BIOTRANSFORMATION OF SHIKONIN BY HUMAN INTESTINAL BACTERIA

The bacterial transformation of shikonin (1) in culture media has been investigated using human intestinal bacteria. Of 24 anaerobes tested, Bacteroides fragilis subsp. thetaotus showed an ability to transform 1 extensively to ten metabolites, five monomers; anhydroalkannin (2), deoxyshikonin (3), cycloshikonin (4), metaboshikonin I (5) and II (6), and five dimers; shikometabolins A (7), B (8), C (9), D (10) and E (1 1), after anaerobic incubation for 3 days. The structures of these met abolites were determined mainly by 2D-NMR including the INADEQUATE exp eriment.