title: Does excretion of secondary metabolites always involve a measurable metabolic cost? Fate of plant antifeedant salicin in common brushtail possum, Trichosurus vulpecula.
abstract: Salicin was administered orally to six brushtail possums by incorporation in food for six days at three dose levels (0.05, 0.5, and 1.5% wet weight), giving mean +/- SD daily intakes of 0.31 +/- 0.09, 2.76 +/- 0.75, and 6.04 +/- 1.12 mmol salicin. Metabolites were identified by mass spectrometry and assayed by HPLC. Salicyl alcohol glucuronide accounted for 56-64% of urinary metabolites over the three doses, salicyluric acid 15-26%, salicin 10-18%, and there were smaller amounts of free (2-4%) and conjugated (0-6%) salicylic acid. beta,2-Dihydroxyphenylpropionic acid was a minor metabolite. The hydrolysis of dietary salicin enabled reconjugation of its aglycone, salicyl alcohol, with a more polar sugar, glucuronic acid, thus enhancing its renal excretion and resulting in little net loss of substrates for conjugation and a low measurable metabolic cost of excretion.
authors.affiliation: School of Pharmacy, University of Tasmania, Hobart Tas, Australia.
authors.forename: S
authors.initials: S
authors.lastname: McLean
authors.forename: G J
authors.initials: GJ
authors.lastname: Pass
authors.forename: W J
authors.initials: WJ
authors.lastname: Foley
authors.forename: S
authors.initials: S
authors.lastname: Brandon
authors.forename: N W
authors.initials: NW
authors.lastname: Davies
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001592:Benzyl Alcohols / Q000378:metabolism / Q000493:pharmacokinetics*; D004305:Dose-Response Relationship, Drug; D004734:Energy Metabolism; D005960:Glucosides; D008297:Male; D008394:Marsupialia / Q000502:physiology*; D013058:Mass Spectrometry; D010945:Plants, Edible / Q000737:chemistry*
chemical_list: D001592:Benzyl Alcohols; D005960:Glucosides; C005696:salicin