NMR study of the solution structure of curcumin.
Curcumin [1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione] is derived from the rhizomes of Curcuma longa. Although early studies concluded that curcumin exists predominantly as a keto-enol tautomer, 1b, in several recent articles the solution structure of curcumin has been represented as a beta-diketone tautomer, 1a. We have investigated the structure of curcumin in solvents ranging in polarity from CDCl3 to mixtures of DMSO-d6 in water, and in buffered aqueous DMSO-d6 solutions with pH values varying from 3 to 9. The solution structure of curcumin was determined on the basis of NMR techniques, including DEPT, HMQC, HMBC, and COSY. The results of the NMR studies show definitely that curcumin exists in solution as keto-enol tautomers, 1b.
Payton
Florastina
F
Department of Chemistry and Coordinated Instrumentation Facility, Tulane University, New Orleans, Louisiana 70118, USA.
Sandusky
Peter
P
Alworth
William L
WL
D030024:Curcuma / Q000737:chemistry*; D003474:Curcumin / Q000737:chemistry*; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D027343:Rhizome / Q000737:chemistry; D013237:Stereoisomerism
D003474:Curcumin