Larvicidal activity of Caesalpinia ferrea Mart. and Lippia origanoides Cham. Against Aedes aegypti (LINNAEUS, 1762) (Diptera: Culicidae)

The control of Aedes aegypti has been considered one of the most important public health challenges worldwide. Chemical compounds have long been used for this purpose, but resistance to these molecules has also increased. Therefore, over the last few years several studies have focused on the development of alternative tools, particularly those based on plant metabolites. The purpose of this study was to assess the larvicidal activity of Caesalpinia ferrea and Lippia origanoides against Ae. aegypti. Larvae (L3) of Ae. aegypti Liverpool and Rockefeller strains, as well as of the Recife population were exposed to different concentrations of C. ferrea (ranging from 13.1 to 105 mg/mL) and L. origanoides (ranging from 16.3 to 130 mg/mL), and the mortality rate was evaluated up to 48 hours after the beginning of the experiment. All tested groups and ontrol group were quadruplicated. For C. ferrea, mortality ranged from 42.5% to 100% for Ae. aegypti Liverpool strain, from 67% to 100% for Ae. aegypti Rockfeller strain, and 57% to 100% for Ae. aegypti Recife population after 48 hours of larval exposure. For L. origanoides, the larvicidal activity ranged from 75% to 100% for Ae. aegypti Liverpool strain, from 61.5% to 100% for Ae. aegypti Rockfeller strain, and from 60.5% to 100% for Ae. aegypti Recife population. The hydro ethanol extract of C. ferrea and L. origanoides presented larvicidal activity against Ae. aegypti.

Phytochemical screening and antimicrobial activity testing of crude hydroalcoholic extract from leaves of Sphagneticola trilobata (Asteraceae) / Triagem fitoquímica e atividade antimicrobiana do extrato hidroalcoólico bruto das folhas de Sphagneticola trilobata (Asteraceae)

ABSTRACT: This study aimed to perform phytochemical analysis and to test the antimicrobial activity of the crude hydroalcoholic extract obtained from the leaves of Sphagneticola trilobata. Classes of secondary metabolites present in the extract were identified through phytochemical screening using analytical thin-layer chromatography. Antimicrobial activity was evaluated by testing cultures of Staphylococcus aureus, S. epidermidis, Staphylococcus spp., Escherichia coli, Serratia marcescens, Enterococcus faecalis, Pseudomonas aeruginosa, Salmonella Typhimurium, and Klebsiella pneumoniae isolated from human skin and those of Staphylococcus spp. isolated from dog skin using the broth microdilution method. In the phytochemical screening, classes of anthracenic derivatives and mono-, sesqui-, and diterpenes were identified. Colorimetric analysis showed total phenol and total flavonoid contents of 21.7 ± 0.009 mg of gallic acid equivalents per gram of sample and 0.23 ± 0.005 mg of catechin equivalents per gram of sample, respectively. Microbiological analysis revealed that the hydroalcoholic extract of S. trilobata exhibited antimicrobial activity against cultures of Staphylococcus spp., E. coli, S. marcescens, and E. faecalis isolated from human skin and those of Staphylococcus spp. isolated from dog skin. Thus, crude hydroalcoholic extract of leaves of S. trilobata contained flavonoids and terpenoids as secondary metabolites, which contributed to its antimicrobial activity against skin bacteria isolated from different sources.

RESUMO: Este estudo teve como objetivo realizar a triagem fitoquímica preliminar e testar a atividade antimicrobiana do extrato hidroalcoólico bruto das folhas de Sphagneticola trilobata. A identificação das classes de metabólitos secundários presentes no extrato foi realizada através da cromatografia em camada delgada analítica (CCDA). Para determinar a quantidade de fenóis e flavonoides totais foram utilizados os métodos espectrofotométricos de Folin-Ciocalteu e complexação com AlCl3, respectivamente. Para avaliar a atividade antimicrobiana foram testadas culturas de Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus spp., Escherichia coli, Serratia marcescens, Enterococcus faecalis, Pseudomonas aeruginosa, Salmonella Typhimurium, Klebsiella pneumoniae isoladas de pele humana e culturas de Staphylococcus spp. isoladas de pele de cães pelo método de microdiluição em caldo. Na triagem fitoquímica foi verificada reação positiva para a presença de derivados antracênicos, mono, sesqui e diterpenos. As análises colorimétricas mostraram conteúdos de fenóis totais e flavonoides totais de 21,7 ± 0,009 miligramas de equivalentes de ácido gálico por grama de amostra e 0,23 ± 0,005 miligramas de equivalentes de catequina por grama de amostra, respectivamente. Na análise microbiológica, o extrato hidroalcoólico das folhas de Sphagneticola trilobata apresentou atividade antimicrobiana frente às culturas de Staphylococcus spp., Escherichia coli, Serratia marcescens e Enterococcus faecalis. Todas as culturas de Staphylococcus spp. isoladas de pele de cães foram sensíveis ao extrato. Conclui-se que o extrato hidroalcoólico bruto das folhas de Sphagneticola trilobata possui entre seus metabólitos secundários os flavonoides e terpenoides que contribuíram com a atividade antimicrobiana frente às bactérias isoladas de pele de diferentes origens.