Efficacy of hydroethanolic extract of Randia aculeata seed against the southern cattle tick Rhipicephalus (Boophilus) microplus (Acari: Ixodidae) on naturally infested cattle under field conditions

Abstract

Abstract Rhipicephalus (Boophilus) microplus tick infestation is a major problem for cattle industry in tropical and subtropical regions. Chemical products are commonly applied to control it; however, their indiscriminate use has resulted in the appearance of resistant lineages. Plants have been used as an alternative to conventional acaricidal drugs. Recently, we demonstrated the higher acaricidal activity of hidroethanolyc extract of Randia aculeata seed (EHRA) against R. microplus under laboratory conditions. The utility of EHRA seed as acaricidal need to be determined under field conditions. For this reason, the aim of this study was (a) evaluate the efficacy of the EHRA against R. microplus by sprayed on naturally infested calves under field conditions (b) determine the effect of the EHRA seed on AChE activity in larvae R. microplus and (c) evaluate the stability of total phenolic compounds in EHRA after exposure to heating, UV irradiation and storage. Fourty-five male calves were divided in three groups and doused by spray G1: water, G2: EHRA 20% and G3: coumaphos 0.3%. AChE activity on R. microplus larvae was determined by a colorimetric assay. Total phenolic content was determined using the Folin-Ciocalteau method after to exposure of EHRA to heat, UV light and storage under sunlight and dark. Significantly fewer number of ticks were observed after 24 h on the treated group compared to control group (p < 0.001). EHRA significantly inhibited in vitro acetylcholinesterase activity in R. microplus larvae at all tested concentrations (p < 0.01). Heat, UV light and storage time under sunlight resulted in a significant decrease (p < 0.05) in total phenolic content. Our results contributed new data for the elucidation of the mechanisms of EHRA acaricide action and to further evaluate the use as a new alternative control agent against R. microplus under in vivo conditions