Tea Research Institute of the Chinese Academy of Agricultural Sciences, China
Tea catechins have various activities that greatly benefit human health, for example, antioxidative, anti-hypertensive and anticarcinogenic activities. Catechins and their oxidation products are one of the major secondary metabolites accumulated in tea plants which are major contributors to tea quality attributes. Catechins composition and content determine the processing suitability of tea cultivars. Understanding of the genetic basis of catechin traits is important for tea breeding programs.
In this study, natural variations of catechin content were detected among a set of representative Chinese core collection tea germplasms including wild related species, landraces, improved cultivars and genetic materials, etc. Two of them with different catechin contents, morphological characteristics and other important agronomical traits were selected to produce a controlled F1 segregation population. A high density SSR/SNP genetic linkage map was constructed for QTLs analysis. Two major and stable QTLs associated with catechin content was identified using the linkage mapping.Flavonoid-3',5'-hydroxylase (F3ʼ5ʼH), chalcone syntheses(CHS) were subsequently found to be the functional genes using BSR-Seq and association analysis. Meanwhile, ten functional SNP loci were validated in F3ʼ5ʼH and CHS, respectively. Two functional markers were successfully developed for further marker-assisted selection and molecular breeding of catechin content in tea plants.
Liang Chen completed his PhD on Tea Science from Zhejiang University, China and postdoctoral studies from Cornell University, USA. He also visited Japan, Italy and The Netherlands as senior visiting professor. Now, he is the professor on tea genetic resources, genetics, breeding and genomics in the Tea Research Institute, Chinese Academy of Agricultural Sciences (TRICAAS). He is the leading expert of Tea Germplasm Group of the CAAS through the Agricultural Science and Technology Innovation Program. He has been appointed twice as Honorary Scientist of the RDA of the Republic of Korea. He has published more than 50 papers in reputed international journals and has been serving as several editorial board members of reputed committees.
1Novosibirsk State Pedagogical University, Russia
2Institute of Solid State Chemistry and Mechanochemistry of Siberian Branch of Russia Academy of Sciences, Russia
Quercetin is the dietary flavonoid that has attracted the attention mainly because of its biological activity and its widespread availability in dietary sources: fruits and vegetables. Quercetin has different pharmacological actions including anti-inflammatory, anticancer, antidiabetic, neuroprotective, cardioprotective, anti-allergic etc. (M. Buleaet al., 2019). But the best form of its intake and the mechanisms of its antidiabetic action are unclear now.
To solve these issues, at least partially, an experiment was performed on Sprague-Dawley rats (n=62). The animals were divided into 7 groups (G): the G1-control, the rest were injected with 10% solution of alloxan (0.1 ml/100 g body mass) to produce diabetes mellitus (DM). Animals of G1 and G2 were kept on standard diet, rats of G3-G7 took quercetin (5 mg /100 g b.m.) per os. Rats of G3 and G4 received the initial quercetin, G5 - quercetin, adsorbed on the surface of cellulose; G6 - quercetin, mechanochemically adsorbed on cellulose; G7 - quercetin, encapsulated in the cellulose molecule.
It was found that the initial quercetin (G3-G4) reduced the blood glucose concentration already on the 3-d day of the study from 33.3 to 25 mmol/l, but only for 3 days, while adsorbed on the surface (G5) and encapsulated quercetin (G7) significantly decreased the level of glucose to 18.4 mmol/l only from the 9-th day of observation till the end of experiment - the 24-th day.
Analysis of the glycogen content in the liver revealed that in animals with DM, consuming standard food, there was a decrease of polysaccharide from 402±38 to 221±60* mg/100 g of wet weight, while in rats receiving adsorbed and encapsulated quercetin the glycogen content was significantly higher and almost reached the control level - 322±33 and 328±44 mg/100 g of wet weight, respectively.
Plasma analysis showed that all forms of quercetin, but especially G5 and G7, contributed to a decrease (in mmol/l), compare with G2, in such parameters as creatinine (from 109.910±6.87 to 68.2±2.3), urea (from 18.3±1.6 to 7.0±0.6), uric acid (from 105.3±10.2 to 33.8±3.6), phosphorus (from 3.23±0.6 to 2.0±0.2) and also increased the total protein to control values (from 41.0±1.0 to 70.2±1.6).
Thus, the adsorbed and encapsulated quercetin had the most pronounced effects on some parameters of carbohydrate, lipid, protein and mineral metabolism in rats. The mechanisms of their action require the further study.
The research was partly carried out at the expense of a grant from the Russia science Foundation (project no. 16-13-10200)
Aizman Roman is the Head of the Dept. of Human Anatomy, Physiology and Life Safety, Director of the Scientific Research Institute of Health and Safety, Professor of Novosibirsk State Pedagogical University, Russia.