Bacterial deconjugation of arbutin by Escherichia coli

Cystinol(R) akut containing arbutin was developed as an antiseptic since it liberates hydroquinone in the urine. The in vivo release of hydroquinone from arbutin with or without addition of glusulase or an E.coli suspension was investigated in 4 volunteers. They ingested 6 dragees Cystinol(R), akut (420 mg arbutin equivalent to 168 mg hydroquinone), urine was sampled and assayed by a validated HPLC method. Results: In comparison to incubation with glusulase the E. coli-suspension resulted in a 2.3fold higher increase in free hydroquinone. When separating bacteria from the urine, the hydroquinone concentration in bacteria was 20fold higher than in the supernatant. Consequences: Glucuronic acid or sulfuric acid conjugates of hydroquinones obviously are taken up, enriched and metabolized to hydroquinone by bacteria. Deconjugation of hydroquinone likely is catalyzed by intracellular enzymes presumably present in bacterial cytoplasm; comparable activities in eucaryotic cells usually are localized in lysosomes. Alkalization of the urine seems not to be a prerequisite to improve the antiseptic properties of hydroquinone released from arbutin.