Application of microcalorimetry of Escherichia coli growth and discriminant analysis to the quality assessment of a Chinese herbal injection (Yinzhihuang)

Abstract

This paper describes a novel approach to the quality control of a Chinese herbal injection based on microcalorimetric determination of its effect on the biothermal active fingerprint (BTAF) of Escherichia coli (E. coli) growth. Yinzhihuang Injection (YZHI) was selected for this proof of concept study. Reference samples of YZHI were collected and compared with test (stressed) samples prepared under different stress conditions. The BTAF of E. coli growth was found to be affected by YZHI and the changes were analyzed on the basis of eleven biothermokinetic parameters. Similarity and multivariate statistical analysis were used to investigate the differences between reference and test samples and discriminant analysis was used to delineate the altered samples. Reference samples were found to have coincident BTAFs with similarity index >0.99. Stressed samples showed differences in the BTAF which increased in line with decreased quality. Discriminant formulae were developed based on a sensitivity parameter which could identify all altered samples. In conclusion, BTAF can be used to assess the quality of YZHI both qualitatively and quantitatively and has the potential to provide a sensitive method for quality control of Chinese herbal injections.

Keywords

• Biothermal active fingerprint
• Microcalorimetry
• Quality control
• Chinese herbal injection
• Escherichia coli