Birch bark extract

Birch bark extract promotes wound healing; however, the specific mechanism of action has not been fully elucidated. In vitro studies in primary human keratinocytes and fibroblasts and ex vivo studies in porcine skin have shown that the dry extract from birch bark and its component betulin modulate inflammatory mediators. Specifically, pro-inflammatory cytokines such as cyclooxygenase 2 (COX-2), interleukin 6 (IL-6) and interleukin 8 (IL-8) are upregulated at both RNA and protein levels. The anti-inflammatory activity of other birch bark extract components such as oleanolic acid, erythrodiol, betulinic acid, and lupeol has also been reported.

Birch bark extract also plays a role in the formation of new skin barriers by promoting cellular proliferation, migration, adhesion, deposition of matrix, and keratinocyte differentiation. The dry extract from birch bark and its components betulin, lupeol, and erythrodiol promote keratinocyte migration. In human keratinocytes, birch bark extract induces keratinocyte differentiation by promoting the expression of differentiation markers such as keratin, type I cytoskeletal 10 (KRT 10) and involucrin (INV) as well as the adhesion protein transglutaminase. Also, It has been suggested that the purified triterpene extract derived from birch bark promotes keratinocyte differentiation by, at least in part, upregulating the non-selective transient receptor potential canonical (subtype) 6 (TRPC6) cation channel.