Akademik Veri Yönetim Sistemi
HELVETICA CHIMICA ACTA, cilt.83, sa.7, ss.1509-1516, 2000 (SCI-Expanded)
Two dammarane-type saponins with a novel aglycone derived from the parent 16,22-epoxy-24-methylidenedammarane and lotoside A, a new lotogenin derivative, were isolated from the MeOH extract of the stem bark of the Brazilian medicinal plant Zizyphus joazeiro, in addition to the known saponin 3 beta-((O-[O-[alpha-L-arabinofuranosyl-(1 --> 2)]-O-[beta-D-glucopyranosyl-(1 --> 3)]]-alpha-L-arabinopyranosyl)oxy))ujubogenin (1). The structures of the new compounds were determined as 16,22-epoxy-3 beta-[(beta l-D-glucopyranosyl)oxy]-24-methylidenedammarane-15 alpha,16 alpha,20 beta-triol (2), 16,22-epoxy-3 beta-((O-[O-[beta-D-glucopyranosyl-(1 --> 2)]-O-[beta-D-apiofuranosyl-(1 --> 3)]]-beta-D-glucopyranosyl-(1 --> 2)-alpha-L-arabinopyranosyl)oxy)-24-methylidenedammarane-15 alpha,16 alpha,20 beta-triol (3), and 3 beta-((O-[O-[beta-D-glucopyranosyl-(1 --> 2)]-O-]beta-D-apiofuranosyl-(1 --> 3)]]-beta-D-glucopyranosyl-(1 --> 2)-alpha-L-arabinopyranosyl)oxy)lotogenin (4) by means of 1D- and 2D-NMR spectroscopy, as well as FAB mass spectrometry. For the novel aglycone, we propose the name joazeirogenin and, for the new saponins, joazeiroside A (2) and B (3). Joazeirogenin was found to be 16,22-epoxy-24-methylidenedammarane-3 beta,15 alpha,16 alpha,20 beta-tetrol.