Background: Organophosphates and pyrethroids are used widely in Brazil to control Aedes aegypti, the main vector of dengue viruses, under the auspices of the National Programme for Dengue Control. Resistance to these insecticides is widespread throughout Brazil. In Ceará the vector is present in 98% of districts and resistance to temephos has been reported previously. Here we measure resistance to temephos and the pyrethroid cypermethrin in three populations from Ceará and use biochemical and molecular assays to characterise resistance mechanisms. Results: Resistance to temephos varied widely across the three studied populations, with resistance ratios (RR₉₅) of 7.2, 30 and 192.7 in Juazeiro do Norte, Barbalha and Crato respectively. The high levels of resistance detected in Barbalha and Crato (RR₉₅ ≥ 30) imply a reduction of temephos efficacy, and indeed in simulated field tests reduced effectiveness was observed for the Barbalha population. Two populations (Crato and Barbalha) were also resistant to cypermethrin, whilst Juazeiro do Norte showed only an altered susceptibility. The Ile1011Met kdr mutation was detected in all three populations and Val1016Ile in Crato and Juazeiro do Norte. 1011Met was significantly associated with resistance to cypermethrin in the Crato population. Biochemical tests showed that only the activity of esterases and GSTs, among the tested detoxification enzymes, was altered in these populations when compared with the Rockefeller strain. Conclusions: Our results demonstrate that two A. aegypti populations from Ceará are under strong selection pressure by temephos, compromising the field effectiveness of this organophosphate. Our results also provide evidence that the process of reducing resistance to this larvicide in the field is difficult and slow and may require more than seven years for reversal. In addition, we show resistance to cypermethrin in two of the three populations studied, and for the first time the presence of the allele 1016Ile in mosquito populations from northeastern Brazil. A significant association between 1011M et and resistance was observed in one of the populations. Target-site mechanisms seem not to be implicated in temephos resistance, reinforcing the idea that for the studied populations, detoxification enzymes most likely play a major role in the resistance to this insecticide.

Individual human subjects are differentially attractive to mosquitoes and other biting insects. Previous investigations have demonstrated that this can be attributed partly to enhanced production of natural repellent chemicals by those individuals that attract few mosquitoes in the laboratory. The most important compounds in this respect include three aldehydes, octanal, nonanal and decanal, and two ketones, 6-methyl-5-hepten-2-one and geranylacetone [(E)-6,10-dimethylundeca-5,9-dien-2-one]. In olfactometer trials, these compounds interfered with attraction of mosquitoes to a host and consequently show promise as novel mosquito repellents.

The purpose of this study was to assess the in vitro antimicrobial activity of alkaloid-enriched extracts from Prosopis juliflora (Fabaceae) pods in order to evaluate them as feed additives for ruminants. As only the basic chloroformic extract (BCE), whose main constituents were juliprosopine (juliflorine), prosoflorine and juliprosine, showed Gram-positive antibacterial activity against Micrococcus luteus (MIC = 25 μg/mL), Staphylococcus aureus (MIC = 50 μg/mL) and Streptococcus mutans (MIC = 50 μg/mL), its influence on ruminal digestion was evaluated using a semi-automated in vitro gas production technique, with monensin as the positive control. Results showed that BCE has decreased gas production as efficiently as monensin after 36 h of fermentation, revealing its positive influence on gas production during ruminal digestion. Since P. juliflora is a very affordable plant, this study points out this alkaloid enriched extract from the pods of Prosopis juliflora as a potential feed additive to decrease gas production during ruminal digestion.

Spondias mombin L. is used in folk medicine for the treatment of inflammation and gastrointestinal diseases. Our study investigated the antiulcer activity of S. mombin ethanolic extract (SmEE) and its majority compounds gallic acid (GA) and ellagic acid (EA). Phytochemical characterization was performed by HPLC. The SmEE was screened for in vitro antioxidant activities using phosphomolybdenum, ABTS, DPPH, and FRAP assays. The antiulcer activity of SmEE, GA, EA, or GA + EA was evaluated by gastric lesion models induced by absolute ethanol and indomethacin. Following this, it is capable of stimulating mucus production, antisecretory capacity, and the influence of −SH groups and NO in the effect of SmEE. Its healing activity was demonstrated by acetic acid‐induced chronic ulcer model. Anti‐Helicobacter pylori activity was assessed by determining the MIC of the SmEE (64–1024 μg/mL). The HPLC results identified the presence of gallic acid and ellagic acid in SmEE. The extract showed antioxidant activity in vitro. SmEE (50, 100, and 200 mg/kg) reduced the area of ulcerative lesions induced by ethanol in 23.8, 90.3, and 90.2%, respectively. In NSAID model, the SmEE induced protection of 36.8, 49.4, and 49.9%, respectively. GA (10 mg/kg) or EA (7 mg/kg) or the association of GA + EA (10 + 7 mg/kg) inhibited the ethanol‐induced lesions in 71.8, 70.9, and 94.9%, respectively, indicating synergistic action. SmEE (100 mg/kg) decreased acid secretion and H⁺ concentration in the gastric contents, increased levels of mucus, and showed to be dependent of −SH groups and NO on the protection of the gastric mucosa. In chronic ulcer model, SmEE reduced the gastric area lesion. SmEE showed anti‐H. pylori activity. In conclusion, our study showed that SmEE has antiulcerogenic activity. GA and EA are isolated gastric protectors and, when associated, acted synergistically to protect the gastric mucosa.

The antibiotic activities of the ethanol extracts from 16 species of plants used in Brazilian folk medicine have been determined against Staphylococcus aureus, Micrococcus flavus, Bacillus cereus, B. subtilis, Salmonella enteretidis, Escherichia coli, Pseudomonas aeruginosa, Proteus mirabilis, Serratia marcescens, Mycobacterium phlei, M. smegmatis and M. fortuitum, and the yeasts Candida albicans and C. krusei. Among 32 extracts assayed, only those from Lafoensia pacari and Pterodon polygalaeflorus showed activity against the bacterial strains, and none were active against the yeasts. The ethanolic extract from the leaves of L. pacari showed minimum inhibitory concentration (MIC) values of 312.5 to 2500, 250, 625 and 1250 mg/mL, respectively, against eight different Gram-positive strains of Staphylococcus aureus, the Gram-negative Proteus mirabilis and the acid-fast bacilli Mycobacterium phlei, M. fortuitum and M. smegmatis. The ethanolic extract from the stem of L. pacari showed an MIC value of 625 mg/mL against S. aureus. Chemical analysis revealed that the crude extracts contained tannins, steroids, phenols, flavonoids, triterpenes and saponins: the activities were sufficiently high to present the possibility of future identification of the active components by bioassay-guided fractionation and purification. As atividades antibióticas de extratos etanólicos de 16 espécies de plantas usadas em medicina popular no Brasil foram determinadas contra Staphylococcus aureus, Micrococcus flavus, Bacillus cereus, B. subtilis, Salmonella enteretidis, Escherichia coli, Pseudomonas aeruginosa, Proteus mirabilis, Serratia marcescens, Mycobacterium phlei, M. smegmatis e M. fortuitum, contra as leveduras Candida albicans e C. krusei. Entre os trinta e dois extratos testados, somente aqueles derivados de Lafoensia pacari e Pterodon polygalaeflorus mostraram atividade contra as cepas bacterianas e nenhum deles apresentou atividade contra as leveduras. O extrato etanólico das folhas de L. pacari mostrou valores de concentração inibitória mínima (CIM) na faixa entre 312,5 a 2500 mg/mL, 250 mg/mL, 625 mg/mL, e 1250 mg/mL, respectivamente, contra oito diferentes variedades de Staphylococcus aureus Gram-positivas, Proteus mirabilis Gram-negativas e os bacilos acido-resistentes Mycobacterium phlei, M. fortuitum e M. smegmatis. O extrato etanólico do caule de L. pacari apresentou valores de CIM de 625 mg/mL contra S. aureus. Análise química revelou que os extratos brutos continham taninos, esteróides, fenóis, flavonóides, triterpenos e saponinas: as atividades foram altas o suficiente para possibilitar o isolamento guiado pelo bioensaio e a identificação futura dos compostos ativos