Unambiguous structure assignment of standards is essential for metabolome characterization of infected plants. Complete structure elucidation of eleven natural polyphenols, resveratrol (1), (-)-epicatechin (2), pelargonidin chloride (3), cyanidin chloride (4), cyanin chloride (5), keracyanin chloride (6), caftaric acid (7), quinic acid (8), procyanidin B1 (9), procyanidin B2 (10), and procyanidin C1 (11) by 1H-, 13C, COSY-, TOCSY-, ROESY-, and HMBC-NMR is described. The sinusoidal modulation frequency of 1H-13C-cross-peaks (J-HMBC) was fitted iteratively to sin(πJH,Ctvar) and yielded 2,3J-coupling values for 1H-13C-correlations in the natural polyphenols. Satisfactory fit to standard Karplus-equations was achieved for glycosides directly attached to the aromatic core in cyanin chloride. Molecular dynamics simulation data in vacuum at the AM1-level of theory were shown to approximate the NMR-solution data reasonably well. Analysis of these standards enables the characterization of unknown plant metabolites produced by bacterially stressed Thompson grape plants provided by the USDA. Initial steps for structure elucidation of 72 unknown fractions is discussed. In addition, selective HCl-catalyzed H/D-exchange was observed for aromatic protons H6 and H8 in flavonoid structures containing a 5,7-meta-disubstituted chromelynium core with free OH-groups. The exchange took place readily in compounds 3, 4, and 6, whereas 1, 2, and 5 did not exchange.
| Identifer | oai:union.ndltd.org:pacific.edu/oai:scholarlycommons.pacific.edu:uop_etds-5029 |
| Date | 01 January 2014 |
| Creators | Serebnitskaya, Ilona |
| Publisher | Scholarly Commons |
| Source Sets | University of the Pacific |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | University of the Pacific Theses and Dissertations |
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