Curcumin and quercetin synergistically attenuate subacute diazinon-induced inflammation and oxidative neurohepatic damage, and acetylcholinesterase inhibition in albino rats

In Vitro and In Vivo Supplementation with Curcumin Promotes Hippocampal Neuronal Synapses Development in Rats by Inhibiting GSK-3β and Activating β-catenin

The human fetal thyroid gland is not capable of producing thyroid hormones independently until 20 weeks of gestation, and if maternal thyroid hormone synthesis is inadequate in early pregnancy, fetal brain and nerve development may be affected by maternal hypothyroidism. Curcumin, which is isolated from turmeric (Curcuma longa), has been shown to be effective in repairing neurological disorders and is effective in relieving nerve damage when consumed over a long period of time. In this experiment, we investigated the effect of curcumin supplementation on synaptic development of rat hippocampal neurons. A cell model of oxidative damage and a young rat model of hypothyroidism were constructed, and model cells and rats were treated with triiodothyronine (T3), tetraiodothyronine (T4), and curcumin, respectively. Damage of nerve cells and animal brain tissues was examined, and the effect of curcumin in alleviating the blocked neurodevelopment was investigated. Further modulation of GSK-3β/β-catenin was performed to investigate the mechanism of action of curcumin. Ultimately, we found that T3-, T4-, and curcumin-treated model cells and young rats had increased numbers of synapses and good neurodevelopment. At the same time, we found that curcumin inhibited the production of GSK-3β and Axin to activate β-catenin. The inhibition of β-catenin weakened the therapeutic effect of curcumin, and the differences between the indicators and the model group disappeared. Both cellular and animal experiments supported that curcumin effectively alleviated the oxidative cell damage caused by thyroxine deficiency and activated the synaptogenic ability of nerve synapses by inhibiting GSK-3β and protecting β-catenin activity.

Persistent diazinon induced neurotoxicity: The effect on inhibitory avoidance memory performance, amyloid precursor proteins, and TNF-α levels in the prefrontal cortex of rats

INTRODUCTION

Organophosphate pesticides (Ops) like diazinon (DZN) have well-known neurotoxic effects and low-level chronic exposure has been linked to detrimental neurobehavioral impairments and memory deficits. However, it's not entirely clear how DZN-induced biological changes, particularly in the prefrontal cortex (PFC) contribute to these effects. The purpose of this study is to investigate the impact of DZN exposure on inhibitory avoidance (IA) memory function, amyloid precursor expression (APP), and proinflammatory tumor necrosis factor-α (TNF-α) levels in the rat cortex.

MATERIALS AND METHODS

Rats were divided into 4 groups and recived 2 mg/kg DZN for 5-days or 12-weeks and two control groups recived the same volume of vehicle. IA memory was assesed using the shuttle box apparatus. Rats were sacrificed and the prefrontal cortex PFC were removed. Real-time PCR and Western blotting were used to messure TNF-α, and amyloid protein precursors gene expression and protein levels.

RESULTS

Our findings indicated that DZN caused body weight loss and a notable decline in performance on the IA memory. Additionally, 5-days exposure increased APP and APLP2 protein levels in the PFC, while 12-weeks exposure decreased these levels. Furthermore, expression of APP and APLP2 gens were decreased in PFC. TNF-α levels increased as a result of 5-days exposure to DZN, but these levels dropped to normal after 12-weeks administration, and this observation was significant.

CONCLUSION

Taken together, exposure to low doses of DZN leads to disturbances in IA memory performance and also alternations in amyloid beta precursors that can be related to increased risk of Alzheimer's disease.

Dual-targeted nanoparticles with removing ROS inside and outside mitochondria for acute kidney injury treatment

Mitochondrial oxidative stress and inflammation are the main pathological features of acute kidney injury (AKI). However, systemic toxicity of anti-inflammatory drugs and low bioavailability of antioxidants limit the treatment of AKI. Here, the lipid micelle nanosystem modified with l-serine was designed to improve treatment of AKI. The micelle kernels coating the antioxidant drug 4-carboxybutyl triphenylph-osphine bromide-modified curcumin (Cur-TPP) and quercetin (Que). In the cisplatin (CDDP)-induced AKI model, the nanosystem protected mitochondrial structure and improved renal function. Compared to mono-targeted group, the mitochondrial ROS content of renal tubular epithelial cells acting in the dual-target group decreased about 1.66-fold in vitro, serum creatinine (Scr) and urea nitrogen (BUN) levels were reduced by 1.5 and 1.2 mmol/L in vivo, respectively. Mechanistic studies indicated that the nanosystem inhibited the inflammatory response by interfering with the NF-κB and Nrf2 pathways. This study provides an efficient and low-toxicity strategy for AKI therapy.

Protective effects of Biebersteinia multifida on sub-chronic toxicity of DZN in male Wistar rats: biochemical, hematological, and oxidative stress indices

The protective effect of Biebersteinia Multifida on diazinon-induced toxicity in male Wistar rats was investigated over 8 weeks. Impacts of diazinon (10 mg/kg daily), Biebersteinia Multifida (500 mg/kg daily), and coadministration of them on oxidative stress parameters besides hematological and biochemical indices were assessed in various groups. The gas chromatography-mass spectrometry analysis was performed to identify the antioxidant components of plant extract by comparing the mass spectra and retention indices with those given in the literature. Pseudocholinesterase level demonstrated a significant attenuation in the Biebersteinia Multifida+diazinon-treated group in comparison to the diazinon group at the end of the 8th week. Statistical significant differences in hematological and biochemical indices were detectable when the diazinon group was compared to Biebersteinia Multifida+diazinon-treated rats. While diazinon destroyed hepatic and renal functions, Biebersteinia Multifida protected the liver and kidney from diazinon toxic effects by normalizing related function indices at the end of the 8th week. By diminishing malondialdehyde and enhancing the ferric-reducing power, Biebersteinia Multifida minimized the hazardous effect of diazinon-induced oxidative stress. Following these results, the beneficial effects of Biebersteinia Multifida in reducing the toxicity of diazinon should be taken into consideration.

The relationship between the cholinergic mechanism of toxicity and oxidative stress in rats during subacute diazinon poisoning

Diazinon is an organophosphate pesticide (OP) that has significant potential for accidental and intentional poisoning of wildlife, domestic animals and humans. The aim of the study is to investigate the correlation between cholinesterase activity and oxidative stress parameters in liver and diaphragm by continuous monitoring as a function of time during prolonged use of diazinon. Wistar rats were treated orally with diazinon (55 mg/kg/day): 7, 14, 21 and 28 days. At the end of each period, blood, liver and diaphragm were collected to examine cholinesterase activity and enzymatic/non-enzymatic oxidative stress parameters: superoxide dismutase 1 (SOD1), catalase (CAT), thiobarbituric acid substances (TBARS), protein carbonyl groups. In all four time periods, there was a significant change in acetylcholinesterase (AChE) in erythrocytes and butyrylcholinesterase (BuChE) in blood plasma, CAT in liver and diaphragm and SOD1 in diaphragm. Parameters significantly altered during the cholinergic crisis included: cholinesterases and TBARS in liver and diaphragm and partially SOD1 in liver. Protein carbonyl groups in liver and diaphragm were significantly altered outside the cholinergic crisis. In the liver, there was a very strong negative correlation between BuChE and TBARS in all four time periods and BuChE and CAT on day 7. In the diaphragm, a very strong negative correlation was found between AChE and TBARS at days 7 and 14, and a very strong positive correlation between AChE and SOD1 at days 14, 21 and 28. A better understanding of the relationship between cholinergic overstimulation and oxidative stress may help to better assess health status in prolonged OPs intoxication.

Co-delivery of curcumin and quercetin in shellac nanocapsules for the synergistic antioxidant properties and cytotoxicity against colon cancer cells

Synergistic bioactivity of dietary polyphenols can enhance functional food development to prevent chronic diseases like cancer. In this study, physicochemical properties and cytotoxicity of curcumin and quercetin co-encapsulated in shellac nanocapsules at different mass ratios were investigated and compared to nanocapsules with one polyphenol and their unencapsulated counterparts. At curcumin and quercetin mass ratio of 4:1, encapsulation efficiency was approximately 80% for both polyphenols, and the nanocapsules showed the highest synergistic antioxidant properties and cytotoxicity for HT-29 and HCT-116 colorectal cancer cells. The nanocapsules had discrete structures smaller than 50 nm and remained stable during 4-week refrigerated storage, and the encapsulated polyphenols were amorphous. After simulated digestions, 48% of the encapsulated curcumin and quercetin were bioaccessible, the digesta retained nanocapsule structures and cytotoxicity, and the cytotoxicity was higher than nanocapsules with only one polyphenol and free polyphenol controls. This study provides insights on utilizing multiple polyphenols as promising anti-cancer agents.

Epigallocatechin gallate improves meiosis maturation against Diazinon exposure in porcine oocytes

Diazinon (DZN) is a refractory organophosphorus pesticide (OP) in the surrounding environment due to its overuse in agriculture. The antioxidant activity of Epigallocatechin gallate (EGCG) from green tea is at least 100 times greater than that of vitamin C. This study aimed to study the effects of DZN on the meiotic maturation of porcine oocytes, as well as the protective roles of EGCG. Firstly, the effects of DZN and EGCG on meiotic nuclear maturation of porcine oocytes were detected, and then embryonic development was investigated by chemical parthenogenetic activation. Next, the spindle assembly, mitochondrial membrane potential (MMP), reactive oxygen species (ROS), DNA damage, and finally the early apoptosis of oocytes were examined by immunofluorescence staining. The results revealed that DZN exposure significantly reduced the quality of porcine oocytes, such as failure of nuclear and cytoplasmic maturation, evidenced by abnormal spindle assembly, disordered chromosome alignment, low MMP, observably increased ROS, severe DNA damage, and early apoptosis. Appropriate EGCG could significantly reduce all these defects caused by DZN. In conclusion, EGCG can help prevent the harm that DZN exposure can do. These findings offer convincing support for enhancing the oocyte quality from EGCG through daily ordinary beverages.

Exploring the Inhibition of Quercetin on Acetylcholinesterase by Multispectroscopic and In Silico Approaches and Evaluation of Its Neuroprotective Effects on PC12 Cells

This study investigated the inhibitory mechanism of quercetin in acetylcholinesterase (AChE) and its neuroprotective effects on β-amyloid_25-35-induced oxidative stress injury in PC12 cells. Quercetin inhibited AChE in a reversible mixed manner with an IC₅₀ of 4.59 ± 0.27 µM. The binding constant of quercetin with AChE at 25 °C was (5.52 ± 0.05) × 10⁴ L mol^-1. Hydrogen bonding and van der Waals forces were the main interactions in forming the stable quercetin-AChE complex. Computational docking revealed that quercetin was dominant at the peripheral aromatic site in AChE and induced enzymatic allosterism; meanwhile, it extended deep into the active center of AChE and destabilized the hydrogen bond network, which caused the constriction of the gorge entrance and prevented the substrate from entering the enzyme, thus resulting in the inhibition of AChE. Molecular dynamics (MD) simulation emphasized the stability of the quercetin-AChE complex and corroborated the previous findings. Interestingly, a combination of galantamine hydrobromide and quercetin exhibited the synergistic inhibition effect by binding to different active sites of AChE. In a β-amyloid_25-35-induced oxidative stress injury model in PC12 cells, quercetin exerted neuroprotective effects by increasing the glutathione level and reducing the malondialdehyde content and reactive oxygen species levels. These findings may provide novel insights into the development and application of quercetin in the dietary treatment of Alzheimer's disease.

Diazinon toxicity in hepatic and spleen mononuclear cells is associated to early induction of oxidative stress

Diazinon is an organophosphorus pesticide, which may have potential toxic effects on the liver and immune system; however, the underlying mechanisms remain mostly unidentified. This work is aimed at evaluating the oxidative stress and cell cycle alterations elicited by low-dose diazinon in a rat liver cell line (BRL-3A) and spleen mononuclear cells (SMC) from Wistar rats. Diazinon (10-50 μM) caused early reactive oxygen species (ROS) generation (from 4 h) as well as increased O₂^•- level (from 0.5 h), which led to subsequent lipid peroxidation at 24 h, in BRL-3A cells. In SMC, diazinon (20 μM) produced similar increases in ROS levels, at 4 and 24 h, with the highest O₂^•- level being found at 4 h. Low-dose diazinon induced G1-phase arrest and cell death in hepatic cells and SMC. Therefore, diazinon could affect the liver and the immunological system through the premature oxidative stress induction.Abbreviations: O₂^•-: superoxide anion radical; ROS: reactive oxygen species; SMC: spleen mononuclear cells; TBARS: thiobarbituric acid reactive substances.

Neuroprotective efficacy of berberine following developmental exposure to chlorpyrifos in F1 generation of Wistar rats: Apoptosis-autophagy interplay

Chlorpyrifos (CPF), an organophosphate insecticide commonly used in agriculture and household applications, is considered a developmental neurotoxicant. This study aimed to explain the neuroprotective role of Berberine (BBR) against CPF-induced autophagy dysfunction and apoptotic neurodegeneration in the developing hippocampus. F1 generation of Wistar rats was exposed to CPF (3 mg/kg b.wt.) and co-treated with BBR (10 mg/kg b.wt) in two different exposure regimens, gestational (GD9-12 and GD17-21) and lactational (PND1-20). Our results demonstrated that CPF intoxication instigated cognitive and neurobehavioral impairment, oxidant-antioxidant imbalance, and histomorphological alterations in CA1, CA3, and DG regions of the offsprings. Furthermore, mRNA expression of pro-apoptotic genes (caspase3 and Bax) was upregulated, and that of anti-apoptotic BCl₂ was downregulated. In addition, exposure to CPF also activated the autophagy inhibitor (mTOR) transcription and subsequently downregulated the expression of autophagy markers beclin1 and LC3-II. In contrast, gestational and lactational co-treatment of BBR significantly upregulated the enzymatic anti-oxidant bar of the hippocampus and attenuated histological alterations. Moreover, BBR co-treatments reduced apoptotic neurodegeneration in the hippocampal region by regulating the expression of apoptotic genes and upregulated the levels of autophagy, confirmed by ultrastructural studies, decreased gene expression and immunostaining of mTOR and increased, and increased expression gene expression and immunostaining of LC3-II positive cells. Our results confirm that treatment with BBR induces autophagy, which plays a neuroprotective role in CPF-induced developmental neuronal apoptosis in the F1 generation of Wistar rats by regulating the balance between autophagy and apoptosis.

Curcumin improves the protective effects of quercetin against atrazine-induced testicular injury in adult Wistar rats

This study evaluated the beneficial protective effect of cotreatment of curcumin (CUR) and quercetin (QUE) on atrazine (ATZ)-induced testicular toxicity in rats. ATZ challenge diminished luteinizing hormone, follicular stimulating hormone, testosterone and myeloperoxidase enzyme activity, but these effects were attenuated on co-treatment with CUR and QUE. Also, co-treatment of CUR + QUE was better than separate administration of QUE at diminishing malondialdehyde and glutathione and improving tumour necrosis factor-α concentration, germ cell numbers (spermatogonia, spermatocytes and round spermatids) and epididymal sperm quality. Histologically, smaller sized tubules with degenerated epithelia and few germ cells were seen in the seminiferous tubules of the ATZ group whereas CUR + QUE pretreatment improved the histo-morphologic features of the tubules compared to the ATZ group and was also better than separate administration of QUE. We conclude that CUR can improve the protective effects of QUE against ATZ-induced testicular injury by enhancing the levels of reproductive hormones, recovering testicular biochemical parameters and improving the histological features of the testes.

A Comprehensive Review on the Therapeutic Potential of Curcuma longa Linn. in Relation to its Major Active Constituent Curcumin

Curcuma longa Linn. (C. longa), popularly known as turmeric, belongs to the Zingiberaceae family and has a long historical background of having healing properties against many diseases. In Unani and Ayurveda medicine, C. longa has been used for liver obstruction and jaundice, and has been applied externally for ulcers and inflammation. Additionally, it is employed in several other ailments such as cough, cold, dental issues, indigestion, skin infections, blood purification, asthma, piles, bronchitis, tumor, wounds, and hepatic disorders, and is used as an antiseptic. Curcumin, a major constituent of C. longa, is well known for its therapeutic potential in numerous disorders. However, there is a lack of literature on the therapeutic potential of C. longa in contrast to curcumin. Hence, the present review aimed to provide in-depth information by highlighting knowledge gaps in traditional and scientific evidence about C. longa in relation to curcumin. The relationship to one another in terms of biological action includes their antioxidant, anti-inflammatory, neuroprotective, anticancer, hepatoprotective, cardioprotective, immunomodulatory, antifertility, antimicrobial, antiallergic, antidermatophytic, and antidepressant properties. Furthermore, in-depth discussion of C. longa on its taxonomic categorization, traditional uses, botanical description, phytochemical ingredients, pharmacology, toxicity, and safety aspects in relation to its major compound curcumin is needed to explore the trends and perspectives for future research. Considering all of the promising evidence to date, there is still a lack of supportive evidence especially from clinical trials on the adjunct use of C. longa and curcumin. This prompts further preclinical and clinical investigations on curcumin.

Toxicity of curcumin nanoparticles towards alveolar macrophage: Effects of surface charges

Curcumin has been used for chronic lung diseases management due to its diversified molecular actions. However, the potential cytotoxicity which occurs in cells following the exposure to high concentrations of curcumin has been overlooked. This study evaluated the toxic events of curcumin nanoparticles (Cur-NPs) with alterable surface polarity in alveolar macrophages (NR8383). We aimed to establish the correlation between the toxicity of Cur-NPs with different surface charges and the internalization mechanisms of the NPs. Toxicity data showed that positively charged Cur-NPs (IC₅₀: 9.77 ± 0.5 μg/mL) was the most potent against NR8383, followed by negatively charged Cur-NPs (IC₅₀:13.33 ± 0.9 μg/mL) and neutral Cur-NPs (IC₅₀:18.68 ± 1.2 μg/mL). Results from mitochondrial membrane potential, ATP content and intracellular ROS in NR8383 showed similar ranking to the toxicity assay. The predominant uptake pathway for positively and negatively charged Cur-NPs was via clathrin-mediated endocytosis, while neutral Cur-NPs was internalized via phagocytosis, micropinocytosis and clathrin-mediated endocytosis. Positively charged Cur-NPs mediates the cytotoxicity of NR8383 via lysosomal and mitochondrial-associated destabilization upon entry. In conclusion, the cytotoxicity of Cur-NPs on NR8383 is surface-charge dependent, which in turn is associated to the uptake pathway and localization of Cur-NPs in cells.

Curcumin and Quercetin-Loaded Lipid Nanocarriers: Development of Omega-3 Mucoadhesive Nanoemulsions for Intranasal Administration

Curcumin (CUR) and quercetin (QU) are potential compounds for treatment of brain diseases such as neurodegenerative diseases (ND) because of their anti-inflammatory and antioxidant properties. However, low water solubility and poor bioavailability hinder their clinical use. In this context, nanotechnology arises as a strategy to overcome biopharmaceutical issues. In this work, we develop, characterize, compare, and optimize three different omega-3 (ω-3) fatty acids nanoemulsions (NEs) loaded with CUR and QU (negative, cationic, gelling) prepared by two different methods for administration by intranasal route (IN). The results showed that formulations prepared with the two proposed methods exhibited good stability and were able to incorporate a similar amount of CUR and QU. On the other side, differences in size, zeta potential, in vitro release kinetics, and permeation/retention test were observed. Considering the two preparation methods tested, high-pressure homogenization (HPH) shows advantages, and the CQ NE- obtained demonstrated potential for sustained release. Toxicity studies demonstrated that the formulations were not toxic for Caenorhabditis elegans. The developed ω-3 fatty acid NEs have shown a range of interesting properties for the treatment of brain diseases, since they have the potential to increase the nose-to-brain permeation of CUR and QU, enabling enhanced treatments efficiency.

The protective effects of erdosteine on subacute diazinon-induced oxidative stress and inflammation in rats

In today's world, pesticides are commonly used to control pests and in advanced agriculture. As an organophosphorus insecticide (OPI), diazinon (DZN) is a commonly used substance. However, the widespread usage of DZN increases the probability of incidence of toxication. This toxication has been reported to be shaped not through cholinergic syndromes that are experienced as a result of acetylcholinesterase inhibition, which is the primary effect of these cases. It is rather shaped by the altering of the facilitation of oxidative stress and inflammatory response. In this study, the protective effect of administering erdosteine (ERDOS) subacute DZN exposure was investigated. A total of 24 male Wistar albino rats were separated into 4 groups (with 6 rats in each group), namely, the control, DZN (15 mg/kg/day), ERDOS (10 mg/kg/day), and DZN + ERDOS (15 mg/kg/day DZN + 10 mg/kg/day ERDOS) groups. These medications were given through oral gavage for 28 days. With the whole blood, plasma, and serum samples taken from the rats, oxidant-antioxidant parameters and cytokine levels were measured. The MDA and NOx levels and SOD and CAT enzyme activities of the DZN group were higher than those of the control group, while the GSH levels and TAC and GPx activities of the DZN group were lower than those of the control group (p < 0.05). It was also found that cytokine (IL-1β, IL-10, and TNF-α) levels in the DZN group were higher than those in the control group (p < 0.05). On the other hand, the ERDOS implementations were detected to ameliorate the harmful effects of DZN on the oxidant-antioxidant parameters and cytokine levels (p < 0.05). Conclusively, besides the known mucolytic efficacy of ERDOS, it may also be stated to display free radical scavenger, antioxidant, and anti-inflammatory characteristics to inhibit some proinflammatory cytokines that are specifically involved in oxidative stress. Additionally, the ameliorating property of ERDOS can be benefited from in possible DZN-induced toxication cases.

The Interplay of the Unfolded Protein Response in Neurodegenerative Diseases: A Therapeutic Role of Curcumin

Abnormal accumulation of misfolded proteins in the endoplasmic reticulum and their aggregation causes inflammation and endoplasmic reticulum stress. This promotes accumulation of toxic proteins in the body tissues especially brain leading to manifestation of neurodegenerative diseases. The studies suggest that deregulation of proteostasis, particularly aberrant unfolded protein response (UPR) signaling, may be a common morbific process in the development of neurodegeneration. Curcumin, the mixture of low molecular weight polyphenolic compounds from turmeric, Curcuma longa has shown promising response to prevents many diseases including current global severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and neurodegenerative disorders. The UPR which correlates positively with neurodegenerative disorders were found affected by curcumin. In this review, we examine the evidence from many model systems illustrating how curcumin interacts with UPR and slows down the development of various neurodegenerative disorders (ND), e.g., Alzheimer's and Parkinson's diseases. The recent global increase in ND patients indicates that researchers and practitioners will need to develop a new pharmacological drug or treatment to manage and cure these neurodegenerative diseases.

Evaluating the effects of anticoagulant rodenticide bromadiolone in Wistar rats co-exposed to vitamin K: impact on blood-liver axis and brain oxidative status

The aim of this study was to investigate the beneficial effects of vitamin K relate to protection against detrimental effects of bromadiolone. Wistar rats (n = 30) were divided in three groups (n = 10): control group and two groups treated with bromadiolone (0.12 mg/kg) and bromadiolone + vitamin K (0.12 mg/kg + 100 mg/kg) over the period of four days. The main findings in the bromadiolone-exposed rats, such as damaged hepatocytes, high levels of globulin, total proteins and lymphocytes, and altered albumin/globulin ratio, collectively indicate an acute inflammatory process. Morphological changes in erythrocytes include microcytosis, hypochromia, hyperchromia, hemolysis, stomatocytosis, and spherocytosis. Significantly low values of RBC, Hct, and hemoglobin concentrations indicate impairments of the hematopoietic pathway causing combined anemia. The selected dose of bromadiolone caused a non-significant increase of catalase activity and a significant increase of the total protein content in brain tissue homogenates. Vitamin K supplementation reduced many of the harmful effects of bromadiolone. The cytoprotective role of vitamin K was proved to be of great importance for the preservation of structural changes on the membranes of hepatocytes and erythrocytes, in addition to the known role in the treatment of coagulopathies. The results of the study suggest valuable properties of vitamin K in the prevention and treatment of various types of anemia caused by bromadiolone toxicity. Future research is necessary to determine the adequate dose and treatment duration with vitamin K in disorders caused by the cumulative action of bromadiolone and possibly other pesticides.

Methomyl-induced nephrotoxicity and protective effect of curcumin in male rats

We investigated the ameliorative effect of the curcumin against methomyl-induced potential nephrotoxicity in Wistar albino male rats. In the present study, curcumin (100 mg kg^-1 bw), methomyl (0,8 mg kg^-1 bw) and methomyl plus curcumin were given to rats by oral for 28 days (for subacute examination). Concentrations of blood urea nitrogen, uric acid and creatinine in serum and malondialdehyde level and activities of antioxidant enzyme (superoxide dismutase, catalase, glutathione peroxidase and glutathione S transferase) and histopathological alterations in kidney tissues were studied. Methomyl caused an increment in the concentrations of blood urea nitrogen, creatinine, uric acid and MDA levels. In addition, methomyl caused a diminution in the activities of superoxide dismutase, catalase, glutathione peroxidase and glutathione S transferase. Tubular and glomerular degenerations occurred in the kidney tissues of methomyl-received rats. However, coadministration of curcumin with methomyl significantly minimized the adverse effects of methomyl on kidney function parameters, lipid peroxidation and antioxidant enzyme activities and histological structure of kidney tissue. The results showed that curcumin significantly mitigated methomyl-induced nephrotoxicity in rats.

A review on pharmacological activities and synergistic effect of quercetin with small molecule agents

BACKGROUND

Quercetin is a natural flavonoid, which widely exists in nature, such as tea, coffee, apples, and onions. Numerous studies have showed that quercetin has multiple biological activities such as anti-oxidation, anti-inflammatory, and anti-aging. Hence, quercetin has a significant therapeutic effect on cancers, obesity, diabetes, and other diseases. In the past decades, a large number of studies have shown that quercetin combined with other agents can significantly improve the overall therapeutic effect, compared to single use.

PURPOSE

This work reviews the pharmacological activities of quercetin and its derivatives. In addition, this work also summarizes both in vivo and in vitro experimental evidence for the synergistic effect of quercetin against cancers and metabolic diseases.

METHODS

An extensive systematic search for pharmacological activities and synergistic effect of quercetin was performed considering all the relevant literatures published until August 2021 through the databases including NCBI PubMed, Scopus, Web of Science, and Google Scholar. The relevant literatures were extracted from the databases with following keyword combinations: "pharmacological activities" OR "biological activities" OR "synergistic effect" OR "combined" OR "combination" AND "quercetin" as well as free-text words.

RESULTS

Quercetin and its derivatives possess multiple pharmacological activities including anti-cancer, anti-oxidant, anti-inflammatory, anti-cardiovascular, anti-aging, and neuroprotective activities. In addition, the synergistic effect of quercetin with small molecule agents against cancers and metabolic diseases has also been confirmed.

CONCLUSION

Quercetin cooperates with agents to improve the therapeutic effect by regulating signal molecules and blocking cell cycle. Synergistic therapy can reduce the dose of agents and avoid the possible toxic and side effects in the treatment process. Although quercetin treatment has some potential side effects, it is safe under the expected use conditions. Hence, quercetin has application value and potential strength as a clinical drug. Furthermore, quercetin, as the main effective therapeutic ingredient in traditional Chinese medicine, may effectively treat and prevent coronavirus disease 2019 (COVID-19).

The protective effects of hesperidin and curcumin on 5-fluorouracil-induced nephrotoxicity in mice

Nephrotoxicity is a very important complication of 5-fluorouracil (5-FU)-treated cancer patients. Increased oxidative stress, kidney damage, and apoptosis play an important role in the pathogenesis of nephrotoxicity caused by 5-FU. In this study, protective effects of two natural compounds, hesperidin and curcumin, on experimentally induced kidney damage in mice with 5-FU were determined. Application of 5-FU resulted in severe histopathological changes and severe renal failure with increased serum urea and creatinine levels. Also, 5-FU-induced kidney damage, increased levels of malondialdehyde (MDA), decreased superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR) activity, and glutathione (GSH) level have been demonstrated. Also, where 5-FU is in the concentration of caspase-3 and 8-OHdG immune-positive cells and therefore causes apoptosis and DNA damage in kidney tissue cells. However, especially high doses of hesperidin and curcumin treatment significantly improved 5-FU-induced oxidative stress/lipid peroxidation, apoptosis/DNA damage, and renal dysfunction. Based on these data, our results suggest that hesperidin and curcumin may be used as new and promising agents against 5-FU-induced nephrotoxicity.

Multi-organ Toxicity Attenuation by Cerium Oxide and Yttrium Oxide Nanoparticles: Comparing the Beneficial Effects on Tissues Oxidative Damage Induced by Sub-acute Exposure to Diazinon

BACKGROUND

Excessive use of diazinon, as an organophosphate pesticide (OP), contributes to cytotoxic and pathologic cellular damage and, in particular, oxidative stress. However, metal-oxide nanoparticles (NPs), such as cerium oxide (CeO2) and yttrium oxide (Y2O3), with the property of free radical scavenging demonstrated beneficial effects in the alleviation of oxidative stress biomarkers.

OBJECTIVE

The aims of this study include evaluating beneficial effects of CeO2 NPs, Y2O3 NPs, and their combination against diazinon-induced oxidative stress in different tissues of brain, heart, lung, kidney, liver, and spleen.

METHODS

Eight randomized groups of 6 adult male Wistar rats were formed. Each group of rats administered a different combination of diazinon, CeO2 and Y2O3 NPs daily and levels of oxidative stress markers, such as reactive oxygen species (ROS), lipid peroxidation (LPO), total thiol molecules (TTM) and total anti-oxidant power (TAP) and catalase enzyme, were measured after 2 weeks of the treatment.

RESULTS

Measurements of the mentioned markers in the brain, heart, lung, kidney, liver, and spleen showed that the administration of NPs could significantly alleviate the oxidative stress induced by diazinon. However, the findings of this study illustrated that the combination of both CeO2 and Y2O3 NPs led to a better reduction in oxidative stress markers.

CONCLUSION

Sub-acute exposure of diazinon in rats led to increased levels of oxidative stress markers in pivotal tissues such as the brain, heart, lung, kidney, liver, and spleen. CeO2 and Y2O3 NPs neutralize the oxidative stress to compensate diazinon-induced tissue damages. Lay Summary: Organophosphate pesticides (OPs), which are mainly used for pest control, are responsible for the entry of pesticides into the human food cycle. Organophosphate such as diazinon increases the molecular biomarkers of oxidative stress inside the cells of vital tissues such as the heart, liver, lungs, etc. Metal oxide nanoparticles (NPs) such as cerium oxide (CeO2) and yitrium oxide (Y2O3) can have free radical scavenging potential under oxidative stress and through various mechanisms. Although these nanoparticles reduce oxidative stress, it should be borne in the design of the study that additional doses of these substances reverse the beneficial effects.

Action Mechanisms of Curcumin in Alzheimer's Disease and Its Brain Targeted Delivery

AD is a chronic neurodegenerative disease. Many different signaling pathways, such as Wnt/β-catenin, Notch, ROS/JNK, and PI3K/Akt/mTOR are involved in Alzheimer’s disease and crosstalk between themselves. A promising treatment involves the uses of flavonoids, and one of the most promising is curcumin; however, because it has difficulty permeating the blood–brain barrier (BBB), it must be encapsulated by a drug carrier. Some of the most frequently studied are lipid nanocarriers, liposomes, micelles and PLGA. These carriers are further conjugated with brain-targeting agents such as lactoferrin and transferrin. In this review paper, curcumin and its therapeutic effects, which have been examined in vivo, are analyzed and then the delivery systems to the brain are addressed. Overall, the analysis of the literature revealed great potential for curcumin in treating AD and indicated the challenges that require further research.

Repeated endosulfan exposure induces changes in neurochemicals, decreases ATPase transmembrane ionic-pumps, and increased oxidative/nitrosative stress in the brains of rats: Reversal by quercetin

Neurochemical and ATPase deregulations play important role in toxicant-induced neurodegeneration. Previous studies have shown that loss of ATPase ionic-pumps alters neurochemical balance via increased ammonia, oxidative and nitrosative stress. Thus, this study investigated the ameliorative potentials of quercetin on neurochemical, ATPase changes, hyperammonemia and oxidative/nitrosative status in the brains of Wistar rats exposed to endosulfan, a known toxic environmental pesticide that is casually used in many developing countries. Adult rats were divided into five treatment groups (n = 5). Groups 1-2 received normal saline and corn oil (vehicle) (10 mL/kg/day), group 3 received quercetin (20 mg/kg/day) orally for 28 days consecutively. However, animals in groups 4-5 were given endosulfan (5 mg/kg/day, p.o) for 28 days. But, from the 14th to 28th day, group 4 additionally received vehicle (10 mL/kg/day, p.o.), while group 5 was treated with quercetin (20 mg/kg/day, p.o.). Thereafter, brain levels of neurochemicals, ATPase activities, ammonia and oxidative/nitrosative stress were investigated by employing standardized biochemical assay protocols. Quercetin increased endosulfan-induced decreased levels of norepinephrine, dopamine, GABA, and decreased elevated concentrations of glutamate and serotonin. Quercetin normalized the increased levels of acetylcholinesterase and ammonia. Furthermore, quercetin significantly reversed the decrease in Na⁺/K⁺, Ca²⁺, Mg²⁺-ATPase activities induced by endosulfan. Also, quercetin increased superoxide dismutase, catalase and glutathione peroxidase activities, and reduced nitrite and peroxynitrite levels in brains of rats. These findings further provide evidence of the ameliorative potential of quercetin against endosulfan-induced neurotoxicity via attenuation of neurochemical, ATPase changes, and inhibition of acetylcholinesterase activity, ammonia release and oxidative/nitrosative stress in rat brains.

Molecular effects of curcumin on the experimental autoimmune encephalomyelitis

Experimental autoimmune encephalomyelitis (EAE) is an animal model of multiple sclerosis (MS). Previous studies have shown that myelin degradation during MS and EAE resulted in reduced expression of some of the proteins, e.g., the MBP (myelin basic protein), and increased expression of genes such as iNOS (Inducible nitric oxide synthase) and NOGO-A in the affected patients. In the present study, EAE was induced by immunizing Wistar rats (n=12) with homogenized spinal cord of guinea pig and Freund's complete adjuvant. Curcumin is an active ingredient in turmeric with anti-inflammatory properties, which has been studied in this article. In this study, the effect of curcumin administration on the change of the expression of MBP, NOGO-A, and iNOS genes was evaluated using the RT-PCR (Reverse transcription-polymerase chain reaction) technique. The obtained results indicated it could be concluded that curcumin was able to improve EAE by increasing the amount of MBP gene expression and reducing the intensity of NOGO-A expression.

Comparative immuno-modulatory effects of basil and sesame seed oils against diazinon-induced toxicity in rats; a focus on TNF-α immunolocalization

Diazinon (DZN), a common organophosphorus insecticide (OPI), has hazardous effect to human and animals with its ubiquitous use. Considering the implication of reactive oxygen species (ROS) in the OPIs toxicity, the present study was aimed to evaluate the ameliorative properties of basil (BO) and sesame (SO) seed oils against the toxic effect of DZN. Forty adult male albino rats were divided into four experimental groups (n = 10 rats/group); control, DZN (10 mg/kg b.w/day), DZN + BO (5 ml/kg b.w/day), and DZN + SO (8 ml/kg b.w/day) groups, treated for a period of 4 weeks. DZN-exposed animals showed significant elevation in serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), blood urea nitrogen (BUN), and creatinine (Cr) with a significant decline in testosterone level compared with control. On the other hand, DZN + BO and DZN + SO groups revealed significant decreases in ALT, AST, BUN, and Cr with a significant increase in testosterone level when compared with DZN-exposed animals. Oxidative/antioxidant indices revealed significant increases of malondialdehyde (MDA) levels along with significant decreases of superoxide dismutase (SOD), glutathione peroxidase (Gpx), and catalase (CAT) activities among DZN-treated rats compared with control. Distinctly lower levels of MDA and increased activities of SOD, Gpx, and CAT were evident in both DZN + BO and DZN + SO groups when compared with DZN-exposed animals. Inflammatory and immuno-modulatory markers assessment showed a significant increase in TNF-α with a significant decline in IL-10 level in DZN group; meanwhile, both DZN + BO and DZN + SO groups revealed significant declines in levels of TNF-α with significant increases in IL-10. Corresponds immunohistochemistry, the total scores (TS) of TNF-α immunostainings in hepatorenal, testicular, and epididymal tissues of control, DZN + BO and DZN + SO groups were significantly lower than those values of DZN group. Additionally, the examined tissues of DZN + BO group revealed significant lower TS of TNF-α immunostaining compared with DZN + SO group. The overall data suggested that both BO and SO can be efficiently used as preventive herbal compounds against DZN-induced oxidative stress with special reference to their possible antioxidant, anti-inflammatory, and free radical activities. However, BO has more potent protective effect against DZN-induced tissue injury at both immunohistochemical and molecular levels.

Moringa oleifera seed oil partially abrogates 2,3-dichlorovinyl dimethyl phosphate (Dichlorvos)-induced cardiac injury in rats: evidence for the role of oxidative stress

OBJECTIVES

Cardiovascular diseases are major causes of non-infectious diseases globally. The use of pesticides has been linked with the high global burden of non-communicable diseases. Despite the indiscriminate exposure to dichlorvos (DDVP) by inhalation, no report exists on its possible cardiotoxic effect. This study investigated the cardiotoxicity of DDVP exposure by inhalation and the possible role of Moringa oleifera seed oil.

METHODS

Twenty-one male rats were randomly assigned into 3 groups. Group A (control) received only standard rat diet and water ad' libitum, group B (DDVP) was exposed to DDVP via inhalation for 15 min daily in addition to rat diet and water, and group C (DDVP + M. oleifera seed oil) received treatment as group B as well as 300 mg/kg of M. oleifera seed oil p.o for 28 days.

RESULTS

Significant reductions in body weight gain and cardiac weight were observed in DDVP-exposed animals (p<0.05). Similarly, 28 days of exposure to DDVP led to a significant increase in lactate dehydrogenase, creatinine kinase and troponin (p<0.05). DDVP-exposed rats also showed a significant increase in malondialdehyde, and a significant decline in superoxide dismutase and glutathione peroxidase (p<0.05). However, catalase was comparable in DDVP-exposed and control rats. Histopathological observations of the cardiac tissue revealed that DDVP caused marked fat degeneration and necrosis of the myocardial layer. The changes in DDVP-exposed rats were significantly, though not completely, restored by M. oleifera seed oil administration.

CONCLUSIONS

This study provides novel mechanistic information on the cardiotoxicity of DDVP inhalation, and the antioxidant potential of M. oleifera seed oil.

Diazinon impairs bioenergetics and induces membrane permeability transition on mitochondria isolated from rat liver

Diazinon (DZN) is a broad-spectrum insecticide extensively used to control pests in crops and animals. Several investigators demonstrated that DZN produced tissue toxicity especially to the liver. In addition, the mitochondrion was implicated in DZN-induced toxicity, but the precise role of this organelle remains to be determined. The aim of this study was thus to examine the effects of DZN (50 to 150 μM) on the bioenergetics and mitochondrial permeability transition (MPT) associated processes in isolated rat liver mitochondria. DZN inhibited state-3 respiration in mitochondria energized with glutamate plus malate, substrates of complex I, and succinate, substrate of complex II of the respiratory chain and decreased the mitochondrial membrane potential resulting in inhibition of ATP synthesis. MPT was estimated by the extent of mitochondrial swelling, in the presence of 10 µM Ca²⁺. DZN elicited MPT in a concentration-dependent manner, via a mechanism sensitive to cyclosporine A, EGTA, ruthenium red and N-ethylmaleimide, which was associated with mitochondrial Ca²⁺ efflux and cytochrome c release. DZN did not result in hydrogen peroxide accumulation or glutathione oxidation, but this insecticide oxidized endogenous NAD(P)H and protein thiol groups. Data suggest the involvement of mitochondria, via apoptosis, in the hepatic cytotoxicity attributed to DZN.

Curcumin and Selenium Prevent Lipopolysaccharide/Diclofenac-Induced Liver Injury by Suppressing Inflammation and Oxidative Stress

Diclofenac (DCL), an anti-inflammatory drug used to reduce pain and inflammation, ranks in the top causes of drug-induced liver injury. The inflammatory stress induced by inflammagens is implicated in DCL-induced liver injury. Curcumin (CUR) and selenium (Se) possess anti-inflammatory effects; therefore, this study evaluated their protective potential against lipopolysaccharide (LPS)/DCL-induced liver injury. Rats received CUR and/or Se for 7 days followed by a single intravenous administration of LPS 2 h before a single injection of DCL and two other doses of CUR and/or Se 2 and 8 h after DCL. Administration of nontoxic doses of LPS and DCL resulted in liver damage evidenced by the significantly elevated liver function markers in serum. LPS/DCL-induced liver injury was confirmed by histological alterations, increased lipid peroxidation and nitric oxide, and diminished glutathione and superoxide dismutase. CUR and/or Se prevented liver injury, histological alterations, and oxidative stress and boosted antioxidant defenses in LPS/DCL-induced rats. In addition, CUR and/or Se reduced serum C-reactive protein, liver pro-inflammatory cytokines, and the expression of TLR4, NF-κB, JNK, and p38, and upregulated heme oxygenase-1 (HO-1). In conclusion, CUR and/or Se mitigated LPS/DCL-induced liver injury in rats by suppressing TLR4 signaling, inflammation, and oxidative stress and boosting HO-1 and other antioxidants. Therefore, CUR and Se can hinder the progression and severity of liver injury during acute inflammatory episodes.

Copper oxychloride-induced testicular damage of adult albino rats and the possible role of curcumin in healing the damage

The current research study investigated the effect of 80 mg/kg b.wt./day curcumin (cur) against 50, 100, and 200 mg/kg copper oxychloride (COC) for 90 days induced testicular damage using histological, ultrastructural, and biochemical techniques. Histological and cellular abnormalities have been noted in seminiferous tubules of COC-treated group and treated group with Cur- and COC-treated group. The biochemical result showed that serum testosterone was significantly decreased in COC-treated rats and Cur COC-treated rats compared with the control groups. Testes copper content and malondialdehyde was increased, whereas the testes total antioxidant, manganese, ferrous, and zinc levels were decreased (p ≥ 0.05) compared to the control groups. In conclusion, the present work reported that the treatment of rats with 80 mg/kg body weight curcumin prior to treatment with COC did not mitigate the deleterious effects of COC and manifested no signs of protection.

Ameliorative effect of curcumin against lead acetate-induced hemato-biochemical alterations, hepatotoxicity, and testicular oxidative damage in rats

Lead, toxic heavy metal of global concern, induces toxicity in various organs via oxidative stress. Thereby, in this study, the protective role of curcumin against lead acetate-induced toxicity was evaluated. Thirty-two male albino rats were allocated equally into four groups and orally administered with corn oil as a vehicle (Cont.), curcumin (CUR) (400 mg/kg bw), lead acetate (LA) (100 mg/kg bw), and lead acetate plus curcumin (LA + CUR). All rats had received their treatments daily for 4 weeks. The results revealed that LA toxicity induced normocytic normochromic anemia with significant leukocytosis and lymphocytosis. Moreover, LA-intoxicated rats showed a marked elevation in the liver enzyme activities, serum cholesterol, and triglyceride levels. In contrast, sero-immunological parameters, total protein, albumin, globulin, and testosterone levels were significantly reduced compared to the control rats. Additionally, LA-induced hepatic and testicular oxidative damage revealed by marked increased in MDA level with prominent reduction in the antioxidant system. The gene expression of the hepatic pro-inflammatory markers and testicular steroidogenic biomarkers including LHR and aromatase were significantly upregulated; meanwhile, the expressions of testicular StAR, CYP17a, 3B-HDS, SR-B1, and P450SCC were significantly downregulated in the LA-intoxicated group. Curcumin treatment could partially improve the hematological, biochemical, and histopathological alterations induced by LA. Also, it was observed that curcumin significantly restored hepatic pro-inflammatory markers and testicular steroidogenic enzymes. In conclusion, curcumin has antioxidant, anti-inflammatory, and immunomodulatory effects and is able to minimize the LA-induced oxidative damage in rats.

Construction of an environmentally friendly octenylsuccinic anhydride modified pH-sensitive chitosan nanoparticle drug delivery system to alleviate inflammation and oxidative stress

An environmentally friendly octenylsuccinic anhydride modified pH-sensitive chitosan-octenylsuccinic anhydride (OSA-CS) was synthesized. The critical micelle concentration (CMC) of the modified chitosan was 27 μg/mL, the graft polymers can form solubilized curcumin (CUR) and quercetin (QUE) nanoparticles. The drug-loaded nanoparticles had high encapsulation efficiency and drug loading content, the self-assembly of graft polymers formed spherical uniform nanoparticles with an approximate diameter of 150-180 nm. The nanoparticles were stable under storage conditions and in serum. The results revealed that OSA-CS exhibited excellent biocompatibility, no cytotoxicity. Additionally, the results of pH sensitivity and drug release experiments showed that the nanoparticles were highly sensitive to weakly acidic conditions (pH 6.0) and showed a faster release rate, while they were reasonably stable at physiological conditions (pH 7.4). The drug-loaded nanoparticles exhibited higher cellular uptake in vitro, and exhibited stronger anti-inflammatory and antioxidant efficacy. Therefore, OSA-CS-based nanoparticles are a promising hydrophobic drug delivery system for pH-response targeting therapy.

Curcumin attenuates copper-induced oxidative stress and neurotoxicity in Drosophila melanogaster

Curcumin is a hydrophobic polyphenol derived from the rhizome of the Herb Curcuma longa belonging to the family Zingiberaceae. Curcumin possesses antioxidative, anti-inflammatory and anti-depressant-like properties. In this study, we evaluated the rescue role of Curcumin in Copper²⁺-induced toxicity in D. melanogaster. Adult, wild type flies were exposed to Cu²⁺ (1 mM) and/or Curcumin (0.2 and 0.5 mg/kg diet) in the diet for 7 days. The results indicated that Cu²⁺- fed flies had reduced survival compared to the control group. Copper toxicity was also associated with a marked decrease in total thiol (T-SH), as well as catalase and glutathione S-transferase activities, contemporaneous with increased acetylcholinesterase (AChE) activity, nitric oxide (nitrate and nitrite) and dopamine levels. Co-exposure of flies to Cu²⁺ and Curcumin prevented mortality, inhibited AChE activity and restored dopamine to normal levels (p < 0.05). Moreover, Curcumin restored eclosion rates, and the cellular antioxidant status, as well as alleviated the accumulation of nitric oxide level in the flies. Curcumin ameliorated oxidative damage in the flies as evidenced by the survival rates, longevity assay as well as the restoration of antioxidant status. Our findings thus suggest that Curcumin ameliorated Cu²⁺-induced neurotoxicity in D. melanogaster and as such could be considered an effective therapeutic agent in the prevention and treatment of disorders, where oxidative stress is implicated.

Synthesis of gold and silver nanoparticles using flavonoid quercetin and their effects on lipopolysaccharide induced inflammatory response in microglial cells

Quercetin is a plant origin phytochemical with several pharmaceutical activities such as antioxidant, immunomodulatory, and anti-inflammatory effects. However, consumption of quercetin is limited due to its low aqueous solubility and poor bioavailability. The aim of the present study was to synthesize silver and gold nanoparticles of quercetin with a view to improve its aqueous phase solubility and investigate the effects on LPS-induced neuroinflammation in BV-2 microglial cells. The average size of silver and gold-quercetin nanoparticles was 53 and 27 nm, respectively. Absorption peaks in the UV-Vis spectra were observed at 555 and 405 nm for gold and silver-quercetin nanoparticles, respectively. The particle size and mapping of silver and gold-quercetin nanoparticles were also determined using a STEM detector. The inflammatory stimulation of the BV-2 cells with LPS caused an elevated release of proinflammatory prostaglandin, E2, nitric oxide (NO), upregulated cyclooxygenase-2, inducible NO synthase mRNA, and protein levels, which were markedly inhibited by the pretreatment with gold-quercetin nanoparticles (highly soluble in water) without causing any cytotoxic effects. The findings of the present study suggest that the potential of gold-quercetin nanoparticles are much better than quercetin and that gold-quercetin nanoparticles might provide protection against inflammatory neurodegenerative disease via suppression of acute microglial activation.