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Activation of Insulin‐like Activity of Proanthocyanidins from Cinnamon
Author(s) -
Lampke Stephanie Mae,
Pavlovich James,
Polansky Marilyn,
Anderson Richard,
Graves Donald
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.5.a939-b
Subject(s) - proanthocyanidin , chemistry , fractionation , insulin , incubation , mass spectrometry , antioxidant , biochemistry , food science , chromatography , polyphenol , endocrinology , biology
Earlier it was found that water soluble extracts of cinnamon have insulin‐like activity and could affect insulin signaling pathways in epidymal fat cells and 3T3‐L1 adipocytes. Activity has been shown to be associated with proanthocyanidins from cinnamon. Fractionation of extracts by HPLC has yielded various oligomers with bioactivity. The maximal insulin‐like activity of fraction 6, containing a trimeric proanthocyanidin A, was negligible when assayed as purified under acidic conditions, but was equivalent to that of saturating amounts of insulin when the fraction was adjusted to pH 9.4 and incubated overnight at room temperature prior to the assay. By using electrospray mass spectrometry we have identified oxidized forms derived from dimeric and trimeric proanthocyanidins by incubation at alkaline pH values. Addition of phenylenediamine adds mass to these forms consistent with oxidative reactions forming quinone products. Research was supported in part by a grant from Cottage Hospital, Santa Barbara, CA to D. Graves.