Potential use of antioxidants for the treatment of chronic inflammatory diseases

The excessive production of various reactive oxidant species over endogenous antioxidant defense mechanisms leads to the development of a state of oxidative stress, with serious biological consequences. The consequences of oxidative stress depend on the balance between the generation of reactive oxidant species and the antioxidant defense and include oxidative damage of biomolecules, disruption of signal transduction, mutation, and cell apoptosis. Accumulating evidence suggests that oxidative stress is involved in the physiopathology of various debilitating illnesses associated with chronic inflammation, including cardiovascular diseases, diabetes, cancer, or neurodegenerative processes, that need continuous pharmacological treatment. Oxidative stress and chronic inflammation are tightly linked pathophysiological processes, one of which can be simply promoted by another. Although, many antioxidant trials have been unsuccessful (some of the trials showed either no effect or even harmful effects) in human patients as a preventive or curative measure, targeting oxidative stress remains an interesting therapeutic approach for the development of new agents to design novel anti-inflammatory drugs with a reliable safety profile. In this regard, several natural antioxidant compounds were explored as potential therapeutic options for the treatment of chronic inflammatory diseases. Several metalloenzymes, such as superoxide dismutase, catalase, and glutathione peroxidase, are among the essential enzymes that maintain the low nanomolar physiological concentrations of superoxide (O2•-) and hydrogen peroxide (H2O2), the major redox signaling molecules, and thus play important roles in the alteration of the redox homeostasis. These enzymes have become a striking source of motivation to design catalytic drugs to enhance the action of these enzymes under pathological conditions related to chronic inflammation. This review is focused on several major representatives of natural and synthetic antioxidants as potential drug candidates for the treatment of chronic inflammatory diseases.

Nephroprotective Effect of Hibiscus Sabdariffa Leaf Flavonoid Extracts via KIM-1 and TGF-1β Signaling Pathways in Streptozotocin-Induced Rats

Diabetes-induced kidney damage represents a substantial health hazard, emphasizing the imperative to explore potential therapeutic interventions. This study investigates the nephroprotective activity of flavonoid-rich extracts from Hibiscus sabdariffa leaves in streptozotocin-induced diabetic rats. The flavonoid-rich extracts of H. sabdariffa leaves was obtained using a standard procedure. The animals were induced with streptozotocin and thereafter treated with both low (LDHSFL) and high doses (HDHSFL) of flavonoid-rich extracts from H. sabdariffa leaves and metformin (MET), and other groups are diabetic control (DC) and normal control (NC). The study assesses diverse renal parameters, encompassing kidney redox stress biomarkers, serum electrolyte levels, kidney inflammatory biomarkers, serum concentrations of creatinine, urea, and uric acid, kidney phosphatase activities, renal histopathology, and relative gene expressions of kidney injury molecule-1 (KIM-1) and transforming growth factor beta-1 (TGF-1β), comparing these measurements with normal and diabetic control groups (NC and DC). The findings indicate that the use of extracts from H. sabdariffa leaves markedly (p < 0.05) enhanced renal well-being by mitigating nephropathy, as demonstrated through the adjustment of various biochemical and gene expression biomarkers, indicating a pronounced antioxidative and anti-inflammatory effect, improved kidney morphology, and mitigation of renal dysfunction. These findings suggest that H. sabdariffa leaf flavonoid extracts exhibit nephroprotective properties, presenting a potential natural therapeutic approach for the treatment of diabetic nephropathy.

Classification and application of metal-based nanoantioxidants in medicine and healthcare

Antioxidants play an important role in the prevention of oxidative stress and have been widely used in medicine and healthcare. However, natural antioxidants have several limitations such as low stability, difficult long-term storage, and high cost of large-scale production. Along with significant advances in nanotechnology, nanomaterials have emerged as a promising solution to improve the limitations of natural antioxidants because of their high stability, easy storage, time effectiveness, and low cost. Among various types of nanomaterials exhibiting antioxidant activity, metal-based nanoantioxidants show excellent reactivity because of the presence of an unpaired electron in their atomic structure. In this review, we summarize some novel metal-based nanoantioxidants and classify them into two main categories, namely chain-breaking and preventive antioxidant nanomaterials. In addition, the applications of antioxidant nanomaterials in medicine and healthcare are also discussed. This review provides a deeper understanding of the mechanisms of metal-based nanoantioxidants and a guideline for using these nanomaterials in medicine and healthcare.

Are Supra-Physiological Plant-Based Antioxidants Ready for the Clinic? A Scoping Review of Hormetic Influences Driving Positive Clinical Outcomes

Background: A pro-inflammatory metabolic state is key to the chronic disease epidemic. Clinicians' ability to use nutrients to balance inflammation via oxidant homeostasis depends on the quality of antioxidants research. Understanding the intersection of two prominent theories for how antioxidants quell inflammation-nutritional hormesis and oxidant scavenging-will enable therapeutic antioxidant use in clinical practice. Purpose: We sought to survey the literature to answer the question: has the hormetic response of exogenous antioxidants been studied in humans and if so, what is its effect Research Design: This review investigates the less well-established theory, nutritional hormesis. To understand the state of hormetic response research, we conducted a literature review describing the relationship between exogenous antioxidants, hormesis, and chronic disease. We used an adaptive search strategy (PubMed and Scopus), retrieving 343 articles, of which 218 were unique. Most studies reviewed the hormetic response in plant and cell models (73.6%) while only 2.2% were in humans. Results: Given the limited robust evidence, clinicians lack research-based guidance on the appropriate therapeutic dose of exogenous antioxidants or, more concerning, supra-physiological dosing via supplements. A critical hurdle in searching the literature is the lack of standardized nomenclature describing the hormetic effect, challenging the ability of clinicians to make informed decisions. Conclusion: Non-human research shows a biphasic, hormetic relationship with antioxidants but observational studies have yet to translate this into the complexities of human biochemistry and physiology. Therefore, we cannot accurately translate this into clinical care. To remedy this insufficiency, we suggest: (1) Improved data collection quality: controlled diet, standardized antioxidant measurements, bioavailability assessed via biomarkers; (2) Larger, harmonized datasets: research subject transparency, keyword standardization, consensus on a hormesis definition.

Effects of green tea polyphenols against metal-induced genotoxic damage: underlying mechanistic pathways

This review is based upon evidence from the published effects of green tea polyphenols (GTP) on genotoxic damage induced by metals with carcinogenic potential. First, the relationship between GTP and antioxidant defense system is provided. Subsequently, the processes involved in the oxidative stress generated by metals and their relationship to oxidative DNA damage is examined. The review demonstrated that GTP generally decrease oxidative DNA damage induced by exposure to metals such as arsenic (As), cadmium (Cd), cobalt (Co), copper (Cu), chromium (Cr), iron (Fe), and lead (Pb). The pathways involved in these effects are related to: (1) direct scavenging of free radicals (FR); (2) activation of mechanisms to repair oxidative DNA damage; (3) regulation of the endogenous antioxidant system; and (4) elimination of cells with genetic damage via apoptosis. The results obtained in the studies reviewed demonstrate potential for possible use of GTP to prevent and treat oxidative damage in populations exposed to metals. Further, GTP may be considered as adjuvants to treatments for metal-associated diseases related to oxidative stress and DNA damage.

Oxidative stress, free radicals and antioxidants: potential crosstalk in the pathophysiology of human diseases

Introduction: Free radicals are reactive oxygen species that constantly circulate through the body and occur as a side effect of many reactions that take place in the human body. Under normal conditions, they are removed from the body by antioxidant processes. If these natural mechanisms are disrupted, radicals accumulate in excess and contribute to the development of many diseases. Methodology: Relevant recent information on oxidative stress, free radicals, reactive oxidative species, and natural and synthetic antioxidants was collected by researching electronic databases such as PubMed / Medline, Web of Science, and Science Direct. Results: According to the analysed studies, this comprehensive review provided a recent update on oxidative stress, free radicals and antioxidants and their impact on the pathophysiology of human diseases. Discussion: To counteract the condition of oxidative stress, synthetic antioxidants must be provided from external sources to supplement the antioxidant defense mechanism internally. Because of their therapeutic potential and natural origin, medicinal plants have been reported as the main source of natural antioxidants phytocompounds. Some non-enzymatic phytocompounds such as flavonoids, polyphenols, and glutathione, along with some vitamins have been reported to possess strong antioxidant activities in vivo and in vitro studies. Thus, the present review describes, in brief, the overview of oxidative stress-directed cellular damage and the unction of dietary antioxidants in the management of different diseases. The therapeutic limitations in correlating the antioxidant activity of foods to human health were also discussed.

Dietary polyphenols and their relationship to the modulation of non-communicable chronic diseases and epigenetic mechanisms: A mini-review

Chronic Non-Communicable Diseases (NCDs) have been considered a global health problem, characterized as diseases of multiple factors, which are developed throughout life, and regardless of genetics as a risk factor of important relevance, the increase in mortality attributed to the disease to environmental factors and the lifestyle one leads. Although the reactive species (ROS/RNS) are necessary for several physiological processes, their overproduction is directly related to the pathogenesis and aggravation of NCDs. In contrast, dietary polyphenols have been widely associated with minimizing oxidative stress and inflammation. In addition to their antioxidant power, polyphenols have also drawn attention for being able to modulate both gene expression and modify epigenetic alterations, suggesting an essential involvement in the prevention and/or development of some pathologies. Therefore, this review briefly explained the mechanisms in the development of some NCDs, followed by a summary of some evidence related to the interaction of polyphenols in oxidative stress, as well as the modulation of epigenetic mechanisms involved in the management of NCDs.

Accelerated Senescence and Apoptosis in the Rat Liver during the Progression of Diabetic Complications

Background

Chronic hyperglycaemia of diabetes causes long-term damage and impaired function of multiple organs. However, the pathological changes in the liver following long-term diabetes remain unclear. This study aimed to determine the pathological complications of long-term diabetes in the rat liver.

Methods

Intraperitoneal injection of streptozotocin (STZ) was used to induce diabetes in rats at a single dose (60 mg/kg body weight [BW]). Rats were euthanised at 1 month (DM1 group), 2 months (DM2 group) and 4 months (DM4 group) following diabetes induction with six rats in each group. Immunohistochemistry was performed against SOD1, CD68, p53 and p16 antibodies. Messenger RNA (mRNA) expressions of SOD1, SOD2, GPx, CD68, p53, p21 and caspase-3 genes were measured by reverse transcription-polymerase chain reaction.

Results

Hepatic p53 mRNA expression was significantly higher in DM1, DM2 and DM4 groups compared to the control group. The p21 and caspase-3 mRNA expressions were significantly upregulated in the DM2 and DM4 groups. The p16-positive cells were obviously increased, particularly in the DM4 group. Bivariate correlation analysis showed mRNA expressions of p21 and caspase-3 genes were positively correlated with the p53 gene.

Conclusion

Diabetic rats exhibited increased apoptosis and senescence in the liver following a longer period of hyperglycaemia.

Preliminary Phytochemical Screening, In Vitro Antidiabetic, Antioxidant Activities, and Toxicity of Leaf Extracts of Psychotria malayana Jack

Psychotria malayana Jack belongs to the Rubiacea and is widespread in Southeast Asian countries. It is traditionally used to treat diabetes. Despite its potential medicinal use, scientific proof of this pharmacological action and the toxic effect of this plant are still lacking. Hence, this study aimed to investigate the in vitro antidiabetic and antioxidant activities, toxicity, and preliminary phytochemical screening of P. malayana leaf extracts by gas chromatography-mass spectrometry (GC-MS) after derivatization. The antidiabetic activities of different extracts of this plant were investigated through alpha-glucosidase inhibitory (AGI) and 2-NBDG glucose uptake using 3T3-L1 cell line assays, while the antioxidant activity was evaluated using DPPH and FRAP assays. Its toxicological effect was investigated using the zebrafish embryo/larvae (Danio rerio) model. The mortality, hatchability, tail-detachment, yolk size, eye size, beat per minute (BPM), and body length were taken into account to observe the teratogenicity in all zebrafish embryos exposed to methanol extract. The LC₅₀ was determined using probit analysis. The methanol extract showed the AGI activity (IC₅₀ = 2.71 ± 0.11 μg/mL), insulin-sensitizing activity (at a concentration of 5 µg/mL), and potent antioxidant activities (IC₅₀ = 10.85 μg/mL and 72.53 mg AAE/g for DPPH and FRAP activity, respectively). Similarly, the water extract exhibited AGI activity (IC₅₀ = 6.75 μg/mL), insulin-sensitizing activity at the concentration of 10 μg/mL, and antioxidant activities (IC₅₀ = 27.12 and 33.71 μg/mL for DPPH and FRAP activity, respectively). The methanol and water extracts exhibited the LC₅₀ value higher than their therapeutic concentration, i.e., 37.50 and 252.45 µg/mL, respectively. These results indicate that both water and methanol extracts are safe and potentially an antidiabetic agent, but the former is preferable since its therapeutic index (LC₅₀/therapeutic concentration) is much higher than for methanol extracts. Analysis using GC-MS on derivatized methanol and water extracts of P. malayana leaves detected partial information on some constituents including palmitic acid, 1,3,5-benzenetriol, 1-monopalmitin, beta-tocopherol, 24-epicampesterol, alpha-tocopherol, and stigmast-5-ene, that could be a potential target to further investigate the antidiabetic properties of the plant. Nevertheless, isolation and identification of the bioactive compounds are required to confirm their antidiabetic activity and toxicity.

L-carnitine: Searching for New Therapeutic Strategy for Sepsis Management

In this review, we discussed the biological targets of carnitine, its effects on immune function, and how L-carnitine supplementation may help critically ill patients. L-carnitine is a potent antioxidant. L-carnitine depletion has been observed in prolonged intensive care unit (ICU) stays, while L-carnitine supplementation has beneficial effects in health promotion and regulation of immunity. It is essential for the uptake of fatty acids into mitochondria. By inhibiting the ubiquitin-proteasome system, down-regulation of apelin receptor in cardiac tissue, and reducing β-oxidation of fatty acid, carnitine may decrease vasopressor requirement in septic shock and improve clinical outcomes of this group of patients. We also have an overview of animal and clinical studies that have been recruited for evaluating the beneficial effects of L-carnitine in the management of sepsis/ septic shock. Additional clinical data are required to evaluate the optimal daily dose and duration of L-carnitine supplementation.

Superoxide dismutase: an updated review on its health benefits and industrial applications

Many short-lived and highly reactive oxygen species, such as superoxide anion (O₂^-) and hydrogen peroxide (H₂O₂), are toxic or can create oxidative stress in cells, a response involved in the pathogenesis of numerous diseases depending on their concentration, location, and cellular conditions. Superoxide dismutase (SOD) activities as an endogenous and exogenous cell defense mechanism include the potential use in treating various diseases, improving the potential use in treating various diseases, and improving food-stuffs preparation dietary supplements human nutrition. Published work indicates that SOD regulates oxidative stress, lipid metabolism, inflammation, and oxidation in cells. It can prevent lipid peroxidation, the oxidation of low-density lipoprotein in macrophages, lipid droplets' formation, and the adhesion of inflammatory cells into endothelial monolayers. It also expresses antioxidant effects in numerous cancer-related processes. Additionally, different forms of SOD may also augment food processing and pharmaceutical applications, exhibit anticancer, antioxidant, and anti-inflammatory effects, and prevent arterial problems by protecting the proliferation of vascular smooth muscle cells. Many investigations in this review have reported the therapeutic ability and physiological importance of SOD. Because of their antioxidative effects, SODs are of great potential in the medicinal, cosmetic, food, farming and chemical industries. This review discusses the findings of human and animal studies that support the advantages of SOD enzyme regulations to reduce the formation of oxidative stress in various ways.

Do naturally occurring antioxidants protect against neurodegeneration of the dopaminergic system? A systematic revision in animal models of Parkinson's disease

Parkinson's disease (PD) is the second most common neurodegenerative disease and is characterized by a significant decrease in dopamine levels, caused by progressive degeneration of the dopaminergic neurons in the nigrostriatal pathway. Multiple mechanisms have been implicated in its pathogenesis, including oxidative stress, neuroinflammation, protein aggregation, mitochondrial dysfunction, insufficient support for neurotrophic factors and cell apoptosis. The absence of treatments capable of slowing or stopping the progression of PD has increased the interest in the natural antioxidant substances present in the diet, since they have multiple beneficial properties and it is possible that they can influence the mechanisms responsible for the dysfunction and death of dopaminergic neurons. Thus, the purpose of this systematic review is to analyze the results obtained in a set of studies carried out in the last years, which describe the neuroprotective, antioxidant and regenerative functions of some naturally occurring antioxidants in experimental models of PD. The results show that the exogenous no enzymatic antioxidants can significantly modify the biochemical and behavioral mechanisms that contribute to the pathophysiology of Parkinsonism in experimental animals. Therefore, it is possible that they may contribute to effective neuroprotection by providing a significant improvement in neuropathological markers. In conclusion, the results of this review suggest that exogenous antioxidants can be promising therapeutic candidates for the prevention and treatment of PD.

Medicinal Prospects of Antioxidants From Algal Sources in Cancer Therapy

Though cancer therapeutics can successfully eradicate cancerous cells, the effectiveness of these medications is mostly restricted to several deleterious side effects. Therefore, to alleviate these side effects, antioxidant supplementation is often warranted, reducing reactive species levels and mitigating persistent oxidative damage. Thus, it can impede the growth of cancer cells while protecting the normal cells simultaneously. Moreover, antioxidant supplementation alone or in combination with chemotherapeutics hinders further tumor development, prevents chemoresistance by improving the response to chemotherapy drugs, and enhances cancer patients' quality of life by alleviating side effects. Preclinical and clinical studies have been revealed the efficacy of using phytochemical and dietary antioxidants from different sources in treating chemo and radiation therapy-induced toxicities and enhancing treatment effectiveness. In this context, algae, both micro and macro, can be considered as alternative natural sources of antioxidants. Algae possess antioxidants from diverse groups, which can be exploited in the pharmaceutical industry. Despite having nutritional benefits, investigation and utilization of algal antioxidants are still in their infancy. This review article summarizes the prospective anticancer effect of twenty-three antioxidants from microalgae and their potential mechanism of action in cancer cells, as well as usage in cancer therapy. In addition, antioxidants from seaweeds, especially from edible species, are outlined, as well.