In vitro tracheospasmolytic effect and acute toxicity screening of Coptosapelta flavescens Korth root ’s water extract

Abstract

There are no data available regarding the bronchospasmolytic activity and toxicity of water extract of Coptosapelta flavescens Korth root (WECFR). Therefore, this study aimed to determine: a. the in vitro tracheospasmolytic effect of WECFR; b. safety of WECFR using the brine shrimp lethality test (BSLT) and immobilization of Daphnia magna larvae (IDL). In study, a guinea pig tracheal ring was contracted with methacholine and cumulative doses of WECFR solution were administered. A dose-response curve (DRC) was plotted of the percentage of the tracheal ring relaxation response. To test whether the relaxation mechanism occured through stimulation of beta2-adrenergic receptors, the tracheal ring was incubated with propranolol. Data analyzed using analysis of variance, showed that the DRC of WECFR was obtained with p < 0.05 compared to the DRC of control, indicating that WECFR had a tracheospasmolytic effect. The DRC for propranolol-blocked WECFR did not shift to the right compared to the DRC of WECFR, confirming that the relaxation mechanism did not occur through the beta2-adrenergic receptors. Study b. assessed safety using BSLT and IDL. After exposing the larvae to WECFR and control for 24 and 48 h, respectively, the number of dead larvae was counted. Data analyzed using Probit program, showed that the lethal dose 50 of WECFR towards Artemia salina and Daphnia magna larvae was > 1000 ppm, which means that it was not toxic. This studies demonstrate that WECFR exhibits tracheospasmolitic effect, but not through beta2-adrenergic receptors; WECFR is safe for Artemia salina and Daphnia magna larvae.