title: Effects of human oral mucosal tissue, saliva, and oral microflora on intraoral metabolism and bioactivation of black raspberry anthocyanins.
abstract: Our oral cancer chemoprevention trial data implied that patient-specific differences in local retention and metabolism of freeze-dried components of black raspberries (BRB) affected therapeutic responsiveness. Subsequent studies have confirmed that anthocyanins are key contributors to BRB's chemopreventive effects. Consequently, functional assays, immunoblotting, and immunohistochemical analyses to evaluate levels and distribution of BRB anthocyanin-relevant metabolic enzymes in human oral tissues were conducted. Liquid chromatography/tandem mass spectrometry (LC/MS-MS) analyses of time course saliva samples collected following BRB rinses were conducted to assess local pharmacokinetics and compare the capacities of three different BRB rinse formulations to provide sustained intraoral levels of anthocyanins. Protein profiles showed the presence of key metabolic enzymes in all 15 oral mucosal tissues evaluated, whereas immunohistochemistry confirmed these enzymes were distributed within surface oral epithelia and terminal salivary ducts. β-Glucosidase assays confirmed that whole and microflora-reduced saliva can deglycosylate BRB anthocyanins, enabling generation of the bioactive aglycone, cyanidin. LC/MS-MS analyses showed retention of parent anthocyanins and their functional, stable metabolite, protocatechuic acid, in saliva for up to 4 hours after rinsing. Furthermore, postrinse saliva samples contained glucuronidated anthocyanin conjugates, consistent with intracellular uptake and phase II conversion of BRB anthocyanins into forms amenable to local recycling. Our data show that comparable to the small intestine, the requisite hydrolytic, phase II and efflux transporting enzymes necessary for local enteric recycling are present and functional in human oral mucosa. Notably, interpatient differences in anthocyanin bioactivation and capacities for enteric recycling would impact treatment as retention of bioactivated chemopreventives at the target site would sustain therapeutic effectiveness.
authors.affiliation: Division of Oral Maxillofacial Surgery, Pathology & Anesthesiology, College of Dentistry, 2191B Postle Hall, 305 W. 12th Ave, The Ohio State University, Columbus, OH 43210, USA. mallery.1@osu.edu
authors.forename: Susan R
authors.initials: SR
authors.lastname: Mallery
authors.forename: Deric E
authors.initials: DE
authors.lastname: Budendorf
authors.forename: Matthew P
authors.initials: MP
authors.lastname: Larsen
authors.forename: Ping
authors.initials: P
authors.lastname: Pei
authors.forename: Meng
authors.initials: M
authors.lastname: Tong
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Holpuch
authors.forename: Peter E
authors.initials: PE
authors.lastname: Larsen
authors.forename: Gary D
authors.initials: GD
authors.lastname: Stoner
authors.forename: Henry W
authors.initials: HW
authors.lastname: Fields
authors.forename: Kenneth K
authors.initials: KK
authors.lastname: Chan
authors.forename: Yonghua
authors.initials: Y
authors.lastname: Ling
authors.forename: Zhongfa
authors.initials: Z
authors.lastname: Liu
mesh_terms: D000328:Adult; D000872:Anthocyanins / Q000737:chemistry / Q000378:metabolism*; D016588:Anticarcinogenic Agents / Q000494:pharmacology; D002853:Chromatography, Liquid / Q000379:methods; D004317:Doxorubicin / Q000031:analogs & derivatives / Q000737:chemistry; D005638:Fruit; D020719:Glucuronides / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D013058:Mass Spectrometry / Q000379:methods; D008875:Middle Aged; D008956:Models, Chemical; D009061:Mouth Mucosa / Q000187:drug effects / Q000382:microbiology* / Q000473:pathology*; D012463:Saliva / Q000378:metabolism*
chemical_list: D000872:Anthocyanins; D016588:Anticarcinogenic Agents; D020719:Glucuronides; C074869:7-deoxy-13-dihydroadriamycinone; C017154:cyanidin; D004317:Doxorubicin