Purpose of Review: The discrepancy between strong bioactivity and health promoting effects of black tea polyphenols despite their poor bioavailability is an elusive phenomenon in tea research. We discuss the theaflavin core benzotropolone and its derivatives as appealing entities filling the missing link. Recent Findings: Health promoting and therapeutic effects of black tea are well documented. Theaflavines are considered to be the major bioactives showing strong anti-oxidative and anti-inflammatory effects. All three isoforms of theaflavins (e.g. TF-1, TF-2 and TF-3) and some higher complex thearubigins contain the benzotropolone (BZ) skeleton as their core structure. Natural occurring BZs such as purpurogallin and others are speculated as potential, but unconfirmed, secondary metabolites of theaflavins by means of biotransformation through gut microbiota. Strong anti-inflammatory bioactivities of BZs corresponding to therapeutic effects had been described. Summary: Benzotropolone derivatives as core structure of theaflavins and other high molecular black tea polyphenols potentially generated by bioconversion might be a missing link explaining the “tea mystery”. Future studies exploiting the molecular mechanisms of biotransformation, particularly microbial treatment and bioactivity will be needed to further consolidate the role of benzotropolones as promising candidates for therapeutic applications.
All Science Journal Classification (ASJC) codes
- Drug Discovery
- Black tea