structural transformation of gardenoside and its related iridoid compounds by acid and beta-glucosidase

Abstract In the course of studies on the metabolism of iridoid compounds, three new compounds derived from 6α-hydroxygeniposide and 6β-hydroxygeniposide, obtained from gardenoside by the hydrochloric acid treatment, were isolated after the hydrolysis with β-glucosidase. The aglycone of 6β-hydroxygeniposide was elucidated as 6β-hydroxygenipin. On the other hand, the aglycones of 6α-hydroxygeniposide were identified as the mixture of stereoisomers, 6α-hydroxygenipin and 6α-hydroxy-1-EPI-genipin.