Immunomodulatory effects of nanocurcumin in arsenic-exposed rats

Curcumin-PLGA based nanocapsule for the fluorescence spectroscopic detection of dopamine

The main purpose of this paper is to design curcumin loaded PLGA nanocapsules for the selective detection of dopamine using fluorescence spectroscopy. In the present work curcumin loaded PLGA nanocapsules were synthesized using a solid-in-oil-in water (s/o/w) emulsion technique. The prepared nanocapsules were coated with a poly(diallyldimethylammonium)chloride (PDDA) polymer to increase the entrapment of curcumin into the core of PLGA polymer. PLGA-Cur-PDDA nanocapsules were characterized using different microscopic and spectroscopic techniques. Unlike free curcumin, the formed CUR-PLGA-PDDA NCs were established as nanoprobes for the selective detection of dopamine molecules. The selectivity and specificity of nanocapsules toward dopamine was achieved by measuring the fluorescence emission spectra of the NCs in the presence of other interference molecules such as tryptophan, melamine, adenine, etc. It was noticed that increasing the concentration of the different molecules had no significant change in the fluorescence signal of the nanocapsules. These results confirm the strong quenching between dopamine and curcumin in the nanocapsules. Hence, this fluorescence emission technique was found to be selective, easy and fast with low cost for the determination of dopamine in a concentration range up to 5 mM with a detection limit equal to 22 nM.

Phytochemicals in the Management of Arsenic Toxicity

Arsenic toxicity is a major concern due to its deleterious consequences for human health. Rapid industrialization also has weakened the quality of the environment by introducing pollutants that may disrupt balanced ecosystems, adversely and irreversibly impacting humans, plants, and animals. Arsenic, an important toxicant among all environmental hazards, can lead to several detrimental effects on cells and organs, impacting the overall quality of life. Nevertheless, arsenic also has a rich history as a chemotherapeutic agent used in ancient days for the treatment of diseases such as malaria, cancer, plague, and syphilis when other chemotherapeutic agents were yet to be discovered. Arsenicosis-mediated disorders remain a serious problem due to the lack of effective therapeutic options. Initially, chelation therapy was used to metabolically eliminate arsenic by forming a complex, but adverse effects limited their pharmacological use. More recently, plant-based products have been found to provide significant relief from the toxic effects of arsenic poisoning. They act by different mechanisms affecting various cellular processes. Phytoconstituents such as curcumin, quercetin, diallyl trisulfide, thymoquinone, and others act via various molecular pathways, primarily by attenuating oxidative damage, membrane damage, DNA damage, and proteinopathies. Nonetheless, most of the phytochemicals reviewed here protect against the adverse effects of metal or metalloid exposure, supporting their consideration as alternatives to chelation therapy. These agents, if used prophylactically and in conjunction with other chemotherapeutic agents, may provide an effective approach for management of arsenic toxicity. In a few instances, such strategies like coadministration of phytochemicals with a known chelating agent have led to more pronounced elimination of arsenic from the body with lesser off-site adverse effects. This is possible because combination treatment ensures the use of a reduced dose of chelating agent with a phytochemical without compromising treatment. Thus, these therapies are more practical than conventional therapeutic agents in ameliorating arsenic-mediated toxicity. This review summarizes the potential of phytochemicals in alleviating arsenic toxicity on the basis of available experimental and clinical evidence.

Purification and characterization of Se-enriched Grifola frondosa glycoprotein, and evaluating its amelioration effect on As3+ -induced immune toxicity

BACKGROUND

Selenium (Se)-enriched glycoproteins have been a research highlight for the role of both Se and glycoproteins in immunoregulation. Arsenic (As) is a toxicant that is potentially toxic to the immune function and consequently to human health. Several reports suggested that Se could reduce the toxicity of heavy metals. Moreover, more and more nutrients in food had been applied to relieve As-induced toxicity. Hence glycoproteins were isolated and purified from Se-enriched Grifola frondosa, and their preliminary characteristics as well as amelioration effect and mechanism on As³⁺ -induced immune toxicity were evaluated.

RESULTS

Four factions, namely Se-GPr11 (electrophoresis analysis exhibited one band: 14.32 kDa), Se-GPr22 (two bands: 20.57 and 31.12 kDa), Se-GPr33 (three bands: 15.08, 20.57 and 32.78 kDa) and Se-GPr44 (three bands: 16.73, 32.78 and 42.46 kDa), were obtained from Se-enriched G. frondosa via DEAE-52 and Sephacryl S-400 column. In addition, Se-GPr11 and Se-GPr44 are ideal proteins that contain high amounts of almost all essential amino acids. Thereafter, the RAW264.7 macrophage model was adopted to estimate the effect of Se-GPr11 and Se-GPr44 on As³⁺ -induced immune toxicity. The results showed that the pre-intervention method was the best consequent and the potential mechanisms were, first, by improving the oxidative stress state (enhancing the activity of superoxide dismutase and glutathione peroxidase, decreasing the levels of reactive oxygen species and malondialdehyde); secondly, through nuclear factor-κB and mitogen-activated protein kinase-mediated upregulation cytokines (interleukin-2 and interferon-γ) secretion induced by As³⁺ .

CONCLUSION

The results suggested Se-enriched G. frondosa may be a feasible supplement to improve health level of the As³⁺ pollution population. © 2021 Society of Chemical Industry.

Effect of curcumin nanoparticles on streptozotocin-induced male Wistar rat model of Alzheimer's disease

Alzheimer's disease (AD) is a progressive neurodegenerative disease that afflicts millions of people all over the world. Intracerebroventricular (ICV) injection of a sub-diabetogenic dose of streptozotocin (STZ) was established as an experimental animal model of AD. The present study was conducted to evaluate the efficacy of curcumin nanoparticles (CNs) against the behavioral, neurochemical and histopathological alterations induced by ICV-STZ. The animals were divided into: control animals, the animal model of AD that received a single bilateral ICV microinjection of STZ, and the animals protected by a daily oral administration of CNs for 6 days before the ICV-STZ injection. The animals of all groups were subjected to surgical operation on the 7th day of administration. Then the administration of distilled water or CNs was continued for 8 days. The ICV-STZ microinjection produced cognitive impairment as evident from the behavioral Morris water maze (MWM) test and induced oxidative stress in the cortex and hippocampus as indicated by the significant increases in lipid peroxidation and nitric oxide (NO) levels and the significant decrease in reduced glutathione (GSH) levels. It also produced a significant increase in acetylcholinesterase (AChE) and tumor necrosis-alpha (TNF-ɑ) and a significant decrease in Na+,K + -ATPase. In addition, a significant increase in amino acid neurotransmitters occurred in the hippocampus, whereas a significant decrease was obtained in the cortex of STZ-induced AD rats. CNs ameliorated the behavioral, immunohistochemical and most of the neurochemical alterations induced by STZ in the hippocampus and cortex. It may be concluded that CNs might be considered as a promising therapeutic agent for the treatment of AD.

Comparative Study between Curcumin and Nanocurcumin Loaded PLGA on Colon Carcinogenesis Induced Mice

Colorectal cancer is the third most common cancer. Because curcumin (CUR) has anti-inflammatory and anticancer properties, research has been undertaken to indicate that nanocurcumin compounds can be used to treat a variety of cancers. CUR in nanoform has been found to have a stronger effect than conventional CUR. The purpose of this study was to show that CUR-loaded poly lactic-co-glycolic acid nanoparticles (PLGA) (CUR-loaded PLGA) have anti-inflammatory and anticancer effects on colon carcinogenesis in male dimethyl hydrazine (DMH) mice as a comparative study between the nanoform of curcumin and normal curcumin, focusing on the anticancer effect of nanocurcumin. Mice were separated into six groups: No treatment was given to Group I (negative Group-I). Group II was treated with CUR. Group III was treated with CUR-loaded PLGA. Group IV was treated with DMH. Group V received DMH and curcumin. Group VI received DMH and CUR-loaded PLGA. At the conclusion of the trial, the animals were slain (6 weeks). Inflammatory indicators and vascular endothelial growth factor (VEGF) levels all changed significantly in this study, as the following inflammatory markers as TNF showed percent of change compared to the DMH group. Recovery percentage for Groups V and VI, respectively, were 9.18 and 55.31%. In addition, IL1 was 7.45 and 50.37% for Groups V and VI, respectively. The results of IL6 were 4.86 and 25.79% for Groups V and VI, respectively. The vascular endothelial growth factor (VEGF) recovery percent was 16.98 and 45.12% for Groups V and VI, respectively. Following the effect of DMH on colon mucosa shape, the researchers looked at the effect of CUR-loaded PLGA on colon histology. It was shown that CUR-loaded PLGA affects the cell cycle and PCNA expression. We conclude that nanocurcumin is an important anti-inflammatory and cancer-fighting agent.

Mechanistic insight into immunomodulatory effects of food-functioned plant secondary metabolites

Medicinally important plant-foods offer a balanced immune function, which is essential for protecting the body against antigenic invasion, mainly by microorganisms. Immunomodulators play pivotal roles in supporting immune function either suppressing or stimulating the immune system's response to invading pathogens. Among different immunomodulators, plant-based secondary metabolites have emerged as high potential not only for immune defense but also for cellular immunoresponsiveness. These natural immunomodulators can be developed into safer alternatives to the clinically used immunosuppressants and immunostimulant cytotoxic drugs which possess serious side effects. Many plants of different species have been reported to possess strong immunomodulating properties. The immunomodulatory effects of plant extracts and their bioactive metabolites have been suggested due to their diverse mechanisms of modulation of the complex immune system and their multifarious molecular targets. Phytochemicals such as alkaloids, flavonoids, terpenoids, carbohydrates and polyphenols have been reported as responsible for the immunomodulatory effects of several medicinal plants. This review illustrates the potent immunomodulatory effects of 65 plant secondary metabolites, including dietary compounds and their underlying mechanisms of action on cellular and humoral immune functions in in vitro and in vivo studies. The clinical potential of some of the compounds to be used for various immune-related disorders is highlighted.

Fabrication and in vitro Evaluation of 4-HIA Encapsulated PLGA Nanoparticles on PC12 Cells

Purpose

4-Hydroxyisophthalic acid (4-HIA) is a bioactive compound present in the roots of Decalepis hamiltonii, which has attracted considerable attention in attenuating oxidative stress-related neurodegenerative diseases. However, its efficacy is limited because of its low solubility and bioavailability. Therefore, the present study aimed to encapsulate 4-HIA using biocompatible copolymer polylactide-co-glycolide (PLGA) and evaluate its antioxidant and neuroprotective potential.

Methods

The nanoparticles (NPs) were fabricated by solid/oil/water (s/o/w) emulsion technique and characterized using XRD, SEM, HR-TEM, and FTIR spectroscopy. Antioxidant assays such as 1,1 diphenyl-2-picrylhydrazyl (DPPH), superoxide, and hydroxyl radical scavenging ability were performed to assess the antioxidant potential of the fabricated NPs.

Results

The bioactive component, 4-HIA, was efficiently encapsulated by the PLGA polymer and was found to be spherical and smooth with a size <10nm. 4-HIA showed better scavenging capability in DPPH and superoxide assays as compared to 4-HIA encapsulated PLGA and butylated hydroxytoluene (BHT). In contrast, 4-HIA encapsulated PLGA NPs exhibited a significant hydroxyl radical scavenging activity than 4-HIA and BHT alone. Further, the encapsulated NPs efficiently curtailed hydrogen peroxide (H₂O₂)-induced cytotoxicity in PC12 cells.

Conclusion

Our findings indicate that 4-HIA encapsulated PLGA NPs might be a therapeutic intervention towards the effective management of oxidative stress as it has exhibited efficient neuroprotective potential against H₂O₂-induced oxidative stress in PC12 cells.

The Effect of Curcumin Nanoparticles on Cisplatin-Induced Cardiotoxicity in Male Wistar Albino Rats

The cardiotoxicity of chemotherapeutic drugs as cisplatin has become a major issue in recent years. The present study investigates the efficacy of curcumin nanoparticles against the cardiotoxic effects of cisplatin by assessment of oxidative stress parameters, Na+,K+-ATPase, acetylcholinesterase (AchE) and tumor necrosis factor-alpha (TNF-α) in cardiac tissue in addition to serum lactate dehydrogenase (LDH). Rats were divided into three groups: control rats that received saline for 14 days; cisplatin-treated rats that received a single intraperitoneal (i.p.) injection of cisplatin (12 mg/kg) followed by a daily oral administration of saline (0.9%) for 14 days and rats treated with a single i.p. injection of cisplatin (12 mg/kg) followed by a daily oral administration of curcumin nanoparticles (50 mg/kg) for 14 days. Cisplatin resulted in a significant increase in lipid peroxidation, nitric oxide (NO), and TNF-α and a significant decrease in reduced glutathione (GSH) levels and Na+, K+- ATPase activity. Moreover, significant increases in cardiac AchE and serum lactate dehydrogenase activities were recorded. Treatment of cisplatin-injected animals with curcumin nanoparticles ameliorated all the alterations induced by cisplatin in the heart of rats. This suggests that curcumin nanoparticles can be used as an important therapeutic adjuvant in chemotherapeutic and other toxicities mediated by oxidative stress and inflammation.

Counteracting arsenic toxicity: Curcumin to the rescue?

Arsenicosis leads to various irreversible damages in several organs and is considered to be a carcinogen. The effects of chronic arsenic poisoning are a result of an imbalance between pro- and antioxidant homeostasis, oxidative stress, as well as DNA and protein damage. Curcumin, the polyphenolic pigment extracted from the rhizome of Curcuma longa, is well-known for its pleiotropic medicinal effects. Curcumin has been shown to have ameliorative effects in arsenic-induced genotoxicity, nephrotoxicity, hepatotoxicity, angiogenesis, skin diseases, reproductive toxicity, neurotoxicity, and immunotoxicity. This review aims to summarize the scientific evidence on arsenic toxicity in various organs and the ameliorative effects of curcumin on the arsenic toxicity.

Effect of the Aqueous Extract of Lantana grisebachii Stuck Against Bioaccumulated Arsenic-Induced Oxidative and Lipid Dysfunction in Rat Splenocytes

Arsenic (As) is a worldwide immunotoxic agent that is in contaminated waters and consumed by mammals. Phytotherapy may counteract its harmful effects. Lantana grisebachii Stuck (LG, Verbenaceae) and its extract are proposed as protective, given vvits in vitro bioactivity. The aim was to determine the protective capacity of the aqueous LG extract on splenocytes exposed in vivo to arsenic. Splenocytes were obtained from an arsenicosis model (Wistar rats consuming orally 0 [control; C] or 5 mg/Kg/d of As) that received 0-100 mg/Kg/d of LG extract for 30 days. As content (total reflection X-ray fluorescence), fatty acid profile (gas chromatography), γ-glutamyl transpeptidase activity (Szasz method), peroxides (xylenol orange-based assay), and nitrites (Griess reaction) were then assayed in viable splenocytes. Data were analyzed with ANOVA and the Tukey's test (p < .05). It was observed that the splenocytes contained 2.2 mg/Kg of this elemental arsenic. With γ-glutamyl transpeptidase inhibition and consequent triggering of hydroperoxides (p < .05), it was observed to increase saturated fatty acids and alter lipid profiles. LG treatment avoided damaging effects with values similar to unexposed C (p < .05), and cellular arsenic concentration (p < .0001). In conclusion, the aqueous extract of L. grisebachii counteracted arsenic toxicity in rat splenocytes by preventing its cellular accumulation and induction of lipid and redox disturbances, which may impair immune function.

Nanocurcumin ameliorates Staphylococcus aureus-induced mastitis in mouse by suppressing NF‑κB signaling and inflammation

Mastitis is the inflammation of the mammary glands caused by bacteria. It causes severe economic loss to dairy industry. Curcumin, a polyphenol obtained from turmeric, has considerable anti-inflammatory effect. Since it is rapidly eliminated from the body, its oral bioavailability is low. However, nanoformulation of curcumin significantly enhances its therapeutic efficiency by improving its oral bioavailability. We evaluated whether nanocurcumin could be more effective than normal curcumin against bovine Staphylococcus aureus mastitis in mouse model. Curcumin-loaded PLGA nanoparticles (CUR-NP) were prepared by solid-in-oil-in-water emulsion method. The mouse model of mastitis was induced by inoculation of a field strain of S. aureus (bovine mastitis isolate) on the 9th day of parturition through the duct of the mammary gland. CUR-NP and curcumin were given orally for 7 days (day 2 to day 8 of parturition) prior to S. aureus inoculation. We determined the levels of inflammatory cytokines and the mRNA expression of NF‑κB. S. aureus infection increased the levels of tumor necrosis factor‑α, interleukin‑1β and myeloperoxidase in mammary tissues and C-reactive protein in serum. Both CUR-NP and curcumin significantly attenuated the levels of these cytokines. However, comparatively, the ameliorative efficiency of CUR-NP was better than normal curcumin. S. aureus infection-induced NF‑κB mRNA expression was significantly reduced to the healthy control level by CUR-NP. Our study demonstrates that the nanoformulation of curcumin can reduce pro-inflammatory mediators in S. aureus-infected mammary tissues by improving NF‑κB signaling. Besides, compared to normal curcumin, this nanoformulation appears to be a better alternative against murine mastitis.

Combinatorial drug delivery strategy employing nano-curcumin and nano-MiADMSA for the treatment of arsenic intoxication in mouse

Chelation therapy is the mainstream treatment for heavy metal poisoning. Apart from this, therapy using antioxidant/herbal extracts are the other strategies now commonly being tried for the treatment. We have previously reported individual beneficial efficacy of nanoparticle mediated administration of an antioxidant like 'curcumin' and an arsenic chelator 'monoisoamyl 2,3-dimercaptosuccinic acid (MiADMSA)' for the treatment of arsenic toxicity compared to bulk drugs. The present paper investigates our hypothesis that a combination drug delivery therapy employing two nanosystems, a chelator and a strong antioxidant, may produce more pronounced therapeutic effects compared to individual effects in the treatment of arsenic toxicity. An in-vivo study was conducted wherein arsenic as sodium arsenite (100 ppm) was administered in drinking water for 5 months to Swiss albino mice. This was followed by a treatment protocol comprising of curcumin encapsulated chitosan nanoparticles (nano-curcumin, 15 mg/kg, orally for 1 month) either alone or in combination with MiADMSA encapsulated polymeric nanoparticles (nano-MiADMSA, 50 mg/kg for last 5 days) to evaluate the therapeutic potential of the combination treatment. Our results demonstrated that co-treatment with nano-curcumin and nano-MiADMSA provided beneficial effects in a synergistic way on the adverse changes in oxidative stress parameters and metal status induced by arsenic.

Immunomodulatory potential of nanocurcumin-based formulation

Vitamins, minerals, and nanocurcumin play a substantial role in various nutraceutical/pharmaceutical formulations that are widely used in therapeutics, cosmetics, and dietary supplements. The current study aimed to investigate the comparative in vitro immunomodulatory effect of a novel nanocurcumin-based formulation with curcumin in LPS-induced cytokine expression, NK cells' activity, and phagocytosis. The proinflammatory cytokines (TNF-α, IL-1β, and MIP-1α) and NK cells' activity were measured in cell supernatants using ELISA assay; however, phagocytosis activity was performed using colorimetric analysis. The chemical characterization of novel nanocurcumin-based formulation using LC-MS (R _t 19.02 min) and mass spectra analysis (m/z 369.04) confirmed the presence of the curcumin in highest peak concentration. MTT assay in three tested cell-lines showed that the formulation was found non-toxic at all the tested concentrations. The expression of TNF-α, IL-1β, and MIP-1α in splenocytes was significantly (p ≤ 0.001) inhibited. Besides, the NK cells' activity and phagocytosis (macrophage) were increased significantly (p ≤ 0.001). Overall, the promising results of this study indicated the significant immunomodulatory effect of nanocurcumin-based formulation compared to the curcumin, which could be used against various inflammatory disorders such as allergy, asthma, autoimmune diseases, coeliac disease, inflammatory bowel disease, etc.

Effects of arsenic on porcine dendritic cells in vitro

Exposure to arsenic (As) is an ongoing, and in some places increasing, health problem. Still, however, the effects of As exposure on the immune system are not well understood. Dendritic cells (DC) are a critical immune cell that bridges the innate and adaptive immune systems. To determine the impact of inorganic (i)As exposure on DC, the effects of (geo)anthropogenically relevant levels of NaAsO₂ on the function of porcine monocyte-derived DC (MoDC) were evaluated in an in vitro model. The results showed a low dose of iAs reduced the phagocytic capacity of MoDC. Furthermore, although surface expression of DC activation markers, such as major histocompatibility complex (MHC)-II, CD80/86, CD40 and CD25, were only slightly changed, MoDC T-cell proliferation-inducing capacity was remarkably diminished by iAs treatment. Additionally, iAs induced significant interleukin (IL)-6 secretion by MoDC after 12- or 24-h incubation, whereas IL-1β secretion was only significantly up-regulated after 12 h. The secretion patterns of IL-8, tumor necrosis factor α (TNFα and IL-10 by iAs-treated MoDC were almost similar to that by mock-treated MoDC. Considering the broad roles of DC in immunobiology, this finding deepens the understanding of molecular mechanisms/functional consequences underpinning the immunopathology, inflammation, and increases in infection arising from As exposure.

Nano drug delivery systems: a new paradigm for treating metal toxicity

INTRODUCTION

The standard medical treatment for metal toxicity is chelation therapy. Chelating agents work by forming less toxic complexes with the toxic metal ions which are readily excreted from the body. These compounds, based on their hydrophilic/lipophilic property, can either remove toxic metal ions from extracellular sites or can penetrate the intracellular compartments to facilitate the removal of toxic metal ions. However, there are various disadvantages associated with this kind of therapy, notably, selectivity. Other problems and challenges are that the therapy regime is expensive, time consuming and has poor patient compliance. Two chelating agents, dimercaptosuccinic acid (DMSA) and dimercaptopropionicsulfonate (DMPS) have gained increased acceptance among clinicians, undoubtedly improving the management of metal intoxications.

AREAS COVERED

The present review provides an insight into the conventional chelating agents, new chelators under development, and the new opportunities presented by the use of nanotherapy for the treatment of metal poisoning cases.

EXPERT OPINION

Today's research should not only focus towards development of alternate chelators but also targeted therapy such as the nanotherapy.

Exposure to arsenic via drinking water induces 5-hydroxymethylcytosine alteration in rat

Arsenic exposure has been implicated to alter DNA methylation process in vitro and in vivo, but it remains obscure whether it disrupts DNA demethylation process, which is pivotal for epigenetic regulation. The objective of this descriptive study was to investigate the relationship between arsenic exposure and 5-methylcytosine (5mC), 5-hydroxymethylcytosine (5hmC) alterations in various organs. In this study, we exposed male Sprague-Dawley rats to sodium arsenite (0.5, 2 or 10 ppm) via drinking water for 8 weeks. Spleen accumulated 2- to 3-fold higher arsenic levels than liver and heart. Lower arsenic levels were observed in the kidney, pancreas and lung. No significant arsenic-induced global 5mC alterations were observed in the majority of investigated organs. However, arsenic induced organ-specific alterations of 5hmC and/or 5hmC/5mC in some investigated organs, i.e. lung, heart, kidney, pancreas and spleen. Our observations suggest that 5hmC is a more sensitive biomarker of arsenic-induced impacts on epigenetic processes than 5mC. Moreover, demethylation via hydroxylation of 5mC appears to play a central role in the toxic mechanism of arsenic.

Protective action of curcumin and nano-curcumin against arsenic-induced genotoxicity in rats in vivo

We explored whether nanoformulation of curcumin can cause better protective effect than free curcumin against arsenic-induced genotoxicity. Curcumin-loaded Poly(lactic-co-glycolic acid) nanoparticles (CUR-NP) were prepared by emulsion technique. The CUR-NP were water soluble and showed biphasic release pattern. Rats were divided into 5 groups of 6 each. Group I served as the control. Group II rats were exposed to sodium arsenite (25 ppm) daily through drinking water for 42 days. Groups III, IV and V were maintained as in Group II, however, they were also administered empty nanoparticle, curcumin (100 mg/kg bw) and CUR-NP (100 mg/kg bw), respectively, by oral gavage during the last 14 days of arsenic exposure. On the 43rd day, genotoxic effects were evaluated in bone marrow cells. Arsenic increased chromosomal aberrations, micronuclei formation and DNA damage. Both free curcumin and CUR-NP attenuated these arsenic-mediated genotoxic effects. However, the result suggests that nanoformulation have better protective effect than free curcumin at the same dose level.

Protective effect of curcumin against heavy metals-induced liver damage

Occupational or environmental exposures to heavy metals produce several adverse health effects. The common mechanism determining their toxicity and carcinogenicity is the generation of oxidative stress that leads to hepatic damage. In addition, oxidative stress induced by metal exposure leads to the activation of the nuclear factor (erythroid-derived 2)-like 2/Kelch-like ECH-associated protein 1/antioxidant response elements (Nrf2/Keap1/ARE) pathway. Since antioxidant and chelating agents are generally used for the treatment of heavy metals poisoning, this review is focused on the protective role of curcumin against liver injury induced by heavy metals. Curcumin has shown, in clinical and preclinical studies, numerous biological activities including therapeutic efficacy against various human diseases and anti-hepatotoxic effects against environmental or occupational toxins. Curcumin reduces the hepatotoxicity induced by arsenic, cadmium, chromium, copper, lead and mercury, prevents histological injury, lipid peroxidation and glutathione (GSH) depletion, maintains the liver antioxidant enzyme status and protects against mitochondrial dysfunction. The preventive effect of curcumin on the noxious effects induced by heavy metals has been attributed to its scavenging and chelating properties, and/or to the ability to induce the Nrf2/Keap1/ARE pathway. However, additional research is needed in order to propose curcumin as a potential protective agent against liver damage induced by heavy metals.

Optimization of curcumin nanoemulsion for intranasal delivery using design of experiment and its toxicity assessment

The objective of the study was to optimize curcumin nanoemulsion for intranasal delivery using design of experiment. Box-Behnken design was constructed using oil, surfactant and co-surfactant concentration as independent variables and their affect on response y1 (globule size) and y2 (zeta potential) were studied. The ANOVA test identified the significant factors that affected the responses. For globule size, percentage of oil, surfactant and co-surfactant were identified as significant model terms whereas for zeta potential, oil and co-surfactant were found to be significant. Critical factors affecting the responses were identified using perturbation and contour plots. The derived polynomial equation and contour graph aid in predicting the values of selected independent variables for preparation of optimum nanoemulsion with desired properties. Further, 2(4) factorial design was used to study influence of chitosan on particle size and zeta potential. The formulations were subjected to in vitro cytotoxicity using SK-N-SH cell line and nasal ciliotoxicity studies. The developed formulations did not show any toxicity and were safe for intranasal delivery for brain targeting. In vitro diffusion studies revealed that nanoemulsions had a significantly higher release compared to drug solution. Ex vivo diffusion studies were carried out using sheep nasal mucosa fixed onto Franz diffusion cells. Mucoadhesive nanoemulsion showed higher flux and permeation across sheep nasal mucosa.