Brazilian propolis protects Saccharomyces cerevisiae cells against oxidative stress

Betulinic acid mitigates oxidative stress-mediated apoptosis and enhances longevity in the yeast Saccharomyces cerevisiae model

Betulinic acid (BA), a pentacyclic triterpenoid found in certain plant species, has been reported to have several health benefits including antioxidant and anti-apoptotic properties. However, the mechanism by which BA confers these properties is currently unknown. Saccharomyces cerevisiae, a budding yeast with a short life cycle and conserved cellular mechanism with high homology to humans, was used as a model for determining the role of BA in aging and programmed cell death (PCD). Treatment with hydrogen peroxide (H₂O₂) exhibited significantly increased (30-35%) survivability of antioxidant (sod1Δ, sod2Δ, cta1Δ, ctt1Δ, and tsa1Δ) and anti-apoptotic (pep4Δ and fis1Δ) mutant strains when cells were pretreated with BA (30 µM) as demonstrated in spot and CFU (Colony forming units) assays. Measurement of intracellular oxidation level using the ROS-specific dye H₂DCF-DA showed that all tested BA-pretreated mutants exhibited decreased ROS than the control when exposed to H₂O₂. Similarly, when mutant strains were pretreated with BA and then exposed to H₂O₂, there was reduced lipid peroxidation as revealed by the reduced malondialdehyde content. Furthermore, BA-pretreated mutant cells showed significantly lower apoptotic activity by decreasing DNA/nuclear fragmentation and chromatin condensation under H₂O₂-induced stress as determined by DAPI and acridine orange/ethidium bromide staining. In addition, BA treatment also extended the life span of antioxidant and anti-apoptotic mutants by ∼10-25% by scavenging ROS and preventing apoptotic cell death. Our overall results suggest that BA extends the chronological life span of mutant strains lacking antioxidant and anti-apoptotic genes by lowering the impact of oxidative stress, ROS levels, and apoptotic activity. These properties of BA could be further explored for its use as a valuable nutraceutical.

Comparative study of the antioxidant activity of the essential oils of five plants against the H2O2 induced stress in Saccharomyces cerevisiae

The purpose of this work was to investigate the protective effect of five essential oils (EOs); Rosmarinus officinalis, Thymus vulgaris, Origanum compactum Benth., Eucalyptus globulus Labill. and Ocimum basilicum L.; against oxidative stress induced by hydrogen peroxide in Saccharomyces cerevisiae. The chemical composition of the EOs was analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC/MS). The in vitro antioxidant activity was evaluated and the protective effect of EOs was investigated. Yeast cells were pretreated with different concentrations of EOs (6.25–25 µg/ml) for an hour then incubated with H₂O₂ (2 mM) for an additional hour. Cell viability, antioxidants (Catalase, Superoxide dismutase and Glutathione reductase) and metabolic (Succinate dehydrogenase) enzymes, as well as the level of lipid peroxidation (LPO) and protein carbonyl content (PCO) were evaluated. The chemical composition of EOs has shown the difference qualitatively and quantitatively. Indeed, O. compactum mainly contained Carvacrol, O. basilicum was mainly composed of Linalool, T. vulgaris was rich in thymol, R. officinalis had high α-Pinene amount and for E. globulus, eucalyptol was the major compound. The EOs of basil, oregano and thyme were found to possess the highest amount of total phenolic compounds. Moreover, they have shown the best protective effect on yeast cells against oxidative stress induced by H₂O₂. In addition, in a dose dependent manner of EOs in yeast medium, treated cells had lower levels of LPO, lower antioxidant and metabolic enzymes activity than cells exposed to H₂O₂ only. The cell viability was also improved. It seems that the studied EOs are efficient natural antioxidants, which can be exploited to protect against damages and serious diseases related to oxidative stress.

Oxidative stress alleviating potential of galactan exopolysaccharide from Weissella confusa KR780676 in yeast model system

In the present study, galactan exopolysaccharide (EPS) from Weissella confusa KR780676 was evaluated for its potential to alleviate oxidative stress using in vitro assays and in vivo studies in Saccharomyces cerevisiae (wild type) and its antioxidant (sod1∆, sod2∆, tsa1∆, cta2∆ and ctt1∆), anti-apoptotic (pep4∆ and fis1∆) and anti-aging (sod2∆, tsa1∆ and ctt1∆)) isogenic gene deletion mutants. Galactan exhibited strong DPPH and nitric oxide scavenging activity with an IC₅₀ value of 450 and 138 µg/mL respectively. In the yeast mutant model, oxidative stress generated by H₂O₂ was extensively scavenged by galactan in the medium as confirmed using spot assays followed by fluorescencent DCF-DA staining and microscopic studies. Galactan treatment resulted in reduction in the ROS generated in the yeast mutant cells as demonstrated by decreased fluorescence intensity. Furthermore, galactan exhibited protection against oxidative damage through H₂O₂ -induced apoptosis inhibition in the yeast mutant strains (pep4∆ and fis1∆) leading to increased survival rate by neutralizing the oxidative stress. In the chronological life span assay, WT cells treated with galactan EPS showed 8% increase in viability whereas sod2∆ mutant showed 10–15% increase indicating pronounced anti-aging effects. Galactan from W. confusa KR780676 has immense potential to be used as a natural antioxidant for nutraceutical, pharmaceutical and food technological applications. As per our knowledge, this is the first report on in-depth assessment of in vivo antioxidant properties of a bacterial EPS in a yeast deletion model system.

Enzyme activity and expression of catalases in response to oxidative stress in Sporothrix schenckii

Sporothrix schenckii is a dimorphic fungus, pathogenic to humans and animals, which is usually infective in the yeast form. Reactive oxygen species (ROS) play an important role in the host's defense, damaging the pathogen's DNA, proteins, and lipids. To prevent oxidative damage, the ROS are detoxified by pathogen-derived antioxidant enzymes such as catalases (CATs). In this work, we analyzed the activity and expression level of three S. schenckii genes, designated as CAT1, CAT2, and CAT3, that putatively encoded for three isoforms of monofunctional CAT with a predicted molecular weight of 57.6, 56.2, and 81.4 kDa, respectively. Our results demonstrate that oxidative stress induced by exogenous H₂O₂ leads to an altered lipid peroxidation, modifying CAT activity and the expression levels of the CAT genes, being CAT1 and CAT3 the genes with the highest expression in response to the oxidizing agent. These results show that CAT isoforms in S. schenckii can be regulated in response to oxidative stress and might help to control ROS homeostasis in the fungus-host interaction.

The effect of Brazilian propolis type-3 against oral microbiota and volatile sulfur compounds in subjects with morning breath malodor

OBJECTIVES

To evaluate propolis type-3 mouthrinse effects on the concentration of volatile sulfur compounds (VSCs) and on tongue dorsum microbial profile.

MATERIALS AND METHODS

A three-step double-blind, crossover, randomized study with 10 individuals divided into three groups: I-placebo (P); II-ethanolic extract of propolis type-3 3% (EEP); and III-chlorhexidine 0.12% (CHX) and instructed to rinse twice daily for 5 days. Each experimental period was followed by a 21-day washout interval. Morning mouth breath was assessed by VSC concentrations and microbiological samples were obtained from tongue dorsum at baseline and the end of period of rinses and analyzed using checkerboard DNA-DNA hybridization technique for 39 bacterial species.

RESULTS

CHX and EEP presented the lowest VSC concentration when compared with placebo (p < 0.05). Even in the absence of mechanical plaque control, CHX and EEP treatments reduced VSC levels and there were no statistical differences for VSC measurement between CHX and EEP. There was a significant reduction in mean counts of 10 species including some VSC producers (Prevotella intermedia, Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia) by EEP. Total counts of organisms, gram-negative and gram-positive bacterial species showed a decrease for EEP and CHX (p < 0.05). In addition, no statistical difference was observed between EEP and CHX (p > 0.05). A positive correlation was observed between decrease of bacterial counts and decrease of VCSs concentration for the EEP and CHX.

CONCLUSIONS

The use of a 3% propolis type-3 mouthrinse is an effective way to prevent morning bad breath. Thus, propolis may be a promising agent for the treatment of halitosis.

CLINICAL RELEVANCE

Propolis type-3 may be used as adjuvant treatment for morning breath malodor.

Determination of the Phytochemical Composition and Antioxidant Potential of Eugenia copacabanensis and Myrciaria tenella Leaves (Myrtaceae) Using a Saccharomyces cerevisiae Model

Eugenia copacabanensis and Myrciaria tenella are present in restingas of the Atlantic Forest, but little information is available about their chemical and biological potential. In this context, the hexane, dichloromethane, ethyl acetate and butanol fractions from the leaves of methanolic extract were analyzed by GC/MS and HPLC-DAD and the antioxidant potential was determined by DPPH and ABTS assays and using a Saccharomyces cerevisiae model. Dereplication allowed the identification of 68 compounds, 42 and 41 of which, respectively, are first reported here for E. copacabanensis and M. tenella. In vivo results revealed that the ethyl acetate and butanol fractions showed expressive antioxidant protection in the BY4741 and Δgsh1 strains, with greater impact on glutathione-deficient cells. With a high diversity of phenolic compounds, these polar fractions of E. copacabanensis and M. tenella leaves are potential protectors against intracellular oxidative stress.

To bee or not to bee? The bee extract propolis as a bioactive compound in the burden of lifestyle diseases

Propolis is a polyphenolic plant resin collected by bees to protect hives against pathogens and temperature drop. It exhibits antibacterial, antioxidant, and antiinflammatory properties. Propolis has been reported to possess antidiabetic properties and display beneficial effects against cardiovascular disease, gut dysbiosis, and chronic kidney disease. It has an excellent clinical safety profile, with no known toxic effects described so far. In this review, we discuss the salutogenic effects of propolis, with particular reference to modulating notable features of chronic kidney disease, notably those involving cardiovascular risks.

Protective effect of quercetin in combination with caloric restriction against oxidative stress-induced cell death of Saccharomyces cerevisiae cells

Impairment of antioxidant enzymes activities has been well reported in several human diseases. Effective anti-ageing strategies involving antioxidant supplementation and/or caloric restriction (CR) are receiving a great attention to mitigate free radical-mediated oxidative damage in several disease conditions to improve active longevity. Therefore, in this work, we have evaluated the protective effect of quercetin under non restriction (NR) and CR conditions on the sensitivity of Saccharomyces cerevisiae mutant strains (sod1∆, sod2∆, cta1∆, ctt1∆, tsa1∆ and glr1∆) deficient in antioxidant defence systems (superoxide dismutase, catalase, thioredoxin peroxidase and glutathione reductase) against H₂ O₂ -induced oxidative stress. Our results demonstrate that quercetin in combination with CR has strongly reduced the H₂ O₂ -mediated stress in the yeast mutant cells compared to NR conditions. Furthermore, we show that quercetin in combination with CR enhanced the percentage viability of yeast cells during chronological ageing. Our research findings suggest that antioxidant supplementation in combination with CR might have potent beneficial effects than individual therapies against free radical-mediated oxidative stress. SIGNIFICANCE AND IMPACT OF THE STUDY: Oxidative stress results from an imbalance between free radicals and antioxidant defense systems in our body. Supplementation with exogenous antioxidants is necessary to neutralize the free radical mediated damage. Polyphenols are a group of naturally occurring plant compounds with strong free radical-scavenging activity and exhibits potent anti-aging property by mitigating oxidative stress. On the other hand, caloric restriction (CR) has been reported to be a popular leading anti-aging approach to ameliorate age-associate macromolecular damages in various chronic human diseases. Evaluation of protective effects of antioxidant supplementation in combination with CR against free radical mediated oxidative stress is pivotal for the development of novel anti-aging strategies to improve active longevity.

Biological control of yeast contamination of industrial foods by propolis

Bee glue (Propolis, PR), mixture of beeswax and resin is collected from honeybee (Apis mellifera) of different plant parts. The antimicrobial potential of PR against food borne yeast was reported. The experiment was designed to examine the way of antimicrobial impact of PR on food borne yeasts (Cryptococcus laurentii and Candida famata) and its usage use as biological strategy for the preservation of soft foods against microbial spoilage. The study also highlights, the ability of ethanol and water- PR extracts, discouraged growth of tested yeast. Antifungal properties were also determined using electron microscope while biochemical analysis was determined using free and proteinic amino acid technique and oxidative enzymes were determined using HPLC analysis. Antioxidant enzymes were determined using ELISA assay. The highest effect was recorded on C. laurentii however, the lowest effect shows on C. famata. The electron microscopic studies clearly disclosed the effect of water PR distillate on the external shape and internal organs of some tested yeast e.g. C. laurentii and C. famata. The result indicated some differences on concentrations of bio-chemical analyses for these tested yeasts treated with 70% water- PR extracts of different food materials. Moreover, biochemical analysis results also reported that the treated yeast indicated natural preservative to food products and considered as best alternative to the (chemical) preservatives currently employed.

In vitro activity of essential oils against adult and immature stages of Ctenocephalides felis felis

Essential oils (EOs) are considered a new class of ecological products aimed at the control of insects for industrial and domestic use; however, there still is a lack of studies involving the control of fleas. Ctenocephalides felis felis, the most observed parasite in dogs and cats, is associated with several diseases. The aim of this study was to evaluate the in vitro activity, the establishment of LC50 and toxicity of EOs from Alpinia zerumbet (Pers.) B. L. Burtt & R. M. Sm, Cinnamomum spp., Laurus nobilis L., Mentha spicata L., Ocimum gratissimum L. and Cymbopogon nardus (L.) Rendle against immature stages and adults of C. felis felis. Bioassay results suggest that the method of evaluation was able to perform a pre-screening of the activity of several EOs, including the discriminatory evaluation of flea stages by their LC50. Ocimum gratissimum EO was the most effective in the in vitro assays against all flea stages, presenting adulticide (LC50 = 5.85 μg cm-2), ovicidal (LC50 = 1.79 μg cm-2) and larvicidal (LC50 = 1.21 μg cm-2) mortality at low doses. It also presented an excellent profile in a toxicological eukaryotic model. These findings may support studies involving the development of non-toxic products for the control of fleas in dogs and cats.

Characterization of lapachol cytotoxicity: contribution of glutathione depletion for oxidative stress in Saccharomyces cerevisiae

Over the years, quinones or its derivatives have been extensively studied due to their broad therapeutic spectrum. However, due to the significant structural differences between the individual naturally occurring quinones, investigation of the precise mechanism of their action is essential. In this context, we have analyzed the mechanism of lapachol [4-hydroxy-3-(3-methylbut-2-enyl)naphthalene-1,2-dione] toxicity using Saccharomyces cerevisiae as eukaryotic model organism. Analyzing yeast (wild type, sod1∆, and gsh1∆) cell growth, we observed a strong cytostatic effect caused by lapachol exposure. Moreover, survival of cells was affected by time- and dose-dependent manner. Interestingly, sod1∆ cells were more prone to lapachol toxicity. In this sense, mitochondrial functioning of sod1∆ cells were highly affected by exposure to this quinone. Lapachol also decreased glutathione (GSH) levels in wild type and sod1∆ cells even though glutathione disulfide (GSSG) remained unchanged. We believe that reduction of GSH contents has contributed to the enhancement of lipid peroxidation and intracellular oxidation, effect much more pronounced in sod1∆ cells. Overall, the collected data suggest that although lapachol can act as an oxidant, it seems that the main mechanism of its action initially consists in alkylation of intracellular targets such as GSH and then generating oxidative stress.

Onion skin extract as a protective agent against oxidative stress in Saccharomyces cerevisiae induced by cadmium

Onion skin extract is a source of bioactive compounds demonstrating a high antioxidant activity. The purpose of this research was to investigate the effect of onion skin extract at the level of oxidative stress markers in Saccharomyces cerevisiae exposed to cadmium. The generation of reactive oxygen species (ROS), antioxidant enzymes activity, total content of glutathione, and the level of lipid peroxidation in yeast cells were determined. Research showed that onion skin extract protected the yeast cells from the occurrence of oxidative stress induced by cadmium. Cells treated with onion skin extract and cadmium were characterized by lower generation of ROS, antioxidant enzymes activity, lipid peroxidation, and higher level of glutathione content than cells treated with cadmium only. However, the protective effect was dependent on the onion skin extract concentration in yeast medium. PRACTICAL APPLICATIONS: The presented studies are of comprehensive character regarding antioxidant properties of the onion skin extract, using Saccharomyces cerevisiae as a model organism. The research results give the opportunity to conduct further research on the use of onion skin extract in functional food or dietary supplements production, as a cellular protector against negative consequence of oxidative stress. It should also be mentioned that the major research material was onion skin which is a troublesome waste material for onion producers. Consequently, the study result will, to a certain extent provide an opportunity to increase interest in the problem of rational use of the waste material, according to a sustainable development idea.

Astaxanthin supplementation reduces dichlorvos-induced cytotoxicity in Saccharomyces cerevisiae

This study evaluates the protective effect of astaxanthin against dichlorvos cytotoxicity in yeast Saccharomyces cerevisiae. Dichlorvos induce a dose-dependent cytotoxicity in yeast cells, which is mediated by oxidative stress. Our experimental results showed pre-treatment with astaxanthin enhances cell viability by 20-30% in yeast cells exposed to dichlorvos. A decrease in DCF fluorescence intensity and lipid peroxidation, increased SOD activity, and glutathione levels in astaxanthin-treated cells indicate that astaxanthin protected the cells against dichlorvos-induced oxidative stress. Reduced chromatin condensation and nuclear fragmentation in astaxanthin pre-treated cells also indicate that astaxanthin rescued the cells from dichlorvos-induced apoptosis. Our overall results suggest that dichlorvos induces oxidative stress-mediated cytotoxicity in yeast cells, and that was rescued by astaxanthin pre-treatment.

Constancy of the bioactivities of propolis samples collected on the same apiary over four years

Natural products, like propolis, have been subject of interest by several industries mainly due to their biological activities. However, besides being produced in low amounts propolis has a great variability in terms of chemical composition and bioactivities' profiles, constituting a problem for the development of propolis-based products and for its acceptance by the medical community. The aim of this work relates to the study of the bioactivities, in particular the antioxidant and the antimicrobial properties, as well as the chemical characterization of Portuguese propolis samples collected in an apiary sited at Gerês (G) along four consecutive years. Ethanol extracts of the four propolis samples (G.EEs) display antimicrobial activity, especially against Gram-positive spore forming bacteria. Antioxidant activity, evaluated by three different in vitro assays, was confirmed in vivo by flow cytometry using Saccharomyces cerevisiae as eukaryotic cell model. Cells incubated with G.EEs prior to H₂O₂ incubation, or incubated with G.EEs and H₂O₂ simultaneously, display higher viability than cells incubated only with H₂O₂, suggesting that G.EEs protect yeast cells against induced oxidative stress. All tested propolis samples exhibit very similar antimicrobial and antioxidant activities. Chemical analysis of G.EEs revealed no significant differences in terms of phenolic profiles, namely in the compounds to which propolis bioactivities are ascribed, thus supporting the more constant behavior evidenced by these propolis samples. This work highlights the valuable properties of this bee product and reveals a constancy of bioactivities in a Portuguese propolis sample over four years, raising awareness to the potentialities of this natural product often regarded as a beekeeping waste.

Propolis supplementation attenuates the negative effects of oxidative stress induced by paraquat injection on productive performance and immune function in turkey poults

Paraquat (PQ) is used as a herbicide in agriculture and causes oxidative and inflammatory damage to animal tissues. The current study was conducted to investigate the positive effects of dietary propolis (PR), as a potent naturally produced antioxidant, on growth performance and immune function of turkey poults exposed to oxidative stress induced by PQ injection. Native male turkey poults (n = 120, 49-d-old) were randomly assigned into 4 groups: poults received a basal diet with a daily subcutaneous PQ injection of 5 mg/kg BW for 7 consecutive days (PQ group), an experimental diet containing 1 g/kg PR with a daily subcutaneous PQ injection for 7 days (PR+PQ group), or received the experimental PR diet with a daily subcutaneous injection of 0.5 mL sterile saline for 7 days (PR group); while the control poults received a basal diet with a daily subcutaneous saline injection for 7 consecutive days (C group). The productive performance in the PQ group showed a significant (P < 0.05) reduction in the weight gain (WG) and feed intake (FI), and impaired feed conversion ratio (FCR). Propolis supplementation in the PR+PQ group significantly ameliorated the PQ effects on WG and FCR. Turkey poults of the PQ and PR+PQ groups had a significant augmentation in the blood malondialdehyde (MDA), tumor necrosis factor-α (TNFα), and corticosterone levels, and in contrast, a significant reduction in the triiodothyronine (T₃), when compared to the C group. While propolis significantly reduced the MDA and corticosterone, and increased the T₃ levels in the PR+PQ group compared to the PQ group. Furthermore, the dietary PR supplementation significantly limited the PQ-suppressive effects on cell- and humoral-mediated immunity and lymphocyte proliferation of turkey poults. In addition, propolis supplementation in the PR and PR+PQ groups markedly reversed the PQ-induced DNA fragmentation and heat shock protein 70 (Hsp70) over-expression in blood cells. It can be concluded that PR could improve turkey immunity and performance, particularly under inflammation and oxidative stress induced by PQ exposure.

The PWWP domain of the human oncogene WHSC1L1/NSD3 induces a metabolic shift toward fermentation

WHSC1L1/NSD3, one of the most aggressive human oncogenes, has two isoforms derived from alternative splicing. Overexpression of long or short NSD3 is capable of transforming a healthy into a cancer cell. NSD3s, the short isoform, contains only a PWWP domain, a histone methyl-lysine reader involved in epigenetic regulation of gene expression. With the aim of understanding the NSD3s PWWP domain role in tumorigenesis, we used Saccharomyces cerevisiae as an experimental model. We identified the yeast protein Pdp3 that contains a PWWP domain that closely resembles NSD3s PWWP. Our results indicate that the yeast protein Pdp3 and human NSD3s seem to play similar roles in energy metabolism, leading to a metabolic shift toward fermentation. The swapping domain experiments suggested that the PWWP domain of NSD3s functionally substitutes that of yeast Pdp3, whose W21 is essential for its metabolic function.

Parasite Killing of Leishmania (V) braziliensis by Standardized Propolis Extracts

Treatments based on antimonials to cutaneous leishmaniasis (CL) entail a range of toxic side effects. Propolis, a natural compound widely used in traditional medical applications, exhibits a range of biological effects, including activity against infectious agents. The aim of this study was to test the potential leishmanicidal effects of different propolis extracts against Leishmania (Viannia) braziliensis promastigotes and intracellular amastigotes in vitro. Stationary-phase L. (V) braziliensis promastigotes were incubated with medium alone or treated with dry, alcoholic, or glycolic propolis extract (10, 50, or 100 μg/mL) for 96 h. Our data showed that all extracts exhibited a dose-dependent effect on the viability of L. (V) braziliensis promastigotes, while controlling the parasite burden inside infected macrophages. Dry propolis extract significantly modified the inflammatory profile of murine macrophages by downmodulating TGF-β and IL-10 production, while upmodulating TNF-α. All three types of propolis extract were found to reduce nitric oxide and superoxide levels in activated L. braziliensis-infected macrophages. Altogether, our results showed that propolis extracts exhibited a leishmanicidal effect against both stages of L. (V) braziliensis. The low cell toxicity and efficient microbicidal effect of alcoholic or glycolic propolis extracts make them candidates to an additive treatment for cutaneous leishmaniasis.

rtfA controls development, secondary metabolism, and virulence in Aspergillus fumigatus

Invasive aspergillosis by Aspergillus fumigatus is a leading cause of infection-related mortality in immune-compromised patients. In order to discover potential genetic targets to control A. fumigatus infections we characterized rtfA, a gene encoding a putative RNA polymerase II transcription elongation factor-like protein. Our recent work has shown that the rtfA ortholog in the model fungus Aspergillus nidulans regulates morphogenesis and secondary metabolism. The present study on the opportunistic pathogen A. fumigatus rtfA gene revealed that this gene influences fungal growth and conidiation, as well as production of the secondary metabolites tryptoquivaline F, pseurotin A, fumiquinazoline C, festuclavine, and fumigaclavines A, B and C. Additionally, rtfA influences protease activity levels, the sensitivity to oxidative stress and adhesion capacity, all factors important in pathogenicity. Furthermore, rtfA was shown to be indispensable for normal virulence using Galleria mellonella as well as murine infection model systems.