New acylated triterpenoid saponins from Maesa lanceolata

Citation
S. Apers et al., New acylated triterpenoid saponins from Maesa lanceolata, PHYTOCHEM, 52(6), 1999, pp. 1121-1131
Citations number
8
Categorie Soggetti
Agricultural Chemistry","Animal & Plant Sciences
Journal title
PHYTOCHEMISTRY
ISSN journal
00319422 → ACNP
Volume
52
Issue
6
Year of publication
1999
Pages
1121 - 1131
Database
ISI
SICI code
0031-9422(199911)52:6<1121:NATSFM>2.0.ZU;2-I
Abstract
Ten new acylated triterpenoid saponins were isolated from the leaves of Mae sa lanceolata. For their structure elucidation extensive use was made of ho mo- and heteronuclear 2D NMR techniques such as COSY, NOESY, HSQC and HMBC. All saponins identified contained the same tetraglycosidic side chain, but the triterpenoid moiety showed a variable esterification pattern. Monoeste r, diester and triester derivatives were present. Maesasaponin I was a 21-m onoester derivative, i.e. {3 beta-O-[alpha-L-rhamnopyranosyl-(1 --> 2)-beta -D-galactopyranosyl-(1 --> 3)]-[beta-D-galactopyranosyl-( -->)]-beta-D-gluc uronopyranosyl}-21 beta-angeloyloxy-13 beta,28-oxidoolean-16a, 22a, 28 alph a-triol. Maesasaponins III, IV3, V-3 and VI2 had an additional acetyl, prop anoyl, n-butanoyl and angeloyl substituent, respectively, in position 22. M aesasaponins II, IV2, V-2, VI3 and VII1 were characterised as the 16-acetyl derivatives of maesasaponins I, III, IV3, V-3 and VI2, respectively. Struc tures of saponins previously reported in M. lanceolata had to be revised. ( C) 1999 Elsevier Science Ltd. All rights reserved.