RESUMO
SCOPE: Manuka honey, which shows strong nonperoxide-dependent antibacterial activity, contains unique components, such as methyl syringate 4-O-ß-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. Then, manuka honey (15 g) was fed to healthy human volunteers. MSYR-GA, MSYR-S, and MSYR were detected in both plasma and urine. Within plasma, their levels were highest within 0.5 h to 1 h post-ingestion, and most metabolites disappeared within 3 h. In conjunction with the disappearances, a significant amount of metabolites along with trace leptosperin was excreted in urine within 4 h. To elucidate the detailed metabolisms of leptosperin and MSYR, each compound was separately administered to mice. In each case, MSYR-GA, MSYR-S, and MSYR were detected in both plasma and urine. CONCLUSION: This study shows the major molecular pathway for leptosperin and MSYR metabolism and could facilitate an understanding of biological functions of manuka honey post ingestion.
Assuntos
Ácido Gálico/análogos & derivados , Glicosídeos/metabolismo , Mel/análise , Leptospermum/química , Adulto , Animais , Ácido Gálico/química , Ácido Gálico/metabolismo , Glicosídeos/química , Humanos , Camundongos , Camundongos Endogâmicos ICRRESUMO
Syringic acid is one of the key skeletal structures of plant-derived chemicals. The derivatives of syringic acid have certain biological functions. In this study, a monoclonal antibody to syringic acid-based phytochemicals was prepared and characterized. The obtained antibody reacted with methyl syringate, syringic acid, and leonurine. Methyl syringate is a characteristic compound found in manuka honey, other honey varieties, and plants. Manuka honey was fractionated using HPLC, and the reactivity of the fractions with the antibody was examined. The antibody reacted with the fraction in which methyl syringate was eluted. The amount of methyl syringate in honeys as estimated by ELISA using the antibody had a good linearity compared with that estimated by HPLC. These results suggest that the antibody is applicable for the immunochemical detection of syringic acid derivatives in plants and foods.
