Acaricidal Activity of Colchicum autumnale (autumn crocus) Extract against Hyalomma spp. In vitro

Hyalomma spp. is responsible for the transmission of protozoan, bacterial, rickettsial, and viral diseases and causes huge economic loss to the livestock industry.Recently, there is a wide number of promising attempts to evaluate and use herbal preparations for ticks control.This study aimed to evaluate the acaricidal activity of aqueous and ethanol extracts of Colchicum autumnale (C. autumnale) rhizome and leaf against the Hyalomma spp. in vitro. The acaricidal activities of the Colchicum leaf aqueous (CLA), Colchicum leaf ethanolic (CLE), Colchicum rhizome aqueous (CRA), and Colchicum rhizome ethanolic (CRE) extracts were evaluated at concentrations of 50, 100, and 150 mg/ml and controls (distilled water and Cypermethrin) following 0.25, 0.5, 0.75, and 1 h of exposure. It is worth mentioning that the spraying method was used in these experiments. Data were analyzed through GraphPad Prism 5 software. In addition, the chemical composition of aqueous leaf extract was analyzed using gas chromatography-mass spectrometry (GC–MS). The carbamodithioic acid (30.04%) was the major chemical constituent identified. Based on the results, CLA, CLE, CRA, and CRE extracts had an acaricidal effect; however, this effect was more potent in CLE. The CLE extract showed a 100% mortality rate at 50, 100, and 150 mg/ml concentrations and 1 h of exposure. The effectiveness of CRA on the Hyalomma spp. was very low. The median lethal concentration (LC50) values were obtained at 100 mg/ml. The results indicated that C. autumnaleleaves contained potent acaricidal ingredients and might provide new acaricidal compounds for the effective control of Hyalomma spp. However, further studies are required to evaluate the efficacy of C. autumnale in vivo.