Biomaterial Database

Carbon-13 CP-MAS nuclear magnetic resonance studies of teas. 2003

Antonio Martínez-Richa, and Pedro Joseph-Nathan

Facultad de Química, Universidad de Guanajuato, Noria alta s/n, Gto 36050, Guanajuato, Mexico. richa@quijote.ugto.mx <richa@quijote.ugto.mx>

13C CP-MAS NMR spectra of green and black tea were obtained and assigned based on the solid-state NMR spectra of tropolone, (+)-catechin hydrate, gallic acid, caffeine and flavone derivatives. The peak shape and chemical shifts observed for carbonyl carbons in CP-MAS spectra of teas indicate the existence of different chemical species, mainly free phenollic acids and ester derivatives of flavonoids. The peak patterns allow to establish differences between both teas.

UI	MeSH Term	Description	Entries
D008958	Models, Molecular	Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.	Molecular Models,Model, Molecular,Molecular Model
D010636	Phenols	Benzene derivatives that include one or more hydroxyl groups attached to the ring structure.
D011108	Polymers	Compounds formed by the joining of smaller, usually repeating, units linked by covalent bonds. These compounds often form large macromolecules (e.g., BIOPOLYMERS; PLASTICS).	Polymer
D002247	Carbon Isotopes	Stable carbon atoms that have the same atomic number as the element carbon but differ in atomic weight. C-13 is a stable carbon isotope.	Carbon Isotope,Isotope, Carbon,Isotopes, Carbon
D002250	Carbon Radioisotopes	Unstable isotopes of carbon that decay or disintegrate emitting radiation. C atoms with atomic weights 10, 11, and 14-16 are radioactive carbon isotopes.	Radioisotopes, Carbon
D002392	Catechin	An antioxidant flavonoid, occurring especially in woody plants as both (+)-catechin and (-)-epicatechin (cis) forms.	Catechinic Acid,Catechuic Acid,(+)-Catechin,(+)-Cyanidanol,(+)-Cyanidanol-3,(-)-Epicatechin,(2R,3R)-2-(3,4-Dihydroxyphenyl)-3,5,7-chromanetriol,2H-1-Benzopyran-3,5,7-triol, 2-(3,4-dihydroxyphenyl)-3,4-dihydro-, (2R-cis)-,3,3',4',5,7-Flavanpentol,Catergen,Cianidanol,Cyanidanol-3,Epicatechin,KB-53,Z 7300,Zyma,Cyanidanol 3,KB 53,KB53
D005419	Flavonoids	A group of phenyl benzopyrans named for having structures like FLAVONES.	2-Phenyl-Benzopyran,2-Phenyl-Chromene,Bioflavonoid,Bioflavonoids,Flavonoid,2-Phenyl-Benzopyrans,2-Phenyl-Chromenes,2 Phenyl Benzopyran,2 Phenyl Benzopyrans,2 Phenyl Chromene,2 Phenyl Chromenes
D013045	Species Specificity	The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.	Species Specificities,Specificities, Species,Specificity, Species
D013662	Tea	The infusion of leaves of CAMELLIA SINENSIS (formerly Thea sinensis) as a beverage, the familiar Asian tea, which contains CATECHIN (especially epigallocatechin gallate) and CAFFEINE.	Black Tea,Green Tea,Black Teas,Green Teas,Tea, Black,Tea, Green,Teas, Black,Teas, Green
D014334	Tropolone	A seven-membered aromatic ring compound. It is structurally related to a number of naturally occurring antifungal compounds (ANTIFUNGAL AGENTS).