Investigation of anti-microbial activity of catechin on Escherichia coli growth by microcalorimetry

Catechin is a major monomer of Chinese Rhubarb. Chinese Rhubarb has been claimed to have a therapeutic value as a bacteriostatic drug. It is also known that total rhubarb anthraquinone mixture and its individual components such as emodin are the effective components. However, the catechins component in Chinese Rhubarb such as catechin has not been characterized. In the present study, the power–time curves of Escherichia coli growth were obtained and the action on them by addition of catechin in different concentrations in vitro were studied by microcalorimetry. The results suggest E. coli growth is inhibited by catechin in a dose-dependent manner starting from the concentration of 0.05 to 1.6 mg mL−1. The correspondence analysis reveals k2 and P2 are the significant parameters to evaluate the anti-microbial effect. Microcalorimetry is a useful tool to evaluate the anti-microbial effect with its sensitive and significant quantitative information.