Antibacterial and Phytochemical Evaluation of Three Medicinal Plants of Bangladesh

The present study was carried out to illustrate the relative evaluation of phytochemical constituents and antimicrobial activity of leaves of Eclipta alba and Aphanamixis polystachya and bark of Premna integrifolia in two different solvents. A preliminary phytochemical analysis was done and concluded that the presence of alkaloids, tannins, flavonoids and glycoside in both extracts of the above plants. The antimicrobial activity was tested using disc diffusion method against eight pathogenic bacteria using Kanamycin as antibiotic standards. The outcome showed that the antibacterial activity was effective in chloroform and ethyl acetate fractions of tested extracts. The MIC was determined in two different solvents of both extracts and observed that chloroform and ethyl acetate possess minimum inhibition in both extracts. From the current investigation, it can be concluded that Eclipta alba, Aphanamixis polystachya and Premna integrifolia crude extracts have quite effective antimicrobial activity and potent phytochemical constituents. INTRODUCTION: The use of plants and plant products could be traced as far back as the beginning of human civilization. Medicinal plants are a source of great economic value all over the world. Nature has bestowed on us a very rich botanical wealth and a large number of diverse types of plants grow in different parts of the country. In Bangladesh, thousands of species are known to have medicinal value and the use of different parts of several medicinal plants to cure specific ailments has been in vogue since ancient times . Herbal medicine is still the mainstay of about 75-80% of the whole population and the major part of traditional therapy involves the use of plant extract and their active constituents . Following the advent of modern medicine, herbal medicine suffered a set back, but during last two or three decades advances in phytochemistry and in identification in plant compounds effective against certain diseases have renewed the interest in herbal medicines . Nowadays multiple drug resistance has developed due to the indiscriminate use of commercial antimicrobial drugs commonly used in the treatment of infectious disease. This results in the need of higher dose use with increased risk of drug toxicity or consideration to change the regimen. In addition to this problem, antibiotics are sometimes associated with adverse effects on the host including hypersensitivity, immunesuppression and allergic reactions. This situation force scientists to search for new antimicrobial substances. Given the alarming incidence of antibiotic resistance in bacteria of medical importance, there is a constant need for new and effective therapeutic agents. Therefore, there is a need to develop alternative antimicrobial drugs for the treatment of infectious diseases from medicinal plants . The beneficial medicinal effects of plant materials typically results from combinations of secondary product present in plant.