Ameliorative effects of gallic acid, quercetin and limonene on urethane-induced genotoxicity and oxidative stress in Drosophila melanogaster

Ribose-cysteine and levodopa abrogate Parkinsonism via the regulation of neurochemical and redox activities in alpha-synuclein transgenic Drosophila melanogaster models

Parkinson's disease (PD), the most prevalent type of parkinsonism, is a progressive neurodegenerative condition marked by several non-motor and motor symptoms. PD is thought to have a complex aetiology that includes a combination of age, genetic predisposition, and environmental factors. Increased expression of α-synuclein (α-Syn) protein is central to the evolvement of neuropathology in this devastating disorder, but the potential of ribose-cysteine and levodopa in abating pathophysiologic changes in PD model is unknown. Crosses were set up between flies conditionally expressing a pathological variant of human α-Syn (UAS-α-Syn) and those expressing GAL4 in neurons (elav-GAL4) to generate offspring referred to as PD flies. Flies were randomly assigned to five groups (n = 40) from the total population of flies, with each group having five replicates. Groups of PD flies were treated with either 500 mg/kg ribose-cysteine diet, 250 mg/kg levodopa diet, or a combination of the two compounds for 21 days, whereas the control group (w1118) and the PD group were exposed to a diet without ribose-cysteine or levodopa. In addition to various biochemical and neurochemical assays, longevity, larval motility, and gravitaxis assays were carried out. Locomotive capability, lifespan, fecundity, antioxidant state, and neurotransmitter systems were all significantly (p < 0.05) compromised by overexpression of α-Syn. However, flies treated both ribose cysteine and levodopa showed an overall marked improvement in motor functions, lifespan, fecundity, antioxidant status, and neurotransmitter system functions. In conclusion, ribose-cysteine and levodopa, both singly and in combination, potentiated a therapeutic effect on alpha-synuclein transgenic Drosophila melanogaster models of Parkinsonism.

Genotoxic and genoprotective effects of phytoestrogens: a systematic review

Phytoestrogens are xenoestrogens found in plants with a myriad of health benefits. However, various studies reported the genotoxic effects of these substances. Thus, we reviewed in vitro and in vivo studies published in PubMed, Scopus, and Web of Science to evaluate the genotoxic and the genoprotective potential of phytoestrogens. Only studies written in English and intended to study commercially available phytoestrogens were included. The screening was performed manually. Moreover, the underlying mechanism of action of phytoestrogens was described. Around half of those studies (43%) reported genoprotective results. However, several studies revealed positive results for genotoxicity with specific model organisms and with dose/concentration dependence. The assessment of the selected articles showed substantial differences in the used concentrations and a biphasic response was recorded in some phytoestrogens. As far as we know, this is the first study to assess the genotoxic and genoprotective effects of phytoestrogens systematically.

Drosophila melanogaster as a Translational Model System to Explore the Impact of Phytochemicals on Human Health

Fruits, vegetables, and spices are natural sources of bioactive phytochemicals, such as polyphenols, carotenoids, flavonoids, curcuminoids, terpenoids, and capsaicinoids, possessing multiple health benefits and relatively low toxicity. These compounds found in the diet play a central role in organism development and fitness. Given the complexity of the whole-body response to dietary changes, invertebrate model organisms can be valuable tools to examine the interplay between genes, signaling pathways, and metabolism. Drosophila melanogaster, an invertebrate model with its extensively studied genome, has more than 70% gene homology to humans and has been used as a model system in biological studies for a long time. The notable advantages of Drosophila as a model system, such as their low maintenance cost, high reproductive rate, short generation time and lifespan, and the high similarity of metabolic pathways between Drosophila and mammals, have encouraged the use of Drosophila in the context of screening and evaluating the impact of phytochemicals present in the diet. Here, we review the benefits of Drosophila as a model system for use in the study of phytochemical ingestion and describe the previously reported effects of phytochemical consumption in Drosophila.

Overview of Beneficial Effects of (Poly)phenol Metabolites in the Context of Neurodegenerative Diseases on Model Organisms

The rise of neurodegenerative diseases in an aging population is an increasing problem of health, social and economic consequences. Epidemiological and intervention studies have demonstrated that diets rich in (poly)phenols can have potent health benefits on cognitive decline and neurodegenerative diseases. Meanwhile, the role of gut microbiota is ever more evident in modulating the catabolism of (poly)phenols to dozens of low molecular weight (poly)phenol metabolites that have been identified in plasma and urine. These metabolites can reach circulation in higher concentrations than parent (poly)phenols and persist for longer periods of time. However, studies addressing their potential brain effects are still lacking. In this review, we will discuss different model organisms that have been used to study how low molecular weight (poly)phenol metabolites affect neuronal related mechanisms gathering critical insight on their potential to tackle the major hallmarks of neurodegeneration.

Immunomodulatory, trypanocide, and antioxidant properties of essential oil fractions of Lippia alba (Verbenaceae)

BACKGROUND

Parasite persistence, exacerbated and sustained immune response, and continuous oxidative stress have been described to contribute to the development of the cardiac manifestations in Chronic Chagas Disease. Nevertheless, there are no efficient therapies to resolve the Trypanosoma cruzi infection and prevent the disease progression. Interestingly, trypanocide, antioxidant, and immunodulatory properties have been reported separately for some major terpenes, as citral (neral plus geranial), limonene, and caryophyllene oxide, presents in essential oils (EO) extracted from two chemotypes (Citral and Carvone) of Lippia alba. The aim of this study was to obtain L. alba essential oil fractions enriched with the aforementioned bioactive terpenes and to evaluate the impact of these therapies on trypanocide, oxidative stress, mitochondrial bioenergetics, genotoxicity, and inflammatory markers on T. cruzi-infected macrophages.

METHODS

T. cruzi-infected J774A.1 macrophage were treated with limonene-enriched (ACT1) and citral/caryophyllene oxide-enriched (ACT2) essential oils fractions derived from Carvone and Citral-L. alba chemotypes, respectively.

RESULTS

ACT1 (IC50 = 45 ± 1.7 μg/mL) and ACT2 (IC50 = 80 ± 1.9 μg/mL) exhibit similar trypanocidal effects to Benznidazole (BZN) (IC50 = 48 ± 2.5 μg/mL), against amastigotes. Synergistic antiparasitic activity was observed when ACT1 was combined with BZN (∑FIC = 0.52 ± 0.13 μg/mL) or ACT2 (∑FIC = 0.46 ± 1.7 μg/mL). ACT1 also decreased the oxidative stress, mitochondrial metabolism, and genotoxicity of the therapies. The ACT1 + ACT2 and ACT1 + BZN experimental treatments reduced the pro-inflammatory cytokines (IFN-γ, IL-2, and TNF-α) and increased the anti-inflammatory cytokines (IL-4 and IL-10).

CONCLUSION

Due to its highly trypanocidal and immunomodulatory properties, ACT1 (whether alone or in combination with BZN or ACT2) represents a promising L. alba essential oil fraction for further studies in drug development towards the Chagas disease control.

Drosophila as an emerging model organism for studies of food-derived antioxidants

Dietary supplementation with antioxidants provides health benefits by preventing diseases caused by oxidative stress and damage. Consequently, there has been growing interest in the study of antioxidative foods and their active ingredients. Oxidative stress and antioxidative responses are mechanistically conserved from Drosophila to mammals. Therefore, as a well-established model organism with a short life cycle and advantages of genetic manipulation, the fruit fly has been increasingly employed to assess functions of antioxidants in vivo. In this review, the antioxidative defense mechanisms, methods used and assays developed in Drosophila to evaluate antioxidant supplementation, are highlighted. The main manifestations of antioxidation include reduction of reactive species, up-regulation of endogenous antioxidants, inhibition on oxidative damage to biomacromolecules, enhanced resistance against oxidative stress and extension of lifespan, which are related to the activations of nuclear factor erythroid 2-related factor 2-antioxidant response element pathway and other adaptive responses. Moreover, the key considerations and future perspectives for the application of Drosophila models in the studies of food-derived antioxidants are discussed.

Toxicological assessment of a bioactive extract from Triplaris gardneriana Wedd. seeds using alternative models

The Triplaris gardneriana Wedd. seeds extract has great therapeutic potential due to numerous biological activities such as antioxidant, antibacterial and anti-inflammatory, which are associated with phenolic content. Although this herbal preparation has shown many benefits, recently their toxicity profile has begun to be explored. In this present study, the toxic effects of T. gardneriana seeds ethanolic extract (EETg) on biological systems of different taxonomical groups and levels of complexity (from cell culture to lower vertebrates) were assessed, through a variety of viability and toxicological assays. It was found that EETg did not impair the Saccharomyces cerevisiae growth at the highest tested concentration (200 µg/mL), and no toxicant evidence was observed in Aedes aegypti larvae or in Drosophila melanogaster adult stage. Contrarily, the extract reduced the viability of undifferentiated Caco-2 cells (250 µg/mL, 40% of viable cells), but did not affect differentiated ones. The embryotoxicity in Danio rerio model showed a LC₅₀ of 7.41 mg/L (95% confidence interval, 4.78 - 11.49 mg/L). EETg did not show signs of toxicity in the majority of the models used, but lethality and malformations in zebrafish embryos occurred. Further analyses are needed to better understand the selective toxicity mechanism of EETg on zebrafish, as well as whether the toxic effects happen in higher vertebrates.

Simultaneous exposure to vinylcyclohexene and methylmercury in Drosophila melanogaster: biochemical and molecular analyses

Background

Exposure to vinylcyclohexene (VCH) and methylmercury (MeHg⁺) can induce oxidative stress and gene modulation. Several studies have been evaluating the effects of VCH and MeHg⁺, but little is known about interactive effects between them. This work aimed to assess the exposure and co-exposure effects of MeHg⁺ and VCH on oxidative stress and gene modulation in Drosophila melanogaster.

Methods

Reactive species production, glutathione S-transferase (GST) and acetylcholinesterase (AChE) activities were evaluated after exposure and co-exposure to VCH (1 mM) and MeHg⁺ (0.2 mM) for one or three days in the head and body (thorax and abdomen) of flies. The expression of genes related to redox state and inflammatory response was evaluated after exposure and co-exposure to VCH and MeHg⁺ for three days.

Results

Survival decreased only in flies co-exposed to VCH and MeHg⁺ for three days. All treatments increased total reactive species production after one day of exposure. However, no significant changes were observed in the head after three days of exposure. One day of exposure to VCH caused an increase in the head GST activity, whereas MeHg⁺ induced an increase after three days of exposure. Regarding the body, all treatments increased GST activity after one day of exposure, but only the flies exposed to MeHg⁺ presented an increase in GST activity after three days of exposure. Treatments did not alter AChE activity in the head. As for gene expression, there was a significant increase in the Relish transcription factor gene in the flies’ body, but Nrf2, Keap1, Jafrac1, TrxR1, and NF-κβ were not altered.

Conclusion

The results suggest that exposure to VCH and MeHg⁺ induce oxidative stress and activation of an inflammatory response in fruit flies.

The Drosophila Model: Exploring Novel Therapeutic Compounds against Neurodegenerative Diseases

Polyphenols are secondary metabolites of plants, fruits, and vegetables. They act as antioxidants against free radicals from UV light, pathogens, parasites, and oxidative stress. In Drosophila models, feeding with various polyphenols results in increased antioxidant capacity and prolonged lifespan. Therefore, dietary polyphenols have several health advantages for preventing many human diseases, including cardiovascular diseases, cancer, and neurodegenerative diseases. However, the exact role of polyphenols in neurodegenerative diseases is still yet to be completely defined. This review focuses on the most recent studies related to the therapeutic effect of polyphenols in neurodegenerative disease management and provides an overview of novel drug discovery from various polyphenols using the Drosophila model.

Eggplant fruits protect against DNA damage and mutations

Eggplant belongs to the Solanaceae family, and it has an important antioxidant capability that has been shown to counteract oxidation, which is harmful to health and many diseases. In this present study, we evaluated the antigenotoxic effects of six eggplants ((Solanum aculeatissimum Jacq. 'Ma-khuea-lueang'; ML), (Solanum aculeatissimum Jacq. 'Ma-khuea-pro'; MP), (Solanum aculeatissimum Jacq. 'Ma-khuea-sawoei'; MS), (Solanum melongena Linn. 'Ma-khuea-khai-tao'; MKT), (Solanum melongena Linn. 'Ma-khuea-muang klom'; MM) and (Solanum torvum Sw. 'Ma-khuea-phuang'; MPH)) against urethane-induced somatic mutation and recombination test (SMART) in Drosophila melanogaster and hydrogen peroxide-induced oxidative DNA damage in human lymphocytes. First, we determined all of the eggplant extracts of their antioxidant properties including radical scavenging activities, reducing antioxidant power and total phenolic contents, surprisingly ML extract showed the highest level of activity. In SMART, larvae were fed with each lyophilized eggplant. The results revealed that no sample was mutagenic. Interestingly, we found that all six eggplants had a potent inhibitory effect against urethane-induced mutagenicity. Moreover, the protective effect of each eggplant extract against oxidative DNA damage in human lymphocytes was investigated using the single-cell gel electrophoresis (comet) assay. The treatment cells with six eggplant extracts prevented DNA human lymphocytes in response to hydrogen peroxide, especially ML extract exhibited higher an inhibition percentage than other samples. This study demonstrated that these eggplants seem to be safe for consumption and their extracts could protect against DNA damage. Thus, these eggplants have the potential to provide health benefits associated with prevention or reduced risk of developing chronic diseases, such as cancer.

Garcinia kola seed biflavonoid fraction (Kolaviron), increases longevity and attenuates rotenone-induced toxicity in Drosophila melanogaster

Rotenone, a naturally occurring and commonly used pesticide, has been established as a model for inducing Parkinson's Disease (PD) in rodents. Kolaviron is a biflavonoid complex from Garcinia kola seeds with anti-oxidative and anti-inflammatory properties. Here, we evaluated the ameliorative role of Kolaviron on rotenone-induced toxicity in Drosophila melanogaster. Flies for longevity study were exposed to Kolaviron (100-500mg/kg diet) throughout the lifespan. For biochemical study, Groups A, B and C flies were treated with ethanol (2.0%, control, vehicle), Kolaviron (200mg/kg diet) and rotenone (250μM) respectively. Flies in Group D were co-treated with both rotenone (250μM) and Kolaviron (200mg/kg diet) for 7days. Subsequently, selected markers of antioxidant status, inflammatory and neurotoxicity were evaluated in the flies. The results from longevity experiment showed that Kolaviron (200, 100, 300 and 400mg/kg) extended lifespan of flies by 38.2%, 20.6%, 11.8% and 2.9% respectively. Also, Kolaviron attenuated rotenone-induced inhibition of catalase, glutathione-S-transferase and acetylcholinesterase activities and depletion of total thiols content in flies. Moreover, Kolaviron prevented rotenone-induced increases in hydrogen peroxide and nitric oxide (nitrite and nitrate) levels and improved rotenone-induced decrease in locomotor performance of flies (p<0.05). Overall, this study evidenced for the first time, the lifespan extension property of Kolaviron and its chemoprotective role on rotenone-induced toxicity in D. melanogaster via anti-oxidative and anti-inflammatory mechanisms.

Protective effects of tea polyphenols and β-carotene against γ-radiation induced mutation and oxidative stress in Drosophila melanogaster

Background

The commonly consumed antioxidants β-carotene and tea polyphenols were used to assess their protective effects against γ-radiation induced sex-linked recessive lethal (SLRL) mutation and oxidative stress in Drosophila melanogaster. Third instar larvae and adult males of wild-type Oregon-K (ORK) were fed on test agents for 24 and 72 h respectively before exposure to 10Gy γ-irradiation. The treated/control flies were used to assess the induction of SLRLs. We also evaluated antioxidant properties of these phytochemicals in the third instar larvae.

Results

Different stages of spermatogenesis in adult males showed a decrease in γ-radiation induced SLRL frequencies upon co-treatment with test agents. A similar trend was observed in larvae. Furthermore, a significant increase in antioxidant enzymatic activities with a decrease in malondialdehyde content was observed.

Conclusion

β-carotene and tea polyphenols have exerted antigenotoxic and antioxidant effects in Drosophila. This study demonstrated the suitability of Drosophila as an alternative to mammalian testing for evaluating the antigenotoxic and antioxidant activity of natural products.