Methodological research on the quality evaluation of Radix Isatidis based on antibacterial potency

Abstract This paper aims to introduce a method for evaluating the quality of Radix Isatidis, based on antibacterial potency. Taking the diameter of the inhibition zone as an index, a single-factor examination was carried out to evaluate the influences of the bacteria concentration, culivating time, and bacterium generations on the antibacterial potency. An antibacterial potency evaluation method was established and it was used to evaluate the Radix Isatidis from different sources. A desirable test result can be achieved when the following conditions are met: bacteria concentration was 0.38 MCF, cultivating time was 15 h, and bacteria were in 3rd generation or 4th generation. Antibacterial potency of Radix Isatidis has shown no apparent differences between different batches of GAP (about 3.80 U), but with a noticeable difference in terms of geographical areas (0.83 U-6.77 U). This method can be used for the quality control and evaluation of Radix Isatidis.