C-Glucosidic ellagitannin oligomers from Melaleuca squarrosa Donn ex Sm., Myrtaceae.
C-glucosidic ellagitannin dimers were classified as types A-C according to a putative biogenetic oligomerization mode. They were characterized by different positions of the C-C bond between the phenolic acyl unit in one monomer and the benzylic C-1 of the open-chain glucose core in the other monomer. In recent years, four C-glucosidic tannins, melasquanins A-D (18-21), have been found in the leaves of Melaleuca squarrosa Donn ex Sm. (Myrtaceae). These are characterized as a dimer (melasquanin A) of a dimerization mode (type D), and trimers (melasquanins B-D) based on spectroscopic analysis including various two-dimensional nuclear magnetic resonance (2D NMR) experiments. Melasquanins B (19) and D (21) are C-glucosidic tannin trimers with a structure containing, non-repeating condensation modes, which was hitherto unknown.
Yoshida
Takashi
T
College of Pharmaceutical Sciences, Matsuyama University, Bunkyo-cho, Matsuyama 790-8578, Japan. tyoshida@cc.matsuyama-u.ac.jp
Ito
Hideyuki
H
Yoshimura
Morio
M
Miyashita
Kyoko
K
Hatano
Tsutomu
T
D047348:Hydrolyzable Tannins / Q000737:chemistry* / Q000378:metabolism*; D031650:Melaleuca / Q000737:chemistry* / Q000378:metabolism*; D015394:Molecular Structure
D047348:Hydrolyzable Tannins