Molecular Formula | C29H24O12 |
Molar Mass | 564.49 |
Density | 1.777±0.06 g/cm3(Predicted) |
Melting Point | 237-240 °C (decomp)(Solv: water (7732-18-5)) |
Boling Point | 1079.6±65.0 °C(Predicted) |
Flash Point | 336.5°C |
Solubility | Soluble in ethyl acetate, methanol. |
Appearance | Brown yellow powder |
Color | Red to Very Dark Red |
pKa | 6.65±0.20(Predicted) |
Storage Condition | -20°C |
MDL | MFCD03427500 |
Physical and Chemical Properties | Products derived from the fermentation of tea |
Safety Description | 24/25 - Avoid contact with skin and eyes. |
WGK Germany | 3 |
HS Code | 29329990 |
Overview | Theaflavins are important quality components and functional components in black tea. They have various biological activities and pharmacological effects such as lowering blood lipids, lowering blood pressure, anti-oxidation, anti-radiation, antibacterial, and anti-cancer. They are known as "soft gold in tea", and the content of theaflavins in black tea is only 0.5%-2.0%. Theaflavins are a general term for a class of compounds that are soluble in ethyl acetate and have benzophenols formed by the oxidation of polyphenols. Theaflavins have 12 components, of which theaflavins (TF), theaflavin-3-gallate (TFMG), theaflavin-3, 3 '-bisgallate (TFdiG) and theaflavin-3'-gallate (TFM'G) are the four most important theaflavins (see the above figure for chemical structure). The purified product of theaflavins is orange-yellow needle-like crystals with a melting point of 237~240 ℃, soluble in water, methanol, ethanol, acetone, n-butanol and ethyl acetate, and insoluble in ether. Insoluble in chloroform and benzene. Theaflavins solution is bright orange-yellow, the aqueous solution is weakly acidic, and the pH is about 5.7. The color is not affected by the pH of the tea soup extract, but there is a tendency of automatic oxidation in alkaline solution, and it increases with the increase of pH. |
active ingredient of black tea | flavanol oxides in black tea are the most important ones. Theaflavins are formed by the coupling oxidation of catechins under the action of oxidase in tea. There is a benzoxanone ring nucleus in the structure. Enzymatic oxidation of L-EGC and L-EC (or interaction with potassium ferricyanide) can obtain theaflavins. However, L-EC and L-EGCG or ECG and EGC can form theaflavin mono-gallate, and L-ECG and L-EGCG can form theaflavin bisgallate. Catechins with ligated hydroxyl groups in the B ring (such as EGC and EGCG) are easy to form diphenyl dimer (such as diflavanols). If the B ring has ortho hydroxyl groups and ligated hydroxyl groups When the catechins coexist, the two B rings will be oxidized into a fused ring to form a diphenolone skeleton. Figure 1 is the structural formula of theaflavins in black tea |
pharmacological action | theaflavins can inhibit the proliferation of human nasopharyngeal carcinoma CNE2 cells and induce their apoptosis. its action is time-dependent and concentration-dependent, and its mechanism of action may be related to the regulation of cell proliferation and the expression of apoptosis genes. theaflavins can reduce serum uric acid in hyperuricemia mice. Its effect of reducing serum uric acid is related to inhibiting xanthine oxidase activity and regulating mRNA and protein expression levels of related anion transporters. theaflavin can enhance the sensitivity of cervical cancer cells to cisplatin, and its mechanism may be related to increasing the expression of apoptosis-related protein Cleaved Caspase 3, Cleaved Caspase 9, PARP and inhibiting the expression of NF-κB signaling pathway related proteins p-IκBα, p-NF-κB and p-Akt. Theaflavins can effectively delay the inflammatory degeneration process of rat chondrocytes by enhancing the activity of chondrocytes synthesis factor, weakening the activity of decomposition factor and inhibiting the inflammatory reaction of cells, and have a certain protective effect on inflammatory chondrocytes. |
tea red | tea red is the product of further transformation after polyphenol coupling oxidation to form theaflavins. it is a heterologous substance with large molecular difference, with a molecular mass of 700 ~ 40000u, or even larger, brown, and is the main substance forming black tea soup color. the content of black tea is 8.25% ~ 15.6%. In the finished black tea, the ratio of theaflavins to theaflavins is 1:10~12. If the content of theaflavins is too high, the tea soup will appear dark. Tea red is a mixture, and no pure substance has been separated. In the tea soup, tea red is present as potassium salt and calcium salt. Theoglobin (TR) is the main component of the red concentration of black tea soup. It has astringency and irritation, but it is much weaker than theaflavins. TR is easily soluble in water, and some can be converted from water into ethyl acetate or isobutyl ketone. When TR was separated by extraction with 80% aqueous ethanol, nitrogen was found, and 14 amino acids were obtained after acid degradation. TR isolated from water leaching of black tea produces anthocyanins, etc., or flavanols and flavanols gallate, or gallic acid under different hydrolysis conditions. TR is one of the chemical indexes to evaluate the quality of black tea. |
black tea chemistry | study the chemical changes of tea composition produced by black tea during processing. Black tea made from fresh leaves has both enzymatic catalysis and thermochemical reaction. fig. 2 is a diagram of chemical changes during the withering process of black tea. Under normal circumstances, the withering temperature is high, the chemical change is accelerated, and the material consumption is large. Too long withering has the same consequences. The time is too short, the material transformation is not sufficient, the taste is often light and green. The water content of withered leaves is about 65 ~ 70%, which is conducive to the formation of theaflavins. At the beginning of twisting, the chemical changes in the fermentation process will follow. Enzymatic oxidative polymerization surrounding catechins is accompanied by a series of other material transformations. After the withered leaves are twisted, the polyphenol oxidase in the protoplast and the tea polyphenols in the vacuole are kneaded together, and the tea polyphenols such as catechins begin to oxidize rapidly. In 1957, Robert first isolated theaflavins from black tea, and proposed that it was derived from (I)-EGC and (I)-EGCG. In 1964, Tongye et al. studied theaflavins and proposed the structure of theaflavins. In 1972, Sanderson studied the reaction and products of oxidative polymerization of major catechins in tea with polyphenol oxidase preparation, and proposed 11 ways of forming theaflavins, and then confirmed that gallic acid was also involved in the formation of theaflavins. According to the experimental results of Collier in 1973, the theaflavins formed in the manufacture of black tea can be summarized into 9 types. In 1981, Sanderson further proposed a possible way to form theaflavins and theahuanins from the oxidative polymerization of catechins. In 1962, Robert first proposed the possible pathway and structure of theaflavins for the coupling oxidation of theaflavins. In 1969, the research of Brown and some chemists believed that tea red is not a single compound, nor is it formed by a single way that theaflavins continue to oxidize, but is formed by the oxides of tea polyphenols and certain amino acids, sugars, and proteins. A product formed by multiple structures involved in polymerization. In 1969, according to the solubility characteristics of tea red in tea soup, Kasan called some substances that are soluble in n-butanol as red as tea red (equivalent to SI tea red), and some brown substances that are insoluble in n-butanol are called high polymers (equivalent to SII tea red), and proposed methods for the determination of theaflavins, tea red and high polymers. |
preparation | weigh 100g of tea powder, add 1000ml of deionized water (90 ℃) to extract for 30min, and take out the extract; Add 500ml of deionized water (90 ℃) to extract for 30min; The combined leaching solution was filtered with 300 mesh filter cloth and treated with 0.05um ceramic membrane to obtain theaflavin microfiltration solution. pump theaflavin microfiltration liquid from the inlet of heavy phase into a two-stage series centrifugal extractor, and at the same time pump 1/2 of the ethyl acetate solution accumulated in the liquid volume of theaflavin microfiltration liquid. the rotating speed of the two series centrifugal extractors is 3000rpm. collect the light phase outlet liquid (I .e. ester phase solution), and obtain theaflavin extract after vacuum concentration at 40 ℃ and spray drying treatment, of which the purity of theaflavin is 21.35%. |
theaflavins determination | determination of orange pigment components formed by catechin oxidation and reflecting the characteristic pigment of black tea during fermentation. Its content is closely related to the soup color and taste freshness of red broken tea, and the correlation coefficient with the quality of red broken tea is 0.875. According to the chemical analysis method of theaflavins to separate the obtained theaflavins solution, with a 1cm colorimetric cup, at the specified wavelength to determine the E value, calculate the percentage of theaflavins. fig. 3 shows the separation procedure of broken red tea. |
physiological activity | theaflavins not only have color and taste properties, but also have more physiological activities. For example, theaflavins have an inhibitory effect on tensin I invertase, which can reduce blood pressure in patients with hypertension. At a concentration of 100~300 mg/kg, theaflavins have an inhibitory effect on the germination and proliferation of Bacillus botulinum, and can inhibit human saliva. Alpha-amylase activity. |
use | used for content determination/identification/pharmacological experiments, etc. Pharmacological effects: It has the effects of regulating blood lipids and preventing cardiovascular diseases |