Activity of berberine on Shigella dysenteriae investigated by microcalorimetry and multivariate analysis

Abstract

In this study, the microcalorimetric method was applied to investigate the activity of berberine on Shigella dysenteriae (S. dysenteriae). Heat flow power (HFP)–time curves of the growth metabolism of S. dysenteriae affected by berberine were determined using the thermal activity monitor (TAM) air isothermal microcalorimeter, ampoule mode, at 37 °C. By analyzing these curves and some quantitative parameters using multivariate analytical methods, similarity analysis (SA) and principal component analysis (PCA), the antibacterial activity of berberine on S. dysenteriae could be accurately evaluated from the change of the two main parameters, the maximum heat flow power Pm2 and total heat output Qt: berberine at low concentration (25 μg mL−1) began to inhibit the growth of S. dysenteriae, high concentrations (50–200 μg mL−1) of berberine had strong antibacterial activity on S. dysenteriae, when the concentration of berberine was higher (250–300 μg mL−1), this antibacterial activity was stronger. All these illustrated that the antibacterial activity of berberine on S. dysenteriae was enhanced with the increase of the concentration of this compound. Berberine can be used as potential novel antibacterial agent for treating multidrug-resistant Shigella. This work provided a useful idea of the combination of microcalorimetry and multivariate analysis for studying the activity of other compounds or drugs on organisms.