Antibacterial Activity of Plumbagin and Root Extracts of Plumbago Zeylanica

Over the past few decades there has been much interest in natural materials as sources of new antibacterial agents. Different extracts from traditional medicinal plants have been tested. Many reports show the effectiveness of traditional herbs against microorganisms; as a result, plants have become one of the bases of modern medicine (Evans et al., 2002). Plants have given the Western pharmacopoeia about 7,000 different pharmaceutically important compounds and a number of top-selling drugs of modern times, such as quinine, artemisinin, shikonin and camptothecin (Tshibangu et al., 2002). The acceptance of traditional medicine as an alternative form of health care and the development of microbial resistance to the available antibiotics has led researchers to investigate the antimicrobial activity of medicinal plants (Bisignano et al., 1996; Lis-Balchin and Deans, 1996; Maoz and Neeman, 1998; Hammer et al., 1999). Silver and Bostian (1993) have documented the use of natural products as new antibacterial drugs. There is an urgent need to identify novel substances active towards highly resistant pathogens (Recio, 1989; Cragg et al., 1997). In an effort to discover new compounds, many research groups screen plant extracts to detect secondary metabolites with the relevant biological activities. In this regard, several simple bioassays have been developed for screening purposes (Hostettmann, 1991). It is thought that herbal remedies have the advantage of combining their active components with many other substances which appear to be inactive but which give the plant as a whole a level of safety and efficiency superior to that of its isolated, pure active components; moreover, in developing countries, synthetic drugs are presently too expensive and also are often adulterated (Shariff, 2001). Plumbago zeylanica L. (Plumbaginaceae) is a tropical shrub. It grows wild as a garden plant in eastern, northern and southern India and Ceylon.