Dynamics of the Cellular Metabolism of Leptosperin Found in Manuka Honey

Yoji Kato, Masaki Kawai, Shota Kawai, Yayako Okano, Natsumi Rokkaku, Akari Ishisaka, Kaeko Murota, Toshiyuki Nakamura, Yoshimasa Nakamura, Shinichi Ikushiro

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


Leptosperin (methyl syringate β-d-gentiobioside) is abundantly found in manuka honey, which is widely used because of its antibacterial and possible anti-inflammatory activities. The aim of this study was to examine the molecular mechanism underlying the metabolism of leptosperin. Five phytochemicals (leptosperin, methyl syringate (MSYR), glucuronate conjugate of MSYR (MSYR-GA), sulfonate conjugate of MSYR (MSYR-S), and syringic acid (SYR)) were separately incubated with HepG2 and Caco-2 cells. After incubation, we found that the concentration of MSYR decreased, whereas the concentrations of SYR, MSYR-GA, and MSYR-S increased. By profiling with inhibitors and carboxylesterases (CES1, 2), we found that the conversion from MSYR to SYR was mediated by CES1. Lipopolysaccharide-stimulated RAW264.7 cells restored MSYR-GA to MSYR possibly by the secreted β-glucuronidase. All of the mice administered with leptosperin, MSYR, or manuka honey showed higher MSYR (13.84 ± 11.51, 14.29 ± 9.19, or 6.66 ± 2.30 nM) and SYR (1.85 ± 0.66, 6.01 ± 1.20, or 8.16 ± 3.10 nM) levels in the plasma compared with that of the vehicle controls (3.33 ± 1.45 (MSYR) and 1.85 ± 0.66 (SYR) nM). The findings of our study indicate that the unique metabolic pathways of these compounds may account for possible functionalities of manuka honey.

Original languageEnglish
Pages (from-to)10853-10862
Number of pages10
JournalJournal of agricultural and food chemistry
Issue number39
Publication statusPublished - Oct 2 2019


  • carboxylesterase
  • leptosperin
  • metabolism
  • methyl syringate
  • syringic acid

ASJC Scopus subject areas

  • Chemistry(all)
  • Agricultural and Biological Sciences(all)


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