Geranins C and D, additional new antiprotozoal A-type proanthocyanidins from Geranium niveum

Two new additional A-type proanthocyanidins have been isolated from Geranium niveum. Their structures were determined by spectroscopic, chemical and chiroptical methods as epi-afzelechin-(4beta-->8,2beta-->O-->7)-gallocatechin (1) and epi-afzelechin-(4beta-->8,2beta-->O-->7)-afzelechin-(4beta-->8,2beta-->O-->7)-afzelechin (2). Proanthocyanidins 1 and 2 were given the trivial names of geranins C and D, respectively. Compound 2 showed moderate antiprotozoal activity against Entamoeba histolytica and Giardia lamblia, whereas 1 exhibited weak activity toward E. histolytica.