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Structural Studies on Stilbene Oligomers Isolated from the Seeds of Melinjo (Gnetum gnemon L.)
Hiroko Tani1, Hiroyuki Koshino2, Tohru Taniguchi3
1Institute for Bee Products & Health Science, Yamada Bee Company, Inc., 194 Ichiba, Kagamino, Okayama 708-0393, Japan.
Abstract:
This paper describes the isolation and structural determination of a new stilbene dimer, named 7a-epi-gnetin C, from melinjo (Gnetum gnemon L.) seed extract. The relative structure was elucidated based on NMR spectroscopic evidence, while the absolute configuration was assigned by a combination of NMR and electronic circular dichroism spectroscopic analysis and chemical conversion. 7a-epi-Gnetin C was evaluated as an antioxidant and was shown to have a comparable activity to the known stilbene oligomers. In addition, the structural revision of gnetin L, a known stilbene dimer, was also discussed.
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