title: Targeted analysis of conjugated and microbial-derived phenolic metabolites in human urine after consumption of an almond skin phenolic extract.
abstract: A single-blind, placebo-controlled, and randomized trial study was carried out with 16 healthy volunteers (7 men and 5 women). The test group ingested an encapsulated almond skin phenolic extract (884 mg of total polyphenols/dose) containing flavan-3-ols, flavonols, and flavanones, whereas the placebo group ingested microcrystalline cellulose. Our aim in this study was to determine changes in the urinary excretion of conjugated and microbial-derived phenolic metabolites before (-2 to 0 h) and after (0-2, 2-6, 6-10, and 10-24 h) intake of the almond polyphenols compared with the placebo group. For the test group, maximum urinary excretion of (epi)catechin and naringenin conjugates derived from phase II metabolism was attained at 2-6 h after consumption of the almond skin extract and excretions differed from the placebo group during this time period (P ≤ 0.0001). However, excretion of conjugated metabolites of isorhamnetin was highest at 10-24 h and did not differ from the placebo group during this time (P > 0.05). Hydroxyphenylvalerolactones reached maximum urinary levels at 6-10 h after consumption of almond polyphenols, and excretion differed from the placebo group during this time period (P = 0.0004). For the test group, excretions of phenolic acids (hydroxyphenylpropionic, hydroxyphenylacetic, hydroxybenzoic, and hydroxycinnamic acids) did not differ from the placebo group at any time period of urine collection (P > 0.05). The findings presented in this work provide evidence concerning the bioavailability of almond skin polyphenols considering the effects of both phase II and microbial metabolism.
authors.affiliation: Instituto de Fermentaciones Industriales, 28006 Madrid, Spain.
authors.forename: Ignacio
authors.initials: I
authors.lastname: Garrido
authors.forename: Mireia
authors.initials: M
authors.lastname: Urpi-Sarda
authors.forename: María
authors.initials: M
authors.lastname: Monagas
authors.forename: Carmen
authors.initials: C
authors.lastname: Gómez-Cordovés
authors.forename: Pedro J
authors.initials: PJ
authors.lastname: Martín-Alvarez
authors.forename: Rafael
authors.initials: R
authors.lastname: Llorach
authors.forename: Begoña
authors.initials: B
authors.lastname: Bartolomé
authors.forename: Cristina
authors.initials: C
authors.lastname: Andrés-Lacueva
mesh_terms: D000328:Adult; D001419:Bacteria / Q000378:metabolism*; D001682:Biological Availability; D003106:Colon / Q000382:microbiology; D005260:Female; D044950:Flavanones / Q000008:administration & dosage; D005419:Flavonoids / Q000008:administration & dosage* / Q000378:metabolism / Q000493:pharmacokinetics* / Q000652:urine; D044948:Flavonols / Q000008:administration & dosage / Q000652:urine; D006801:Humans; D008297:Male; D010636:Phenols / Q000008:administration & dosage / Q000493:pharmacokinetics; D010919:Placebos; D010936:Plant Extracts / Q000008:administration & dosage*; D059808:Polyphenols; D027861:Prunus / Q000737:chemistry*; D011794:Quercetin / Q000031:analogs & derivatives; D012639:Seeds / Q000737:chemistry*
chemical_list: D044950:Flavanones; D005419:Flavonoids; D044948:Flavonols; D010636:Phenols; D010919:Placebos; D010936:Plant Extracts; D059808:Polyphenols; C047368:3-methylquercetin; C404987:flavan-3-ol; D011794:Quercetin