Camellia sinensis species

Tea is a beverage made from the leaves of the Camellia sinensis species of the Theaceae family. This beverage is one of the most ancient and, next to water, is the most widely consumed liquid in the world. Tea leaves contain specific polyphenols and polyphenol oxidase. Following harvesting, fresh tea leaves are subjected to a series of treatment steps that result in the manufacturing of different tea products black tea, green tea, or oolong tea. 

Both Australia and New Zealand have indigenous tea trees in the family Myrtaceae, which were reputedly used for brewing tea by Captain Cook. There is, however, no resemblance between real tea Camellia sinensis, Camelliaceae, and the taste or odor of these species. The Australian tea tree oil from Melaleuca alternifolia and other Melaleuca species has strong antimicrobial potential (see Lis-Balchin et al., 2000, for a review and references). 

Methyl derivatives of xanthine (2,3-dioxypurine) namely caffeine (1,3,7-trimethyl-xanthine), theobromine (3,7-dimethylxanthine) and theophylline (1,3-dimethylxanthine) (Section 1, Appendix) are variously found in plants used for stimulatory drinks such as Ilex paraguayensis (mate) (Aquifoliaceae), Coffea species (coffee) (Rubiaceae), Paullinia cupana (guarana) (Sapindaceae), Cola acuminata (cola) and Theabroma cacao (cocoa) (Sterculiaceae) and Camellia sinensis (tea) (Theaceae). These methylxanthines are variously active as inhibitors of... 

Caffeine is one of most widely consumed alkaloids on a daily basis. As well as being a significant constituent of coffee (Caffea arabica) and tea Camellia sinensis), caffeine is also present in kola Kola species), guarana... 

Camellia sinensis (green tea) Capparis spinosa (caper plant) Capsicum annum (chili pepper) Cassia species (senna)... 

Examples of applications of X-ray spectrometric analytical techniques to elemental determinations in a variety of materials are presented in Table 2.12. Some recent applications papers may be mentioned. Total reflection XRF has been applied by Xie et al. (1998) to the multielement analysis of Chinese tea (Camellia sinensis), and by Pet-tersson and Olsson (1998) to the trace element analysis of milligram amounts of plankton and periphyton. The review by Morita etal. (1998) on the determination of mercury species in environmental and biological samples includes XRF methods. Alvarez et al. (2000) determined heavy metals in rainwaters by APDC precipitation and energy dispersive X-ray fluorescence. Other papers report on the trace element content of colostrum milk in Brazil by XRF (da Costa etal. 2002) and on the micro-heterogeneity study of trace elements in uses, MPI-DING and NIST glass reference materials by means of synchrotron micro-XRF (Kempenaers etal. 2003). 

Zoysa, A.K.N., Loganathan, P. and Medley, M.J. (1998) Phosphate rock dissolution and transformation in the rhizosphere of tea (Camellia sinensis L.) compared with other plant species. European Journal of Soil Science 49, 477-M86. 

Methylxanthines and methyluric acids are secondary plant metabolites derived from purine nucleotides (Figure 6.59). The most well-known methylxanthines are caffeine (1,3,7-trimethylxanthine) and theobromine (3,7-dimethylxanthine), which occur in tea (Camellia sinensis. Camellia ptilophylla, and Camellia taliensis) [242,243], coffee (Coffea arabica, Coffea canephora) [244, 245], cacao (Theobroma cacao) [246], and a number of other nonalcoholic beverages of plant origin Ilex paraguariensis, Paullinia cupana. Cola species and Citrus species [247-249]... 

Caffeine is found in a number of botanically unrelated species, including Coffea arabica (Rubiaceae), Camellia sinensis (Theaceae), or tea. Cola nitida (Sterculaciaceae), or kola nut, and Paullinia cupana (Sapindaceae), or guarana. Caffeine is bound to chlorogenic acid in raw coffee beans, the roasting process liberating the caffeine and other compounds that contribute to the aroma of coffee (Samuelsson 1992). 

Fig. 293 3-Methylxanthme, 1-methylxanthine, and theophylline are synthesized fiom caffeine as part of the caffeine degradation pathway that produces xanthine which is further degraded to CO2 and NH3 by the craivcaitional oxidative piuine catabolism pathway. The conversion of caffeine to theophylline is the rate-limiting step in caffeine-accumulating species such as Coffea arabica and Camellia sinensis. Solid arrows indicate major routes and dotted arrow minor conversions. The pathway was elucidated from data obtained in feeding experiments. Y-Demethylase enzymes involved in caffeine degradation have not yet been characterized in plants. Enzymes NDM iV-demethylase, XDH xanthine dehydrogenase...

All tea comes from the exact same species of plant, Camellia sinensis, a bush whose leaves are turned into a seemingly endless variety of tea—black, green, and white. The range of types and styles is determined by where the bush is grown, the level of maturity at which the leaves are picked, and how the leaves are processed after harvesting. For instance, some varieties of tea leaves are left in a climate-controlled room to oxidize—a process called fermentation—in order to darken them and draw out specific flavors. Note that herbal teas, also called tisanes or infusions, are a totally different matter and can be made from any herb, fruit, or spice. 

---