Study on the Bacteriostatic Activity and Stability of Ethanolic Extract from Yunnan Litsea cubeba

In this study, the antibacterial effects of five different ethanolic concentrations (0%, 55%, 75%, 95%, 100%) EELC (Ethanol extract of Yunnan Litsea cubeba) on two kinds of pathogenic bacteria were determined. Ethanol extracts which had the strongest antibacterial activity and their stability were analyzed. The inhibition zone diameter of different concentrations in ethanolic EELC against E.coil and S.aureus were determined by KB paper method. At the same time, using TTC (2,3,5-triphenyltetrazolium chloride) method detected the MIC of EELC to screen out the best antibacterial activity of EELC. At the end, the temperature, heat treatment time, pH and UV light stability of EELC were further studied. The results showed that 55% and 75% EELC had the best inhibitory effect on S.aureus and E.coli, with MIC of 19 and 819 μg/mL, respectively. 55% EELC treated at 40 ℃, the OD600 was 0.118, which had the optimal antibacterial activity. Furthermore, the antibacterial activity remained stable after treatment for 1~5 hour