A New Iridoid Dimer and Other Constituents from the Traditional Kurdish Plant Pterocephalus nestorianus Nábělek.

Accompanied by other rare compounds, a new iridoid dimer, named kurdnestorianoside (1), showing an unprecedented secologanol configuration, has been isolated for the first time from the Kurdish medicinal plant Pterocephalus nestorianus, which is used in Kurdistan for treating oral diseases and inflammation. The structure of 1 was established from 1D- and 2D-NMR spectroscopic data. Kaempferol 3-O-[3,6-di-O-(E)-p-coumaroyl]-β-d-glucopyranoside (7) showed a remarkable antiproliferative activity against several human tumor cell lines.