Muscarinic-dependent inhibition of gastric emptying and intestinal motility by fractions of Maytenus ilicifolia Mart ex. Reissek.
BACKGROUND
Maytenus ilicifolia Mart. ex. Reissek (Celastraceae) is widely used in Brazilian folk medicine to treat gastric disturbances.


OBJECTIVE
This work intended to characterize the effects of Maytenus ilicifolia on gastrointestinal motility.


METHODS
Gastric emptying and intestinal transit were measured in the same animal. Mice received a semisolid marked with phenol red, half an hour after treatment with extracts. The amount of marker in the stomach and the distance reached in the intestine after 15 min were measured as index of gastrointestinal emptying and intestinal transit, respectively.


RESULTS
Intraperitoneal administration of a flavonoid-rich extract potently reduced the gastric emptying (ED(50)=89 mg/kg) and the intestinal transit (ED(50)=31 mg/kg) of mice. Bio-guided purification of the flavonoid-rich extract by chemical partition with solvents of decreasing polarity yielded fraction insF with about 12-14 times higher activity than the initial flavonoid extract in both the gastric emptying and the intestinal transit. The inhibitory effects of the insF (9.7 mg/kg, i.p.) on gastric emptying and intestinal transit were reversed by co-administration of bethanechol (10 mg/kg, s.c.) but not by co-administration of metoclopramide (30 mg/kg, p.o.) indicating muscarinic but not dopaminergic interaction of the compounds of Maytenus. Chemical investigation of the insF fraction by HPLC-MS allowed the identification of 4 free flavonoids (catechin, epicatechin, quercetin and kaempferol), 29 flavonol glycosides and 8 tannins. The flavonol glycosides ranged from 1 to 4 monosaccharide units, having mainly quercetin and kaempferol as aglycone moieties, and the tannins were composed by catechin/epicatechin and/or afzelechin/epiafzelechin.


CONCLUSIONS
Overall, the results indicate that the components of Maytenus ilicifolia have a potential use in the treatment of gastrointestinal motility disturbances such as diarrhea.
Baggio
Cristiane Hatsuko
CH
Department of Pharmacology, Sector of Biological Sciences, Universidade Federal do Paraná, Curitiba, PR, Brazil.
Freitas
Cristina Setim
CS
Mayer
Bárbara
B
Dos Santos
Ana Cristina
AC
Twardowschy
André
A
Potrich
Francine Bittencourt
FB
Cipriani
Thales Ricardo
TR
de Souza
Lauro Mera
LM
Sassaki
Guilherme Lanzi
GL
Iacomini
Marcello
M
Marques
Maria Consuelo Andrade
MC
Mesia-Vela
Sonia
S
D000818:Animals; D018723:Bethanechol / Q000494:pharmacology; D018678:Cholinergic Agents / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D005260:Female; D005419:Flavonoids / Q000494:pharmacology; D044948:Flavonols / Q000494:pharmacology; D005746:Gastric Emptying / Q000187:drug effects*; D005769:Gastrointestinal Motility / Q000187:drug effects*; D006027:Glycosides / Q000494:pharmacology; D007274:Injections, Intraperitoneal; D029755:Maytenus / Q000737:chemistry; D051379:Mice; D010936:Plant Extracts / Q000008:administration & dosage / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D010946:Plants, Medicinal; D013634:Tannins / Q000494:pharmacology
D018678:Cholinergic Agents; D005419:Flavonoids; D044948:Flavonols; D006027:Glycosides; D010936:Plant Extracts; D013634:Tannins; D018723:Bethanechol