Mass Spectrometry of Selected Components of Biological Interest in Green Tea Extracts

Abstract

Mass spectrometric methods including EIMS, FABMS, and LC/ESIMS have been surveyed as tools for the detection of catechins in extracts of green tea (Camellia sinensis). EIMS provide both molecular weight and structure information, including epimer differentiation, on compounds 1, 2, and 4 and some structural information with compounds 5 and 6. FABMS gives both molecular weight and structure information, by an retro-Diels-Alder mechanism, on all compounds. LC/ESIMS provides unambiguous molecular weight information on all compounds and some additional structural data are evident in the mass spectra of 5 and 6. LC/ESIMS is, thus, shown to be an appropriate method for the direct analysis of crude extracts of green tea. The information obtained in this work will be of importance in future studies involving identification of the components of green tea and for characterization of synthetic analogues.

Characterisation of phenolic acids, flavonoids, proanthocyanidins and antioxidant activity of water extracts from seed coats of marama bean [Tylosema esculentum] – an underutilised food legume

“…Similar mass spectral data for (epi)catechin-3-O-gallate has been reported in green tea (Miketova et al, 1998) and oolong extracts (Dou et al, 2007).…”

Hairy roots of Hypericum perforatum L.: a promising system for xanthone production

“…Five groups of phenolic compounds such as phenolic acids, flavonol glycosides, flavan-3-ols, flavonoid aglycones and xanthones were recorded in HR cultures (Table 1). Their identification was based on the typical UV/Vis spectral data and LC/MS in the negative ionization mode [M-H] -with the subsequent MS 2 , MS 3 and MS 4 analysis for further identification with reference to similar data previously reported [24][25][26][27][28][29][30][31][32][33]. The HPLC analysis of secondary metabolites revealed marked differences between control roots ( Figure 3A) and HR cultures ( Figure 3B).…”

“…The peaks at m/z 301 and 285 correspond to quercetin (F17) and kaempferol (F18), respectively. -at m/z 577 and main fragmentation with loss of 152 amu, characteristic fragmentation pathway by retro Diels-Alder reaction [29] and were recognized as proanthocyanidin dimers. Regarding the group of flavan-3-ols in HR cultures, catechin (F3) was de novo synthesized while compound epicatechin (F7) was 8-fold increased, compared to control roots.…”

Purification and Characterization of a Novel Galloyltransferase Involved in Catechin Galloylation in the Tea Plant (Camellia sinensis)

“…Analysis of enzyme reaction products by LC-MS followed the method of Miketova et al (30). Enzymatic products were analyzed by HPLC, and the area of the product peaks were collected and identified by LC-MS.…”