Picroside IV is an iridoid glycoside originating from the underground parts of Picrorhiza scrophulariiflora and serves as a derivative of Catalpol while demonstrating broad pharmacological functions including neuroprotective, hypoglycemic, anti-inflammatory, anticancer, antispasmodic, antioxidant, and anti-HBV effects. Picroside IV therefore represents a therapeutically valuable bioactive molecule with high relevance in disease prevention and treatment research.

The pharmacokinetic results indicated that the six components (picroside I, picroside II, vanillic acid, androsin, cinnamic acid, and Picroside IV) in TGPR could be quickly absorbed and slowly eliminated. Their bioavailability was less than 12.37%, indicating poor absorption after intragastric dosing. For tissue distribution, the six components in TGPR were detected in the liver, and only androsin could penetrate the blood-brain barrier. Meanwhile, the excretion study demonstrated that vanillic acid was mostly excreted as prototype drugs, and the remaining five components might be widely metabolized in vivo as the metabolites; the unconverted form was excreted mainly by the feces route [1].