Epitheaflavic acid

During fermentation in the preparation of black tea, oxidative polymerization of flavanols occurs with the formation of theaflavin, theaflavingallates, thearubigins, and epitheaflavic acid [44]. 

Berkowitz, J. E., Coggon, R, and Sanderson, G. W. 1971. Formation of epitheaflavic acid and its transformation to thearubigins during tea fermentation. Phytochemistry 10 2271-78. 

Episiaresinolic acid, in D-10210 Epitaxifolin, in P-10050 10-Epiteuclatriol, in G-10133 Epitheaflavic acid, in T-20113 Epitheaflavic acid 3 -gallate, in T-20113 Epitinophylloloside, in E-10101... 

The enzymatic oxidation of flavanols via the corresponding o-quinones gives theaflavins (Formula 21.6, IX-XIt bright ted color, good solubility), bisflavanols (XIH-XV colorless), and epitheaflavic acids (XVI, XVII bright red color, excellent solubility). The theaflavins and epitheaflavic acids are important ben-zotropolone derivatives that impart color to black tea. 

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