資訊請求信函 (有效撰寫專業英文電子郵件) (5 of 6) By designating ABC as my primary interest area in ASME and having received the ABC Newsletter for quite some time, I realize that CGFM could resourcefully support my professional interest in oligomeric proanthocyanidins, which are water-soluble polyphenolic tannins that are present in the female inflorescences (up to 5% dry wt) of the hop plant (Humulus lupulus). Humans are exposed to hop proanthocyanidins through their consumption of beer. Previous studies have characterized proanthocyanidins from hops in terms of their chemical structure and their in vitro biological activities. Chemically, these proanthocyanidins consist mainly of oligomeric catechins, ranging from dimers to octamers, with minor amounts of catechin oligomers that contain one or two gallocatechin units. Additionally, the chemical structures of four procyanidin dimers (B1, B2, B3 and B4) and one trimer, epicatechin-(4β→8)-catechin-(4α→8)-catechin (TR), were elucidated using mass spectrometry, NMR spectroscopy and chemical degradation. When tested as a mixture, the hop oligomeric proanthocyanidins (PC) were found to be potent inhibitors of neuronal nitric oxide synthase (nNOS) activity. Among the oligomers tested, procyanidin B2 was the most inhibitory of nNOS activity. Procyanidin B3, catechin and epicatechin were non-inhibitory against nNOS activity. PC and the individual oligomers were all strong inhibitors of 3-morpholinosydnonimine (SIN-1)-induced oxidation of LDL, with procyanidin B3 displaying the highest antioxidant activity at 0.1μg/mL. Moreover, the catechin trimer (TR) exhibited antioxidant activity that was more than one order of magnitude greater than that of α-tocopherol or ascorbic acid on a molar basis. Given my above research interests and your expertise in this field, could you send me introductory information on your laboratory’s current efforts in these areas? Based on our mutual interests, we are interested in pursuing collaborative activities with your research organization. I look forward to hearing from you.
Posted on: Tue, 20 Aug 2013 03:18:00 +0000
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