Bioactivity of crude extracts of Nerium oleander Linn. extracted in polar and non polar solvents

Abstract

Today, the world is gradually turning to herbal formulations, which are known to be effective against a large repertoire of diseases and ailments. More importantly, they are not known to cause any notable derogatory effects and are readily available at affordable prices. The present study was designed to evaluate the antibacterial activity of crude extracts of Nerium oleander (Apocynaceae) Linn. Crude extracts from different parts (root, stem and leaf) of the plant were extracted using polar (Water and Methanol) and Non-polar (Petroleum ether) solvents and were screened for antibacterial activity by „Disc Diffusion Assay‟ against three Gram negative bacteria (Escherichia coli, Klebsiella pneumoniae and Agrobacterium tumifaciens) and two Gram positive bacteria (Staphylococcus aureus and Bacillus subtilis). Minimum inhibitory concentration, Minimum bactericidal concentration and total activity of extracts against each sensitive pathogen have also been evaluated. Mean and Standard Deviation have also been calcultated. B. subtilis found to be the most susceptible organism followed by K. pneumoniae, S. aureus and E. coli. Pet ether extract of root (IZ=24 mm, MIC=0.078 mg/ml, MBC=0.039 mg/ml, TA=141.02 ml/g) and stem (IZ=20 mm, MIC=0.156 mg/ml, MBC= 0.078 mg/ml, TA= 16.02 ml/g) showed the best antibacterial activity against B. subtilis and K. pneumoniae respectively. Methanolic and water extract of leaf, stem and root, Pet ether extract of stem, Methanolic and water extract of stem and Pet ether extract of root and stem also showed very good activities against B. subtilis, E. coli, K. pneumoniae and A. tumifaciens respectively. The range of MIC and MBC was found to be 1.25-0.078 mg/ml and 0.625-0.039 mg/ml respectively. Results reveal the great antimicrobial potency of tested extracts.