Antifungal and physicochemical properties of Ocimum essential oil loaded in poly(lactic acid) nanofibers.

Poly(lactic acid) (PLA) nanofibres containing different proportions of the essential oils from Ocimum basilicum L. and Ocimum gratissimum L. were prepared by solution blow spinning method. The essential oils were extracted by hydrodistillation and characterized by gas chromatography. MEV, contact angle, DSC and FTIR were used to characterize the nanofibres. The effect of bioative nanofibres on the growth of the fungus and on the production of ochratoxin A were evaluated using the fumigation test. Linalool, 1·8-cineole and camphor were the principal components of the essential oil from O. basilicum, and eugenol was the principal constituent in the oil from O. gratissimum. An increase in the average diameter of the nanofibres was observed with the addition of the essential oils. The essential oils acted as a plasticizer, resulting in a reduction in the crystallinity of the PLA. The encapsulation of essential oils in PLA nanofibres was verified by FTIR. An effective antifungal and antimicotoxygenic activity against Aspergillus ochraceus and Aspergillus westerdjikiae was observed for the bioative nanofibres. These results confirm the potential of PLA nanofibres containing the essential oils for the control of toxigenic fungi that cause the deterioration of food and are harmful to human health.

Tandem Transesterification-Esterification Reactions Using a Hydrophilic Sulfonated Silica Catalyst for the Synthesis of Wintergreen Oil from Acetylsalicylic Acid Promoted by Microwave Irradiation.

SiO2-SO3H, with a surface area of 115 m2/g and pore volume of 0.38 cm3g-1, and 1.32 mmol H+/g was used as a 20% w/w catalyst for the preparation of methyl salicylate (wintergreen oil or MS) from acetylsalicylic acid (ASA). A 94% conversion was achieved in a microwave reactor over 40 min at 120 °C in MeOH. The resulting crude product was purified by flash chromatography. The catalyst could be reused three times.

Catalytic Transformation of Triglycerides to Biodiesel with SiO2-SO3H and Quaternary Ammonium Salts in Toluene or DMSO.

SiO2-SO3H, with a surface area of 115 m2·g-1, pore volumes of 0.38 cm3·g-1 and 1.32 mmol H+/g, was used as a transesterification catalyst. Triglycerides of waste cooking oil reacted with methanol in refluxing toluene to yield mixtures of diglycerides, monoglycerides and fatty acid methyl esters (FAMEs) in the presence of 20% (w/w) catalyst/oil using the hydrophilic sulfonated silica (SiO2-SO3H) catalyst alone or with the addition of 10% (w/w) co-catalyst/oil [(Bun4N)(BF4) or Aliquat 336]. The addition of the ammonium salts to the catalyst lead to a decrease in the amounts of diglycerides in the products, but the concentrations of monoglycerides increased. Mixtures of (Bun4N)(BF4)/catalyst were superior to catalyst alone or Aliquat 336/catalyst for promoting the production of mixtures with high concentrations of FAMEs. The same experiments were repeated using DMSO as the solvent. The use of the more polar solvent resulted in excellent conversion of the triglycerides to FAME esters with all three-catalyst media. A simplified mechanism is presented to account for the experimental results.

Effects of Moro orange juice (Citrus sinensis (l.) Osbeck) on some metabolic and morphological parameters in obese and diabetic rats.

BACKGROUND: Nutritional intervention with the use of phytochemicals is an important method for the treatment and prevention of a metabolic syndrome. The objective of this study was to chemically characterize Moro orange juice. The influence of juice intake on metabolic parameters of rats that were obese, diabetic or both by means of body mass management after the activation of anthocyanins during refrigerated storage was also assessed. RESULTS: Juice intake reversed most of the metabolic abnormalities exhibited by obese rats, including reduction of body mass and improvement of the biochemical profile. The loss of body mass by diabetic animals and obese and diabetic animals was not attributed to juice intake, but to type I diabetes mellitus. In these animals, no improvement was observed in the biochemical profile, liver enzymes and glycemia, so this treatment model was deemed unfeasible. CONCLUSION: The beneficial effects cannot be explained only by the anthocyanin C3G present in the juice, but rather, by the synergism between all the components. Studies in humans are needed to determine whether the ingestion of this orange can be recommended as an effective strategy to prevent or ameliorate complications of obesity. © 2020 Society of Chemical Industry.

Identification of volatile compounds, quantification of glycerol and trace elements in distilled spirits produced in Mozambique.

Distilled spirits, in addition to satisfying the legal requirements with respect to its composition, must possess a sensorial quality capable of satisfying its consumers. The present work describes the analysis of volatile compounds, trace elements and glycerol in thirteen samples of Mozambican spirits collected in different regions of the country. Extraction of volatile components was a accomplished using the headspace SPME technique, the quantification of glycerol was achieved by UV/Vis spectroscopy and the determination of trace elements by atomic absorption spectrometry. Of the 35 volatile compounds identified, 19 were esters, of which ethyl hexanoate, ethyl octanoate, ethyl nonanoate, ethyl decanoate, ethyl laurate, ethyl hexadecanoate, ethyl tetradecanoate, ethyl benzenepropanoate, 3-methylbutyl acetate and isoamyl alcohol were the predominant compounds found in the different samples, contributing to the characteristics and aroma of the beverages. As for glycerol, concentrations below 5 mg L-1 were observed in all the samples studied. The samples were found to be contaminated by metals such as copper, lead and zinc. In addition, the results provided information on the quality of Mozambican spirits regarding some aspects related to the determination of metals and glycerol. This information might stimulate producers to be more attentive to the conditions of production and the risks involved in achieving good quality spirits.

Effect of the essential oils from Melaleuca alternifolia, Melaleuca quinquenervia and Backhousia citriodora on the synthesis of ochratoxin A by Aspergillus niger and Aspergillus carbonarius isolated from tropical wine grapes.

The influence of essential oils (EOs) extracted from the leaves of Melaleuca alternifolia, Melaleuca quinquenervia and Backhousia citriodora on ochratoxin A (OTA) synthesis by fungi was studied. The extraction of EOs was performed by hydrodistillation (Clevenger apparatus) over a 2-h period and subsequently analyzed by GC-MS and GC-FID. The toxigenic activity of the essential oils (31.25; 15.62 and 7.81 µg mL-1) was evaluated by inhibiting the production of OTA by Aspergillus niger and Aspergillus carbonarius in Czapek agar medium culture. The quantification of the toxin was performed by HPLC. The production of OTA was dependent on the fungal species, incubation temperature (15 and 25 °C) and the presence of the essential oils. In tests carried out at 15 °C, the oils caused a reduction in OTA synthesis that ranged from 57.60 to 76.93% and from 54.78 to 98.68% for the fungal species A. carbonarius and A. niger, respectively. At 25 °C, reductions ranged from the 38.66 to 75.93% and from 17.94 to 71.79% for the respective fungi. The study concluded that natural products could be potential biocontrol agents against OTA contamination in food.

Correlation of the presence of acrolein with higher alcohols, glycerol, and acidity in cachaças.

Acrolein is a toxic aldehyde that can be present in various beverages, such as cachaça and other distilled spirits from sugarcane. The objective of this work was to detect and quantify acrolein in samples of cachaça produced by different processes in all regions of Brazil and to evaluate the possible routes of formation of this contaminant from the correlation with other secondary compounds present in the beverage using principal component analysis. Approximately 27.0% of the samples analyzed were outside the limit established by Brazilian legislation for this contaminant, with an average acrolein concentration of 14.01 mg 100 mL-1 anhydrous alcohol (aa). In the other samples, the average concentration was 0.97 mg 100 mL-1 aa. After selecting the variables that most closely correlated with the presence of acrolein in beverages, a positive correlation was found with the presence of butan-2-ol, propan-1-ol and volatile acids, and a slight correlation with the presence of phenolic compounds. Therefore, the presence of acrolein in cachaça can be associated with contamination of the fermentation must by bacteria of the genus Lactobacillus, as a result of the chemical degradation and enzymatic conversion of the glycerol produced during fermentation.

Environmentally Friendly New Catalyst Using Waste Alkaline Solution from Aluminum Production for the Synthesis of Biodiesel in Aqueous Medium.

Red mud (RM) is composed of a waste alkaline solution (pH = 13.3) obtained from the production of alumina. It contains high concentrations of hematite (Fe2O3), goethite (FeOOH), gibbsite [Al(OH)3], a boehmite (AlOOH), anatase (Tetragonal-TiO2), rutile (Ditetragonal dipyramidal-TiO2), hydrogarnets [Ca3Al2(SiO4)3-x(OH)4x], quartz (SiO2), and perovskite (CaTiO3). It was shown to be an excellent catalytic mixture for biodiesel production. To demonstrate the value of RM, an environmentally friendly process of transesterification in aqueous medium using waste cooking oil (WCO), MeOH, and waste alkaline solution (WAS) obtained from aluminum production was proposed. Triglycerides of WCO reacted with MeOH at 60 °C to yield mixtures of fatty acid methyl esters (FAMEs) in the presence of 0.019% (w/w) WAS/WCO using the WAS (0.204 mol L-1, predetermined by potentiometric titration) from aluminum production by the Bayer process. The use of the new catalyst (WAS) resulted in a high yield of the products (greater than 99% yield).

Kinetic, thermodynamic and physical-chemical study of the removal of copper from cachaça using coconut fibers.

The use of coconut fiber as a copper adsorbent in cachaça was optimised, and changes in the chemical quality of the beverage were observed by analytical techniques. The influence of the adsorbent mass and copper concentration parameters was investigated using the Central Composite Design, and the optimum condition was obtained through the use of Response Surface Methodology. The equilibrium of the adsorption reaction was obtained within 120 min. The kinetic data were better adjusted for the Elovich model (Elovich and Zhabrova 1939) and the isotherm data for the Sips model (Sips 1948). The maximum adsorption capacity was 1.38 mg g-1. Slight changes in the physicochemical quality of the beverage were observed, including a decrease in volatile acidity and alcohol content. Copper levels in cachaça decreased from 8.57 mg L-1 to 4.97 mg L-1 after adsorption. Therefore, the use of biomass as a metal ion adsorbent in beverages can be successfully employed.

Active packaging of poly(lactic acid) nanofibers and essential oils with antifungal action on table grapes.

The table grape is a non-climateric fruit that is very susceptible to fungal contamination, in addition to suffering an accelerated loss of quality during storage. The in vitro and in grape antifungal and antiocratoxigenic effects of the essential oils from Alpinia speciosa and Cymbopogon flexuosus against Aspergillus carbonarius and Aspergillus niger were studied. The oils were encapsulated in poly(lactic acid) (PLA) nanofibers as a potential active packaging to be applied to control the degradation of grapes stored during the post-harvest period. Fungal proliferation and ochratoxin A synthesis in A. carbonarius and A. niger decreased in the presence of the active packaging. However, the nanofiber containing the essential oil from C. flexuosus was more efficient in providing a fungicidal effect against A. carbonarius (10% and 20%) and A. niger (20%). In addition, weight loss and color changes were controlled and the parameters of acidity, °Brix, softening and the texture of the grape were maintained. A very small mass loss of the essential oils encapsulated in nanofibers was observed by thermogravimetric analysis, showing that the nanofiber was efficient in enabling the controlled release. The quality and safety of table grapes were maintained for longer periods of storage in the presence of active packaging, so the incorporation of these oils in nanofibers can be a promising way to increase the shelf life of grapes.

Mechanism of action of various terpenes and phenylpropanoids against Escherichia coli and Staphylococcus aureus.

Foodborne, disease-causing microorganisms are increasingly resistant to commercial antibiotics. Thus, there is a need for the development of new agents capable of acting efficiently in the control of these pathogens. Terpenoids and phenylpropanoids stand out for having high biological activity and a broad spectrum of action. The objectives of this study were to evaluate the antibacterial potential of limonene, ß-citronellol, carvone, carvacrol, eugenol and trans-cinnamaldehyde and to investigate the mechanism of activity of these compounds against the bacteria Escherichia coli and Staphylococcus aureus. The terpene and phenylpropanoid compoundswere purchased and their antibacterial potential was assessed by macrodilution. The mechanism of action was verified by tests of potassium ion efflux, salt tolerance, extravasation of cellular contents, absorption of crystal violet and morphological changes analyzed by electron microscopy. Bacteriostatic and bactericidal effects caused by the compounds carvone, carvacrol, eugenol and transcinemaldehyde were observed in both species; antibacterial activity against only S. aureus was observed for ß-citronelol and limonene. Reduced salt tolerance was found for strains of E. coli treated with carvacrol and S. aureus treated with ß-citronelol. There was extravasation of cellular materials induced by treatments with carvone, carvacrol, eugenol and trans-cinnamaldehyde in both microorganisms. The absorption of crystal violet increased for E. coli after incubation with each treatment. Deleterious effects and morphological changes were observed. Therefore, the monoterpenes and phenylpropanoids under study are potentially applicable for antimicrobial use against E. coli and S. aureus, and the mechanism of action involves changes in membrane permeability without cell lysis.

Acaricidal and repellent activity of the essential oils of Backhousia citriodora, Callistemon viminalis and Cinnamodendron dinisii against Rhipicephalus spp.

The ticks Rhipicephalus microplus and Rhipicephalus sanguineus sensu lato (s.l) are of great importance to agriculture, veterinary medicine and public health. Due to a number of problems related to the use of synthetic acaricides, natural products emerge as promising substances for alternative tick control. In the present study, essential oils of Backhousia citriodora, Callistemon viminalis and Cinnamodendron dinisii were extracted by hydrodistillation, characterized by GC-MS and GC-FID and biologically evaluated for acaricidal activity against R. microplus and repellent activity against R. sanguineus s.l. Inhibition of acetylcholinesterase (AChe) by the essential oils was also evaluated. The major constituent of B. citriodora is citral (98.9 %), whereas the essential oil from C. viminalis is rich in 1.8-cineole (78.1 %), α-pinene (12.5 %) and limonene (3.36 %), and that from C. dinisii contains α-pinene (30.8 %), ß-pinene (12.5 %) and sabinene (11.3 %) as the principal constituents. The median lethal concentrations (LC 50) estimated for the essential oils on engorged R. microplus females were 3.276 µL.mL-1 for B. citriodora, 8.195 µL.mL-1 for C. dinisii and 8.936 µL.mL-1 for C. viminalis. The essential oil of B. citriodora showed the best repellent effect against unfed R. sanguineus s.l. adults, demonstrating repellent action up to 3 h after application. The essential oil of C. viminalis was able to reduce AChe activity, with an average inhibitory concentration (IC 50) of 0.33 µg mL-1. Thus, these oils can be considered as sources of bioactive compounds for tick control.

Dehydration of D-fructose to 5-hydroxymethyl-2-furfural in DMSO using a hydrophilic sulfonated silica catalyst in a process promoted by microwave irradiation.

SiO2-SO3H, with a surface area of 115 m2/g, pore volumes of 0.38 cm3g-1 and 1.32 mmol H+/g, was used as a 10% w/w catalyst for the preparation of 5-hydroxymethyl-2-furfural (HMF) from fructose. A conversion of 100% was achieved in a microwave reactor during 10 min at 150 °C in DMSO, with 100% selectivity for HMF, at a molar ratio of fructose: DMSO equal to 1:56. The catalyst could be re-used three times.

Effect of the essential oils of Satureja montana L., Myristica fragrans H. and Cymbopogon flexuosus S. on mycotoxin-producing Aspergillus flavus and Aspergillus ochraceus antifungal properties of essential oils.

Essential oils can be a useful alternative to the use of synthetic fungicides because they have biological potential and are relatively safe for food and agricultural products. The objectives of the present study were to evaluate the antifungal and antimycotoxigenic activities of the essential oils from Satureja montana L., Myristica fragrans H. and Cymbopogon flexuosus S. against Aspergillus flavus and Aspergillus ochraceus, as well as their effects on ergosterol synthesis and membrane morphology. The antifungal potential was evaluated by mycelial growth analysis and scanning electron microscopy. Fungicidal effects against A. flavus, with MFC of 0.98, 15.62 and 0.98 µL/mL, respectively, were observed for the essential oils from S. montana, M. fragrans and C. flexuosus. Aspergillus ochraceus did not grow in the presence of concentrations of 3.91, 15.62 and 0.98 µL/mL of the essential oils from S. montana, M. fragrans and C. flexuosus, respectively. The essential oils significantly inhibited the production of ochratoxin A by the fungus A. ochraceus. The essential oils also inhibited the production of aflatoxin B1 and aflatoxin B2. The biosynthesis of ergosterol was inhibited by the applied treatments. Biological activity in the fungal cell membrane was observed in the presence of essential oils, given that deleterious effects on the morphologies of the fungi were detected. The essential oils under study are promising as food preservatives because they significantly inhibit toxigenic fungi that contaminate food. In addition, the essential oils hindered the biosynthesis of mycotoxins.

The alkylaminoalkanethiosulfuric acids exhibit in-vitro antileishmanial activity against Leishmania (Viannia) braziliensis: a new perspective for use of these schistosomicidal agents.

The alkylaminoalkanethiosulfuric acids (AAATs) are amphipathic compounds effective against experimental schistosomiasis, of low toxicity, elevated bioavailability after a single oral dose and prompt tissue absorption. OBJECTIVES: To explore the in-vitro antileishmanial potential of AAATs using five compounds of this series against Leishmania (Viannia) braziliensis. METHODS: Their effects on promastigotes and axenic amastigotes, and cytotoxicity to macrophages were tested by the MTT method, and on Leishmania-infected macrophages by Giemsa stain. Effects on the mitochondrial membrane potential of promastigotes and axenic amastigotes and DNA of intracellular amastigotes were tested using JC-1 and TUNEL assays, respectively. KEY FINDINGS: The 2-(isopropylamino)-1-octanethiosulfuric acid (I) and 2-(sec-butylamino)-1-octanethiosulfuric acid (II) exhibit activity against both promastigotes and intracellular amastigotes (IC50 25-35 µm), being more toxic to intracellular parasites than to the host cell. Compound I induced a loss of viability of axenic amastigotes, significantly reduced (30%) the mitochondrial membrane potential of both promastigotes and axenic amastigotes and promoted selective DNA fragmentation of the nucleus and kinetoplast of intracellular amastigotes. CONCLUSIONS: In this previously unpublished study of trypanosomatids, it is shown that AAATs could also exhibit selective antileishmanial activity, a new possibility to be investigated in oral treatment of leishmaniasis.

The colors of biotechnology: general overview and developments of white, green and blue areas.

Biotechnology is responsible for the manipulation of living organisms or their components for the production of products that are of benefit to human kind. Due to the wide range of applications, colors have been used to differentiate the main areas of research, such as white (industrial), green (agricultural) and blue (marine and fresh-water), among others. Thus, this review outlines the impacts of these areas of biotechnology, emphasizing their impact and potential to replace carbon-based technologies with more sustainable technologies.

A new series of schistosomicide drugs, the alkylaminoalkanethiosulfuric acids, partially inhibit the activity of Schistosoma mansoni ATP diphosphohydrolase.

The effects of the alkylaminoalkanethiosulfuric acids (AAATs), new schistosomicidal drugs, on Schistosoma mansoni ATP diphosphohydrolase isoforms, members of the NTPDase family, were analyzed. Pre-incubation of worm adult tegument with AAATs derivatives, with small apolar alkyl groups and an apolar alkane portion of 6 or 8 carbon atoms linked to the amino group, inhibited ATPase activity with a Ki 100-1000 microM. Little inhibition (20%) was observed when ADP was the substrate. The 2-[(tert-butyl)amino]-1-ethanethiosulfuric acid (100 microM) which has a less lipophilic structure, inhibited 28% ATPase and 12% ADPase activities, suggesting that the lipophilicity, although important, is not the only requisite for enzyme activity inhibition. The N-(sec-butyl)-2-bromo-1-octanaminium bromide, which contains a bromide atom instead of thiosulphate, inhibited <10% of the enzyme activity, suggesting the involvement of cysteine residue(s) from S. mansoni ATP diphosphohydrolase isoforms in a mixed disulfide formation. Treatment of parasite tegument with 5 mM iodoacetamide or 1 mM dithiothreitol protected ATPase and ADPase activities against inhibition by AAATs, corroborating the participation of disulfide interchange in the AAATs mechanism. Since S. mansoni ATP diphosphohydrolase isoforms and potato apyrase share structural similarities, the latter enzyme was also tested. ADPase activity from potato apyrase was inhibited by 55%, showing a higher sensitivity to 1 mM AAATs than that shown by ADPase activity from the tegument, while the ATPase activities from both samples showed similar inhibition levels. Furthermore, sulfhydryl reagents protected potato apyrase activity. Therefore, it is possible that both soluble S. mansoni ATP diphosphohydrolase and membrane-associated isoforms are targets for the AAATs.

A study of the activity of 2-(alkylamino)-1-phenyl-1-ethanethiosulfuric acids against infection by Schistosoma mansoni in a murine model.

The schistosomicidal activities of seven 2-(alkylamino)-1-phenyl-1-ethanethiosulfuric acids (1a-g) (R=propyl, isopropyl, butyl, isobutyl, t-butyl, sec-butyl, cyclohexyl, respectively) were determined in female Swiss mice infected with Schistosoma mansoni. The compounds were administered in a single oral dose of 800 mg/kg to groups of 15 mice infected with 50 cercariae each. All the compounds were found to be active, a high animal mortality being observed with 1e. These compounds have a high specificity against female worms (64-100% reduction vs. 33-61% reduction in male worms). The test was repeated, a 400-mg/kg sub-dose of 1f also being tested, and similar results were observed. A 94% reduction in the number of female worms was observed when compound 1c was administered in a single 800-mg/kg dose to animals infected with 80 cercariae. Finally, the test was repeated with single 800 mg/kg oral doses of compounds 1e (highly purified) and 1f and a 400-mg/kg sub-dose of 1c. The toxicity of 1e was confirmed, while the animals that received 1c and 1f presented reductions in the worm loads corresponding to 45.9% (male worms) and 84.8% (female worms) for 1c and 50.4% (male worms) and 94.2% (female worms) for 1f.

Improvement of in vitro efficacy of a novel schistosomicidal drug by incorporation into nanoemulsions.

The aim of this article included the development and evaluation of the capacity of nanoemulsions to improve the activity of the novel schistosomicidal drug-2-(butylamino)-1-phenyl-1-ethanethiosulfuric acid (BphEA). BphEA is a compound with a poor solubility in water, which makes its application as a drug difficult. Nanoemulsion formulations presenting anionic (NANOSTOA, NANOST and NANOLP) and cationic (NANOSTE) interfacial charges were prepared to encapsulate BphEA. These formulations were characterized by the encapsulation rate, diameter, and zeta potential. NANOSTOA, NANOST, and NANOLP presented an entrapment efficiency and zeta potential of 18.7+/-1.8% and -33.6+/-1.2 mV; 20.5+/-3.0% and -31.5+/-5.7 mV; as well as 33.8+/-7.2% and -62.6+/-1.3 mV, respectively. NANOSTE presented an entrapment efficiency of 51.8+/-5.0% and a zeta potential of 25.7+/-3.9 mV. The mean droplet size (between 200 and 252 nm) and polydispersity index (between 0.158 and 0.294) were similar for all formulations. The stability study showed no alteration in these formulations' zeta potential and size. The in vitro schistosomicidal activity of BphEA was higher with the use of NANOSTE than with free BphEA. In addition, release studies revealed a good stability of NANOSTE containing BphEA in a biological medium. These results indicate that cationic nanoemulsions can represent an interesting delivery system for the pharmaceutical formulation of BphEA.

Mechanism of action and determination of the best substrate for a thrombin-like enzyme from Lachesis muta muta venom by regression analysis of the kinetic parameters determined with peptidyl p-nitroanilide substrates.

The kinetic behavior of a thrombin-like enzyme from Lachesis muta muta venom has been studied with 13 tripeptidyl p-nitroanilide substrates. Eight substrates were unprotected at the N terminus and were used for the regression analysis of the experimentally determined kinetic parameters 1/Km, kcat and kcat/Km. The individual contribution of each amino acid side chain to the kinetic parameters was calculated. The amino acid sequence of the ideal substrate (D-Pro-Leu-Arg-pNA) was determined from a regression analysis for each kinetic parameter. This result was confirmed experimentally. The structural analysis of the tripeptides showed that the binding to the S3 sub-site had a small effect on Km. The binding of L-Leu to the S2 sub-site increased kcat without changing the value of Km. The analysis of the kinetic parameters revealed that, in the binding of L-Leu to the S2 sub-site, the enzyme bound the transition state configuration of the substrate/product transformation more tightly than that of the substrate.