Chemical Properties
Rhatany is the reddish-brown, bitter-tasting root of Krameria triandra, an undershrub native to the Andean region of South America. The shrub has voluminous roots and several erect or prostrate, very thin, 1 m (39 in.) long stems. The stems initially are hirsute, turning glabrous with age. The small, sessile, lanceolate leaves are covered by coarse, silver-white hairs with hairy, externally green, internally red flowers in the axilla of the uppermost leaves. The plant grows in the Andes region of Bolivia, Colombia, Peru and Brazil. The part used is the roots. Rhatany is bitter, astringent.
Composition
Main constituents include tannins and krameriatannic acid. The phytochemicals reported from rhatany include d-catechin, dl-catechin, epicatechin, gambir-catechin, geoffroyine, gum, N-methyl-tyrosine, phlobaphene, phloroglucin, proanthocyanidins, procyanidins, propelargonidin, protocatechuic-acid, ratanine, rhatany-tannic-acid, tannin and wax. Oligomeric proanthocyanidins were isolated from rhatany root consisted of 2 to 14 flavanol units with mainly 2,3-cis configuration and with a propelagonidin: 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 to 10, and these were also the astringent compounds of rhatany tea and tincture.*
