[1]

Committee AD. 1998. An Agricultural Dictionary. 1458 pp. Beijing: China Agricultural Press

[2]

Xu J. 2006. Studies on comparison of chemical constituents of four species of Camellia Sect. Thea and the central nervous system activity of theaerine, a special purine alkaloid in C. assamica var. kucha. Thesis. Shenyang Pharmaceutical University, China

[3]

Ashihara H, Mizuno K, Yokota T, Crozier A. 2017. Xanthine alkaloids: occurrence, biosynthesis, and function in plants. Progress in the Chemistry of Organic Natural Products 105:1653

doi: 10.1007/978-3-319-49712-9_1
[4]

Wan XC. 2003. Tea Biochemistry. Beijing: China Agricultural Press

[5]

Chen L, Zhou ZX. 2005. Variations of main quality components of tea genetic resources [Camellia sinensis (L. ) O. Kuntze] preserved in the China National Germplasm Tea Repository. Plant Foods for Human Nutrition 60:31−5

doi: 10.1007/s11130-005-2540-1
[6]

Li J. 2013. A correlation study of caffeine contents with theobromine contents transcriptional expression and cSNP of key enzyme genes in tea plants. Thesis. Anhui Agricultural University, China

[7]

Zhou C, Jin J, Yao M, Chen L. 2011. Progress on purine alkaloids metabolism in tea and other plants. Journal of Tea Science 31:87−94

doi: 10.13305/j.cnki.jts.2011.02.010
[8]

Zhang H, Ye C, Zhang R, Ma Y, Zeng P. 1988. A discovery of new tea resource — cocoa tea tree containing theobromine from China. Acta Scientiarum Naturalium Universitatis Sunyatseni 27:131−33

[9]

Teng J. 2018. The biochemical characteristics and N-methyltransferase of purine alkaloid pathway in Camellia gymnogyna Chang from Dayao Mountain. Thesis. South China Agricultural University, China

[10]

Ye C, Zheng X, Yuan C, Gao K, Shi X, Zhang H. 2001. A review of research on cocoa tea, a new resource of caffeine-free tea plant. Guangdong Agricultural Science 2001:12−15

[11]

Yan Z, Huang J, Wang D. 2020. Research progress in natural theobromine-enriched tea plants. Guangdong Agricultural Sciences 47:37−44

[12]

Qin D, Wang Q, Li H, Fang K, Jiang X, et al. 2021. Progress in research on Camellia kucha (Chang et Wang) Chang and its special constituent theacrine. Food Science 42:353−59

[13]

Shi X, Zheng X, Song X, Wang Y, Ye C. 2008. A new combination of Kucha. Acta Scientiarum Naturalium Universitatis Sunyatseni 47:129−30

[14]

Ye C, Lin Y, Su J, Song X, Zhang H. 1999. Purine alkaloids in Camellia assamica var. kucha Chang et Wang. Acta Scientiarum Naturalium Universitatis Sunyatseni 38:82−86

[15]

Cheng Y, Yan Z, Lu J, Ye C, Wang D. 2010. Isolation and preparation of theacrine by high-speed counter-current chromatography from Camellia assamica var. Kucha. Acta Scientiarum Naturalium Universitatis Sunyatseni 49:65−69

[16]

Ashihara H, Sano H, Crozier A. 2008. Caffeine and related purine alkaloids: biosynthesis, catabolism, function and genetic engineering. Phytochemistry 69:841−56

doi: 10.1016/j.phytochem.2007.10.029
[17]

Anaya AL, Cruz-Ortega R, Waller GR. 2006. Metabolism and ecology of purine alkaloids. Frontiers in Bioscience-Landmark 11:2354−70

doi: 10.2741/1975
[18]

Arnold SEJ, Dudenhöffer JH, Fountain MT, James KL, Hall DR, et al. 2021. Bumble bees show an induced preference for flowers when primed with caffeinated nectar and a target floral odor. Current Biology 31:4127−4131.E4

doi: 10.1016/j.cub.2021.06.068
[19]

McLellan TM, Caldwell JA, Lieberman HR. 2016. A review of caffeine's effects on cognitive, physical and occupational performance. Neuroscience & Biobehavioral Reviews 71:294−312

doi: 10.1016/j.neubiorev.2016.09.001
[20]

Ribeiro JA, Sebastião AM. 2010. Caffeine and adenosine. Journal of Alzheimers Disease 20:S3−S15

doi: 10.3233/JAD-2010-1379
[21]

Cellai L, Carvalho K, Faivre E, Deleau A, Vieau D, et al. 2018. The adenosinergic signaling: a complex but promising therapeutic target for Alzheimer's disease. Frontiers in Neuroscience 12:520

doi: 10.3389/fnins.2018.00520
[22]

Fiani B, Zhu L, Musch BL, Briceno S, Andel R, et al. 2021. The neurophysiology of caffeine as a central nervous system stimulant and the resultant effects on cognitive function. Cureus 13:e15032

doi: 10.7759/cureus.15032
[23]

Arendash GW, Cao C. 2010. Caffeine and coffee as therapeutics against Alzheimer's disease. Journal of Alzheimers Disease 20:S117−S126

doi: 10.3233/JAD-2010-091249
[24]

Arendash GW, Mori T, Cao CH, Mamcarz M, Runfeldt M, et al. 2009. Caffeine reverses cognitive impairment and decreases brain amyloid-β levels in aged Alzheimer's disease mice. Journal of Alzheimers Disease 17:661−80

doi: 10.3233/JAD-2009-1087
[25]

Arendash GW, Schleif W, Rezai-Zadeh K, Jackson EK, Zacharia LC, et al. 2006. Caffeine protects Alzheimer's mice against cognitive impairment and reduces brain β-amyloid production. Neuroscience 142:941−52

doi: 10.1016/j.neuroscience.2006.07.021
[26]

Huang Y, Liu Y, Dushenkov S, Ho CT, Huang M. 2009. Anti-obesity effects of epigallocatechin-3-gallate, orange peel extract, black tea extract, caffeine and their combinations in a mouse model. Journal of Functional Foods 1:304−10

doi: 10.1016/j.jff.2009.06.002
[27]

Scott JR, Hassett AL, Brummett CM, Harris RE, Clauw DJ, et al. 2017. Caffeine as an opioid analgesic adjuvant in fibromyalgia. Journal of Pain Research 10:1801−9

doi: 10.2147/JPR.S134421
[28]

Sharangi AB. 2009. Medicinal and therapeutic potentialities of tea (Camellia sinensis L. ) – A review. Food Research International 42:529−35

doi: 10.1016/j.foodres.2009.01.007
[29]

van Dam RM. 2006. Coffee and type 2 diabetes: from beans to beta-cells. Nutrition, Metabolism & Cardiovascular Diseases 16:69−77

doi: 10.1016/j.numecd.2005.10.003
[30]

Guessous I, Pruijm M, Ponte B, Ackermann D, Ehret G, et al. 2015. Associations of ambulatory blood pressure with urinary caffeine and caffeine metabolite excretions. Hypertension 65:691−96

doi: 10.1161/HYPERTENSIONAHA.114.04512
[31]

Coleman WF. 2001. Chocolate: theobromine and caffeine. Journal of Chemical Education 81:1232

doi: 10.1021/ed081p1232
[32]

Ried K, Sullivan TR, Fakler P, Frank OR, Stocks NP. 2017. Effect of cocoa on blood pressure. Cochrane Database of Systematic Reviews

doi: 10.1002/14651858.CD008893.pub3
[33]

van den Bogaard B, Draijer R, Westerhof BE, van den Meiracker AH, van Montfrans GA, et al. 2010. Effects on peripheral and central blood pressure of cocoa with natural or high-dose theobromine: a randomized, double-blind crossover trial. Hypertension 56:839−46

doi: 10.1161/HYPERTENSIONAHA.110.158139
[34]

Sarriá B, Martínez-López S, Sierra-Cinos JL, Garcia-Diz L, Goya L, et al. 2015. Effects of bioactive constituents in functional cocoa products on cardiovascular health in humans. Food Chemistry 174:214−18

doi: 10.1016/j.foodchem.2014.11.004
[35]

Grases F, Rodriguez A, Costa-Bauza A. 2014. Theobromine inhibits uric acid crystallization. A potential application in the treatment of uric acid nephrolithiasis. PLoS One 9:e111184

doi: 10.1371/journal.pone.0111184
[36]

Usmani OS, Belvisi MG, Patel HJ, Crispino N, Birrell MA, et al. 2005. Theobromine inhibits sensory nerve activation and cough. FASEB Journal 19:231−33

doi: 10.1096/fj.04-1990fje
[37]

Tanaka E, Mitani T, Nakashima M, Yonemoto E, Fujii H, et al. 2022. Theobromine enhances the conversion of white adipocytes into beige adipocytes in a PPARγ activation-dependent manner. Journal of Nutritional Biochemistry 100:108898

doi: 10.1016/j.jnutbio.2021.108898
[38]

Cova I, Leta V, Mariani C, Pantoni L, Pomati S. 2019. Exploring cocoa properties: is theobromine a cognitive modulator. Psychopharmacology 236:561−72

doi: 10.1007/s00213-019-5172-0
[39]

Kargul B, Özcan M, Peker S, Nakamoto T, Simmons WB, et al. 2012. Evaluation of human enamel surfaces treated with theobromine: a pilot study. Oral Health & Preventive Dentistry 10:275−82

[40]

Camps-Bossacoma M, Pérez-Cano FJ, Franch A, Castell M. 2018. Theobromine is responsible for the effects of cocoa on the antibody immune status of rats. Journal of Nutrition 148:464−71

doi: 10.1093/jn/nxx056
[41]

Sheng Y, Xiang J, Wang Z, Jin J, Wang Y, et al. 2020. Theacrine from Camellia kucha and its health beneficial effects. Frontiers in Nutrition 7:596823

doi: 10.3389/fnut.2020.596823
[42]

Taylor L, Mumford P, Roberts M, Hayward S, Mullins J, et al. 2016. Safety of TeaCrine®, a non-habituating, naturally-occurring purine alkaloid over eight weeks of continuous use. Journal of the International Society of Sports Nutrition 13:2

doi: 10.1186/s12970-016-0113-3
[43]

Li Y, Chen M, Wang C, Li X, Ouyang S, et al. 2015. Theacrine, a purine alkaloid derived from Camellia assamica var. kucha, ameliorates impairments in learning and memory caused by restraint-induced central fatigue. Journal of Functional Foods 16:472−83

doi: 10.1016/j.jff.2015.05.003
[44]

Duan W, Liang L, Pan M, Lu D, Wang T, et al. 2020. Theacrine, a purine alkaloid from kucha, protects against Parkinson's disease through Sirt3 activation. Phytomedicine 77:153281

doi: 10.1016/j.phymed.2020.153281
[45]

Ouyang S, Zhai Y, Wu Y, Xie G, Wang G, et al. 2021. Theacrine, a potent antidepressant purine alkaloid from a special Chinese tea, promotes adult hippocampal neurogenesis in stressed mice. Journal of Agricultural and Food Chemistry 69:7016−27

doi: 10.1021/acs.jafc.1c01514
[46]

Barnes PJ. 2013. Theophylline. American Journal of Respiratory and Critical Care Medicine 188:901−6

doi: 10.1164/rccm.201302-0388PP
[47]

Suzuki T, Takahashi E. 1976. Caffeine biosynthesis in Camellia sinensis. Phytochemistry 15:1235−39

doi: 10.1016/0031-9422(76)85084-4
[48]

Suzuki T. 1972. The participation of S-adenosylmethionine in the biosynthesis of caffeine in the tea plant. FEBS Letters 24:18−20

doi: 10.1016/0014-5793(72)80815-9
[49]

Koshiishi C, Kato A, Yama S, Crozier A, Ashihara H. 2001. A new caffeine biosynthetic pathway in tea leaves: utilisation of adenosine released from the S-adenosyl-L-methionine cycle. FEBS Letters 499:50−54

doi: 10.1016/S0014-5793(01)02512-1
[50]

Xie G, He R, Kurihara H. 2010. Research progress on biosynthesis and catabolism of tea alkaloids. Chinese Journal of Natural Medicines 8:153−60

doi: 10.3724/SP.J.1009.2010.00153
[51]

Zhang Y, Fu J, Zhou Q, Li F, Shen Y, et al. 2022. Metabolite profiling and transcriptome analysis revealed the conserved transcriptional regulation mechanism of caffeine biosynthesis in tea and coffee plants. Journal of Agricultural and Food Chemistry 70:3239−51

doi: 10.1021/acs.jafc.1c06886
[52]

Li P, Ye Z, Fu J, Xu Y, Shen Y, et al. 2022. CsMYB184 regulates caffeine biosynthesis in tea plants. Plant Biotechnology Journal 20:1012−14

doi: 10.1111/pbi.13814
[53]

Kato M, Mizuno K, Crozier A, Fujimura T, Ashihara H. 2000. Caffeine synthase gene from tea leaves. Nature 406:956−7

doi: 10.1038/35023072
[54]

Jin J, Yao M, Ma C, Ma J, Chen L. 2014. Cloning and sequence analysis of the N-methyltransferase gene family involving in caffeine biosynthesis of tea plant. Journal of Tea Science 34:188−94

doi: 10.13305/j.cnki.jts.2014.02.015
[55]

Jin J, Yao M, Ma C, Ma J, Chen L. 2016. Natural allelic variations of TCS1 play a crucial role in caffeine biosynthesis of tea plant and its related species. Plant Physiology and Biochemistry 100:18−26

doi: 10.1016/j.plaphy.2015.12.020
[56]

Liu Y, Jin J, Yao M, Chen L. 2019. Screening, cloning and functional research of the rare allelic variation of caffeine synthase gene (TCS1g) in tea plants. Scientia Agricultura Sinica 52:1772−83

[57]

Jin J, Yao M, Ma C, Ma J, Chen L. 2016. Association mapping of caffeine content with TCS1 in tea plant and its related species. Plant Physiology and Biochemistry 105:251−59

doi: 10.1016/j.plaphy.2016.04.032
[58]

Ma J, Jin J, Yao M, Ma C, Xu Y, et al. 2018. Quantitative trait loci mapping for theobromine and caffeine contents in tea plant (Camellia sinensis). Journal of Agricultural Food Chemistry 66:13321−27

doi: 10.1021/acs.jafc.8b05355
[59]

Zheng X, Ye C, Kato M, Crozier A, Ashihara H. 2002. Theacrine (1,3,7,9-tetramethyluric acid) synthesis in leaves of a Chinese tea, kucha (Camellia assamica var. kucha). Phytochemistry 60:129−34

doi: 10.1016/S0031-9422(02)00086-9
[60]

Wang S, Chen J, Ma J, Jin J, Chen L, Yao M. 2020. Novel insight into theacrine metabolism revealed by transcriptome analysis in bitter tea (Kucha, Camellia sinensis). Scientific Reports 10:6286

doi: 10.1038/s41598-020-62859-2
[61]

Zhang Y, Li Y, Wang Y, Tan L, Cao Z, et al. 2020. Identification and characterization of N9-methyltransferase involved in converting caffeine into non-stimulatory theacrine in tea. Nature Communications 11:1473

doi: 10.1038/s41467-020-15324-7
[62]

Kalberer P. 1965. Breakdown of caffeine in the leaves of Coffea arabica L. Nature 205:597−98

doi: 10.1038/205597a0
[63]

Ashihara H, Gillies FM, Crozier A. 1997. Metabolism of caffeine and related purine alkaloids in leaves of tea (Camellia sinensis L). Plant and Cell Physiology 38:413−19

doi: 10.1093/oxfordjournals.pcp.a029184
[64]

Ashihara H, Kato M, Crozier A. 2011. Distribution, biosynthesis and catabolism of methylxanthines in plants. In Methylxanthines, ed. Fredholm BB. vol 200. Springer, Berlin, Heidelberg. pp. 11−31 https://doi.org/10.1007/978-3-642-13443-2_2

[65]

Chen J, Ma C, Chen L. 2019. 40 years of research on tea germplasm resources in China. China Tea 41:1−5+46

[66]

Wang X, Chen L, Yang Y. 2011. Establishment of core collection for Chinese tea germplasm based on cultivated region grouping and phenotypic data. Frontiers of Agriculture in China 5:344

doi: 10.1007/s11703-011-1097-z
[67]

Jin J, Zhou C, Ma C, Yao M, Ma J, et al. 2014. Identification on purine alkaloids of representative tea germplasms in China. Journal of Plant Genetic Resources 15:279−85

[68]

Song W, Liu B, Yi B, Jiang H, Ma L, et al. 2011. Identification, evaluation and screening on elite and rare tea germplasms from Yunnan Province. Journal of Tea Science 31:45−52

doi: 10.13305/j.cnki.jts.2011.01.008
[69]

Liu Y, Pang D, Jiang H, Tian Y, Li Y, et al. 2021. Biochemical component analysis and specific resource selection of 66 accessions of tea germplasms in Yunnan. Journal of Southern Agriculture 52:693−99

[70]

Wang Z, Chen L. 2011. Japanese tea cultivars and breeding techniques. China Tea 33:10−13

[71]

Takeda Y. 1994. Differences in caffeine and tannin contents between tea cultivars, and application to tea breeding. Japan Agricultural Research Quarterly 28:117−23

[72]

Ogino A, Tanaka J, Taniguchi F, Yamamoto MP, Yamada K. 2009. Detection and characterization of caffeine-less tea plants originated from interspecific hybridization. Breeding Science 59:277−83

doi: 10.1270/jsbbs.59.277
[73]

Hyun DY, Gi GY, Sebastin R, Cho GT, Kim SH, et al. 2020. Utilization of phytochemical and molecular diversity to develop a target-oriented core collection in tea germplasm. Agronomy-Basel 10:1667

doi: 10.3390/agronomy10111667
[74]

Tang Y, Song W, Yi B, Ji P, Wang P, et al. 2010. Identification and evaluation on low caffeine content in tea germplasm. Southwest China Journal of Agricultural Sciences 23:1051−54

doi: 10.16213/j.cnki.scjas.2010.04.032
[75]

Zhang K, Ding Y, Yang J. 2013. Comparative analysis of catechin and caffeine content of wild tea plant in Sichuan-Chongqing region. Chinese Journal of Applied Environmental Biology 19:379−82

doi: 10.3724/SP.J.1145.2013.00379
[76]

Teng J, Zeng Z, Huang Y. 2018. Compositon characteristics of purine alkaloids and biochemical components of Camellia gymnogyna. Guihaia 38: 568−76

[77]

Jin J, Chai Y, Liu Y, Zhang J, Yao M, et al. 2018. Hongyacha, a naturally caffeine-free tea plant from Fujian, China. Journal of Agricultural Food Chemistry 66:11311−19

doi: 10.1021/acs.jafc.8b03433
[78]

Jin J, Jiang C, Yao M, Chen L. 2020. Baiyacha, a wild tea plant naturally occurring high contents of theacrine and 3''-methyl-epigallocatechin gallate from Fujian, China. Scientific Reports 10:9715

doi: 10.1038/s41598-020-66808-x
[79]

Mohanpuria P, Kumar V, Ahuja PS, Yadav SK. 2011. Producing low-caffeine tea through post-transcriptional silencing of caffeine synthase mRNA. Plant Molecular Biology 76:523−34

doi: 10.1007/s11103-011-9785-x
[80]

Ogino A, Taniguchi F, Yoshida K, Matsumoto S, Fukuoka H, et al. 2019. A new DNA marker CafLess-TCS1 for selection of caffeine-less tea plants. Breeding Science 69:393−400

doi: 10.1270/jsbbs.18161
[81]

Li H, Fang K, Qin D, Jiang X, Wu H. 2021. Comparative transcriptome analysis reveals putative genes responsible for high theacrine content in Kucha (Camellia kucha (Chang et Wang) Chang). Tropical Plant Biology 14:82−92

doi: 10.1007/s12042-020-09280-1