title: Spasmolytic effect of Alternanthera repens on isolated rat ileum.
abstract: Abstract Context: Alternanthera repens (L.) Kuntze (Amaranthaceae) is widely used in Mexican traditional medicine for the treatment of gastrointestinal disorders that are mainly related to diarrhea. Objective: The aim of the present study was to investigate the spasmolytic effect of hexane (Hx), methanol (Me) and aqueous (Aq) extracts as well as chromatographic Me fractions (F1-F6) of A. repens in rat ileum. Materials and methods: Dried and powdered aerial parts were used to obtain the extracts. The rat ileum preparations were incubated in Tyrode's solution gassed (95% O2-5% CO2) at 37 °C. The effect on the contractile response of isolated ileum was evaluated by obtaining cumulative concentration-response curves to CaCl2, KCl, 5-HT and acetylcholine in the absence and presence of different doses of Aq (0.56-2.09 mg/mL), Me (0.24-0.91 mg/mL) and Hx (0.24-0.91 mg/mL) extracts, as well as six Me fractions of 0.66 mg/mL (F1 to F6). Results: The A. repens Me (0.24 mg/mL) caused an inhibitory response of the Ca2+-induced contractions, with IC50values of 0.18 ± 0.061 and 0.67 ± 0.061 mM in the presence and absence of the Me, respectively. Me fractions F2 to F4 presented a significant inhibitory effect (F(3,8)= 60.17, p = 0.0001), causing a reduction in the CaCl2-induced contractions and shifting the Ca2+(0.39 to 1.81 mM) concentration-response curves to the right. With respect to the effect on 5-HT-induced contractions, IC50values Hx extract (0.24 mg/mL) were 5.44 ± 0.08 × 10-6M and 3.38 ± 0.07 × 10-6M in the presence and absence of the Hx, respectively. Discussion and conclusion: The spasmolytic effects induced by Me and Me fractions of A. repens may involve a serotonergic and Ca2+influx blockade mechanisms, which may justify the use of A. repens extracts as an effective traditional treatment against diarrhea.
authors.affiliation: Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Los Reyes Iztacala , Tlalnepantla, Estado México , México and.
authors.forename: María E
authors.initials: ME
authors.lastname: Garín-Aguilar
authors.forename: Delfa
authors.initials: D
authors.lastname: Benavides-Catalán
authors.forename: David
authors.initials: D
authors.lastname: Segura Cobos
authors.forename: Guadalupe
authors.initials: G
authors.lastname: Ramírez Sotelo
authors.forename: Ana Belem
authors.initials: AB
authors.lastname: Piña Guzmán
authors.forename: Gustavo
authors.initials: G
authors.lastname: Valencia-Del Toro