Hasubanan Alkaloids with δ-Opioid Binding Affinity from the Aerial Parts of Stephania japonica

Abstract

Two new (1 and 2) and six known hasubanan alkaloids (3-8) and one morphinane alkaloid (9) were isolated from the leaves of the North Queensland rainforest vine Stephania japonica. The structures of 1 and 2 were determined by interpretation of their 1D and 2D NMR spectra. The hasubanan alkaloids showed affinity for the human d-opioid receptor with IC50 values ranging from 0.7 to 46 卮 The compounds were also tested for their affinity to 孠and ?-opioid receptors and shown to be inactive against ?-opioid receptors, but were of similar potency against the 孯pioid receptor.