- Sutha . P*
Abstract : ABSTRACT Bauhinia racemosa was used traditionally to take care of analgesic, anti-pyretic, anti inflammatory, antioxidant activity, anti-spasmodic, and antimicrobial activity properties. In this context, I decided to evaluate the antimicrobial and larvicidal property of Bauhinia racemosa . The aim of the study was to investigate the antimicrobial and larvicidal activities of plant extracts (aqueous,ethanol) from Bauhinia racemosa against ten microorganisms comprising of eight bacteria (Streptomyces fulvissimus, Klebsiella pneumonia, Shigella flexneri ,Escherichiae coli, Bacillus subtilis, Streptococcus pyogenes, Pseudomonus aeuruginosa ,Proteus mirabilis) and two fungi (Aspergillus niger,Candida albicans) using well diffusion method and larvicidal activity were tested on the larvae of the dengue-vector, Aedes aegypti. Phytochemical screening of the extracts was conducted to determine the active toxic compounds. Various concentrations (20 , 40, 60,80 mg/ml) of the plant extracts were tested against fourth instar larvae of A. aegypti. Phytochemical screening revealed the presence of alkaloids, flavonoids, tannins, saponins, glycosides and steroids. These compounds are known to possess insecticidal and larvicidal properties causing the mortality of insects and other pests. Alcohol and aqueous extracts showed significant larvicidal activity against A. aegypti mosquito larvae. Insecticidal susceptibility tests were carried out using WHO standard method and the mortality was observed after 24 and 48 hours exposure. The tested extracts showed moderate to good larvicidal activities. However, the maximum larval mortality was detected in ethanol extract. Ethanol extract showed larvicidal activity against A. aegypti with LC50 value of 76mg/ml & 64mg/ml at 24 & 48 hours respectively. Also exhibited the LC90 value of 117mg/ml & 100mg/ml at 24 & 48 hours respectively. Similarly, Aqueous extracts of Bauhinia recemosa showed larvicidal activity against A. aegypti with LC50 value of 86mg/ml & 70mg/ml at 24 &48 hours respectively. Also exhibited the LC90 value of 139 &125 mg/ml at 24 & 48 hours respectively. The results of the present study revealed that ethanol extract possessed high larvicidal activity when compared to aqueous with LC50and LC90 values.
Keyword : Larvicidal activity(Ades aegpyti), Antimicrobial activity, Aqueous & Ethanol extracts, Bauhinia recemosa