Oligomeric proanthocyanidins from mangosteen pericarps |
| |
| Authors: | Fu Caili Loo Alvin Eng Kiat Chia Fiona Ping Ping Huang Dejian |
| |
| Institution: | Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Republic of Singapore. |
| |
| Abstract: | Oligomeric proanthocyanidins were extracted from mangosteen pericarps and fractionated by a Sephadex LH-20 column to give 0.66% yield (dry matter). (13)C and (1)H NMR signals showed the presence of predominantly procyanidins together with a few prodelphinidin units along with small amounts of stereoisomers of afzelechin/epiafzelechin, catechin/epicatechin, and gallocatechin/epigallocatechin. Depolymerization with benzylmercaptan resulted in epicatechin thioether as the major product, and the mean degree of polymerization was determined to be 6.6. The electron spray ionization-mass spectrometry and matrix-assisted laser desorption/ionization time-of-flight mass spectra revealed the dominant B type oligomers with mainly epicatechin units and with a small amount of A type oligomers. The isolated proanthocyanidins are potent peroxyl radical scavengers as evidenced by the high oxygen radical scavenging capacity at 1.7 x 10 (4) micromol TE/g, much higher than that of pine bark and grape seed extracts. |
| |
| Keywords: | |
| 本文献已被 PubMed 等数据库收录！ |
|
