In vitro antibacterial activity of leaf extract of Leucas aspera against human pathogenic bacteria

Thalavaipandian et al.,

Leucas aspera | Phytochemical constituents

Vol: 3; Iss: 5;  May-17 | ISSN: 2454-5422

To study the phytoconstituents and antibacterial activity of Leucas aspera, leaf extracts of petroleum ether, ethyl acetate and aqueous were tested against human pathogenic bacteria. About forty gram of powered leaf was extracted successively with 200 ml of aqueous (97- 103 0C), ethyl acetate (77-850C) and petroleum ether (62-660C). The preliminary phytochemical analysis of the leaf extract revealed the presence of glycosides, tannins and terpenoids in petroleum ether and aqueous extract, alkaloids, coumarins, glycosides, flavonoids, quinines, saponins, tannins, terpenoids and almost all the tested compounds in the ethyl acetate extract. The crude extract of petroleum ether, ethyl acetate and aqueous were screened for antibacterial activity. Among the three extractions, the extract of ethyl acetate showed potent antibacterial activity by inhibiting the growth of all the tested human pathogenic bacteria, Maximum inhibition zone of 23mm, 23mm, 21mm and 20mm against the growth of Streptococcus faecalis, Pseudomonas aeruginosa, Shigella dysenteriae, and Corynebacterium diphtheria respectively. Minimum Inhibitory Concentrations (MIC) of crude extract of Leucas aspera was determined against gram positive and gram negative bacterial pathogens ranged from 600μg/ml to 2400μg/ml. Further, Minimum Bacterial Concentration (MBC) of 1200μg/ml was observed against the growth of Staphylococcus faecalis and Pseudomonas aeruginosa, 2400μg/ml against Bacillus subtilis and Shigella dysenteriae, 4800μg/ml against Corynebacterium diphtheria and Salmonella typhi respectively. The findings of this study revealed that the metabolites of leaf of Leucas aspera are the potential source for the development of new antibacterial compounds.