title: Echinacea sanguinea and Echinacea pallida extracts stimulate glucuronidation and basolateral transfer of Bauer alkamides 8 and 10 and ketone 24 and inhibit P-glycoprotein transporter in Caco-2 cells.
abstract: The use of Echinacea as a medicinal herb is prominent in the United States, and many studies have assessed the effectiveness of Echinacea as an immunomodulator. We hypothesized that Bauer alkamides 8, 10, and 11 and ketone 24 were absorbed similarly either as pure compounds or from Echinacea sanguinea and Echinacea pallida ethanol extracts, and that these Echinacea extracts could inhibit the P-glycoprotein transporter in Caco-2 human intestinal epithelial cells. Using HPLC analysis, the permeation rate of Bauer alkamides by passive diffusion across Caco-2 cells corresponded with compound hydrophilicity (alkamide 8 > 10 > 11), independent of the plant extract matrix. Both Echinacea ethanol extracts stimulated apparent glucuronidation and basolateral efflux of glucuronides of alkamides 8 and 10 but not alkamide 11. Bauer ketone 24 was totally metabolized to more hydrophilic metabolites when administered as a single compound, but was also glucuronidated when present in Echinacea extracts. Bauer alkamides 8, 10, and 11 (175-230 µM) and ethanol extracts of E. sanguinea (1 mg/mL, containing ~ 90 µM total alkamides) and E. pallida (5 mg/mL, containing 285 µM total alkamides) decreased the efflux of the P-glycoprotein transporter probe calcein-AM from Caco-2 cells. These results suggest that other constituents in these Echinacea extracts facilitated the metabolism and efflux of alkamides and ketones, which might improve therapeutic benefits. Alkamides and Echinacea extracts might be useful in potentiating some chemotherapeutics, which are substrates for the P-glycoprotein transporter.
authors: Center for Research on Botanical Dietary Supplements, Iowa State University, Ames, IA 50011, USA.
authors: Zhiyi
authors: Z
authors: Qiang
authors: Cathy
authors: C
authors: Hauck
authors: Joe-Ann
authors: JA
authors: McCoy
authors: Mark P
authors: MP
authors: Widrlechner
authors: Manju B
authors: MB
authors: Reddy
authors: Patricia A
authors: PA
authors: Murphy
authors: Suzanne
authors: S
authors: Hendrich
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000037:antagonists & inhibitors* / Q000378:metabolism; D000480:Alkynes / Q000378:metabolism / Q000493:pharmacokinetics*; D018938:Caco-2 Cells / Q000187:drug effects / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D004305:Dose-Response Relationship, Drug; D020900:Echinacea / Q000737:chemistry*; D005452:Fluoresceins / Q000378:metabolism; D020719:Glucuronides / Q000378:metabolism; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D007659:Ketones; D010539:Permeability / Q000187:drug effects; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D010946:Plants, Medicinal / Q000737:chemistry; D053284:Polyunsaturated Alkamides / Q000737:chemistry / Q000378:metabolism / Q000493:pharmacokinetics*
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000480:Alkynes; D005452:Fluoresceins; D020719:Glucuronides; D007659:Ketones; D010936:Plant Extracts; D053284:Polyunsaturated Alkamides; C549757:pentadeca-(8Z,13Z)-dien-11-yn-2-one; C085925:calcein AM