Comparison of the phytoestrogen trans‐resveratrol (3,4′,5‐trihydroxystilbene) structures from x‐ray diffraction and solution NMR

Abstract The NMR‐derived solution structure of trans ‐3,4′,5‐trihydroxystilbene (resveratrol) was compared with two recent literature crystal x‐ray structures, resveratrol in complex with human transthyretin (TTR‐RES) from 1DVS.pdb and resveratrol bound to chalcone synthase (CHS‐RES) from 1CGZ.pdb. 1 H and 13 C NMR spectra of resveratrol were acquired in DMSO‐ d 6 . Assignments were obtained from an analysis of DQF‐COSY, TOCSY, DEPT, HMQC/HSQC, HMBC and INADEQUATE NMR spectra. Past 1 H and 13 C NMR literature assignments are corrected. The dihedral angle 2–1–1′–2′ provides an indication of the relative spatial orientation of the two phenolic rings. Values of 1.62, − 54.10 and 12.6 ± 1.1adeg were found for the 1DVS.pdb, 1CGZ.pdb and NMR resveratrol structures, respectively. The 1DVS.pdb resveratrol structure is ‘flat’ with the two phenolic rings along the same plane. The 1CGZ.pdb structure has these two rings almost orthogonal to each other, and the NMR structure has these two rings much closer to being along the same plane. The angles 1–α—α′ and 1′–α′—α are along the same trace and of similar magnitude for the 1CGZ.pdb and NMR resveratrol structures. For the 1DVS.pdb resveratrol structure, these angles are about 7–10° greater, with α and α′ being 180° out‐of‐phase from the other two structures. The α rings did not overlap, with the NMR result representing a ‘median model’ of the two x‐ray structures. Copyright © 2005 John Wiley & Sons, Ltd.