Cocoa tea (Camellia ptilophylla Chang) is a naturally low caffeine-containing but gallocatechin gallate (GCG)-rich tea cultivar, though its biological activities have not been extensively explored. Herein, we evaluated the in vitro cellular antioxidant, methylglyoxal trapping, and anti-inflammatory activities of water extract of green tea from cocoa tea (CWE) and Yunnan Daye tea (Camellia sinensis) (YWE), and their predominant bioactive components GCG and epigallocatechin gallate (EGCG) for comparative purposes. Primarily, CWE exhibited a higher cellular antioxidant potential than YWE via a cellular antioxidant activity assay, while no significant difference was observed between GCG and EGCG. Moreover, CWE was more potent than YWE in the inhibitory effect on inflammatory responses in lipopolysaccharide-induced RAW 264.7 macrophages, including nitric oxide and interleukin-6 productions. Additionally, CWE showed comparable MGO trapping ability to YWE, although EGCG was more reactive with MGO than with GCG. This study suggested that cocoa tea would be a promising and potential functional beverage as a dietary antioxidant, methylglyoxal trapping, and anti-inflammatory agent.

•Colloidal and chemical profiles of green tea cream are distinct from black tea cream.•Green tea cream particles exhibit larger size and lower electrostatic stability.•Creaming amounts are linearly correlated to original composition of tea infusions.•Catechins and their oxides, proteins and methylxanthines dominate tea cream formation.•In vitro digestion of black tea is more susceptible to precipitation than green tea.Tea cream is prevalent in various types of tea, yet a comparison of the mechanism of creaming in different teas remains uncertain. Here, we compared physicochemical characteristics, phytochemical composition, and simulated digestive profiles of green tea and black tea cream, looking to exploit their concentration and structure based mechanisms and in vitro bioaccessibility. Green tea cream particles were roughly one order of magnitude larger than those of black tea in size. Moreover, creaming concentrations of catechins, proteins and methylxanthines of green tea were dramatically higher than black tea. As major creaming components, gallated catechins, theaflavins, thearubigins, theabrownines, proteins and methylxanthines also exhibited high creaming affinities. Green tea cream particles, which were completely destroyed by simulated digestion, had few impacts on digestive recoveries of catechins and methylxanthines. In comparison, black tea cream particles were more stable under mimicking digestion, and clarification remarkably decreased the in vitro bioaccessibility of catechins and methylxanthines.

In the 1980s, a novel tea species, Cocoa tea (Camellia ptilophylla Chang), was discovered in Southern China with surprisingly low caffeine content (0.2% by dry weight). Although its health promoting characteristics have been known for a while, a very limited amount of scientific research has been focused on Cocoa tea. Herein, a systematic study on Cocoa tea and its chemical components, interactions and bioactivities was performed. YD tea (Yunnan Daye tea, Camellia sinensis), a tea species with a high caffeine content (5.8% by dry weight), was used as a control. By UV-Vis spectrometry, High Performance Liquid Chromatography (HPLC), and Flame Atomic Absorption Spectrometry (FAAS) for chemical composition analysis, C-2 epimeric isomers of tea catechins and theobromine were found to be the major catechins and methylxanthine in Cocoa tea, respectively. More gallated catechins, methylxanthines, and proteins were detected in Cocoa tea compared with YD tea. Moreover, the tendency of major components in Cocoa tea for precipitation was significantly higher than that in YD tea. Catechins, methylxanthines, proteins, iron, calcium, and copper were presumed to be the origins of molecular interactions in Cocoa tea and YD tea. The interactions between catechins and methylxanthines were highly related to the galloyl moiety in catechins and methyl groups in methylxanthines. In vitro anti-inflammatory activity assays revealed that Cocoa tea was a more potent inhibitor of nitric oxide (NO) in lipopolysaccharide (LPS)-stimulated macrophage cells (RAW 264.7) than YD tea. This study constructs a solid phytochemical foundation for further research on the mechanisms of molecular interactions and the integrated functions of Cocoa tea.