Effects of Kudzu Root (Gegen) on Drug-Metabolizing Enzymes and Blood Clotting in Healthy Volunteers

Purpose: The purpose of this study is to understand how the traditional herbal medicine kudzu root (Gegen, Radix Puerariae lobatae) affects the activity of drug metabolizing enzymes in the body, and whether this could lead to interactions with other medicines. Background: Many medicines are broken down in the body by enzymes called cytochrome P450 (CYP) enzymes. Preclinical data suggest that Gegen can inhibit CYP enzymes, which may lead to herb-drug interactions; however, robust clinical evidence in humans remains insufficient. Participants: This study recruited 56 healthy Chinese adults, who were randomly assigned to parallel low and high dose Gegen groups; 52 participants finished the study. Interventions: Participants took a mixture of probe medicines known as a CYP probe cocktail to measure baseline CYP enzyme activity. After receiving either low or high dose Gegen, they received the probe cocktail again to detect changes in enzyme activity. Blood samples were collected to test the probe medicines, their breakdown products, and markers for blood clotting and blood vessel health. Outcome Measures: Primary outcomes include changes in blood levels and metabolic ratios of probe medicines. These values reflect differences in CYP enzyme activity with and without Gegen, and are compared across low and high dose groups. Hypothesis: The study hypothesized that Gegen alters CYP enzyme activity, and that the magnitude of this effect varies with Gegen dose.