(M1130-03-13) Impact of Host Physiological and Pathological Conditions on the Activity of Gut Microbial Beta-Glucuronidases toward Hydrolysis of Baicalin

Purpose: The purpose of this study is to determine the impact of host physiological and pathological conditions on the activity of gut microbial beta-glucuronidases (GUS) towards hydrolysis of baicalin.

Methods: Fecal S9 fractions were prepared using feces collected from different types of rats at different ages using baicalin as the substrate. A Waters Acquity Ultra performance liquid chromatography (UPLC) system was used to quantify the metabolite baicalein to analyze the rate of the reaction of the enzymes. The rates were compared by obtaining enzymes through S9 fractions to confirm microbiota ability to hydrolyze the glucuronide and release of the parent compound, baicalein. Fecal S9 prepared from The Fischer 344 (F344) rats at three different ages (i.e., 5, 9, and 16 weeks) and different inflammatory conditions treated with Docusate Sodium (DSS) or anti-inflammatory agent herbal mixture Xiao-Chai-Hu Tang (XCHT). Additionally, fecal S9 from genetically modified PIRC rats, which spontaneously have inflammation in the colon, was also tested.

Results: The results depicted that age had an impact on hydrolysis of the compound baicalin into its parent compound and Fecal S9 from Pirc rats has lower activity and anti-inflammatory agent XCHT can increase microbial GUS activity. The p< 0.05 making the results statistically significant. The wild type enzymes had a clear increase in Km and Vmax. While PRIC enzymes and enzymes treated with DSS and XCHT had a clear difference in rates, but the Km and Vmax did not increase significantly. The Km for wild type enzymes at ages 5weeks, 9 weeks and 16 weeks were 10.32± 3.41, 24.81 ± 5.09, 64.99± 36.43 respectively. The Vmax for wild type enzymes at ages 5weeks, 9 weeks and 16 weeks were 1.269±0.139, 3.742±0.346, 7.256± 2.65.

Conclusion: The data shows that microbial GUS activity was higher at elder age. These findings indicate that microbial GUS activity is significantly affected by the physiological and pathological factors of the host. It is novel in the fact that it was found for the first time that microbial GUS activity is significantly affected by the physiological and pathological factors of the host.

Acknowledgments: Special Acknowledgement to Dr.Gao and Dr.Ting who aided in all forms.

Fig 2. Impact of ages of wild type enzymes of different ages on hydrolysis of baicalin



Fig 3. Impact of ages of enzymes treated under different conditions on hydrolysis of baicalin



Fig 1. Impact of ages of PRIC genetically modified enzymes on hydrolysis of baicalin