Journal of Ethnopharmacology 66 (1999) 235 – 240 Short communication Preliminary screening of ethnomedicinal plants from India R. Perumal Samy a , S. Ignacimuthu a, *, D. Patric Raja b a Entomology Research Institute, Loyola College, Chennai 600 034, India b St. Xaier’s College, Palayamkottai, Tiruneleli 627 002, India Received 29 September 1998; received in revised form 22 February 1999; accepted 26 February 1999 Abstract Antibacterial activity of aqueous residues of 16 different ethnomedicinal plants have been studied. The effect of the aqueous extract at two different weights of plant residues, 30 and 40 mg, were tested against three gram positive bacteria and seven gram negative bacteria by the filter paper disc diffusion method. Among the tested plants, Cleome gynandropsis and Ageratum conyzoides showed a significant control of the growth of Alkaligens iscolactis, Klebsiella aerogenas, Bacillus cerues and Streptococcus pyogens. The maximum inhibitions were observed in Tridax procumbens, Cleome iscosa, Acalypha indica and Boerhaaia erecta against Aeromonas hydrophilla and Bacillus cerues. © 1999 Elsevier Science Ireland Ltd. All rights reserved. Keywords: Antibacterial activity; Aqueous extracts 1. Introduction Plants are known to contain innumerable bio- logically active compounds (Alade and Irobi, 1993) which possess antibacterial (Brantner and Grein, 1994; Perumal Samy and Ignacimuthu, 1998) properties. Medicinal components from plants play an important role in conventional as well as western medicine. Plant derived medicines have been a part of the evolution of human, healthcare for thousands of years. Plant based medicines were commonly used in India and China. At the same time, indigenous people of the rest of the planet were also utilizing plants for curing diseases. Today, nearly 88% of the global population turn to plant derived medicines as their first line of defense for maintaining health and combating diseases. One hundred and nine- teen secondary plant metabolites derived from * Corresponding author. 0378-8741/99/$ - see front matter © 1999 Elsevier Science Ireland Ltd. All rights reserved. PII:S0378-8741(99)00038-0