Abstract
Oligomeric proanthocyanidins were isolated from rhatany root (Krameria triandra) and characterised by acid hydrolysis, thiolytic degradation, and spectroscopic methods.
They consisted of 2-14 flavanol units with mainly 2,3-cis configuration and with a propelargonidin: procyanidin ratio of 65:35. The predominant
interflavan linkage was [4,8]. [4,6]-Bonds were present in the higher oligomers, presumably
forming branched chain units. The astringency of the drug was mainly due to proanthocyanidins
with degrees of polymerization from 5-10, and these were also the astringent compounds
of rhatany tea and tincture. A pharmacological screening of the extract revealed a
significant antimicrobial effect.
