Abstract:
Polyphenolic fractions in tea are potent bioactive mo
lecules. In this study, the polyphenolic composition
of 25 different types of Kenyan tea cultivars was de
termined using the HPLC and the Folins Ciocalteus
spectrophotometric methods. Total Polyphenols, Total Ca
techins, individual catechins and Antioxidant
Activity were significantly (P<0.05)
different among tea varieties, with green tea had the highest levels
of Total Polyphenols ranging from (19.70-26.12%), TC
(8.51%-17.60%), indivi
dual catechins, and AA
(86.65-94.50%).
In vitro
bioassay carried out using 2, 2’-di
phenyl picrylhydrazyl radical showed
epigallocatechin gallate was the most potent catechin and the most potent in antioxidant activity
(r=0.968***). Epigallocatechin (r=0.659***, p<0.001),
Epicatechigallate (r=0.454*, p<0.001) and
Epicatechin (EC) (r=0.780***, p<0.001) showed signifi
cant (p<0.05) antioxidant activity. Black tea
contained high levels of Theaflavins and Thear
ubigins (2.072% to 17.12%), respectively) which
accounted for its antioxidant activit
y (r=0.803*** and r=0.859***, respectiv
ely). Gallic acid also showed
significant (r=0.530*) contribution to the antioxidant
activity in black
tea. Data obtained from this study
reveals that different Kenyan tea cultivars have
different polyphenolic co
mposition which imparts on
their unique biochemical qualities. Gr
een and white tea products are rich
in catechins, black tea products
are rich in TFs and TRs while purple teas are rich in anthocyanins