Iridoid and lignan glycosides from Lancea tibetica

One new iridoid glucoside, 7-O-E-feruloylgardoside (1) and two new lignan glycosides, 8 '-hydroxyphillyrin (2) and 6-(p-hydroxybenzyl) phillyrin (3), together with three known compounds, khainaoside B (4), phillyrin (5), and lantibeside (6), were isolated from the whole plants of Lancea tibetica. Their structures were elucidated on the basis of spectroscopic methods and X-ray crystallographic analysis. A DPPH free radical scavenging assay showed that 1 and 4 exhibited moderate antioxidant activity (IC50 45.05 +/- 3.04 and 48.00 +/- 3.29 pg/ml) compared with vitamin C (IC50 3.31 +/- 0.16 pg/ml).

Automated summary

One new iridoid glucoside and two new lignan glycosides, along with three known compounds, were isolated from the whole plants of Lancea tibetica. The structures were determined by spectroscopic methods and X-ray crystallographic analysis. One of the new iridoid glucosides and the known compounds exhibited moderate antioxidant activity.