A Novel Type of Dimeric Secoiridoid Glycoside from Lisianthius jefensis R OBYNS et E LIAS

A dimeric secoiridoid glucoside named lisianthioside (l) has been isolated from the roots of Lisianthius jefensis ROBYNS et ELIAS (Gentianaceae). The structure was established by spectroscopic analysis (UV, IR, 1H‐ and 13C‐NMR, DCI‐MS) of glycoside 1, peracetate 1a, aglycone 3 and the dimethoxy derivatives 4a–c. Lisianthioside (1) is the first representative of a novel type of dimeric secoiridoids. Biogenetically derived from two sweroside (2) moieties, the tricyclic aglycone features a symmetrical 12‐membered bislactone ring. In contrast to the moderately bitter sweroside (2), lisianthioside (1) is tasteless.