eng Oriental Scientific Publishing Company Biomedical and Pharmacology Journal 0974-6242 2017-09-25 10 3 1279 1284 10.13005/bpj/1230 16624 article Glory Josephine I. 1 Punnagai K. 2 Muthiah N. S. 1 Department of Pharmacology, Sree Balaji Medical College and Hospital, Chennai, India. Department of Pharmacology, Sri Ramachandra Medical College and Research Institute, Chennai, India. Calliandra haematocephala commonly known as powder puff has wide range of therapeutic properties like anti inflammatory, anticonvulsant, immunomodulatory and blood purifier. Previous Studies showed the antibacterial activity of the flowers and bark of Calliandra haematocephala, So this study is designed to evaluate the antibacterial activity of the ethanolic extract of the leaves of “Calliandra haematocephala“ against selected gram positive and gram negative strains. The leaves of Calliandra haematocephala was subjected to soxhlet extraction using organic solvent of ethanol. The antibacterial activity of  Calliandra haematocephala extract was done using standard disc diffusion method using Muller Hinton agar (MHA) against ten strains of bacteria (Three  gram positive and Seven gram negative strains). Ampicillin is the standard positive control and 20μl of varying concentrations (1000 μg, 750μg and 500 μg) of the extract sample were tested. The antibacterial effect was determined by measuring the diameter of the zone of inhibition. The ethanolic extract of Calliandra haematocephala showed the moderate antibacterial activity against gram negative bacterial strains like Salmonella typhi (12mm) Serratia marcescens (9mm), Shigella flexneri (8mm) and gram positive bacterial strains like Staphylococcus aureus (9mm), Bacillus subtilis (10mm), Micrococcus leteus (10mm) as measured by the zone of inhibition produced by the plant extract when compared with the control drug Ampicillin. However it showed maximal activity against Pseudomonas aeroginousa (12mm).In our study the ethanolic extract of Calliandra haematocephala has shown to have good antibacterial activity against both gram negative and positive bacteria in high concentration. https://biomedpharmajournal.org/vol10no3/in-vitro-antibacterial-activity-of-ethanolic-extract-of-calliandra-haematocephala-against-selected-bacterial-strains/ Antibacterial Activity Agar Disc Diffusion Calliandra Haematocephala Zone of Inhibition