Triterpenoid α-amyrin stimulates proliferation of human keratinocytes but does not protect them against UVB damage

Rhaponticum carthamoides plants ("maral root") are widely used in Siberian folk medicine. The present study reports for the first time the presence of pentacyclic terpenoid, α-amyrin, in methanol extract from leaves of this plant. α-Amyrin induced proliferation of human keratinocytes (HaCaT) by about 18% while other extract components were ineffective. A panel of biochemical and cell-based assays testing the antioxidative and cytoprotective activites of α-amyrin indicated no antioxidative activity of this compound. α-Amyrin did not protect HaCaT cells against the damage caused by UVB radiation.