RESUMO
The thrust of the study was to determine the chemical composition of the essential oils extracted from Thymus pallescens de Noé and Cymbogon citratus Stapf. as well as to evaluate their efficacy in controlling Sitophilus zeamais Motschulsky and Tribolium castaneum (Herbst) in either single or combined populations. Carvacrol (56.04%) and geraniol (20.86%) were identified as the major constituents of T. pallescens and C. citratus respectively. The tested essential oils showed pronounced insecticidal activity against the pest species in relation with the applied doses. T. pallescens EO had the highest efficacy and S. zeamais was found to be more susceptible to both individual and combined treatments. With reference to the contact and fumigation assessments, T. pallescens EO effectuated corrected mortality rates ranging from 42.5-100% to 25-100% in S. zeamais with corresponding lethal concentration (LC50) values of 17.7 µl/ml and 15µL/L air respectively. Whereas, the T. pallescens EO exhibited corrected mortality rates of 42.5-100% and 20-100% with corresponding LC50 values of 18.1 µl/ml and 15.5 µL/L air against T. castaneum in contact and fumigation assessments, respectively. The corrected mortality rates increased for both insect species when using combination treatments, with significant increases in the LC50 values, ranging from 8.59 to 49.9% for both pest species. Analysis of energy biomarkers in the treated insects indicate significantly increased protein and carbohydrate contents and decreased lipids levels. The study therefore demonstrated the bio-insecticidal toxicity of the EOs from T. pallescens and C. citratus against two important maize post-harvest pests, concurrently revealing significant positive and negative insecticidal activity gradients in relation to single or combined populations.
Assuntos
Inseticidas , Óleos Voláteis , Thymus (Planta) , Tribolium , Animais , Óleos Voláteis/farmacologia , Óleos Voláteis/química , Tribolium/efeitos dos fármacos , Inseticidas/farmacologia , Inseticidas/química , Thymus (Planta)/química , Monoterpenos Acíclicos/farmacologia , Monoterpenos Acíclicos/química , Gorgulhos/efeitos dos fármacos , Cimenos/farmacologia , Cimenos/químicaRESUMO
Six new benzophenone glycosides, 2,3',4,5',6-pentahydroxybenzophenone 4-O-(6â³-benzoyl)-ß-d-glucopyranoside (1), 2,3',4,5',6-pentahydroxybenzophenone 4-O-ß-d-glucopyranoside (2), 2,3',4,5',6-pentahydroxybenzophenone 2-O-(2â³-benzoyl)-α-l-arabinopyranoside (3), 2,3',4,5',6-pentahydroxybenzophenone 2-O-α-l-arabinopyranoside (4), 2,3',4,5',6-pentahydroxybenzophenone 2-O-(4â³-acetyl)-ß-d-xylopyranoside (5), and 2,3',4,5',6-pentahydroxybenzophenone 3-C-(4â³-benzoyl)-ß-d-glucopyranoside (6), and five known compounds were isolated from the aerial parts of Hypericum humifusum ssp. austral. The structures of 1-6 were elucidated by mass spectrometry and extensive 1D and 2D NMR spectroscopy.
Assuntos
Benzofenonas/isolamento & purificação , Glicosídeos/isolamento & purificação , Hypericum/química , Benzofenonas/química , Glicosídeos/química , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Estereoisomerismo , TunísiaRESUMO
The chemical composition of the essential oils extracted from some Tunisian Hypericum species and their larvicidal activity against Culex pipiens larvae were evaluated. The chemical compositions of the essential oils from the aerial plant parts were analyzed using gas chromatography-mass spectrometry. One hundred and thirty-four compounds were identified, ranging between 85.1 and 95.4 % of the oil's composition. The components were monoterpene hydrocarbons, oxygenated monoterpenes, sesquiterpene hydrocarbons, oxygenated sesquiterpenes, non-terpenic hydrocarbons, and others. The larvicidal activity of the essential oils was evaluated using a method recommended by WHO. Larvicidal tests revealed that essential oils from the Hypericum species have a significant larvicidal activity against C. pipiens, with LC(50) ranging between 102.82 and 194.70 ppm. The most powerful essential oils against these larvae were Hypericum tomentosum and Hypericum humifusum samples, followed by the essential oil of Hypericum perforatum.
Assuntos
Culex/efeitos dos fármacos , Hypericum/química , Inseticidas/química , Inseticidas/farmacologia , Óleos Voláteis/química , Óleos Voláteis/farmacologia , Animais , Bioensaio , Cromatografia Gasosa-Espectrometria de Massas , Inseticidas/isolamento & purificação , Larva/efeitos dos fármacos , Óleos Voláteis/isolamento & purificação , Análise de Sobrevida , TunísiaRESUMO
BACKGROUND: A number of bio-active secondary metabolites have been identified and reported for several Hypericum species. Many studies have reported the potential use of the plant extracts against several pathogens. However, Hypericum triquetrifolium is one of the least studied species for its antimicrobial activity. The aim of the present study was to evaluate the cytotoxic effect of the essential oils of Hypericum triquetrifolium as well as their antimicrobial potential against coxsakievirus B3 and a range of bacterial and fungal strains. METHODS: The essential oils of Hypericum triquetrifolium harvested from five different Tunisian localities (Fondouk DJedid, Bou Arada, Bahra, Fernana and Dhrea Ben Jouder) were evaluated for their antimicrobial activities by micro-broth dilution methods against bacterial and fungal strains. In addition, the cytotoxic effect and the antiviral activity of these oils were carried out using Vero cell lines and coxsakievirus B3. RESULTS: The results showed a good antibacterial activities against a wide range of bacterial strains, MIC values ranging between 0.39-12.50 mg/ml and MBC values between 1.56-25.0 mg/ml. In addition, the essential oils showed promising antifungal activity with MIC values ranging between 0.39 µg/mL and 12.50 µg/mL; MFC values ranged between 3.12 µg/mL and 25.00 µg/mL; a significant anticandidal activity was noted (MIC values comprised between 0.39 µg/mL and 12.50 µg/mL). Although their low cytotoxic effect (CC50 ranged between 0.58 mg/mL and 12.00 mg/mL), the essential oils did not show antiviral activity against coxsakievirus B3. CONCLUSION: The essential oils obtained from Hypericum triquetrifolium can be used as antimicrobial agents and could be safe at non cytotoxic doses. As shown for the tested essential oils, comparative analysis need to be undertaken to better characterize also the antimicrobial activities of Hypericum triquetrifolium extracts with different solvents as well as their purified fractions and their pure secondary metabolites.
Assuntos
Antibacterianos/farmacologia , Antifúngicos/farmacologia , Antivirais/farmacologia , Hypericum/química , Óleos Voláteis/farmacologia , Extratos Vegetais/farmacologia , Animais , Bactérias/efeitos dos fármacos , Chlorocebus aethiops , Enterovirus Humano B/efeitos dos fármacos , Fungos/efeitos dos fármacos , Células VeroRESUMO
BACKGROUND: In 1957, Tunisia introduced 117 species of Eucalyptus; they have been used as fire wood, for the production of mine wood and to fight erosion. Actually, Eucalyptus essential oil is traditionally used to treat respiratory tract disorders such as pharyngitis, bronchitis, and sinusitis. A few investigations were reported on the biological activities of Eucalyptus oils worldwide. In Tunisia, our previous works conducted in 2010 and 2011 had been the first reports to study the antibacterial activities against reference strains. At that time it was not possible to evaluate their antimicrobial activities against clinical bacterial strains and other pathogens such as virus and fungi. METHODS: The essential oils of eight Eucalyptus species harvested from the Jbel Abderrahman, Korbous (North East Tunisia) and Souinet arboreta (North of Tunisia) were evaluated for their antimicrobial activities by disc diffusion and microbroth dilution methods against seven bacterial isolates: Haemophilus influenzae, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus agalactiae, Streptococcus pneumoniae and Streptococcus pyogenes. In addition, the bactericidal, fungicidal and the antiviral activities of the tested oils were carried out. RESULTS: Twenty five components were identified by GC/FID and GC/MS. These components were used to correlate with the biological activities of the tested oils. The chemical principal component analysis identified three groups, each of them constituted a chemotype. According to the values of zone diameter and percentage of the inhibition (zdi, % I, respectively), four groups and subgroups of bacterial strains and three groups of fungal strains were characterized by their sensitivity levels to Eucalyptus oils. The cytotoxic effect and the antiviral activity varied significantly within Eucalyptus species oils. CONCLUSIONS: E. odorata showed the strongest activity against S. aureus, H. influenzae, S. agalactiae, S. pyogenes, S. pneumoniae and against all the tested fungal strains. In addition, E. odorata oil showed the most cytotoxic effect. However, the best antiviral activity appeared with E. bicostata. Virus pretreatment with E. bicostata essential oil showed better antiviral activity (IC(50) = 0.7 mg/ml, SI = 22.8) than cell-pretreatment (IC(50) = 4.8 mg/ml, SI = 3.33). The essential oil of E. astringens showed antiviral activity only when incubated with virus prior to cell infection. This activity was dose-dependent and the antiviral activity diminished with the decreasing essential oil concentration.
Assuntos
Anti-Infecciosos/farmacologia , Eucalyptus/química , Óleos Voláteis/química , Óleos Voláteis/farmacologia , Óleos de Plantas/química , Óleos de Plantas/farmacologia , Anti-Infecciosos/química , Bactérias/efeitos dos fármacos , Eucalyptus/classificação , Fungos/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Vírus/efeitos dos fármacosRESUMO
The chemical composition of the essential oils of five populations of Hypericum triquetrifolium Turra from Tunisia and their intraspecific variability were analyzed in detail by GC/MS. One hundred seventy-four compounds were identified, representing averages of 87.9 to 98.7% of the oil composition. The components are represented here by homologous series of monoterpene hydrocarbons, oxygenated monoterpenes, sesquiterpenes hydrocarbons, oxygenated sesquiterpenes, non-terpenic hydrocarbons, and others. Sesquiterpene hydrocarbons were the most abundant chemical compounds. Multivariate chemometric techniques, such as cluster analysis (CA) and principal-component analysis (PCA), were used to characterize the samples according to the geographical origin. By statistical analysis, the analyzed populations were classified into four chemotype groups.
Assuntos
Hypericum/química , Monoterpenos/análise , Óleos Voláteis/química , Sesquiterpenos/análise , Análise por Conglomerados , Cromatografia Gasosa-Espectrometria de Massas , Análise de Componente Principal , TunísiaRESUMO
The essential oils of fifteen Eucalyptus species harvested from the Jbel Abderrahman and Korbous arboreta (North East Tunisia) were screened for their antibacterial activities by the agar disc diffusion method. Eighteen major components as identified by GC/FID and GC/MS were selected for a study of the chemical and biological activity variability. The main one was 1,8-cineole, followed by spathulenol, trans-pinocarveol, α-pinene, p-cymene, globulol, cryptone, ß-phellandrene, viridiflorol, borneol, limonene and isospathulenol. The chemical principal component analysis identified five species groups and subgroups, where each group constituted a chemotype, however that of the values of zone diameter of the inhibition (zdi) identified six groups of Eucalyptus oils, characterized by their antibacterial inhibition ability. The strongest activity was shown by E. platypus oil against Enterococcus faecalis and by E. lamannii oil against Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli. A correlation between the levels of some major components and the antibacterial activities was observed.
Assuntos
Antibacterianos/química , Eucalyptus/química , Óleos Voláteis/química , Folhas de Planta/química , Óleos de Plantas/química , Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Análise por Conglomerados , Testes de Sensibilidade a Antimicrobianos por Disco-Difusão/normas , Gentamicinas/farmacologia , Modelos Biológicos , Óleos Voláteis/farmacologia , Óleos de Plantas/farmacologia , Análise de Componente Principal , Padrões de Referência , TunísiaRESUMO
In the present study the chemical composition of the essential oils from aerial parts and flowers of Achillea ligustica All., collected in Lipari (Aeolian Islands) was evaluated by GC and GC-MS. (Z)-Chrysanthenyl acetate was the most abundant component of both oils (29.6% in A1 and 27.8% in F1), followed by viridiflorol (16.8% in A1 and 21.6% in F1), bornyl acetate (8.7% in A1 and 11.6% in F1) and 1,8-cineole (7.4% in A1 and 9.3% in F1). A comparison was made of the composition of the different populations studied so far. Futhermore, the free radical scavenging activity of the oil was determined by DPPH and ABTS methods.
Assuntos
Achillea/química , Sequestradores de Radicais Livres/farmacologia , Óleos Voláteis/análise , Achillea/crescimento & desenvolvimento , Óleos Voláteis/farmacologia , SicíliaRESUMO
Nanoparticles derived from plants known for their high content of flavonoids provide a biologically inspired route to designing therapeutic agents and a means of reducing nanoparticle toxicity. Little is currently known on the antiviral activity of Salvia officinalis L. and Washingtonia filifera H.Wendl aqueous extracts and their corresponding nanoparticles. In the present study, antiviral activity of subset extracts obtained from aerial parts of Salvia officinalis L. and Washingtonia filifera H.Wendl and nanoparticles derived from these plants were investigated against coxsackievirus B3 (CVB3). Different concentrations of extracts (7.8, 15.6, 31.25, 62.5, 125, 250, 500, and 1000 μg/mL) were tested for their cytotoxic effect and the antiviral activity was carried out using three non cytotoxic concentrations against CVB3 in Vero cells. The cell viability was carried out using tetrazolium dye (MTT). The experiment was carried out by incubating the extracts with either virus or cells prior to infection. The silver nanoparticles derived from the tested plant extracts enhance antiviral activity at non cytotoxic concentrations. The biosynthesized nanoparticles may be further characterized to better evaluate their antiviral potential against other viral pathogens.
RESUMO
The natural products are widely used in many fields as pharmaceutical, flavor, industrial, and additive compounds. In many cases, there is a need to evaluate the cytotoxic effect of these products and to determine the non cytotoxic concentration at which they can be used in a safe manner. The objective of the present study was to compare two methods of evaluation the cytotoxic effect of a plant extract. The MTT assay and the PI dye-inclusion assay were used to carry out the experiments. The results were then evaluated by calorimetric and flow cytometry assays. The obtained results showed that a clear difference between the two methods and the cell death using the MTT assay seem to be overestimated. To better evaluate the cytotoxic effect of natural product, we need to carry out several in vitro and in vivo tests before the judgment that a compound is safe to use and at which concentration.
RESUMO
OBJECTIVE@#To study the recombination events among enterovirus strains and the development of specific primers for the detection of enteroviruses in environmental samples.@*METHODS@#Nucleotide sequence analysis of enteroviruses deposited in the international database GenBank (www.ncbi.nlm.nih.gov/Genbank) was conducted to develop specific primers for the detection of these viruses. The specificity and sensitivity of the method were tested using coxackievirus B3 strain Nancy, environmental isolate of human hepatitis A virus and human rotavirus strain WA. Seventy sewage samples were analyzed.@*RESULTS@#Enterovirus genome was detected in all positive samples. The genome of enterovirus was not detected in negative samples. The level of detection of these viruses was 10(2) TCID(50)/mL.@*CONCLUSIONS@#The development of new primers is an important issue for the detection of enteroviruses in the environment and the assessment of risk factors to human health.