Research Department of Biotechnology, Muthayammal College of Arts and Science, Namakkal Dist., Rasipuram-637 408, Tamil Nadu, India 2 Department of Plant Biology and Plant Biotechnology, St. Xavier’s College (Autonomous), Palayamkottai-627 002, Tamil Nadu, India 3 Department of Botany, Arignar Anna Government Arts College, Namakkal, Tamil Nadu, India Asian Pacific Journal of Tropical Biomedicine (2012)S641-S645 Asian Pacific Journal of Tropical Biomedicine journal homepage:www.elsevier.com/locate/apjtb *Corresponding author: Johnson Marimuthu@Antonisamy, Department of Plant Biology and Plant Biotechnology, St. Xavier’s College (Autonomous), Palayamkottai-627 002, Tamil Nadu, India. Tel: + 91 97 91 81 38 25 Fax: + 91 462 2561 765 E-mail: ptcjohnson@gmail.com 1. Introduction Medicinal plants are an important source of inexpensive and practical drugs for people throughout the world. Medicinal plants are plants which contain thousands of substances that could be used for therapeutic purposes or which are precursors for the synthesis of useful drugs [1] . The herbal products today symbolise safety in contrast to the synthetics that are regarded as unsafe to human and environment. Although herbs had been priced for their medicinal, flavouring and aromatic qualities for centuries, the synthetic products of the modern age surpassed their importance, for a while. However, the blind dependence on synthetics is decreasing and people are returning to the naturals with hope of safety and security [2-5] . Over three-quarters of the world population relies mainly on plants and plant extracts for health care. More than 30% of the entire plant species, at one time or other was used for medicinal purposes. As a result of indiscriminate use of antimicrobial drugs in the treatment of infectious diseases, microorganisms have developed resistance to many antibiotics [6] . There is an urge to develop alternative antimicrobial drugs to fulfill the present day requirement. One approach is to screen local medicinal plants, which represent a rich source of novel antimicrobial agents. The deficiency of the drugs available today, propels the discovery of new pharmacotherapeutic agents from medicinal plants [7] . Recent studies are involved in the identification and isolation ARTICLE INFO ABSTRACT Article history: Received 25 June 2012 Received in revised form 5 July 2012 Accepted 7 August 2012 Available online 28 August 2012 Keywords: Peltophorum pterocarpum Phytochemical HPTLC Antimicrobial activity Objective: The present study was aimed to investigate the preliminary phytochemical analysis and HPTLC profiling and the antibacterial activity of P. pterocarpum methanolic flower extracts against the bacteria isolated from human infections. Methods: The preliminary phytochemical screening was performed according to the Harborne method. HPTLC studies were carried out using Harborne and Wagner et al method. The methanolic flower extracts of P. pterocarpum were tested against Salmonella typhi (MTCC 733), Staphylococcus aureus (MTCC 96), Proteus mirabilis (MTCC 742), Bacillus subtilis (MTCC 441) and Escherichia coli (MTCC 443). The antimicrobial activity was tested through well diffusion method. Results: The phytochemical studies on methanolic flower extract of Peltophorum pterocarpum (DC.) Baker ex Heyne. revealed the presence of glycosides, flavonoids, phenolics, saponins, catechin and alkaloids. The HPTLC separation was achieved using ethyl acetate-methanol-ethanol-water (8.1: 1.1: 0.4: 0.8) as the mobile phase. The methanolic extract of P. pterocarpum showed four different Rf values 0.16, 0.31, 0.77 and 0.82 which indicated various glycosides present in the flower extract. The methanolic extract of P. pterocarpum showed the maximum zone of inhibition against Proteus mirabilis followed by Salmonella typhi. Conclusion: Bio-assay revealed the presence of specific and selective antimicrobial compounds in the fractions. Broad range activity of plant extracts as per observations in this study was due to presence of multiple antimicrobial compounds or synergic effects of these compounds. Therefore, standardization of active fractions and study for in vivo efficacy may result in development of better antimicrobial drugs. Contents lists available at ScienceDirect