Anti-HIV bioactive stilbene dimers of Caragana rosea

Bioassay-guided fractionation of the ethanol extract of the aerial parts of Caragana rosea Turcz. led to the isolation of two new (cararosinol C and cararosinol D) and four known [scirpusin A (1), cis-scirpusin A (2), maackin (3), scirpusin B (4)] stilbene dimers. This is the first identification of these compounds from this plant and the first time that compound 2 has been isolated as a natural compound. Their structures were established mainly by spectral means. An in vitro assay against HIV-1 (IIIB), demonstrated compounds 1 and 4 to be active against HIV, with EC50 values of 10 microg/mL and 7 microg/mL respectively.