Analysis of green tea compounds and their stability in dentifrices of different pH levels.
In this study, green tea compounds (flavonoids, alkaloids, and phenolic acids) were analyzed in green tea-containing dentifrices, and their stability at different pH levels was evaluated. The compounds were separated under 0.01% phosphoric acid-acetonitrile gradient conditions and detected by photodiode array detector at 210, 280, 300, 335 nm. Column temperature was set at 20°C based on the results of screening various temperatures. Each compound showed good linearity at optimized wavelength as well as showing good precision and accuracy in dentifrices. Using this method, the stability of compounds was investigated in pH 4, 7, 8, and 10 solutions for 96 h, and in pH 7 and pH 10 solutions for 6 months. The green tea compounds were more stable at low pH levels; purine alkaloids were more stable than flavonoids. In particular, gallocatechin (GC), epigallocatechin (EGC), epigallocatechin gallate (EGCG), gallocatechin gallate (GCG), and myricetin almost disappeared in pH 10 solutions after 96 h. In dentifrices, the compounds were gradually decreased until 6 months in both pH types, while gallic acid was increased because of production of galloyl ester of other green tea compounds. Therefore, it is beneficial to adjust to as low a pH as possible when produce green tea-containing dentifrices.
Department of Dental Hygiene, Hanseo University.
Jong-Hwa
JH
Jang
Yong-Duk
YD
Park
Hyo-Kwang
HK
Ahn
Seung-Jin
SJ
Kim
Joo-Young
JY
Lee
Eun-Cheol
EC
Kim
Yeon-Soo
YS
Chang
Yun-Jung
YJ
Song
Ha-Jeong
HJ
Kwon
D002392:Catechin / Q000031:analogs & derivatives / Q000737:chemistry; D002853:Chromatography, Liquid / Q000379:methods*; D003802:Dentifrices / Q000032:analysis / Q000737:chemistry*; D005419:Flavonoids / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D013662:Tea / Q000737:chemistry*; D013696:Temperature; D014100:Toothpastes / Q000032:analysis / Q000737:chemistry
D003802:Dentifrices; D005419:Flavonoids; D013662:Tea; D014100:Toothpastes; C417940:gallocatechin gallate; C040015:myricetin; D002392:Catechin; C045651:epigallocatechin gallate; C057580:gallocatechol