RESUMEN
The acaricidal activity of crude extracts and fractions from stems and leaves of Petiveria alliacea (Phytolaccaceae) was carried out on larvae and adults of the cattle tick Rhipicephalus (Boophilus) microplus using the larval immersion test (LIT) and adult immersion test (AIT), respectively. Methanolic extracts of stems and leaves of P. alliacea showed 100% mortality on the LIT bioassay. On the other hand, methanolic extracts of leaves and stem on the AIT test showed 26% and 86% of mortality, respectively, egg laying inhibition of 40% and 91%, respectively and hatchability inhibition of 26% and 17%, respectively. Purification of the active stem methanolic extract showed that the activity was present in the n-hexane non-polar fraction. Bioassay-guided purification of the n-hexane fraction produced 10 semi-purified fractions; fraction B had the highest activity against tick larvae (100% mortality). Gas chromatography-mass spectrometry demonstrated that the chemical composition of the active fraction B samples were mainly composed of benzyltrisulfide (BTS) and benzyldisulfide (BDS). These metabolites might be responsible for the acaricidal activity of stem extract of P. alliacea. However, further experiments to evaluate the acaricidal activity of BTS and BDS on larvae and adults of R. (B.) microplus are needed. Our results showed that P. alliacea is a promising biocontrol candidate as acaricide against R. (B.) microplus resistant strains.
Asunto(s)
Acaricidas/farmacología , Phytolaccaceae/química , Extractos Vegetales/farmacología , Rhipicephalus/efectos de los fármacos , Animales , Bovinos , Enfermedades de los Bovinos/parasitología , Femenino , Larva/efectos de los fármacos , Dosificación Letal Mediana , Metanol/química , Oviposición/efectos de los fármacos , Extractos Vegetales/química , Hojas de la Planta/química , Tallos de la Planta/química , Infestaciones por Garrapatas/parasitología , Infestaciones por Garrapatas/veterinariaRESUMEN
The anti-tick effects of the tropical pasture legumes Stylosanthes humilis and Stylosanthes hamata were evaluated and compared with two common grasses, Cenchurus ciliaris and Andropogon gayanus, in the state of Morelos, Mexico, on plots experimentally infested with larvae of the tick Boophilus microplus. The effect was evaluated by recovery of larvae from the experimental plots by flagging during a 4 week period. The anti-tick effect due to Stylosanthes was significantly higher for S. humilis and S. hamata (p < 0.05) and slightly better for S. humilis (3% survival) than for S. hamata (12% survival). Further studies are required to determine the potential role of Stylosanthes plants for tick control in Mexico.