Antimicrobial potential of aqueous extract of Camellia sinensis against representative microbes.

Camellia sinensis is being used for decades for its therapeutic efficacies against physiological problems and microbial infections. This study was undertaken to investigate the antibacterial and antifungal potential of aqueous extract of Camellia sinensis. Antibacterial activity was determined by disc and well diffusion assay. MIC and MBC were calculated by broth dilution method. Miles and Misra technique was used to find out colony forming unit per/ml. All the test organisms revealed a diverse range of vulnerability against aqueous extract. Among Gram positive, MRSA showed to be the most sensitive with least MIC and MBC while among Gram-negative Pseudomonas aeruginosa exhibited the highest sensitivity. In Miles and Misra, a progressive decline in log of CFU/ml was observed. In time-kill assay, a decline was noted in the viable count of S.aureus after exposure to 18% aqueous extract of Camellia sinensis. In the present study aqueous extract of Camellia sinensis found to be effective against Gram positive, Gram negative and fungi. The most important finding of this study is its aqueous extract inhibitory effect against drug-resistant microorganisms e.g. MRSA and P. aeruginosa and Candida albicans.

Production of an antibiotic enterocin from a marine actinobacteria strain H1003 by metal-stress technique with enhanced enrichment using response surface methodology.

Elicitation by chemical means including heavy metals is one of a new technique for drug discoveries. In this research, the effect of heavy metals on marine actinobacteria Streptomyces sp. H-1003 for the production of enterocin, with a strong broad spectrum activity, along optimized fermented medium was firstly investigated. The optimum metal stress conditions consisted of culturing marine actinobacteria strain H-1003 with addition of cobalt ions at 2mM in optimized Gause's medium having starch at 20mg/L for 10 days at 180 revolution/min. Under these conditions, enterocin production was enhanced with a value of 5.33mg/L, which was totally absent at the normal culture of strain H-1003 and much higher than other tested metal-stress conditions. This work triumphantly announced a prodigious effect of heavy metals on marine actinobacteria with fringe benefits as a key tool of enterocin production.