Antibacterial activity of the alkaloid extract and isolated compounds from Croton bonplandianum Baill. (Euphorbiaceae)

Abstract

ABSTRACT:The antibacterial activity of the alkaloid extract from the leaves of Croton bonplandianum Baill. and its main compounds, sparsiflorine and crotsparine, was tested against Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa by the resazurin microtitre-plate method. Pure compounds were identified by spectroscopic techniques, mainly 1D and 2D NMR. The alkaloid extract showed activity particularly against the S. aureus and P. aeruginosa. Regarding the pure compounds, the crotsparine was inactive against the microorganisms assayed, whereas the sparsiflorine indicated a moderate activity similar to the alkaloid extract. The Pseudomonas aeruginosa was the most sensitive of the tested microorganisms with MIC of 0.141 mg/mL. The results suggest that the activity of the extract may be credited mainly to the presence of the sparsiflorine. Although the activity of the sparsiflorine does not get close to the antimicrobial drugs in clinical use, it still could be a lead compound for the development of new antibacterial substances.Keywords: alkaloids, sparsiflorine, crotsparine, antibacterial activity, Croton bonplandianum, Euphorbiaceae. RESUMO: Atividade anti-bacteriana do extrato alcaloide e de compostos isolados de Croton bonplandianum Baill. (Euphorbiaceae).A atividade antibacteriana do extrato alcaloidal das folhas de Croton bonplandianum Baill., além dos principais compostos isolados, esparsiflorina e crotsparina, foi testada contra Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae e Pseudomonas aeruginosa. Foi utilizado o método de microdiluição em placa empregando resazurina como indicador da viabilidade celular. Os compostos isolados foram identificados por técnicas espectroscópicas, principalmente RMN 1D e 2D. O extrato alcaloidal foi ativo principalmente contra S. aureus e P. aeruginosa. Crotsparina mostrou-se inativa contra todos os micro-organismos testados, enquanto esparsiflorina apresentou atividade moderada, a qual foi similar à do extrato bruto. Pseudomonas aeruginosa foi a mais sensível das bactérias testadas, com CIM de 0,141 mg/mL. Os resultados sugerem que a atividade do extrato pode ser devida em grande medida pela presença de esparsiflorina. Apesar de a CIM da esparsiflorina não ter se aproximado daquela apresentada pelos agentes antimicrobianos em uso clínico, tal composto ainda pode compor um protótipo interessante para o desenvolvimento de novas substâncias antibacterianas.

Quantitative Phytochemical Profile and In Vitro Antioxidant Properties of Ethyl Acetate Extracts of Xerophyta spekei (Baker) and Grewia tembensis (Fresen)

“…Plants are important sources of molecules, which can be utilized in developing new antioxidant agents, and it is estimated that 44% of new drugs being developed are of plant origin. 10 Some plants like Senna singueana have previously exhibited antioxidant properties. 11 Plant antioxidants like polyphenols, carotenoids, glutathione have exhibited antioxidant effects by interrupting free radicals’ chain reactions.…”

Traditional uses, phytochemistry and pharmacology of Croton bonplandianum - A review

“…Alkaloid leaves extract of C. bonplandianum its isolated compounds (sparsiflorine and crotsparine) were performed for antibacterial activity against Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa.The alkaloid leaves extract of C. bonplandianum showed activity particularly against the S. aureus and P. aeruginosa while the isolated compound crotsparine and sparsiflorine were found inactive and moderate activity respectively against S. aureus and P. aeruginosa (23). Methanolic leaves and fruits extract of C. bonplandianum showed the highest antimicrobial activityagainst gram positive bacteria while acetone extract ofleaves showed the highest activity against gram negative bacteria (24).…”

Actividad sinérgica in vitro de los alcaloides Crotsparina y Esparsiflorina aislados de Croton bomplandianum frente a Pseudomonas aeruginosa

“…Para separar los componentes principales visualizados en la CCF, el extracto se sometió a cromatografía en columna de forma repetida, a presión atmosférica, con gel de sílice como fase estacionaria (Merck KGaA, Darmstadt, Alemania, diámetro de partícula 0,063-0,2 mm) y una mezcla de diclorometano-metanol 9:1 como eluyente. La identificación fue realizada por CCF por comparación de los valores de relación de frente (Rf) con muestras auténticas, las cuales fueron previamente aisladas en nuestro laboratorio y caracterizadas espectroscópicamente (12) .…”

“…De la misma, dos alcaloides mayoritarios han sido aislados, crotsparina y esparsiflorina (11) . La crotsparina es una proaporfina, mientras que la esparsiflorina es una aporfina ( Ambos compuestos han demostrado poseer actividad antibacteriana de moderada a débil frente a varios microorganismos (12) .…”