In vivo absorption and metabolism of leptosperin and methyl syringate, abundantly present in manuka honey.

Scope: Manuka honey, which shows strong nonperoxide-dependent antibacterial activity, contains unique components, such as methyl syringate 4-O-β-D-gentiobioside (leptosperin) and its aglycone, methyl syringate (MSYR). To determine the potential for biological activity evoked by the ingestion of leptosperin and MSYR, we investigated the absorption and metabolism of these components in manuka honey.

Methods And Results: The incubation of MSYR with liver microsomes or S9 fractions in vitro resulted in the formation of MSYR-glucuronide (MSYR-GA), MSYR-sulfate (MSYR-S), and syringic acid as metabolites.