Antioxidant responses driven by Hesperetin and Hesperidin counteract Parkinson's disease-like phenotypes in Drosophila melanogaster.

The study investigated the protective effects of Hesperetin (HSP) and Hesperidin (HSD) on 1 methyl, 4 phenyl, 1,2,3,6 tetrahydropyridine hydrochloride (MPTP)-induced Parkinsonism in Drosophila melanogaster (D. melanogaster). After a lifespan study to select exposure time and concentrations, flies were co-exposed to MPTP (0.4 mg/g diet), Hesperetin (0.2 and 0.4 mg/g diet), and Hesperidin (0.1 and 0.4 mg/g) for 7 days. In addition to in vivo parameters, we assayed some markers of oxidative stress and antioxidant status (lipid peroxidation, protein carbonylation, thiol content, hydrogen peroxide, and nitrate/nitrite levels, mRNA expression of Keap-1 (Kelch-like ECH associated protein 1), /Nrf2 (Nuclear factor erythroid 2 related factor 2), catalase, and glutathione-S-transferase (GST) activities), and cholinergic (acetyl cholinesterase activity (AChE) and dopaminergic signaling content and the mRNA expression of tyrosine hydroxylase (TH), monoamine oxidase (MAO-like) activity). In addition to increasing the lifespan of flies, we found that both flavonoids counteracted the adverse effects of MPTP on survival, offspring emergence, and climbing ability of flies. Both flavonoids also reduced the oxidative damage on lipids and proteins and reestablished the basal levels of pro-oxidant species and activities of antioxidant enzymes in MPTP-exposed flies. These responses were accompanied by the normalization of the mRNA expression of Keap1/Nrf2 disrupted in flies exposed to MPTP. MPTP exposure also elicited changes in mRNA expression and content of TH as well as in MAO and AChE activity, which were reversed by HST and HSD. By efficiently hindering the oxidative stress in MPTP-exposed flies, our findings support the promising role of Hesperetin and Hesperidin as adjuvant therapy to manage Parkinsonism induced by chemicals such as MPTP.

Biological interactions and attenuation of MPTP-induced toxicity in Drosophila melanogaster by Trans-astaxanthin.

Trans-astaxanthin (TA) is a carotenoid with amphipathic chemical structure found in yeast, and aquatic organisms. It is known to possess both antioxidative and anti-inflammatory properties. This study was carried out to investigate the ameliorative action of TA on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced toxicity in Drosophila melanogaster (Fruit fly). The flies were orally treated with TA (2.5 mg/10 g diet) and/or MPTP (500 µM) for 5 days. Thereafter, we evaluated selected biomarkers of locomotor deficits (acetylcholinesterase (AChE) and negative geotaxis), oxidative stress (hydrogen peroxide (H2O2), protein carbonyls (PC)), antioxidants (total thiols (T-SH), non-protein thiols, glutathione-S-transferase (GST) and catalase), and inflammation (nitric oxide (nitrite/nitrate) in the flies. Furthermore, we investigated molecular docking analysis of TA against Kelch-like ECH-associated protein 1 (Keap1)) of Homo sapiens and D. melanogaster. The results indicated that TA increased MPTP-induced decreased activities of AChE, GST, and catalase, as well as levels of non-protein thiols and T-SH compared with MPTP-treated flies (p < 0.05). Furthermore, TA attenuated inflammation, and improved locomotor deficit in the flies. The molecular docking data showed that TA had docking scores for binding both the Human and Drosophila Keap1, nearly closer to or higher than the standard inhibitor. The attenuating effects of TA against MPTP-induced toxicity could arise from its antioxidative and anti-inflammatory properties as well as its chemical structure.

Ellagic acid mitigates rotenone-induced damage via modulating mitochondria function in Drosophila melanogaster.

Constant, systematic exposure to rotenone has been utilized in animal models to induce Parkinsonism. Ellagic acid is a polyphenol with anti-inflammatory and antioxidative properties which is found in numerous natural fruits. Here, we investigated the therapeutic effects of ellagic acid in rotenone-induced toxicity in Drosophila melanogaster evaluating their antioxidant and mitoprotective properties. Adult flies were treated with rotenone and ellagic acid through their diet for 7 days, thereafter markers of neurotoxicity (acetylcholinesterase, monoamine oxidase, tyrosine hydroxylase), antioxidant and oxidative stress markers (hydrogen peroxide, nitric oxide, lipid peroxidation, protein carbonyl contents, catalase, total thiol, and nonprotein thiol) was measured. Mitochondrial respiration was also evaluated in the flies. Survival assay was carried out with both genders of the flies, and we observed a significant increase in the survival rate of flies exposed to both rotenone and ellagic acid when compared with the increased mortality rate in the groups exposed to rotenone alone. The impaired locomotion, altered redox status, and enzymes of neurotoxicity induced by rotenone were significantly ameliorated by ellagic acid to levels comparable to the control. In addition, rotenone-induced complex 1 inhibition and altered bioenergetic state were restored upon ellagic acid supplementation. These findings show the beneficial properties of ellagic acid against pesticides induced toxicity.

Kaempferol counteracts toxicity induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine in D. melanogaster: An implication of its mitoprotective activity.

The current study aimed to investigate whether kaempferol (KMP), the major bioactive component of green leafy vegetables, could counteract the toxicity elicited by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in Drosophila melanogaster or not. First, we performed a dose-response curve, where adult wild-type flies were fed on diet-containing different concentrations of KMP throughout their lifespan. Afterward, flies were fed on a diet containing MPTP (500 µM) and KMP (20 and 40 µM) for 7 days. The MPTP- fed flies presented a higher mortality rate, lower emergence rate, locomotor deficits, and disruption in circadian rhythm when compared to the control. MPTP exposure induced severe oxidative stress, which was marked by reduction in thiol content, overproduction of reactive species, lipid and protein oxidation, and disruption of enzymes of antioxidant and neurotransmission pathways. MPTP also compromised the mitochondrial dynamics and respiration of flies, affecting the electron transport chain, oxidative phosphorylation, and fusion/fission processes. Besides extending per se the lifespan of flies, KMP counteracted the toxic effects of MPTP on the circadian cycle, survival, climbing, and hatching rates. KMP was also effective in restoring the activities of acetylcholinesterase (AChE) and monoamine oxidase (MAO) enzymes, as well as in normalizing the levels of all oxidant/antioxidant markers disrupted in MPTP-fed flies. Indeed, KMP reestablished the mitochondrial functionality in MPTP- fed flies, restoring the electron transport system linked to mitochondrial complex I and II, and rescuing the mRNA transcription of genes associated with mitochondrial fusion and fission, namely OPA-1 (Optic atrophy 1) and DRP-1 (Dynamin related protein 1). Our results showed the efficacy of KMP in hindering the toxicity induced by MPTP in D. melanogaster and suggest that the mitoprotective action of flavonoid may be boosting its anti-parkinsonism activity in the model. Besides, the study showed that wild-type strains of D. melanogaster proved to be reproducible in vivo model to mimic parkinsonian phenotypes through exposure to the neurotoxin MPTP.

Neurotoxic and behavioral deficit in Drosophila melanogaster co-exposed to rotenone and iron.

Exposure to environmental toxicants has been linked with the onset of different neurodegenerative diseases in animals and humans. Here, we evaluated the toxic effects of co-exposure to iron and rotenone at low concentrations in Drosophila melanogaster. Adult wild-type flies were orally exposed to rotenone (50.0 µM) and ferrous sulfate (FeSO4; 1.0 and 10.0 µM) through the diet for 10 days. Thereafter, we evaluated markers of oxidative damage (Hydrogen Peroxide (H2O2), Nitric Oxide (NO), Protein Carbonyl, and malondialdehyde (MDA)), antioxidant status (catalase, Glutathione S-Transferase (GST), Total Thiol (T-SH) and Non-protein Thiol (NPSH), neurotransmission (monoamine oxidase; MAO and acetylcholinesterase, AChE) and mitochondrial respiration. The results indicated that flies fed rotenone and FeSO4 had impaired locomotion, reduced survival rate, and AChE activity with a corresponding increase in MAO activity when compared with the control (p < 0.05). Furthermore, rotenone and FeSO4 significantly decreased the antioxidant status with a concurrent accumulation of NO, MDA, and H2O2. Additionally, the activity of complex 1 and mitochondria bioenergetic capacity was compromised in the flies. These findings suggest that the combination of rotenone and FeSO4 elicited a possible synergistic toxic response in the flies and therefore provided further insights on the use of D. melanogaster in toxicological studies.

Ackee (Blighia sapida K.D. Koenig) Leaves and Arils Methanolic Extracts Ameliorate CdCl2-Induced Oxidative Stress Biomarkers in Drosophila melanogaster.

Different ethnomedical benefits have been documented on different parts of Ackee (Blighia sapida); however, their roles in ameliorating oxidative damages are not well established. CdCl2 inhibitory effects on some oxidative-stress biomarkers and ameliorative potentials of Ackee leaves (AL) and arils (AS) methanolic extracts were studied using Drosophila melanogaster as a model. One to 3-day-old D. melanogaster flies were orally exposed to different concentrations of CdCl2 in their diet for 7 days. The fly's survival profile and negative geotaxis assays were subsequently analysed. Methanolic extracts of AL and AS treatments showed negative geotaxis behaviour, and extracts were able to ameliorate the effect of Cd2+ on catalase and GST activities and increase total thiol and GSH levels, while it reduced the H2O2 generation (p ≤ 0.05) when compared to the control. Furthermore, Cd2+ exhibited noncompetitive and uncompetitive enzyme inhibition on catalase and GST activities, respectively, which may have resulted in the formation of Enzyme-substrate-Cd2+ transition complexes, thus inhibiting the conversion of substrate to product. This study, thus, suggests that the Cd2+ mechanism of toxicity was associated with oxidative damage, as evidenced by the alteration in the oxidative stress-antioxidant imbalance, and that the AL and AS extracts possess essential phytochemicals that could alleviate possibly deleterious oxidative damage effects of environmental pollutants such as CdCl2. Thus, Ackee plant parts possess essential phytonutrients which could serve as valuable resources in heavy metal toxicity management.

An assessment of the rescue action of resveratrol in parkin loss of function-induced oxidative stress in Drosophila melanogaster.

Loss-of-function mutations in parkin is associated with onset of juvenile Parkinson's disease (PD). Resveratrol is a polyphenolic stilbene with neuroprotective activity. Here, we evaluated the rescue action of resveratrol in parkin mutant D. melanogaster. The control flies (w1118) received diet-containing 2% ethanol (vehicle), while the PD flies received diets-containing resveratrol (15, 30 and 60 mg/kg diet) for 21 days to assess survival rate. Consequently, similar treatments were carried out for 10 days to evaluate locomotor activity, oxidative stress and antioxidant markers. We also determined mRNA levels of Superoxide dismutase 1 (Sod1, an antioxidant gene) and ple, which encodes tyrosine hydroxylase, the rate-limiting step in dopamine synthesis. Our data showed that resveratrol improved survival rate and climbing activity of PD flies compared to untreated PD flies. Additionally, resveratrol protected against decreased activities of acetylcholinesterase and catalase and levels of non-protein thiols and total thiols displayed by PD flies. Moreover, resveratrol mitigated against parkin mutant-induced accumulations of hydrogen peroxide, nitric oxide and malondialdehyde. Resveratrol attenuated downregulation of ple and Sod1 and reduction in mitochondrial fluorescence intensity displayed by PD flies. Overall, resveratrol alleviated oxidative stress and locomotor deficit associated with parkin loss-of-function mutation and therefore might be useful for the management of PD.

Protective capacity of carotenoid trans-astaxanthin in rotenone-induced toxicity in Drosophila melanogaster.

Trans-astaxanthin (TA), a keto-carotenoid found in aquatic invertebrates, possesses anti-oxidative and anti-inflammatory activities. Rotenone is used to induce oxidative stress-mediated Parkinson's disease (PD) in animals. We probed if TA would protect against rotenone-induced toxicity in Drosophila melanogaster. Trans-astaxanthin (0, 0.1, 0.5, 1.0, 2.5, 10, and 20 mg/10 g diet) and rotenone (0, 250 and 500 µM) were separately orally exposed to flies in the diet to evaluate longevity and survival rates, respectively. Consequently, we evaluated the ameliorative actions of TA (1.0 mg/10 g diet) on rotenone (500 µM)-induced toxicity in Drosophila after 7 days' exposure. Additionally, we performed molecular docking of TA against selected pro-inflammatory protein targets. We observed that TA (0.5 and 1.0 mg/10 g diet) increased the lifespan of D. melanogaster by 36.36%. Moreover, TA (1.0 mg/10 g diet) ameliorated rotenone-mediated inhibition of Catalase, Glutathione-S-transferase and Acetylcholinesterase activities, and depletion of Total Thiols and Non-Protein Thiols contents. Trans-astaxanthin prevented behavioural dysfunction and accumulation of Hydrogen Peroxide, Malondialdehyde, Protein Carbonyls and Nitric Oxide in D. melanogaster (p < 0.05). Trans-astaxanthin showed higher docking scores against the pro-inflammatory protein targets evaluated than the standard inhibitors. Conclusively, the structural features of TA might have contributed to its protective actions against rotenone-induced toxicity.

Jobelyn® extends the life span and improves motor function in Drosophila melanogaster exposed to lipopolysaccharide via augmentation of antioxidant status.

Jobelyn® (JB), a dietary supplement, derived from polyphenol-rich leaf sheath of Sorghum bicolor, has been reported to attenuate sensorimotor deficits and oxidative stress evoked by complete Freund-adjuvant in mice. This present study evaluated its effects on the life span, motor function and changes in oxidative stress parameters as well as acetylcholinesterase activity in Drosophila melanogaster exposed to lipopolysaccharide (LPS). The flies (50 per vial), in 5 replicates were fed with LPS (250 µg/kg diet) alone or in combination with JB (0.25-1.0 mg/kg diet) daily for 7 days. The mortality rate and motor function were evaluated on day 7. The flies were afterwards processed for determination of oxidative stress parameters and acetylcholinesterase activity. The effects of JB (0.25-1.0 mg/g diet) on the longevity of Drosophila was also investigated wherein the flies were monitored daily for mortality throughout their lifespan. The flies exposed to LPS (250 µg/kg diet) had reduced life span and elevated oxidative stress when compared with control. However, JB (0.25 and 1.0 mg/kg diet) improved the motor function and also reduced the mortality rate of the flies exposed to LPS. It also restored the cellular antioxidant status and reduced acetylcholinesterase activity, accumulation of hydrogen peroxide as well as nitric oxide in Drosophila fed with LPS. JB also extended the longevity of the flies relative to control. The findings that JB improves motor function and extended the lifespan of Drosophila flies by boosting the antioxidant status and cholinergic function, suggest it might be helpful in delaying the onset of neuropsychiatric illnesses associated with the aging processes.

Beneficial actions of esculentin-2CHa(GA30) on high sucrose-induced oxidative stress in Drosophila melanogaster.

Hyperglycaemia-induced oxidative stress plays a critical role in the development of diabetes and its complications. This study investigated actions of esculentin-2CHa(GA30) on high sucrose-induced oxidative stress in adult Drosophila melanogaster. Adult flies were exposed to diets containing graded concentrations of sucrose in the presence or absence of esculentin-2CHa(GA30) (5.0-10 µmol/kg diet) for 7 days. Effects of high sucrose diet and/or esculentin-2CHa(GA30) on survival and longevity of flies, and markers of oxidative stress, antioxidant status and glucose were assessed. High-sucrose diet (15-30%) and esculentin-2CHa(GA30) (5-10 µmol/kg diet) enhanced the percentage of surviving flies by 33.5%-46.2% (P < 0.01) and 7.4%-26.9% (P < 0.01) respectively. Concentration-dependent reduction in total thiol (19.3-51.3%, P < 0.01), reduced glutathione (22.6-54.9%, P < 0.05-0.01), catalase activity (36.8-57.3%, P < 0.05-0.01) and elevated glucose concentration (1.8-2.9-fold, P < 0.001) were observed in high sucrose-fed flies. Esculentin-2CHa(GA30) alone did not affect levels of total thiol, reduced glutathione, glucose and catalase activity. Improved survival (1.2-1.3-fold, P < 0.05-0.01) and longevity (1.3-fold) were observed in flies treated with the peptide (5.0 and 7.5 µmol/kg diet). Feeding on sucrose and esculentin-2CHa(1-30) (5.0 and 7.0 µmol/kg diet) for 7 days increased total thiol (2 - 3-fold, P < 0.001) and reduced glutathione (1.6-1.8-fold, P < 0.05) levels. Reduced catalase activity (21.4-36.4%, P < 0.01) and reduced glucose level (38.6-49.4%, P < 0.01) were observed in peptide-treated flies. Esculentin-2CHa(1-30) inhibited sucrose-induced generation of hydrogen peroxide (7.5-13.7%, P < 0.05) and nitric oxide (22.3-42.9%, P < 0.01) in adult flies. Overall, findings from this study offered further insights into the anti-oxidative properties of esculentin-2CHa(GA30).

Luteolin-Supplemented diets ameliorates Bisphenol A-Induced toxicity in Drosophila melanogaster.

Bisphenol A (BPA) is an industrial chemical used in the production of various plastic materials. It is associated with reproductive, immunological and neurological disorders. Luteolin, a flavonoid found in fruits and vegetables, possesses anti-oxidative, anti-inflammatory and free radical scavenging properties. Here, we carried out studies to ascertain if Luteolin would ameliorate BPA-induced toxicity in Drosophila melanogaster. Firstly, flies were treated separately with Luteolin (0, 50, 100, 150 and 300 mg/kg diet) and BPA (0, 0.01, 0.05 and 0.1 mM) for 28 days survival assessments. Consequently, Luteolin (150 and 300 mg/kg diet) and/or BPA (0.05 mM) were exposed to D. melanogaster for 7 days for the evaluation of nitric oxide level, eclosion rate, viability assay, histology of fat body, antioxidant (Glutathione-S-transferase, catalase and total thiol), oxidative stress (hydrogen peroxide) and behavioural (negative geotaxis and acetylcholinesterase) markers. The results showed that BPA induced antioxidant-oxidative stress imbalance and behavioural deficit in flies. Luteolin increased survival rate and augmented antioxidant markers in flies. Importantly, Luteolin ameliorated BPA-induced degeneration in the fat body around the rostral, thorax and abdominal regions, oxidative stress, behavioural deficit, reduction in cell viability and eclosion rate of D. melanogaster (p < 0.05). Overall, this study offered further insights on the antioxidative and chemopreventive properties of Luteolin against BPA-induced toxicity.

Resveratrol prolongs lifespan and improves 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced oxidative damage and behavioural deficits in Drosophila melanogaster.

1-Methyl-4-Phenyl-1,2,3,6-Tetrahydropyridine (MPTP) is a neurotoxin that causes Parkinson's disease in animals via mechanisms linked with oxidative stress and inflammation. Resveratrol is a natural polyphenol and a phytoalexin with antioxidative and antiinflammatory properties. Here, we investigated the rescue role of resveratrol on MPTP-triggered toxicity in Drosophila melanogaster for the first time. D. melanogaster (Harwich strain, 1-to 3- days old) were first orally exposed to resveratrol (0, 7.5, 15, 30, 60 and 120 mg/kg diet) and MPTP (0, 250, 500, 1000, 2000, and 3000 µM) for longevity and 7 days survival assays respectively. Consequently, we selected resveratrol (30 and 60 mg/kg diet) to evaluate its rescue role on MPTP (250 and 500 µM)-induced toxicity in D. melanogaster after 3 days of oral treatment. Specifically, we evaluated markers of neurotoxicity (acetylcholinesterase and negative geotaxis), inflammation (nitric oxide), oxidative stress-antioxidant status (hydrogen peroxide, total thiol, catalase and glutathione-S-transferase), cell viability and fecundity. The data showed that resveratrol increased lifespan of D. melanogaster in a dose-dependent manner up to 60 mg/kg diet. Further, resveratrol restored MPTP-induced inhibition of catalase, glutathione-S-transferase and acetylcholinesterase activities in D. melanogaster. Moreover, resveratrol ameliorated MPTP-triggered cell death, histological alterations, behavioural deficits and accumulation of nitric oxide and hydrogen peroxide levels in flies (p < 0.05). Conclusively, the lifespan extension effects of resveratrol and its rescue role on MPTP- mediated toxicity in the flies may be due to its antioxidant and anti-inflammatory properties.