Caco-2 Monolayer Permeability and Stability of Chamaelirium luteum (False Unicorn) Open-Chain Steroidal Saponins

Abstract

Herbal medicines, although significant components of health care for much of the global populace, are still far less stringently regulated than conventional pharmaceuticals. Safety and efficacy concerns arise because of the limited information regarding many of the phytochemicals present in herbal medicines. Chamaelirium luteum (false unicorn) is an indigenous American herb marketed for "women's issues". Recently, the potential bioactives, a new class of open-chain steroidal saponins, have been fully characterized and preliminary bioactivity assays have been performed. The present study utilized the Caco-2 cell monolayer model to evaluate metabolic vulnerability and potential bioavailability of eight saponins and sapogenins from false unicorn. No compound metabolism was detected in Caco-2 cell homogenate. One sapogenin, helogenin, exhibited low-to-moderate permeability across the monolayers. Three saponins - chamaeliroside A, heloside A, and 6-dehydrochamaeliroside A - were found to have moderate permeability. Transport studies indicated active transport of these saponins. In contrast, all saponins with more than two sugar units exhibited low permeability.