title: Inhibition of gastric H+,K+-ATPase activity by flavonoids, coumarins and xanthones isolated from Mexican medicinal plants.
abstract: Medicinal plants are commonly used in Latin American folk medicine for the treatment of gastric problems. In order to understand the properties of some of their chemical constituents, four natural xanthones, an acetylated derivative, two coumarins (mammea A/BA and mammea C/OA) isolated from Calophyllum brasiliense Cambess and two flavonoids (minimiflorin and mundulin) isolated from Lonchocarpus oaxacensis Pittier, and the chalcone lonchocarpin isolated from Lonchocarpus guatemalensis Benth were tested for their activities on gastric H+,K+-ATPase isolated from dog stomach. All the compounds tested inhibited H+,K+-ATPase activity with varied potency. The xanthones inhibited the H+,K+-ATPase with IC50 values ranging from 47 microM to 1.6 mM. Coumarins inhibited H+,K+-ATPase with IC50 values of 110 and 638 microM. IC50 values for the flavonoids ranged from 9.6 to 510 microM among which minimiflorin was the most potent. The results suggest that H+,K+-ATPase is sensitive to inhibition by several types of structurally different natural compounds. The potency of the effects on gastric H+,K+-ATPase depends on the presence, position and number of hydroxyls groups in the molecule. Collectively, these results suggest a potential for important pharmacological and toxicological interactions by these types of natural products at the level of H+,K+-ATPase which may explain, at least in part, the gastroprotective properties, indicated by traditional medicine, of the plants from which these compounds were isolated.
authors.affiliation: Instituto de Química, Universidad Nacional Autónoma de México, D.F. Mexico, Mexico.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Reyes-Chilpa
authors.forename: Cristiane Hatsuko
authors.initials: CH
authors.lastname: Baggio
authors.forename: Dagoberto
authors.initials: D
authors.lastname: Alavez-Solano
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Estrada-Muñiz
authors.forename: Frederick C
authors.initials: FC
authors.lastname: Kauffman
authors.forename: Rosa I
authors.initials: RI
authors.lastname: Sanchez
authors.forename: Sonia
authors.initials: S
authors.lastname: Mesia-Vela
mesh_terms: D000818:Animals; D029759:Calophyllum / Q000737:chemistry; D003374:Coumarins / Q000302:isolation & purification / Q000494:pharmacology*; D029866:Derris / Q000737:chemistry; D004285:Dogs; D004791:Enzyme Inhibitors / Q000302:isolation & purification / Q000494:pharmacology*; D005260:Female; D005419:Flavonoids / Q000302:isolation & purification / Q000494:pharmacology*; D010946:Plants, Medicinal / Q000737:chemistry*; D054328:Proton Pump Inhibitors; D013270:Stomach / Q000201:enzymology*; D044004:Xanthones / Q000302:isolation & purification / Q000494:pharmacology*
chemical_list: D003374:Coumarins; D004791:Enzyme Inhibitors; D005419:Flavonoids; D054328:Proton Pump Inhibitors; D044004:Xanthones