title: Inhibitory effect and mechanisms of an anthocyanins- and anthocyanidins-rich extract from purple-shoot tea on colorectal carcinoma cell proliferation.
abstract: One newly bred variety of tea cultivar, purple-shoot tea, was selected to evaluate its antiproliferative effects on colorectal carcinoma cells, as well as normal colon cells. The phytochemicals and identified catechins of purple-shoot tea extract (PTE) were significantly higher than that of ordinary tea, especially the anthocyanins (surpassed by 135-fold) and anthocyanidins (surpassed by 3.5-fold). PTE inhibited the proliferation of COLO 320DM (IC(50) = 64.9 μg/mL) and HT-29 (IC(50) = 55.2 μg/mL) by blocking cell cycle progression during the G(0)/G(1) phase and inducing apoptotic death. Western blotting indicated that PTE induced cell cycle arrest by reducing the expression of cyclin E and cyclin D1 in COLO 320DM and the upregulation of p21 and p27 cyclin-dependent kinase inhibitors in HT-29. Two cells treated with PTE also indicated the cleavage of PARP, activation of caspase 3, and an increased Bax/Bcl-2 ratio. Our results showed that PTE is a potential novel dietary agent for colorectal cancer chemoprevention.
authors.affiliation: Department of Medical Laboratory Science and Biotechnology, Yuanpei University, Hsinchu 30015, Taiwan.
authors.forename: Chih-Ping
authors.initials: CP
authors.lastname: Hsu
authors.forename: Yi-Ting
authors.initials: YT
authors.lastname: Shih
authors.forename: Bor-Ru
authors.initials: BR
authors.lastname: Lin
authors.forename: Chui-Feng
authors.initials: CF
authors.lastname: Chiu
authors.forename: Chih-Cheng
authors.initials: CC
authors.lastname: Lin
mesh_terms: D000818:Animals; D000872:Anthocyanins / Q000008:administration & dosage*; D017209:Apoptosis / Q000187:drug effects; D002453:Cell Cycle / Q000187:drug effects; D002460:Cell Line; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D003110:Colonic Neoplasms; D015179:Colorectal Neoplasms / Q000473:pathology*; D004847:Epithelial Cells; D005419:Flavonoids / Q000032:analysis; D019073:HT29 Cells; D006801:Humans; D010936:Plant Extracts / Q000008:administration & dosage* / Q000737:chemistry; D051381:Rats; D013662:Tea / Q000737:chemistry*
chemical_list: D000872:Anthocyanins; D005419:Flavonoids; D010936:Plant Extracts; D013662:Tea