RESUMEN

We investigated the in vitro acaricide activity of the methanolic extract (ME) and alkaloid-rich fraction (AF) of Prosopis juliflora on Rhipicephalus microplus and correlated this effect with acetylcholinesterase (AChE) inhibition. The acaricide activity was evaluated using adult and larval immersion tests. Also, we studied the possible interaction mechanism of the major alkaloids present in this fraction via molecular docking at the active site of R. microplus AChE1 (RmAChE1). Higher reproductive inhibitory activity of the AF was recorded, with effective concentration (EC50) four times lower than that of the ME (31.6 versus 121 mg/mL). The AF caused mortality of tick larvae, with lethal concentration 50% (LC50) of 13.8 mg/mL. Both ME and AF were seen to have anticholinesterase activity on AChE of R. microplus larvae, while AF was more active with half-maximal inhibitory concentration (IC50) of 0.041 mg/mL. The LC-MS/MS analyses on the AF led to identification of three alkaloids: prosopine (1), juliprosinine (2) and juliprosopine (3). The molecular docking studies revealed that these alkaloids had interactions at the active site of the RmAChE1, mainly relating to hydrogen bonds and cation-pi interactions. We concluded that the alkaloids of P. juliflora showed acaricide activity on R. microplus and acted through an anticholinesterase mechanism.

Asunto(s)

RESUMEN

We investigated the in vitro acaricide activity of the methanolic extract (ME) and alkaloid-rich fraction (AF) of Prosopis juliflora on Rhipicephalus microplus and correlated this effect with acetylcholinesterase (AChE) inhibition. The acaricide activity was evaluated using adult and larval immersion tests. Also, we studied the possible interaction mechanism of the major alkaloids present in this fraction via molecular docking at the active site of R. microplus AChE1 (RmAChE1). Higher reproductive inhibitory activity of the AF was recorded, with effective concentration (EC50) four times lower than that of the ME (31.6 versus 121 mg/mL). The AF caused mortality of tick larvae, with lethal concentration 50% (LC50) of 13.8 mg/mL. Both ME and AF were seen to have anticholinesterase activity on AChE of R. microplus larvae, while AF was more active with half-maximal inhibitory concentration (IC50) of 0.041 mg/mL. The LC-MS/MS analyses on the AF led to identification of three alkaloids: prosopine (1), juliprosinine (2) and juliprosopine (3). The molecular docking studies revealed that these alkaloids had interactions at the active site of the RmAChE1, mainly relating to hydrogen bonds and cation-pi interactions. We concluded that the alkaloids of P. juliflora showed acaricide activity on R. microplus and acted through an anticholinesterase mechanism.(AU)

A atividade carrapaticida in vitro do extrato metanólico (EM) e da fração de alcaloides (FA) de Prosopis juliflora foi investigada, frente ao Rhipicephalus microplus, e relacionada com a inibição da enzima acetilcolinesterase (AChE). A predição in silico das interações de alcaloides dessa fração com a AChE1 de R. microplus (RmAChE1) foi realizada por acoplamento molecular. A atividade carrapaticida foi avaliada, utilizando-se os ensaios de imersão de adultos e larvas. Maior efeito sobre parâmetros reprodutivos de teleóginas foi verificado para a FA, com valor de Concentração Efetiva 50% (CE50) (31.6 mg/mL), quatro vezes menor do que o valor do EM (121 mg/mL). A FA induziu mortalidade de larvas (Concentração Letal de 50% - CL50 = 13,8 mg/mL). A inibição da atividade da AChE de larvas do carrapato foi observada para EM e FA, sendo a FA mais ativa (Concentração Inibitória 50%- CI50 de 0,041mg/mL). As análises químicas da FA permitiram a identificação dos alcaloides prosopina (1), juliprosinina (2) e juliprosopina (3). No ensaio in silico, observou-se que esses alcaloides podem interagir com o sítio ativo da RmAChE1, principalmente por ligações de hidrogênio e interações cátion-pi. Os alcaloides de P. juliflora têm atividade carrapaticida contra R. microplus, atuando através do mecanismo anticolinesterásico.(AU)

Asunto(s)

RESUMEN

ABSTRACT: This study was conducted to evaluate the in vitro anthelmintic activity of the succinic acid (SA) isolated from sisal waste against gastrointestinal nematodes of goats, using the egg hatching and larvae motility assays. In addition, potential cytotoxicity of SA on Vero cell cultures was investigated by means of MTT (3-4,5-dimethylthiazol-2-yl, 2,5diphenyltetrazolium bromide) test. The SA induced a significant inhibition of egg hatching (P 0.05) at all concentrations tested (60 to 250µg mL-1), and the concentrations to inhibit 50% (EC50) and 90% (EC90) values (mean ± standard deviation) were 90.3±2.8 and 130.6±3.5µg mL-1, respectively. The SA has not shown larvicidal activity. The SA was less toxic to the Vero cells, with the mean percentage of cell viability equal to 85±6.2% at the concentration of 130µg mL-1. The results suggested that SA has potential anthelmintic effect; although, more research is needed to confirm its activity in vivo.

RESUMO: O objetivo deste estudo foi avaliar a atividade anti-helmíntica in vitro do ácido succínico (AS) isolado do resíduo de sisal sobre nematódeos gastrointestinais de caprinos, utilizando os ensaios de inibição da eclosão de ovos e motilidade larval. Além disso, a citotoxicidade do AS em culturas de células Vero foi investigada empregando-se o teste de MTT (brometo de 3-4,5-dimetiltiazol-2-ilo, brometo de 2,5-difeniltetrazólio). O AS promoveu redução significativa no percentual de eclosão de ovos (P 0,05) em todas as concentrações testadas (60 a 250g mL-1). As médias (± desvio padrão) da CE50 e CE90 (Concentração efetiva 50% e 90%) sobre ovos foram de 90.3±2.8 e 130±3.5g mL-1, respectivamente. O AS não apresentou atividade larvicida. O AS foi menos tóxico para as células Vero, com média do percentual de viabilidade celular igual a 85±6.2% na concentração de 130g mL-1. Os resultados sugerem que o AS tem potencial efeito anti-helmíntico, embora sejam necessários a realização de estudos in vivo para confirmar seu uso terapêutico.

Asunto(s)

RESUMEN

ABSTRACT: This study was conducted to evaluate the in vitro anthelmintic activity of the succinic acid (SA) isolated from sisal waste against gastrointestinal nematodes of goats, using the egg hatching and larvae motility assays. In addition, potential cytotoxicity of SA on Vero cell cultures was investigated by means of MTT (3-4,5-dimethylthiazol-2-yl, 2,5diphenyltetrazolium bromide) test. The SA induced a significant inhibition of egg hatching (P 0.05) at all concentrations tested (60 to 250µg mL-1), and the concentrations to inhibit 50% (EC50) and 90% (EC90) values (mean ± standard deviation) were 90.3±2.8 and 130.6±3.5µg mL-1, respectively. The SA has not shown larvicidal activity. The SA was less toxic to the Vero cells, with the mean percentage of cell viability equal to 85±6.2% at the concentration of 130µg mL-1. The results suggested that SA has potential anthelmintic effect; although, more research is needed to confirm its activity in vivo.(AU)

RESUMO: O objetivo deste estudo foi avaliar a atividade anti-helmíntica in vitro do ácido succínico (AS) isolado do resíduo de sisal sobre nematódeos gastrointestinais de caprinos, utilizando os ensaios de inibição da eclosão de ovos e motilidade larval. Além disso, a citotoxicidade do AS em culturas de células Vero foi investigada empregando-se o teste de MTT (brometo de 3-4,5-dimetiltiazol-2-ilo, brometo de 2,5-difeniltetrazólio). O AS promoveu redução significativa no percentual de eclosão de ovos (P 0,05) em todas as concentrações testadas (60 a 250g mL-1). As médias (± desvio padrão) da CE50 e CE90 (Concentração efetiva 50% e 90%) sobre ovos foram de 90.3±2.8 e 130±3.5g mL-1, respectivamente. O AS não apresentou atividade larvicida. O AS foi menos tóxico para as células Vero, com média do percentual de viabilidade celular igual a 85±6.2% na concentração de 130g mL-1. Os resultados sugerem que o AS tem potencial efeito anti-helmíntico, embora sejam necessários a realização de estudos in vivo para confirmar seu uso terapêutico.(AU)

Asunto(s)