Aldenir Feitosa dos Santos

Molluscicidal activity of 2-hydroxy-3-alkyl-1,4-naphthoquinones and derivatives.

In the search for new molluscicidal agents we tested the activity of lapachol and other 2-hydroxy-3-alkylnaphthoquinones possessing nitrogenated alkyl chains, against the snail Biomphalaria glabrata. Lapachol, isolapachol and nor-lapachol showed strong molluscicidal activity against the adult snail (LD(90)<10 ppm) and significant toxicity against snail egg masses (LD(90)<0.2 ppm). As lapachol is easily extracted, and the derivatives can be synthesised without any difficulty, large-scale synthesis and field tests can be conducted, with a view to large-scale molluscicidal programs.

Toxicity of lapachol and isolapachol and their potassium salts against Biomphalaria glabrata, Schistosoma mansoni cercariae, Artemia salina and Tilapia nilotica.

The toxicity of soluble derivatives (potassium salt) of lapachol and isolapachol in different stages of the life cycle of Schistosoma mansoni is evaluated. The potassium salts of isolapachol and lapachol showed significant molluscicidal activity against the adult snail (LC90<7 ppm) and snail egg masses (LC90<3 ppm). Cercaricidal assays revealed strong activities for both compounds. Lethality assays against brine shrimp eggs (Artemia salina Leach) indicated very high toxicity for the potassium salt of isolapachol (LC90=1.54 ppm), differently from the potassium salt of lapachol that can be considered non toxic (LC90=176.3 ppm). The same tendency is observed with piscicidal activity, for which the isolapachol salt has showed higher toxicity. The obtained selectivity ratios concerning LC50 and LC90 for lapachol, in relation to Tilapia nilotica lethality assay are 2.33 and 1.26, respectively. Despite the piscicidal toxicity, the use of the salt of lapachol can be recommended for field tests in Schistosomiasis, with caution.

Molluscicidal activity of the diterpenoids jatrophone and jatropholones A and B isolated fromJatropha elliptica (Pohl) Muell. Arg.

In the search for new molluscicidal natural products, the activity of the crude ethanol extract of the rhizome of Jatropha elliptica (Pohl.) Muell. Arg. was tested. The LC50 was 13.07 ppm. The fractionation and purification of the extract furnished jatrophone and a mixture of jatropholones A and B, as the main compounds. They were tested against the snail Biomphalaria glabrata. Jatrophone showed an LC50 of 1.16 ppm as a molluscicide and an LC50 of 1.14 ppm for the assay of egg mass, while the mixture of jatropholones A and B presented an LC50 of 58.04 ppm as a molluscicide and was not active against the second assay at a concentration up to 100 ppm. Copyright

Toxicity of some glucose/mannose-binding lectins to Biomphalaria glabrata and Artemia salina.

Schistosomiasis or bilharzia, which affects millions of people living in Africa, Asia and Latin America, is closely associated with certain species of aquatic snails. One way of attacking the disease is to eradicate the host snails. Molluscicidal activities of natural compounds are especially important in the widespread control of this tropical disease. As part of our search for natural compounds with molluscicidal properties for the vector control of schistosomiasis, we are now evaluating for the first time the toxicity of the plant lectins from Canavalia brasiliensis (ConBr), Cratylia floribunda (CFL), Dioclea guianensis (Dgui), Dioclea grandiflora (DGL) and Dioclea virgata (Dvir) to Biomphalaria glabrata Say and Artemia salina Leach. Results indicate that all the samples were toxic to A. salina Leach, some of them with values of lethal concentration that kills 90% of the population (LC(90))<10 microg mL(-1). They are also active against B. glabrata Say, killing 100% of adult snails, at a concentration of 50 microg mL(-1). The lectins CFL and Dgui possess properties lethal to mollusks, with values of LC(90)=50.3 microg mL(-1) and LC(90)=41.0 microg mL(-1), respectively.

Synthesis, electrochemistry, and molluscicidal activity of nitroaromatic compounds: effects of substituents and the role of redox potential

Abstract-Molluscicidal bioassays and electrochemical studies (measurement of first wave reduction potential, Epcl) were performed on several synthetic nitroaromatics, in relation to possible correlation between biological activity, redox potential and structural effects. Five of them presented a significant molluscicidal activity on Biomphalaria glabrata (LD50 < 20 ppm). The Epc1 values ranged from -0.532 to -0.857 V versus Ag/AgCl (0.1 M) (-0.260 to -0.585 V versus NHE), all of them, in the favorable range for reduction in vivo. Data comparison between Epc1 and molluscicidal activity indicates that the presence of the electroactive nitro group is important for the biological activity. Correlation with redox potential, however, was not evident. Structural effects seem to be the most important parameter. Higher activity is noticeable for phenols, including the para-nitro azo or hydrazo-containing compounds. No activity was observed for compounds having the benzylic substituent in meta position to the nitro group. These results suggest that activity undoubtedly involves more than reduction characteristics and that the possible formation of electrophilic species, after nitro reduction, can play an important role in molluscicidal activity against B. glabrata.

Electrochemical studies of biologically active arylazoxy compounds. The relationship between redox potentials and molluscicidal activities

Abstract Six arylazoxy compounds and one arylazo derivative, including calvatic acid were studied by cyclic voltammetry, in protic (aqueous/ethanolic phosphate buffer, pH 6.9) and aprotic (DMF+TBAP) media and submitted to molluscicidal bioassays. In protic medium, all the arylazoxycyanides behaved similarly. A 4e − /4H + unique reduction wave generating the hydrazo derivative is evident, as well as its counterpart for oxidation, in the reverse scan, to the azo derivative, which suffers further reduction, in a successive scan. The intermediacy of the azo compound in the reduction process of calvatic acid was recognised, by voltammetric comparison with its chemically reduced azo derivative, which presented a bielectronic reversible wave. Some differences in the electrochemical features are evident for the sulfonyl and carbamoyl azoxyderivatives. In aprotic medium, the electrochemical behaviour of the arylazoxycyanides and the sulfonyl compound was similar, represented by two main waves, the first one reversible, corresponding to the uptake of one electron and a second one, much more intense and irreversible. A stable anion-radical is produced at the first negative potential, followed by a series of electron transfers and kinetically-dependent protonation steps leading, depending on the structure and/or scan rate, to the azo or hydrazo derivatives. For calvatic acid, a more complex feature was evident due to the participation of the acidic proton. For the carbamoyl derivative, the voltammetric behaviour, at low scan rates, showed an irreversible wave, indicative of an unstable anion-radical, prone to suffer a coupled chemical reaction. All the azoxycyanides showed significant activities against the mollusk Biomphalaria glabrata , while the sulfonyl and carbamoyl derivatives were inactive as molluscicides. These activities are reported for the first time, extending the range of biological activities of the arylazoxy group. Despite the small number of compounds studied, a relationship between E pIc (mainly in aprotic medium) and molluscicidal activities was observed, suggesting a trend: the more electrophilic compounds are the more active.

Curcumin or combined curcuminoids are effective in lowering the fasting blood glucose concentrations of individuals with dysglycemia: Systematic review and meta-analysis of randomized controlled trials

&NA; Curcuminoids have received considerable attention as therapeutical adjuvants in the treatment of dysglycemia. The purpose of this meta‐analysis was to evaluate whether the supplementation of turmeric extract, curcuminoids and/or isolated curcumin is more effective than placebo in decreasing fasting blood glucose (FBG) in adults. MEDLINE, CENTRAL, ScienceDirect and gray literature databases were searched. Randomized controlled trials with the following criteria were included: (1) studied individuals older than 18 years, supplemented with curcumin, curcuminoids and/or turmeric extract (2) had a follow‐up ≥4 weeks (3) used a placebo group. Titles and abstracts were screened and potentially eligible articles were retrieved. The primary outcome was FBG. The secondary outcomes were HbA1c and HOMA‐IR. Eleven studies were included. In the overall analysis, turmeric, curcuminoids and curcumin supplementation led to a decrease in FBG (−8.88, 95% CI: [−5.04 to −2.72] mg/dL, p = 0.005). Supplementation of curcuminoids and/or curcumin decreased the concentrations of HbA1c (−0.54, 95% CI: [−1.09 to −0.002] %, p = 0.049) but were not able to decrease HOMA‐IR (−1.26, 95% CI: [−3.71 to −1.19], p = 0.31). Sensitivity analyses revealed that baseline FBG was an important covariate. Heterogeneity was high in the overall analyses and there was evidence of publication bias. Supplementation of isolated curcumin or combined curcuminoids were both effective in lowering the FBG concentrations of individuals with some degree of dysglycemia, but not in non‐diabetic individuals. Isolated curcumin lead to significant decreases of the HbA1c compared to placebo. Graphical abstract Figure. No caption available.

Molluscicidal Activity of Compounds Isolated from Euphorbia conspicua N. E. Br

Euphorbia conspicua latex was fractionated into triterpenic and irritant fractions I and II. The triterpenic fraction afforded 15 known compounds and a new triterpene, 3β-(E)-cinnamoyleuphorbol. 20-O-Acetyl-3-O-angeloylingenol was isolated from irritant fraction II. The compounds euphol, 3β-acetoxyeupha-8,24-diene, 3β-(E)-cinnamoyleuphorbol and 20-O-Acetyl-3-O-angeloylingenol were evaluated for molluscicidal activity. 20-O-Acetyl-3-O-angeloylingenol presented LC100 value of 1 mg mL-1, equivalent to that of the standard molluscicide niclosamide. Compounds euphol, 3β-acetoxyeupha-8,24-diene and 3β-(E)-cinnamoyleuphorbol showed low molluscicidal activity. Mutagenic assays (Ames test with strains TA 98, 100 and 102) were performed with 3β-(E)-cinnamoyleuphorbol in the presence and absence of metabolic activation (S9 mix). In V79 cells, the cytotoxicity of 3β-(E)-cinnamoyleuphorbol was evaluated using the MTT assay and the genotoxicity was assessed using the cytokinesis-block micronucleus assay (CBMN) with or without S9 mix. Mutagenic or genotoxic activity was not detected, and no significant cytotoxicity was observed for 3β-(E)-cinnamoyleuphorbol at lower doses.

Prevalence of Brucella spp in humans

Objective: to determine the seroprevalence of Brucella spp in humans. Method: this is an observational study, developed with 455 individuals between 18 and 64 years old, who use the Estratégia de Saúde da Família (Brazils family health strategy). The serum samples of volunteers underwent buffered acid antigen tests, such as screening, agar gel immunodiffusion and slow seroagglutination test in tubes and 2-Mercaptoethanol. Results: among the samples, 1.98% has responded to buffered-acid antigen, 2.85% to agar gel immunodiffusion test and 1.54% to the slow seroagglutination tests on tubes/2-Mercaptoethanol. The prevalence of Brucella spp was 4.4%, represented by the last two tests. Conclusion: the results of this research suggest that the studied population is exposed to Brucella spp infection.

Formação em odontologia: O papel das instituições de ensino na prevenção do acidente com exposição a material biológico

Estudiantes de odontologia presentan vulnerabilidad a sufrir exposicion accidental a material biologico. El objetivo de este estudio fue analizar el conocimiento y el comportamiento de estudiantes de odontologia de dos instituciones educacionales, una publica y otra privada, contra la ocurrencia de accidentes con exposicion a material biologico y control de infeccion, ademas de la discusion del rol de las instituciones educacionales en este contexto. Este es un estudio transversal, descriptivo de enfoque cuantitativo, en el cual se aplico un cuestionario semi-estructurado, se autoaplico y estandarizo a 224 estudiantes. Se exploro: I- Medidas de proteccion, II- Ocurrencia de accidentes y conocimiento del comportamiento post-accidentes. III- Conocimiento, percepcion de riesgo y clarificaciones recomendadas formalmente. Los resultados demostraron la vulnerabilidad de los estudiantes en relacion con la exposicion a material biologico potencialmente contaminado y que ambas instituciones necesitan reevaluar sus acciones relativas a los riesgos biologicos y prevencion de accidentes. La institucion que mantiene un Comite de Bioseguridad y tiene un protocolo, bien divulgado, en caso de accidentes con exposicion a material biologico, presento mejores resultados en el uso de equipamiento protector, notificacion de accidentes y pruebas de inmunidad despues de vacunas contra la hepatitis B. El estudio concluyo que las instituciones educacionales tienen interes sustancial y estableceran reglas e intervenciones estrategicas para reducir los riesgos.