ABSTRACT
Phytochemical investigations and antimicrobial activity studies for the leaf extracts of Carissa carandas Linn, were carried out. Four solvents i.e. Petroleum ether [60-80°C], Benzene [79-81°C], Chloroform [50.5-61.5°C], and Methanol were used for extraction of active principles from the dried powdered leaf material. The phytochemical tests of extracts revealed the presence of alkaloids, carbohydrates, glycosides, phenolic compounds, tannins and saponins. The antimicrobial screening was done with two Gram [-] ve [Escherichia coli NCIM 2065, Proteus vulgaris NCIM 2027] and two Gram [+] ve [Staphylococcus aureus NCIM 2079, Bacillus subtilis NCIM 2063] bacteria as test micro-organisms. Zones of inhibition produced by these extracts were measured as criteria to evaluate their antimicrobial activity. These zones of inhibition were compared with the standard antibiotic [Ciprofloxacin 30 mcg/ml] under similar conditions. The activity index of antimicrobial activity was calculated by comparing the effect of leaf extract with the effect induced by the standard antibiotic. Among the four micro-organisms tested, Staphylococcus aureus is the only organism found to be sensitive for all the leaf extracts. Benzene extract produced profound antibacterial activity and methanolic extract produced least antibacterial activity when compared with other leaf extracts