title: Differing chemical compositions of three teas may explain their different effects on acute blood pressure in spontaneously hypertensive rats.
abstract: BACKGROUND
  Heavy tea consumption is suggested to be unsuitable for hypertensive people. However, the bioactive substances in different varieties of tea leaves are very different. This study compares the effects of three Chinese teas - C. sinensis, C. ptilophylla and C. assamica var. kucha - on blood pressure (BP) and heart rate in spontaneously hypertensive rats (SHRs).
  
  
  RESULTS
  Intragastric administration of C. sinensis extract led to an acute increase in systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate in SHRs. However, C. ptilophylla and C. assamica var. kucha exerted no obvious influences on SBP, DBP or heart rate. Similar to the extract of C. sinensis, intragastric administration of caffeine also led to an acute increase in BP and heart rate in SHRs. In contrast, theobromine and theacrine - purine alkaloids predominantly contained in C. ptilophylla and C. assamica var. kucha, respectively - had no pressor effects. The effect of caffeine on BP was related to the regulation of plasma epinephrine and norepinephrine levels in SHRs.
  
  
  CONCLUSIONS
  The different effects of C. sinensis, C. ptilophylla and C. assamica var. kucha on BP might be explained, at least partially, by the differences in the varieties and contents of purine alkaloids.
authors.affiliation: Pharmacy College, Jinan University, Guangzhou, China.
authors.forename: Shan-Bing
authors.initials: SB
authors.lastname: Li
authors.forename: Yi-Fang
authors.initials: YF
authors.lastname: Li
authors.forename: Zhong-Fu
authors.initials: ZF
authors.lastname: Mao
authors.forename: Hui-Hua
authors.initials: HH
authors.lastname: Hu
authors.forename: Shu-Hua
authors.initials: SH
authors.lastname: Ouyang
authors.forename: Yan-Ping
authors.initials: YP
authors.lastname: Wu
authors.forename: Bun
authors.initials: B
authors.lastname: Tsoi
authors.forename: Pin
authors.initials: P
authors.lastname: Gong
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kurihara
authors.forename: Rong-Rong
authors.initials: RR
authors.lastname: He
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D002110:Caffeine / Q000494:pharmacology; D028241:Camellia sinensis / Q000737:chemistry* / Q000145:classification; D004837:Epinephrine / Q000097:blood; D006973:Hypertension / Q000097:blood / Q000503:physiopathology; D008297:Male; D009638:Norepinephrine / Q000097:blood; D010936:Plant Extracts / Q000494:pharmacology*; D011918:Rats, Inbred SHR; D017208:Rats, Wistar; D013045:Species Specificity; D013662:Tea / Q000737:chemistry* / Q000145:classification; D013805:Theobromine / Q000494:pharmacology; D014527:Uric Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D014970:Xanthines / Q000494:pharmacology*
chemical_list: D010936:Plant Extracts; D013662:Tea; D014970:Xanthines; D014527:Uric Acid; D002110:Caffeine; C077059:1,3,7,9-tetramethyluric acid; D013805:Theobromine; D009638:Norepinephrine; D004837:Epinephrine
keywords: C. assamica var. kucha; C. ptilophylla; C. sinensis; blood pressure; caffeine; spontaneously hypertensive rats