Inhibition of gastrointestinal release of acetylcholine by quercetin as a possible mode of action of Psidium guajava leaf extracts in the treatment of acute diarrhoeal disease.
The electrically stimulated guinea-pig ileum and spontaneously contracting guinea-pig ileum preparations were employed in studies on the effects of an alcoholic extract and two flavonoid compounds, quercetin and quercetin-3-arabinoside, extracted from the leaves of Psidium guajava. The extract showed a morphine-like inhibition of acetylcholine release in the coaxially stimulated ileum, together with an initial increase in muscular tone, followed by a gradual decrease. The morphine-like inhibition was found to be due to quercetin, starting at concentrations of 1.6 micrograms/ml. The glycoside did not show any such action at concentrations of up to 1.28 mg/ml. The extract inhibited spontaneous contractions in the unstimulated ileum with a concentration-response relationship.
Lutterodt
G D
GD
Department of Pharmacology, School of Medical Sciences, Universiti Sains Malaysia, Penang.
D000109:Acetylcholine / Q000378:metabolism; D000818:Animals; D003967:Diarrhea / Q000188:drug therapy*; D004558:Electric Stimulation; D005419:Flavonoids / Q000494:pharmacology*; D006168:Guinea Pigs; D007082:Ileum / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D066298:In Vitro Techniques; D008519:Medicine, Traditional; D009119:Muscle Contraction / Q000187:drug effects; D010936:Plant Extracts / Q000494:pharmacology; D010946:Plants, Medicinal; D011794:Quercetin / Q000494:pharmacology*
D005419:Flavonoids; D010936:Plant Extracts; D011794:Quercetin; D000109:Acetylcholine