Theaflavin

Theaflavin
IUPAC name	3,4,5-trihydroxy-1,8-bis[(2R,3R)-3,5,7- trihydroxy-2-chromanyl]-6-benzo[7]annulenone
Identifiers
CAS number	4670-05-7
PubChem	114777
SMILES	C1C(C(OC2=CC(=CC(=C21)O)O)C3=CC(=O)C(=C4C(=C3)C (=CC(=C4O)O)C5C(CC6=C(C=C(C=C6O5)O)O)O)O)O
Properties
Molecular formula	C29H24O12
Molar mass	564.49 g mol−1
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Theaflavin (TF) and its derivatives, known collectively as theaflavins, are antioxidant polyphenols Flavan-3-ols that are formed from catechins such as in tea leaves during the enzymatic oxidation (called fermentation by the tea trade) of tea leaves, such as in black tea. Theaflavins are types of thearubigins, and are therefore reddish in color. Analogous compounds include EGCG in green tea, theaflavins are not found in green tea. Despite huge implications regarding health benefits, as of 2008, little is known about the bioavailability of these compounds in black tea,^[1] therefore it is NOT safe to assume that simply drinking black tea will bring out health benefits listed below as there is little known how well compounds are absorbed into the bloodstream. What is known is that EGCG will metabolize into some theaflavins in the liver.

Health

HIV and dementia

Several tea polyphenols, especially those with galloyl moiety, can inhibit HIV-1 replication with multiple mechanisms of action. Theaflavin derivatives have been found to have more potent anti-HIV-1 activity than catechin derivatives in laboratory investigations.^[2]

Epigallocatechin gallate (EGCG), a catechin in green tea, binds to gp120, which works in conjunction with gp41, itself blocked by TF-3 (a theaflavin), both receptors of which HIV hijacks to enter into healthy human immune cells. Therefore, former and latter compounds have considerable potential to block HIV entry, though in real life situations other factors may complicate matters. More studies need to be done. See List section below.

Like EGCG, Theaflavins and Thearubigins compounds found in black teas penetrate the blood brain barrier, and have been shown to be effective against dementia in aging as well as AIDS related dementia plaques in vitro.

Cholesterol

Theaflavins have also been found to reduce blood cholesterol levels in human trials, both total and LDL.^[3]

Cancer

Theaflavins act on numerous points regulating cancer cell growth, survival, and metastasis, including effects at the DNA, RNA, and protein levels.^[1]

• Tea polyphenols including theaflavins are found to reduce angiogenesis^[1], which is implicated in non-liquid cancers, an area of intense current research, by decreasing vascular endothelial growth factor production and receptor phosphorylation.
• Nitric oxide production was reduced by EGCG and black tea theaflavins by suppressing inducible nitric oxide synthase via blocking nuclear translocation of the NF-kappaB as a result of decreased IkappaB kinase activity.^[1]
• Metastasis is inhibited via effects on Urokinase and Matrix metalloproteinases.^[1]
• Three black tea theaflavins, namely theaflavin 3-O-gallate, theaflavin 3’-O-gallate, theaflavin 3,3’di-O-gallate and thearubigins as mimics the effects of insulin/IGF-1 action on mammalian FOXO1a, which is involved in longevity and aging. Furthermore, EGCG's effects on FOX01a are also due to its being converted to Thearubigins.^[1]
• Theaflavin inhibited tumor necrosis factor-alpha mediated Interleukin-8 gene expression, as measured by luciferase assay and Northern blot analysis, at concentrations of 10 and 30 microg/mL.^[1]
• TF-2 inhibits colon cancer linked gene COX-2, even more than EGCG^[4]
• TF-3 is a potent scavenger of superoxide, even more so than EGCG.^[5]

Oxidation

Oxidation of theaflavins produce many products, including bistheaflavin-A and bistheaflavin-B.

List of Theaflavins with health benefits

• Theaflavin-3'-monogallate (TFMG, TF-2) causes apoptosis in colon cancer cells.^[4]
• Theaflavin-3,3'-digallate (TFDG, TF3) binds to gp41 of HIV as well as inhibit 3CLPro of severe acute respiratory syndrome (SARS).^[6]
• 3-Isotheaflavin-3-gallate (TF2B) inhibits 3CLPro of SARS.^[6]

See also

• List of phytochemicals and foods in which they are prominent

References

1. ^ ^{a b c d e f g} Scientific Abstracts: January 2009 Abstracts: Theaflavin - Life Extension
2. ^ Liu S, Lu H, Zhao Q, et al. (2005). "Theaflavin derivatives in black tea and catechin derivatives in green tea inhibit HIV-1 entry by targeting gp41". Biochim. Biophys. Acta 1723 (1-3): 270–81. doi:10.1016/j.bbagen.2005.02.012. PMID 15823507. 
3. ^ Maron DJ, Lu GP, Cai NS, et al. (2003). "Cholesterol-lowering effect of a theaflavin-enriched green tea extract: a randomized controlled trial". Arch. Intern. Med. 163 (12): 1448–53. doi:10.1001/archinte.163.12.1448. PMID 12824094. 
4. ^ ^{a b} AnnieAppleseedProject.org
5. ^ Journal of Agricultural and Food Chemistry:Inhibition of Xanthine Oxidase and Suppression of Intracellular Reactive Oxygen Species in HL-60 Cells by Theaflavin-3,3‘-digallate, (−)-Epigallocatechin-3-gallate, and Propyl Gallate
6. ^ ^{a b} Chia-Nan Chen1, Coney P. C. Lin, Kuo-Kuei Huang, Wei-Cheng Chen, Hsin-Pang Hsieh, Po-Huang Liang and John T.-A. Hsu (2005). "Inhibition of SARS-CoV 3C-like Protease Activity by Theaflavin-3,3'-digallate (TF3)". Evidence-based Compl. And Alt. Medicine 2 (2): 209–215. doi:10.1093/ecam/neh081. PMID 15937562.