Assessment of the polyphenolic composition of the organic extracts of Mauritian black teas: a potential contributor to their antioxidant functions
Version: 1,
Uploaded by: Administrator,
Date Uploaded:
29 August 2022
Warning
You are about to be redirected to a website not operated by the Mauritius Research and Innovation Council. Kindly note that we are not responsible for the availability or content of the linked site. Are you sure you want to leave this page?
There is increasing interest in the emerging view that tea improves the antioxidant status in vivo and thereby helps to
lower risk of certain types of cancer, coronary heart disease and stroke and its component biofactors could provide prophylactic
potential for these diseases. The polyphenolic composition and the antioxidant properties of organic extracts (acetone/methanol)
of Mauritian commercial black teas were evaluated. HPLC data of the individual compounds revealed remarkably high levels
(+)-Catechin ((+)-C), (−)-epicatechin ((−)-EC), (−)-epicatechin 3-gallate ((−)-ECG), (−)-epigallocatechin ((−)-EGC), (−)-
epigallocatechin 3-gallate ((−)-EGCG) and gallic acid. Analysis of hydrolysed extracts indicated that quercetin was the
dominant flavonol aglycone with traces of myricetin and kaempferol. Based on the Ferric Reducing Antioxidant Power (FRAP)
and the Trolox Equivalent Antioxidant Capacity (TEAC) assays Extra tea from Bois Cheri exhibited the highest antioxidant ´
potential. Linear regression analyses showed that the antioxidant capacities of the organic extracts are strongly influenced by
total phenols (TEAC: r = 0.95 and FRAP: r = 0.96) and to a lesser extent by total proanthocyanidin and total flavonoid
contents. Catechins and gallic acid seem to add up to the overall antioxidant capacity of black tea extracts. The fresh tea
leaves had high levels of total phenols, total flavonoids, total proanthocyanidin and exhibited greater antioxidant potential when
compared with black teas. Organic extracts of endemic teas represent useful source of phenolic antioxidants supplements for
prophylactic use.
Keywords
Black teas,dietary antioxidants,organic tea extracts,total phenols,flavonoids,proanthocyanidins,catechins,cancer,coronary heart disease and stroke