A comparison of the production of polyphenol contents and the expression of genes involved in Vietnamese tea cultivars
2019
Nguyen, T. L. | Luu, H. L. | Duong, T. D. | Nguyen, H. D. | Hoang, T. T. Y. | Huynh, T. T. H
Tea (Camellia sinensis) is a popular health beverage which is consumed all over the world due to its good aroma and taste. Tea consumption is also considered to reduce the risk of several diseases in humans, including cardiovascular diseases, diabetes and cancers. Recent studies have shown that polyphenols derived from tea may contribute to the majority of these pharmaceutical properties. Among all the tea polyphenols, catechins are the main components that include (−)-epicatechin (EC), (−)-epicatechin gallate (ECG), (−)-epigallocatechin (EGC), (−)-epigallocatechin-3 gallate (EGCG), (+)-catechin (C), (−)-catechin gallate (CG), (−)-gallocatechin (GC), and (−)-gallocatechingallate (GCG). In the present work, four catechins (C, EGC, ECG, and EGCG) and two anthocyanidins (cyanidin 3-O-glucoside and delphinidin 3-O-glucoside) in two Vietnamese tea cultivars, Trungduxanh and Trungdutim, were quantitatively detected by high-performance liquid chromatography. The total catechin content in Trungduxanh was generally higher than that in Trungdutim. By contrast, the concentrations of the two anthocyanidins were lower in Trungduxanh than that in Trungdutim, suggesting that Trungdutim tea accumulates anthocyanins to produce purple colour in buds and leaves, rather than converting them into catechins. Real-time PCR was also performed to analyse the expression levels of leucocyanidin reductase (LAR) and anthocyanidin reductase (ANR) genes, which are involved in catechin biosynthesis. In accordance with the HPLC analysis, the qPCR results showed that the transcripts of both genes in Trungduxanh tea were more abundant than in Trungdutim tea.
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