High molecular compounds (polysaccharides and proanthocyanidins) from Hamamelis virginiana bark: influence on human skin keratinocyte proliferation and differentiation and influence on irritated skin

Although extracts from Hamamelis bark have long been used in therapy of ski n diseases and in cosmetic formulas there are only few pharmacological inve stigations verifying the activity of distinct Hamamelis bark constituents. Therefore two major classes of constituents, namely polymeric proanthocyani dins and polysaccharides were isolated from Hamamelis bark and tested conce rning their influence on proliferation and differentiation of cultured huma n keratinocytes. While the polysaccharide fraction, consisting mainly of ar abans and arabinogalactans, did not effect human keratinozytes, the proanth ocyanidins strongly increased the proliferation of the cells, while the dif ferentiation was not influenced significantly. Within a preliminary cumulat ive in vivo study on SLS-irritated skin, proanthocyanidins (ProcyanoPlus) w ere proven to reduce transepidermal water loss and erythema formation. Furt hermore, a clinical scoring indicated that procyanidins can influence irrit ative processes significantly. (C) 2001 Elsevier Science Ltd. Ali rights re served.