The present study was undertaken to explore the free radical scavenging, antimicrobial and cytotoxic activity of the methanolic extract of Glycyrrhiza glabra (Fabaceae) using DPPH, disc diffusion and brine shrimp lethality bioassay methods respectively. Different degrees of effect was noticed incase of different methods of study. In antimicrobial screening, G. glabra showed potent antimicrobial activity against almost all the test organisms except Pseudomonas aeruginosa. It exhibited highest sensitivity against Staphylococcus aureus with the zone of inhibition 22 mm. The extract possessed potent cytotoxic activity having LC 50 value of 0.771µg/ml. On the other hand, the free radical scavenging activity was found moderate having IC 50 value of 87.152 µg/ml.

This study was conducted to evaluate the antibacterial and cytotoxic activities of extracts from leaf and fruit parts of the plant Averrhoa bilimbi (Oxalidaceae). Methanol was used as solvent and antibacterial effect was measured using disc diffusion test. The susceptibility of the microorganisms to the extracts of this plant was compared with standard antibiotic kanamycin. Fruit extract exhibited more potent antimicrobial activity against a wide variety of Gram-positive and Gram-negative bacteria compared to leaf extract. The antimicrobial activity was highest for the fruit extract against the Gram-negative Salmonella paratyphi (23.0 ± 0.50 mm) and the Grampositive Bacillus megaterium (19.0 ± 0.40 mm) bacteria, somewhat weaker against the Staphylococcus aureus, Bacillus subtilis, while with the leaf extract poor activity was observed against all 12 bacteria. Minimum inhibitory concentration (MIC) values were determined and it was found that the fruit extract was more potent against Salmonella paratyphi, Salmonella typhi, Shigella dysenteriae and Vibro parahemolyticus. The cytotoxic activity of fruit extract was found highly potent (12.96 μg/ml) where as the leaf also showed significant activity (92.51 μg/ml).

ABSTRACT:Two triterpenoids, lupeol (1) and stigmasterol were isolated from the petroleum ether soluble fraction of the methanolic extract of Ixora lutea Hutch. In our preliminary screening, the petroleum ether, carbon tetrachloride, chloroform soluble fractions of methanol extract of the leaves and stem were subjected to antioxidant, antimicrobial and brine shrimp lethality bioassay. All of the fractions showed moderate to potent antioxidant activity, of which the chloroform soluble fraction demonstrated the strongest antioxidant activity with the IC 50 value of 3.0 µg/ml. In case of antimicrobial screening, all extractives showed mild growth inhibitory activity. However, in the brine shrimp lethality bioassay, the petroleum ether soluble fraction was found to be most cytotoxic among the partitionates having LC 50 value 0.938 µg/ml.