International Journal of Pharmaceutical Chemistry and Toxicology
Year Of Started:      2015 Published By:   SBT JOURNALS
Frequency:   Quarterly ISSN:                APPLIED

In vitro assessment of antioxidant capacity of Sri Lankan black tea (Camellia sinensis L.), during storage and its relation to phenolic content.


Black tea is reported to contain natural antioxidants mainly with inherited polyphenolic compounds. In this study, the effect of storage on antioxidant capacity and total polyphenols content of black tea (stored at 25 2 0C and 50 5% RH) produced from major three agro-climatic elevations in Sri Lanka were studied for 36 months period with 6 months assessment interval. The antioxidant capacity measured by DPPH assay had shown significant (P < 0.05) and time-dependent decrease over the experimental period. Compared to fresh black tea, after 36 months of storage even under controlled environment there was shown 38% (high-grown), 41% (mid-grown) and 83% (low-grown) reduced antioxidant capacity. According to FRAP assay, rapid time-dependent antioxidant activity reduction was evident up to 18 months: by 14% in high-grown, 14% in mid-grown and 15% in low-grown, and thereafter the decline was slowed up to 36 months. Interestingly, a time-dependent decrease was observed in the total polyphenols content by 9% in high-grown, by 12% in mid-grown and by 22% in low-grown over the 36 months period. In conclusion, a time-dependant reduction of antioxidant capacity was evident in black tea in this study and it may be due to depletion of total polyphenols content during storage.

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