Pharmacokinetics, excretion balance, and tissue distribution of [14C]-labeled glycolipids and long chain fatty acids from Dacryopinax spathularia in rats

The pharmacokinetics, excretion balance, and tissue distribution of [14C]-labeled glycolipids from Dacryopinax spathularia (herein referred to as “AM-1”) and [14C]-LCFA equivalents following single or repeated administration to Sprague Dawley rats were evaluated to support the safety assessment of these naturally derived jelly mushroom glycolipids for use as a food ingredient. Rats received equimolar doses of either [14C]-AM-1 or [14C]-LCFA via oral or intravenous administration followed by collection of biological samples at specified intervals. Approximately 88%-101% of the administered dose was recovered in expired air, urine, feces, and carcass following single or repeated oral administration of [14C]-AM-1 at 100 mg/kg or equimolar doses of [14C]-LCFA at 46 mg/kg. Cmax and AUClast for [14C]-AM-1- and [14C]-LCFA-equivalents-derived radioactivity detected by quantitative whole body autoradiography was highest in the tissues of the GI tract, as expected following oral administration. The remaining tissues had low concentrations of test article equivalents relative to the administered dose and no target tissues for residence or accumulation were identified. AM-1 and LCFA are poorly absorbed by the oral route and are primarily eliminated in the feces without absorption. Oral bioavailability of both AM-1 and LCFA including their metabolites is low at approximately 11%.