Research progress on theaflavins: efficacy, formation, and preparation

Abstract

Background: Theaflavins (TFs) are a category of natural compounds characterized with the benzotropolone skeleton. The prominent benefits of TFs have been well documented. Amount of research were conducted and excellent achievements were disclosed during the past years. However, as far as we know, there is no comprehensive review about TFs.Scope and approach: This review summarized the recent research progress. The activity of TFs on anti-oxidation, anti-mutagenicity, hypolipidemic, anti-inflammatory, anti-cancer, anti-viral effect as well as the epidemiological cure were sorted. Converging pioneer literature and deduction, the underlying formation mechanism of TFs was proposed. Subsequently, acquisition of TFs was pointed out to be the fundament for further research. Accelerated by enzyme, bio-synthesis of TFs were reviewed simultaneously. At the end, employing modern analysis instrument and technology, isolations of TFs were enumerated.Key findings and conclusions: Structure of the skeleton as well as functional groups were paramount related with the bio-activity of TFs. Meanwhile, oxidation pathway of two catechin molecules to form TFs were hypothesized. Also, ascertainment of the several therapeutic efficiency of the family members of TFs would be the next step in the future.

Theaflavin alleviates inflammatory response and brain injury induced by cerebral hemorrhage via inhibiting the nuclear transcription factor kappa β-related pathway in rats

“…Theaflavin (TF), first found by Roberts et al 17 from black tea, has been demonstrated as having various biological functions, such as radical scavenging, antimutagenicity, hypolipidemic, anticancers, antiviral, as well as anti-inflammatory activity. 18 Kim et al 19 demonstrated that TFs significantly reduced the mRNA level of the lipopolysaccharide (LPS)-induced IL-6, monocyte chemoattractant protein-1, and intercellular adhesion molecule-1 in bone marrow-derived macrophages, inhibited the cytosolic IκBα protein degradation, and blocked the nuclear translocation of RelA (NF-κβ-p65), suggesting that inhibition of pro-inflammatory mediator production by TFs occurred via blocking of NF-κβ signaling pathway. Ukil et al 20 also found that pretreatment with TF- 3,3′-digallate markedly inhibited trinitrobenzene sulfonic acid (TNBS)-induced increases in nuclear localization of NF-κβ, cytosolic IkappaB kinase activity, and preserved IκBα in colon tissue.…”

Synthesis of Theaflavins and Their Functions

“…TFs include TF1, TF2a, TF2b, and TF3 ( Figure 1 ). It is known that TFs account for 2–6% in the dry weight of solids in brewed black tea approximately [ 4 ].…”

“…TFs possess a benzotropolone skeleton. These compounds are produced from their parent catechins ( Figure 2 ) [epicatechin (EC), ECG, epigallocatechin (EGC), and EGCG] by polyphenol oxidase (PPO) or peroxidase (POD) in fresh green tea leaves during the production of black tea leaves or green tea fermentation [ 1 , 2 , 3 , 4 ].…”

“…Enzymes such as polyphenol oxidase and peroxidase are present in tea plant leaves, which, for non-fermented tea, are either steamed, boiled, microwaved or electrically heated to inactivate endogenous oxidases. Black tea leaves are tea leaves in which green tea catechins are oxidized by endogenous polyphenol oxidase or peroxidase during the fermentation process [ 1 , 2 , 3 , 4 ].…”

Anti-diabetic effects of a theaflavin-enriched black tea extract in the obese ZDF rat model

“…Theaflavines are considered to be the major bioactives. Four different isoforms such as theaflavin (TF-1), theaflavin-3-O-gallate (TF-2a), theaflavin-3′-O-gallate (TF-2b) and theaflavin-3,3′-O-O-digallate (TF-3) have been described with strong anti-oxidative and anti-inflammatory effects (de Mejia et al, 2009;Gosslau et al, 2018;He, 2017;Ho et al, 2008;Khan and Mukhtar, 2007;Li et al, 2013;Sang et al, 2011;Sharma and Rao, 2009;Yang et al, 2009). Previously, significant anti-inflammatory effects of our theaflavin-enriched black tea extract (BTE) in cell-based, animal, and clinical settings had been demonstrated (Arent et al, 2010;Gosslau et al, 2011;Gosslau et al, 2008).…”