Objectives: Scutellaria baicalensis has been a subject of research interest due to its potential multiple therapeutic benefits. This study was to examine the distribution of baicalein, wogonin, oroxylin A and their glucuronide/sulfate-conjugated metabolites in plasma, colon, small intestine, lung, liver, pancreas, kidney, and prostate tissues and in pancreatic tumor in a xenograft animal model. In addition, we examined metabolic stability of baicalin in these tissues.
Methods: A mouse xenograft model was prepared by injection of 3 × 10 human pancreatic cancer MiaPaCa-2 cells subcutaneously into nude mice. Mice were randomly allocated to control diet (AIN-76A) and 1% S. baicalensis diet (n = 8 per group) for 13 weeks. Levels of baicalein, wogonin, oroxylin A, and their conjugates in mouse tissues were measured by high-pressure liquid chromatography after enzymatic hydrolysis and then extraction.
Results: A substantial amount of baicalin (34%-63%) was methylated to oroxylin A and its conjugates in various organs during absorption. Whereas plasma contained predominantly conjugates of baicalein, wogonin, and oroxylin A, both aglycones and conjugates were found in all other tissues investigated and in tumor.
Conclusions: Substantial accumulation of bioactive metabolites are found in target tissues, suggesting strong potential for S. baicalensis use as a preventive or adjuvant supplement for pancreatic cancer.