A newly validated HPLC–DAD-UV method to study the effects of medicinal plants extracts, fractions and isolate compounds on gastric emptying in rodents

In this study, we developed and validated a chromatographic method by High-performance Liquid Chromatography coupled to Diode-Array Ultraviolet Detector for quantification of acetaminophen in small volumes of plasma. This analytical method is particularly suitable for studies of gastric emptying time and pharmacokinetics in small rodents. Orally administered acetaminophen is promptly and completely absorbed in the intestines, with negligible absorption from the stomach. Owing to these kinetic features, acetaminophen can be used to study gastric emptying. The newly-validated analytical method was employed to investigate whether plants used as anti-dyspeptics in the Brazilian traditional medicine affect the gastric emptying. Lyophilized aqueous extracts from leaves of Baccharis trimera (Less) DC., Asteraceae (carqueja), Maytenus ilicifolia Mart. Ex Reissek, Celastraceae (espinheira-santa) and Lippia alba (Mill.) N.E.Br. ex Britton & P. Wilson, Verbenaceae (erva-cidreira) were administered by gavage to female Wistar rats 30 min before a single oral dose of acetaminophen (50 mg/kg). L. alba extract (50 mg/kg) did not alter acetaminophen plasma concentration versus time curve an indication that it has no effect on gastric emptying. Extracts of B. trimera (50 mg/kg) and M. ilicifolia (30 and 50 mg/kg, but not 10 mg/kg), however, slightly delayed gastric emptying. M. ilicifolia given by intraperitoneal route (30 mg/kg) also retarded gastric emptying. In conclusion, the newly-validated analytical method is adequate for studying the effects of medicinal plants on gastric emptying.