New Dammaranes, Esterified with Malonic Acid, from Leaves of Betula pendula

Abstract

Three known and five new dammarane triterpenes, esterified with malonic acid at C-3 with hemolytic activity were identified from the ethanol-water extract of leaves of Betula pendula Roth: 12-O-acetyl-3α,12β,20(S),24(R)-tetrahydroxydammar-25-en-3-yl hydrogen propanedioate, 12-O-acetyl-3α,12β20(S),24(S)-tetrahydroxydammar-25-en-3-yl hydrogen propanedionate, 12-O-acetyl-3α,12β,17α,20(S),24(R)-pentahydroxydammar-25-en-3-yl hydrogen propanedioate, [12β-acetoxy-4,4,8,10,14-pentamethyl-17-(2-methyl-5-oxotetrahydrofuran2(S)-yl)-hexadecahydrocyclopenta[a]phenanthren-3α-yl] hydrogen propanedioate, 12-O-acetyl-3α,12β,20(S),25-pentahydroxydammar-23(E)-en-3-yl hydrogen propanedioate, and one which was new for Betula pendula but found in other Betula species: 12-O-acetyl-20,24-epoxy-3α,12β,20(S),24(R),25-pentahydroxydammar-3-yl hydrogen propanedioate. The structures were elucidated by MS, ¹H-NMR, ¹³C-NMR, ¹H-¹H-COSY, DEPT, ¹H-¹³C-NMR (HMQC, HMBC) experiments.

Betula pendula - Betulaceae - saponins - triterpenes - dammarane esters