Analysis and antiproliferative activity of bark extractives of Betula neoalaskana and B. papyrifera. Synthesis of the most active extractive component - Betulin 3-caffeate

Abstract

The chemical content of outer birch bark extractive from the North American birches Betula papyrifera Marshall (paper birch) and B. neoalaskana Sargent (Alaskan paper birch) has been evaluated by GC/MS, HPLC and NMR spectroscopy. The comparative antiproliferative activity of the extractive and major triterpenoid components was studied using a number of human and murine malignant (P19, N2/D1, K1735-M2, PC-3 and CaOV3) and normal (BJ) cell lines. Betulin 3-caffeate was found to exhibit the highest antiproliferative activity among all triterpenoid components, including betulinic acid. Synthesis of betulin 3-caffeate from betulin has been developed.