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Tea, as one of the most popular beverages with various bioactivities, is commonly produced from the fresh leaves of two widely cultivated tea plants, Camellia sinensisand C. sinensisvar. assamica. Both plants belong to the genus Camelliasection Thea, which was considered to have 12 species and 6 varieties according to Min’s taxonomic system. Most species, except the cultivated species, are known as wild tea plants and have been exploited and utilized to produce tea by the local people of its growing areas. Thus far, six species and varieties have been phytochemically studied, leading to the identification of 398 compounds, including hydrolyzable tannins, flavan-3-ols, flavonoids, terpenoids, alkaloids, and other phenolic and related compounds. Various beneficial health effects were reported for tea and its components, involving antioxidant, antitumor, antimutagenic, antidiabetic, hypolipidemic, anti-inflammatory, antimicrobial, antiviral, antifungal, neuroprotective, hepatoprotective, etc. In this review, the geographical distribution of tea plants and the chemical constituents (1–398) reported from the genus Camelliasection Theaand some tea products (green, black, oolong, and pu-erh tea) that have ever been studied between 1970 and 2018 have been summarized, taking species as the main hint, and the main biological activities are also discussed.

Camellia sinensisvar. pubilimba, one variety of the genus Camelliasect. Thea(Theaceae), has been used for producing green tea mainly by the local people of its growing areas of Guangxi province, China. Forty compounds, including eight C-8 N-ethyl-2-pyrrolidinone-substituted flavan-3-ols (1–8) and their substituted unit N-ethyl-5-hydroxy-2-pyrrolidinone (9), four flavan-3-ol monomers (10–13) and one dimer (14), nine flavonoids (15–23), three hydrolyzable tannins (24–26), two lignans (27–28), 11 simple phenolics (29–39), and caffeine (40), were first isolated and identified from the leaves. Their structures were determined by detailed spectroscopic analysis and comparison with the literature data and authentic samples. Both 1and 4were obtained as a mixture of the N-ethyl-2-pyrrolidinone C-5 enantiomers (1aand 1band 4aand 4b), respectively, while the resolution of another three pairs of enantiomers (2and 3, 5and 6, and 7and 8) was achieved. Among them, 1bis a new compound whose NMR data together with its enantiomer (1a) were reported for the first time, while 2and 3are two new natural products. Most of the isolates exhibited significant antioxidant activities, stronger than ascorbic acid and trolox, while parts of the isolates, particularly C-8 N-ethyl-2-pyrrolidinone-substituted flavan-3-ols, showed obvious inhibitory effects on acetylcholinesterase (AChE). The results indicated that C. sinensisvar. pubilimbais a valuable plant resource for tea production.