Introduction
Plants are invaluable sources of pharmaceutical products. India, in particular has yielded an incredible array of
plant products that have drawn the attention
of ethno pharmacologists from around the world. Medicinal plants are
important substances for the study of their traditional uses through the
verification of pharmacological effects and can be natural composite
sources that act as new anti-infectious agents. In order to find out new
sources of drugs, a number of plants have been screened for wide range
of biological activities. About 3,000 materials from 2,764 plant species
have been screened for their pharmacological and chemotherapeutic
properties (Anon, 1988). Traditionally used medicinal plants produce a
variety of compounds of known therapeutic properties (Iyengar, 1976;
Harborne, 1989; Chopra
et al., 1992). Plants used in
ethno medicine for the production of bioactive compounds are used and
rationalize the use of these medicinal plants in health care (Morales
et al., 2008). Most of their properties are due to secondary metabolites produced by plants.
E. alba is reported in literature for its
various biological activities such as: calm the mind, removes memory
disorders, relieve swollen glands, strengthens spleen, works as a
general tonic, useful for treatment of edema, fevers and rheumatic joint
pains, stimulate digestion, hepatitis, enlarged spleen, antioxidant
activity and skin disorders (Chopra
et al., 1956; Karnick and Kulkarni, 1990; Karthikumar
et al., 2007). Wedelolactone exhibited Trypsin inhibitory effect (Samiulla
et al., 2003; Syed
et al., 2003), suppresses LPS-induced caspase-11 expression in cultured cells by directly inhibiting the IKK complex (Kobori
et al.,
2004), treatment of cirrhosis of the liver and infectious hepatitis (Murphy et al., 1979), possessing potent anti-hepatotoxic activity (Wagner et al., 1986). The shoot extract of E. alba showed antimicrobial (Anonymous 1952, Kosuge et al., 1985; Wiart et al.,
2004), antifungal activity (Venkatesan and Ravi 2004) and weak
cytotoxicity against the M-109 cell lines by alkaloids Verazine (Abdal
Kadar et al., 1998), antiviral activity against Ranikhet disease virus (Khin et al., 1978), effective against internal and external parasites (Lans et al., 2001) G. intestinalis (Sawangjaroen et al., 2005), antibacterial (Kumar et al., 2007).
The microbes used for the detection of antimicrobial activity were chosen for certain reasons.
E. coli is best-known member of normal micro biota of the human intestine and a versatile gastrointestinal pathogen.
S. typhimurium
can be found in a broad range of hosts as well as in the environment.
Its infection is a serious health problem in developing countries and
represents constant concern for the food industry.
S. epidermidis
was used due to its clinical relevance as the major cause of infection
in the immunosuppressed prosthetic heart valve in joint implants.
B. subtilis common saprophytic water and soil bacteria, causes laboratory contamination and conjunctivitis in humans (Ross, 2001).
However, up to date, research has been done to investigate various pharmacological activities and
antimicrobial activity of only crude extracts of this traditionally
used herb. We report here our findings on antibacterial effects of
wedelolactone (Fig. 1), the principle active compound, extracted from
E. alba.
