Tannins from Hamamelis virginiana: identification of proanthocyanidins and hamamelitannin quantification in leaf, bark, and stem extracts.

The tannins in leaf, bark, and stem extracts of HAMAMELIS VIRGINIANA were analyzed. Four proanthocyanidins were isolated by HPLC. One was a procyanidin polymer containing only one type of flavanol unit; the other three were polymers of procyanidin and prodelphinidin containing two types of flavanol units. A method of assay of hamamelitannin showed the bark extract to be 31 times richer in hamamelitannin than the leaf extract and 87 times richer than the stem extract.