Spasmolytic activity of Hyptis macrostachys Benth. (Lamiaceae)

Abstract

Hyptis is a worldwide genus cited by its medicinal uses. Hyptis macrostachys Benth., a species popularly known in Brazil as “alfavaca-brava” and “hortela‑do‑mato”, is used in folk medicine to relief asthma, cough and bronchitis symptoms. Thus, this study investigated a possible spasmolytic effect of the aerial parts ethanol extract from H. macrostachys Benth. (HM-EtOHPA) on several smooth muscle models. On the rat aorta, the uterus was observed and guinea pig trachea HM‑EtOHPA did not show relevant spasmolytic action in all tested concentrations (243 to 729 μg/ml). However, on guinea pig ileum, HM‑EtOHPA (9 to 729 μg/ml) significantly (p < 0.001) inhibited in a concentration-dependent manner the contractions induced by carbachol (CCh) 10-6 M and histamine 10‑6 M as well as relaxed this organ in an equipotent and concentration‑dependent (1 to 729 μg/ml) manner when pre-contracted with CCh 10‑6 M, histamine 10-6 M and KCl 40 mM, suggesting its actions in the voltage‑gated calcium channels (CaV) blockade. Since HM-EtOHPA (9 to 729 μg/ml) inhibited Ca2+‑induced contractions in Ca2+-free depolarizing medium and relaxed ileum pre-contracted with S-(-)-Bay K8644 (3 × 10-7 M) in a concentration‑dependent manner, the hypothesis of Cav was confirmed. Thus, H. macrostachys Benth. showed a selective spasmolytic action on guinea pig ileum by blocking Ca2+ entry through CaV . Key words: Lamiaceae, Hyptis macrostachys Benth., relaxant, antispasmodic, calcium channel.