Thymoquinone: An Effective Natural Compound for Kidney Protection

Kidney disease is a common health problem worldwide. Acute or chronic injuries may interfere with kidney functions, eventually resulting in irreversible kidney damage. A number of recent studies have shown that the plant-derived natural products have an extensive potential for renal protection. Thymoquinone (TQ) is an essential compound derived from Nigella Sativa (NS), which is widely applied in the Middle East as a folk medicine. Previous experiments have demonstrated that TQ has a variety of potential pharmacological effects, including anti-oxidant, antibacterial, antitumor, immunomodulatory, and neuroprotective activities. In particular, the prominent renal protective efficacy of TQ has been demonstrated in both in vivo and in vitro experiments. TQ can prevent acute kidney injuries from various xenobiotics through anti-oxidation, anti-inflammatory, and anti-apoptosis effects. In addition, TQ exhibited significant pharmacological effects on renal cell carcinoma, renal fibrosis, and urinary calculi. The essential mechanisms involve scavenging ROS and increasing anti-oxidant activity, decreasing inflammatory mediators, inducing apoptosis, and inhibiting migration and invasion. The purpose of this review is to conclude the pharmacological effects and the potential mechanisms of TQ in renal protection, shedding new light on the exploration of medicinal phyto-protective agents targeting kidneys.

A Review of the Occurrence of Rheumatoid Arthritis and Potential Treatments through Medicinal Plants from an Indian Perspective

Arthritis is a medical condition that affects the joints and causes inflammation, pain, and stiffness. There are different types of arthritis, and it can affect people of all ages, even infants and the elderly. Recent studies have found that individuals with diabetes, heart disease, and obesity are more likely to experience arthritis symptoms. According to the World Health Organization, over 21% of people worldwide suffer from musculoskeletal problems. Roughly 42.19 million individuals in India, constituting around 0.31% of the populace, have been documented as having Rheumatic Arthritis (RA). Compared to other common diseases like diabetes, cancer, and AIDS, arthritis is more prevalent in the general population. Unfortunately, there is no specific cure for arthritis, and treatment plans usually involve non-pharmacological methods, surgeries, and medications that target specific symptoms. Plant-based remedies have also been shown to be effective in managing inflammation and related complications. In addition to therapies, maintaining a healthy diet, exercise, and weight management are essential for managing arthritis. This review discusses the causes, prevalence, diagnostic methods, current and prospective future treatments, and potential medicinal plants that may act as anti-inflammatory or anti-rheumatic agents. However, more research is necessary to identify the underlying mechanisms and active molecules that could improve arthritis treatment.

Effect of saffron, black seed, and their main constituents on inflammatory cytokine response (mainly TNF-α) and oxidative stress status: an aspect on pharmacological insights

Tumor necrosis factor-α (TNF-α), an inflammatory cytokine, is produced by monocytes and macrophages. It is known as a 'double-edged sword' because it is responsible for advantageous and disadvantageous events in the body system. The unfavorable incident includes inflammation, which induces some diseases such as rheumatoid arthritis, obesity, cancer, and diabetes. Many medicinal plants have been found to prevent inflammation, such as saffron (Crocus sativus L.) and black seed (Nigella sativa). Therefore, the purpose of this review was to assess the pharmacological effects of saffron and black seed on TNF-α and diseases related to its imbalance. Different databases without time limitations were investigated up to 2022, including PubMed, Scopus, Medline, and Web of Science. All the original articles (in vitro, in vivo, and clinical studies) were collected on the effects of black seed and saffron on TNF-α. Black seed and saffron have therapeutic effects against many disorders, such as hepatotoxicity, cancer, ischemia, and non-alcoholic fatty liver, by decreasing TNF-α levels based on their anti-inflammatory, anticancer, and antioxidant properties. Saffron and black seed can treat a variety of diseases by suppressing TNF-α and exhibiting a variety of activities such as neuroprotective, gastroprotective, immunomodulatory, antimicrobial, analgesic, antitussive, bronchodilator, antidiabetic activity, anticancer, and antioxidant effects. To uncover the beneficial underlying mechanisms of black seed and saffron, more clinical trials and phytochemical research are required. Also, these two plants affect other inflammatory cytokines, hormones, and enzymes, implying that they could be used to treat a variety of diseases.

Cold plasma approach fortifies the topical application of thymoquinone intended for wound healing via up-regulating the levels of TGF-ß, VEGF, and α-SMA in rats

Wound healing is a series of coordinated events that involve tissue repair and regeneration. Cold atmospheric plasma approach sheds the light on the mechanism that initiates the inflammatory responses throughout the healing cascade. The present study was planned to assess the effect of thymoquinone treated with cold plasma (TQcp) on the rat wound model compared to thymoquinone (TQ). To assess the wound healing potential of TQcp, a full-thickness wound model was used. The induced wound was smeared, starting just after excision, twice daily with TQcp and TQ for 7 days. Our findings revealed that TQcp improved the skin healing potential by augmenting the skin regeneration indices as evidenced by enhancing the new production of hyaluronic acid and collagen type I. TQcp significantly reduced the skin content of tumor necrosis factor- α and inhibited the hypertrophic scarring by up-regulating the skin content of transforming growth factor-beta. Furthermore, TQcp enhanced the levels of interleukin-10, alpha smooth muscle actin and vascular endothelial growth factor, demonstrating a great potential for wound healing that also reflected in the histopathological and ultra-structural picture of the skin. Finally, our results demonstrated that TQcp revealed a significant potential for wound healing than TQ alone.

Piperine suppresses inflammatory fibroblast-like synoviocytes derived from rheumatoid arthritis patients Via NF-κB inhibition

Rheumatoid Arthritis (RA) is a common autoimmune disease recognized by hyperplasia of synoviocytes and chronic joint inflammation. Activation of fibroblast-like synoviocytes (FLSs) is one of the main features of RA which can trigger inflammation leading to articular cartilage and joint destruction. Aberrant activation of NF-κB signaling cascade was found to be responsible for the high proliferation and defective apoptosis of FLSs and subsequent inflammation in RA. Piperine is a principal constituent of piper species frequently used as antitumor and anti-inflammatory natural compound. In this study we aimed to assess the anti-inflammatory effect of piperine on RA-FLS through NF-κB inhibition. FLSs were isolated from 68 RA patients and 30 healthy controls and were exposed to piperine. The main assays were MTT assay, flow cytometric analysis, PI staining, reverse transcription-PCR (RT-PCR), and ELISA. Results showed that piperine can induce the apoptosis and reduce the proliferation of RA-FLSs in vitro. Moreover, piperine directly reduced the phosphorylation of NF-kB and the expression of NF-κB target genes related to RA-FLSs proliferation (c-Myc and Cycline D1), apoptosis inhibition (Bcl2 and Bcl-xl) and inflammation (COX2, IL-1β, TNF-α,IL-6, CCL5 and CXCL10) while increasing the expression of apoptosis related ones (Bax) in vitro. Piperine also reduced the protein levels of cytokines and chemokines secreted by FLSs as a result of NF-κB inhibition. In conclusion, our results provide evidence for the anti-inflammatory capacity of piperine through inhibition of NF-κB pathway in FLSs proposing this compound as a suitable alternative for chemical treatment of RA.

Antinociceptive Action of Thymoquinone-Loaded Liposomes in an In Vivo Model of Tendinopathy

Tendinopathies represent about 45% of musculoskeletal lesions and they are a big burden in clinics characterized by activity-related pain, focal tendon tenderness and intra-tendinous imaging changes. Many approaches have been proposed for tendinopathies' management (e.g., nonsteroidal anti-inflammatory drugs, corticosteroids, eccentric exercises, laser therapy), unfortunately with very little support of efficacy or serious side effects, thus making the identification of new treatments fundamental. The aim of the study was to test the protective and pain reliever effect of thymoquinone (TQ)-loaded formulations in a rat model of tendinopathy induced by carrageenan intra-tendon injection (20 µL of carrageenan 0.8% on day 1). Conventional (LP-TQ) and hyaluronic acid (HA)-coated TQ liposomes (HA-LP-TQ) were characterized and subjected to in vitro release and stability studies at 4 °C. Then, TQ and liposomes were peri-tendon injected (20 µL) on days 1, 3, 5, 7 and 10 to evaluate their antinociceptive profile using mechanical noxious and non-noxious stimuli (paw pressure and von Frey tests), spontaneous pain (incapacitance test) and motor alterations (Rota rod test). Liposomes containing 2 mg/mL of TQ and covered with HA (HA-LP-TQ2) reduced the development of spontaneous nociception and hypersensitivity for a long-lasting effect more than the other formulations. The anti-hypersensitivity effect matched with the histopathological evaluation. In conclusion, the use of TQ encapsulated in HA-LP liposomes is suggested as a new treatment for tendinopathies.

Molecular mechanisms and signaling pathways of black cumin (Nigella sativa) and its active constituent, thymoquinone: a review

BACKGROUND

Nigella sativa and its main bioactive ingredient, thymoquinone, exhibit various pharmacological activities, including neuroprotective, nephroprotective, cardioprotective, gastroprotective, hepatoprotective, and anti-cancer effects. Many studies have been conducted trying to elucidate the molecular signaling pathways that mediate these diverse pharmacological properties of N. sativa and thymoquinone. Accordingly, the goal of this review is to show the effects of N. sativa and thymoquinone on different cell signaling pathways.

METHODS

The online databases Scopus, PubMed and Web of Science were searched to identify relevant articles using a list of related keywords such as Nigella sativa, black cumin, thymoquinone, black seed, signal transduction, cell signaling, antioxidant, Nrf2, NF-κB, PI3K/AKT, apoptosis, JAK/STAT, AMPK, MAPK, etc. Only articles published in the English language until May 2022 were included in the present review article.

RESULTS

Studies indicate that N. sativa and thymoquinone improve antioxidant enzyme activities, effectively scavenges free radicals, and thus protect cells from oxidative stress. They can also regulate responses to oxidative stress and inflammation via Nrf2 and NF-κB pathways. N. sativa and thymoquinone can inhibit cancer cell proliferation through disruption of the PI3K/AKT pathway by upregulating phosphatase and tensin homolog. Thymoquinone can modulate reactive oxygen species levels in tumor cells, arrest the cell cycle in the G2/M phase as well as affect molecular targets including p53, STAT3 and trigger the mitochondrial apoptosis pathway. Thymoquinone, by adjusting AMPK, can regulate cellular metabolism and energy hemostasis. Finally, N. sativa and thymoquinone can elevate brain GABA content, and thus it may ameliorate epilepsy.

CONCLUSIONS

Taken together, the improvement of antioxidant status and prevention of inflammatory process by modulating the Nrf2 and NF-κB signaling and inhibition of cancer cell proliferation through disruption of the PI3K/AKT pathway appear to be the main mechanisms involved in different pharmacological properties of N. sativa and thymoquinone.

Dietary Thymoquinone Alone or Combined with Swimming Exercise Protect against Microcystin-LR-Induced Oxidative Injury in Mice

Microcystin-leucine-arginine (MCLR) is the most abundant cyanotoxin produced by cyanobacteria. It induces potent cytotoxicity through oxidative stress and DNA damage. Thymoquinone (TQ) is a natural nutraceutical antioxidant derived from black cumin (Nigella sativa). Physical exercise (EX) improves whole-body metabolic homeostasis. Therefore, this study examined the protective role of swimming exercise and TQ against MC-induced toxicity in mice. Fifty-six healthy adult male albino mice (25-30 g) were randomized into seven groups; group (I) was the negative control and received oral physiological saline for 21 days; group (II) received water EX for 30 min daily; group (III) was intraperitoneally injected with TQ (5 mg/kg daily, for 21 days); group (IV) was intraperitoneally administered MC (10 μg/kg daily, for 14 days) and acted as the positive toxic control; group (V) was treated with MC and water EX; group (VI) was injected with MC and TQ; finally, group (VII) was treated with MC with TQ and water EX. In comparison with the control group, the results showed hepatic, renal, and cardiac toxicity in the MCLR-treated group, indicated by a significant increase (p < 0.05) in serum levels of alkaline phosphatase (ALP), aspartate aminotransferase (AST), alanine transferase (ALT), cholesterol, lactate dehydrogenase (LDH), creatine kinase (CK), creatine kinase-myocardial band (CK-MB), urea, creatinine, interleukin-6, interleukin -1β, and tumor necrosis factor-α levels. In addition, there were significant elevations (p < 0.05) in malondialdehyde (MDA) and nitric oxide (NO) levels and a significant decrease in reduced glutathione (GSH), glutathione peroxidase (GPx), catalase (CAT), and superoxide dismutase (SOD) in hepatic, cardiac, and renal tissues. Treatment with either TQ or water EX significantly improved (p < 0.05) the MC-induced toxicity with superiority of the TQ group in the restoration of normal ranges; however, cotreatment with both TQ and swimming EX showed the most improvement and restoration to normal ranges as a result of increasing EX clinical efficacy by TQ.

Mitochondrial Dysfunction and Induction of Apoptosis in Hepatocellular Carcinoma and Cholangiocarcinoma Cell Lines by Thymoquinone

Thymoquinone (TQ), a plant-based bioactive constituent derived from the volatile oil of Nigella sativa, has been shown to possess some anti-neoplastic activities. The present study aimed to investigate the mitochondria and apoptosis observed when TQ is applied against hepatocellular carcinoma (HepG2) and cholangiocarcinoma (HuCCT1) cells, two of the most common primary tumors of the liver. All cell lines were treated with increasing concentrations of TQ for varying durations. The anti-proliferative effect of TQ was measured using the methoxyphenyl-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay and resulted in dose- and time-dependent growth inhibition in both cell lines. Cell cycle, apoptosis, and assessment of mitochondria viability by morphology assessment and evaluation of the mitochondrial membrane potential were investigated. The present study confirms that TQ caused cell cycle arrest at different phases and induced apoptosis in both cell lines. A systematic review of rodent animal models was also carried out. Overall, our data seem to represent the most robust results, suggesting that TQ possesses promising therapeutic potential as an anti-tumor agent for the treatment of hepatocellular carcinoma and cholangiocarcinoma.

Black Seed (Nigella sativa): A Favourable Alternative Therapy for Inflammatory and Immune System Disorders

In the recent years, various food additives, medicinal plants, and their bioactive components have been utilized in anti-inflammatory and immunomodulatory therapy. Nigella sativa is a key dietary supplement and food additive which has a strong traditional background. It is also one of the most broadly studied seeds in the global pharmaceutical and nutraceutical sector. N. sativa seeds are potential sources of natural metabolite such as phenolic compounds and alkaloids. The anti-inflammatory and immunomodulatory abilities of these seeds, most peculiarly with reference to some inflammatory and immune mediators, are reviewed. N. sativa and its bioactive compounds modulate inflammatory and immunomodulatory mediators including tumor necrosis factor-alpha (TNF-α), interferon gamma (IFN-γ), nuclear factor kappa B (NF-kB) cyclooxygenase (COX), lipoxygenase (LOX), transforming growth factor beta (TGF-β), interleukins, and immunoglobulin levels. This paper comprehensively describes the biomarkers and signaling pathways underlying the anti-inflammatory and immunomodulatory potential of N. sativa. This review also explains the scientific basis and the pharmacological properties of core bioactive ingredients of N. sativa responsible for these biological activities which indicates that their bioactive components could be possibly regarded as favorable therapy for disorders linked to inflammation and immune-dysregulation.

Therapeutic implications and clinical manifestations of thymoquinone

Thymoquinone (TQ), a natural phytochemical predominantly found in Nigella sativa, has been investigated for its numerous health benefits. TQ showed anti-cancer, anti-oxidant, and anti-inflammatory properties, validated in various disease models. The anti-cancer potential of TQ is goverened by anti-proliferation, cell cycle arrest, apoptosis induction, ROS production, anti-metastasis and anti-angiogenesis, inhibition of cell migration and invasion action. Additionally, TQ exhibited antitumor activity via the modulation of multiple pathways and molecular targets, including Akt, ERK1/2, STAT3, and NF-κB. The present review highlighted the anticancer potential of TQ . We summarize the anti-cancer, anti-oxidant, and anti-inflammatory properties of TQ, focusing on its molecular targets and its promising action in cancer therapy. We further described the molecular mechanisms by which TQ prevents signaling pathways that mediate cancer progression, invasion, and metastasis.

Thymoquinone's Antiviral Effects: It is Time to be Proven in the Covid-19 Pandemic Era and its Omicron Variant Surge

The COVID-19 pandemic has impacted every country in the world. With more than 400 million cases and more than 5.5 million deaths. The FDA either approved or authorized the emergency use for three vaccines against COVID-19. The treatment options of COVID-19 are very limited. Multiple complementary and alternative medicine modalities were suggested to be efficacious in the treatment of COVID-19 such as Thymoquinone. The effects of Thymoquinone have been examined and multiple studies indicate a promising beneficial effect. However, the current body of research is limited in terms of its scope, quality, and quantity. While higher-quality studies are required, physicians do not routinely recommend the use of marketed supplements of natural products, including Thymoquinone for COVID-19. Given the numerous suggested positive effects of Thymoquinone, including anti-inflammatory and antimicrobial properties, additional research is required to confirm or refute these promising benefits. Complementary and alternative medicine is an area that requires additional evidence-based practice and research to confirm effects observed in clinical practice.

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.

The Role of Bioactive Compounds of Nigella sativa in Rheumatoid Arthritis Therapy-Current Reports

Black cumin (Nigella sativa, NS) is included in the Ranunculaceae family and is classified as a medicinal plant due to very high levels of various bioactive compounds. They determine its therapeutic effects, including anti-inflammatory, anti-allergic, anti-cancer, hypoglycemic, antioxidant, hypotensive, hypolipidemic, and immunomodulating properties. The results of scientific studies indicate a supporting role of black cumin in the treatment of autoimmune diseases, including rheumatoid arthritis, due to the health-promoting properties of its bioactive ingredients. The aim of the current article is to analyze the results of scientific publications on the role of bioactive ingredients contained in black cumin in the treatment of rheumatoid arthritis.

Thymoquinone loading into hydroxyapatite/alginate scaffolds accelerated the osteogenic differentiation of the mesenchymal stem cells

Background

Phytochemical agents such as thymoquinone (TQ) have osteogenic property. This study aimed to investigate the synergic impact of TQ and hydroxyapatite on mesenchymal stem cell differentiation. Alginate was also used as drug vehicle.

Methods

HA scaffolds were fabricated by casting into polyurethane foam and sintering at 800 °C, and then, 1250 °C and impregnated by TQ containing alginate. The adipose-derived stem cells were aliquoted into 4 groups: control, osteogenic induced-, TQ and osteogenic induced- and TQ-treated cultures. Adipose derived-mesenchymal stem cells were mixed with alginate and loaded into the scaffolds

Results

The results showed that impregnation of HA scaffold with alginate decelerated the degradation rate and reinforced the mechanical strength. TQ loading in alginate/HA had no significant influence on physical and mechanical properties. Real-time RT-PCR showed significant elevation in collagen, osteopontin, and osteocalcin expression at early phase of differentiation. TQ also led to an increase in alkaline phosphatase activity. At long term, TQ administration had no impact on calcium deposition and proliferation rate as well as bone-marker expression.

Conclusion

TQ accelerates the differentiation of the stem cells into the osteoblasts, without changing the physical and mechanical properties of the scaffolds. TQ also showed a synergic influence on differentiation potential of mesenchymal stem cells.

Therapeutic perspectives of the black cumin component thymoquinone: A review

The dietary phytochemical thymoquinone (TQ), belonging to the family of quinones, mainly obtained from the black and angular seeds of Nigella sativa, is one of the promising monoterpenoid hydrocarbons, which has been receiving massive attention for its therapeutic potential and pharmacological properties. It plays an important role as a chemopreventive and therapeutic agent in the treatment of various diseases and illnesses. The aim of this review is to present a summary of the most recent literature pertaining to the use of TQ for the prevention and treatment of various diseases along with possible mechanisms of action, and the potential use of this natural product as a complementary or alternative medicine. Research findings indicated that TQ exhibits numerous pharmacological activities including antioxidant, anti-inflammatory, cardioprotective, hepatoprotective, antidiabetic, neuroprotective, and anticancer, among others. Conclusions of this review on the therapeutic aspects of TQ highlight the medicinal and folk values of this compound against various diseases and ailments. In short, TQ could be a novel drug in clinical trials, as we hope.

Recent Findings on Thymoquinone and Its Applications as a Nanocarrier for the Treatment of Cancer and Rheumatoid Arthritis

Cancer causes a considerable amount of mortality in the world, while arthritis is an immunological dysregulation with multifactorial pathogenesis including genetic and environmental defects. Both conditions have inflammation as a part of their pathogenesis. Resistance to anticancer and disease-modifying antirheumatic drugs (DMARDs) happens frequently through the generation of energy-dependent transporters, which lead to the expulsion of cellular drug contents. Thymoquinone (TQ) is a bioactive molecule with anticancer as well as anti-inflammatory activities via the downregulation of several chemokines and cytokines. Nevertheless, the pharmacological importance and therapeutic feasibility of thymoquinone are underutilized due to intrinsic pharmacokinetics, including short half-life, inadequate biological stability, poor aqueous solubility, and low bioavailability. Owing to these pharmacokinetic limitations of TQ, nanoformulations have gained remarkable attention in recent years. Therefore, this compilation intends to critically analyze recent advancements in rheumatoid arthritis and cancer delivery of TQ. This literature search revealed that nanocarriers exhibit potential results in achieving targetability, maximizing drug internalization, as well as enhancing the anti-inflammatory and anticancer efficacy of TQ. Additionally, TQ-NPs (thymoquinone nanoparticles) as a therapeutic payload modulated autophagy as well as enhanced the potential of other drugs when given in combination. Moreover, nanoformulations improved pharmacokinetics, drug deposition, using EPR (enhanced permeability and retention) and receptor-mediated delivery, and enhanced anti-inflammatory and anticancer properties. TQ's potential to reduce metal toxicity, its clinical trials and patents have also been discussed.

Exploring the role of polyphenols in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic, inflammatory and autoimmune disorder which is mainly characterized by inflammation in joints, bone erosions and cartilaginous destruction that leads to joint dysfunction, deformation, and/or permanent functional impairment. The prevalence of RA is increasing, incurring a considerable burden on healthcare systems globally. The exact etiology of RA is unknown, with various pathways implicated in its pathophysiology. Non-steroidal anti-inflammatory drugs (NSAIDs) including celecoxib, diclofenac and ibuprofen, disease-modifying anti-rheumatic drugs (DMARD) including azathioprine, methotrexate and cyclosporine, biological agents including anakinra, infliximab, and rituximab and immunosuppressants are used for symptomatic relief in patients with RA, but these medications have severe adverse effects such as gastric ulcers, hypertension, hepatotoxicity and renal abnormalities which restrict their use in the treatment of RA; new RA treatments with minimal side-effects are urgently required. There is accumulating evidence that dietary polyphenols may show therapeutic efficacy in RA through their antioxidant, anti-inflammatory, apoptotic, and immunosuppressant activities and modulation of the tumor necrosis factor-α (TNF-α), interleukin (IL)-6, mitogen-activated protein kinase (MAPK), IL-1β, c-Jun N-terminal kinase (JNK), and nuclear factor κ light-chain-enhancer of activated B cell (NF-κB) pathways. While resveratrol, genistein, carnosol, epigallocatechin gallate, curcumin, kaempferol, and hydroxytyrosol have also been studied for the treatment of RA, the majority of data are derived from animal models. Here, we review the various pathways involved in the development of RA and the preclinical and clinical data supporting polyphenols as potential therapeutic agents in RA patients. Our review highlights that high-quality clinical studies are required to decisively establish the anti-rheumatic efficacy of polyphenolic compounds.

Nigella sativa in controlling Type 2 diabetes, cardiovascular, and rheumatoid arthritis diseases: Molecular aspects

Oxidative stress is an important factor in the etiology of several chronic diseases that include cardiovascular disease (CVD), Type 2 diabetes (T2D), and rheumatoid arthritis (RA). Oxidative stress can lead to inflammation, and this can contribute to these chronic diseases. Reducing inflammation and oxidative stress may, therefore, be useful in the prevention and treatment of these conditions. One of the treatment options for chronic diseases is the use of traditional medicine and herbs, such as Nigella sativa. This is one of the herbs that have recently been assessed for its ability to reduce inflammation and oxidative stress. We have reviewed the reported effects of N. sativa on risk factors of chronic diseases (CVD, DM, and RA) with emphasis on molecular and cellular mechanisms in controlling inflammation and oxidative stress. Various mechanisms have been proposed to contribute to the beneficial properties of N. sativa, including a reduction of lipid peroxidation via its antioxidant properties; agonist of peroxisome proliferator-activated receptor gamma in adipose tissue; activation of AMP-activated protein kinase, increased antioxidants, inhibition of nuclear factor-kappa B pathway; increased in interleukin-10 expression, CD4+ T-cell percentage, T regulatory cell percentage (CD4+ CD25+ T-cell) in peripheral blood, and CD4+/CD8+ ratio, but to prove this claim, it is necessary to conduct experimental and well-designed clinical trial studies with a larger sample size on the effects of N. sativa on these chronic diseases.

Anti-inflammatory effects of thymoquinone and its protective effects against several diseases

Thymoquinone (TQ, 2-methyl-5-isopropyl-1, 4-benzoquinone), a monoterpene molecule present in Nigella sativa L., has an anti-inflammatory, anti-oxidant, and anti-apoptotic properties in several disorders such as asthma, hypertension, diabetes, inflammation, bronchitis, headache, eczema, fever, dizziness and influenza. TQ exerts its anti-inflammatory and anti-oxidant effects via several molecular pathways, including the release of cytokines, and activation of cyclooxygenase-2 (COX2), nuclear factor erythroid 2-related factor 2 (Nrf2), phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT), nuclear factor kappa-light-chain-enhancer of activated B (NF-Κβ). In this review, recent reports on the anti-inflammatory efficacy of TQ in heart disorders, respiratory diseases, neuroinflammation, diabetes and arthritis are summarized. We suggest that further investigation is necessary to better characterize the efficacy of TQ as a therapeutic agent.

Repurposing of the Herbals as Immune-Boosters in the Prevention and Management of COVID-19: A Review

Coronavirus disease (COVID) is highly contagious, and negligence of it causes high morbidity and mortality globally. The highly infectious viral disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was abbreviated as COVID-19 (Coronavirus disease 2019) by World Health Organization first time on February 11, 2020, and later on, WHO declared COVID-19 as a global pandemic on 11/3/2020. Epidemiological studies demonstrated that the SARS CoV-2 infects the overall population, irrespective of age, gender, or ethnic variation, but it was observed in clinical studies that older and compromised immunity population is much more prone to COVID-19. SARS-CoV-2 majorly spread through aeration route in droplet form on sneezing and coughing, or by contact when touching eyes, nose or mouth with the infected hands or any other organs, resulting from mild to severe range of SARS-CoV-2 infection. This literature-based review was done by searching the relevant SCI and SCOPUS papers on the pandemic, SARS-CoV-2 and COVID-19, herbal formulation, and Ayurveda from the databases, Academia, Google Scholar, PubMed, and ResearchGate. The present review attempts to recognize the therapeutic strategies to combat COVID-19 because of the current human risk. Indian system of medicine, including herbals, has immense potential in treating and managing various viral infections and provides evidence to utilize Ayurvedic medication to improve immunity. Cumulative research findings suggest that Ayurvedic formulations and herbal immunomodulators (Tino sporacordifolia, Withania somnifera, Crocus sativus, Zafran, Allium sativum, Zingiber officinale, Albizia lebbek, Terminalia chebula, Piper longum, Mangifera indica, Ocimum sanctum, Centella asiatica ) are promising in the treatment of outrageous viral infections without exerting adverse effects. Considering the ancient wisdom of knowledge, the herbal formulations would compel healthcare policymakers to endorse Ayurveda formulations to control the COVID-19 pandemic significantly.

Targeting Inflammatory Mediators: An Anticancer Mechanism of Thymoquinone Action

BACKGROUND

Thymoquinone is a promising anticancer molecule, the chemopreventive role of which is well-known at least in vitro and in the animal model. In this review article, we focused on the anti-inflammatory activities of thymoquinone in cancer cells.

METHOD

Research data on inflammation, cancer and thymoquinone were acquired from PubMed, Scopus, Web of Science and Google Scholar. We reviewed papers published since the mid of the last century, and the most cited papers of the last ten years.

RESULTS

Studies indicate that thymoquinone possesses immunomodulatory activities, in addition to its chemopreventive role, as thymoquinone can target and modulate inflammatory molecules, like nuclear factor kappa B (NF-κβ), interleukins, tumor necrosis factor-α (TNF-α), and certain growth factors. As chronic inflammation plays an important role in cancer development, controlling inflammatory pathways is an important mechanism of an anticancer molecule, and modulation of inflammatory pathways might be one of the key mechanisms of thymoquinone's anticancer activities.

CONCLUSION

This article reviewed the role of inflammation on cancer development, and the action of thymoquinone on inflammatory molecules, which have been proved in vitro and in vivo. Much attention is required for studying the role of thymoquinone in immunotherapeutics and developing this molecule as a future anticancer drug.

Thymoquinone in autoimmune diseases: Therapeutic potential and molecular mechanisms

Autoimmune diseases (AUDs) are a multifactorial disease, among which rheumatoid arthritis, systemic lupus erythematosus and multiple sclerosis are more prevalent. Several anti-inflammatory, biologics, and AUD-modifying drugs are found effective against them, but their repeated use are associated with various adverse effects. In this review article, we have focused on the regulation of inflammatory molecules, molecular signaling pathways, immune cells, and epigenetics by natural product thymoquinone on AUDs. Studies indicate that thymoquinone can regulate inflammatory molecules including interferons, interleukins, tumor necrosis factor-α (TNF-α), oxidative stress, regulatory T cells, and various signaling pathways such as nuclear factor kappa beta (NF-κβ), janus kinase/signal transduction and activator of transcription (JAK-STAT), mitogen-activated protein kinase (MAPK) at the molecular level and epigenetic alteration. As these molecules and signaling pathways with defective immune function play an important role in AUD development, controlling these molecules and deregulated molecular mechanism is a significant feature of AUD therapeutics. Interestingly thymoquinone is reported to possess all these potential. This article reviewed the deregulated mechanism of AUDs, and the action of thymoquinone on inflammatory molecules, immune cells, signaling pathways, and epigenetic machinery. Thymoquinone can be regarded as a potential drug candidate for AUD treatment.

Volatile compounds of black cumin (Nigella sativa L.) seeds cultivated in Bangladesh and India

The compositional analysis of volatile compounds of Nigella sativa L. seeds obtained from India and Bangladesh was carried out in this study. Apart from the proportion of volatile compounds, the chemical composition of seeds from both sources were similar. The major volatile compounds in Bangladesh seeds were p-cymene (36.35%), thymoquinone (29.77%), α-thujene (12.40%), carvacrol (2.85%), β-pinene (2.41%), limonene (1.64%), methyl linoleate (1.33%) and sabinene (1.18%), contribution of these is 87.93% of the total volatile oil. On the other hand, the major volatile compounds in Indian seeds were p-cymene (41.80%), α-thujene (13.93%), thymoquinone (10.27%), methyl linoleate (4.02%), carvacrol (3.65%), β-pinene (2.96%), d-limonene (2.11%), 4,5-epoxy-1-isopropyl-4- methyl-1-cyclohexene (1.80%), sabinene (1.50%) and 4-terpineol (1.22%); contribution of these were 83.24% of the total volatile oil. In both seeds, p-cymene, thymoquinone, and α-thujene were the major components. Importantly, N. sativa seeds of Bangladesh contained almost 3-fold thymoquinone compared to Indian seeds. In conclusion, the seeds from Bangladesh contain a higher amount of terpene ketones (29.86%) represented by thymoquinone in comparison to Indian seeds (10.61%); on the other hand, Indian seeds contained a higher amount of terpene hydrocarbons (63.18%) mainly p-cymene, compared to Bangladesh seeds (54.53%). This is the first study to report detailed compositional analysis and comparison of Nigella sativa L. seeds from Bangladesh and India.

Natural products action on pathogenic cues in autoimmunity: Efficacy in systemic lupus erythematosus and rheumatoid arthritis as compared to classical treatments

Systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA), which are characterized by self-perpetuating inflammation and tissue/organ damage, resulting from the failure of lymphocyte auto-tolerance, cause morbidity and mortality worldwide. The current drugs or therapies including conventional non-steroidal anti-inflammatory drugs (NSAIDs) and disease-modifying anti-rheumatic drugs (DMARDs), as well as several biologic therapies such as B cell-targeted, T cell-targeted, cytokines-targeted and cytokines receptors-targeted therapy, cannot completely cure SLE and RA, and are always accompanied by unexpected side effects. Therefore, more studies have explored new methods for therapy and found that the herbal medicine as well as its natural products (NPs) exhibited promising therapeutic value through exerting effects of immunomodulation, anti-inflammation, anti-oxidation, and anti-apoptosis, etc. via regulating abnormal responses in kidney, innate and adaptive immune systems, intestine, synoviocytes, as well as bone system including chondrocytes, osteoclasts, joints and paw tissues. In the present review, we will elucidate the current mainstream drugs and therapies for SLE and RA, and summarize the efficacy and mechanisms of NPs in the treatment of SLE and RA based on available findings including in vitro and in vivo animal models, as well as clinical studies, and further analyze the existing challenges, in order to provide comprehensive evidence for improvement of SLE and RA therapy by NPs and to promote management of these two autoimmune diseases.

Novel thymoquinone lipidic core nanocapsules with anisamide-polymethacrylate shell for colon cancer cells overexpressing sigma receptors

The biggest challenge in colorectal cancer therapy is to avoid intestinal drug absorption before reaching the colon, while focusing on tumor specific delivery with high local concentration and minimal toxicity. In our work, thymoquinone (TQ)-loaded polymeric nanocapsules were prepared using the nanoprecipitation technique using Eudragit S100 as polymeric shell. Conjugation of anisamide as a targeting ligand for sigma receptors overexpressed by colon cancer cells to Eudragit S100 was carried out via carbodiimide coupling reaction, and was confirmed by thin layer chromatography and ¹H-NMR. TQ nanocapsules were characterized for particle size, surface morphology, zeta potential, entrapment efficiency % (EE%), in vitro drug release and physical stability. A cytotoxicity study on three colon cancer cell lines (HT-29, HCT-116, Caco-2) was performed. Results revealed that the polymeric nanocapsules were successfully prepared, and the in vitro characterization showed a suitable size, zeta potential, EE% and physical stability. TQ exhibited a delayed release pattern from the nanocapsules in vitro. Anisamide-targeted TQ nanocapsules showed higher cytotoxicity against HT-29 cells overexpressing sigma receptors compared to their non-targeted counterparts and free TQ after incubation for 48 h, hence delineating anisamide as a promising ligand for active colon cancer targeting.

Thymoquinone reduces ischemia and reperfusion-induced intestinal injury in rats, through anti-oxidative and anti-inflammatory effects

OBJECTIVES

The aim of the present study was to investigate the effect of thymoquinone on ischemia/reperfusion (I/R) injury at 150 min or/and 24 h of reperfusion in male Wistar Rats.

MATERIAL AND METHODS

The therapeutic value of thymoquinone on cellular damage caused by reactive oxygene species or inflammatory processes during intestinal ischemia/reperfusion was investigated using pharmacological function studies on smooth muscle contractile responses of acetylcholine (Ach) and KCl, along with myeloperoxidase activity, malondialdehyhde, glutathione and cytokine levels such as tumor necrosis factor (TNF)-α and interleukin (IL)-1β in serum and ileum tissue of rats. Thymoquinone was administered at a dose of 50 mg/kg orally for three times: 30 min, 24 h and 48 h prior to the surgical procedure. Soon after reperfusion timing (150 min or 24 h), the contractility traces to KCl and acetylcholine of the ileum smooth muscle were recorded through isolated organ bath.

RESULTS

Pretreatment with thymoquinone reversed the disrupted contractility of the ileum smooth muscle at the 24 h reperfusion. Increased malondialdehyde and depleted glutathione levels and high myeloperoxidase activity determined in the ileum I/R tissue returned to reasonable amounts by pretreatment of Thymoquinone, which attenuated malondialdehyde quantity, restored glutathione level and inhibited myeloperoxidase activity. In addition, both serum and tissue TNF-α and IL-1β activities were modulated by thymoquinone at 24 h of intestinal I/R.

CONCLUSION

The results indicate that thymoquinone may have therapeutic value due to its immunomodulating, radical scavenging and/or antioxidant effects in intestinal I/R injury including oxidant damage mechanisms.

Cancer: Thymoquinone antioxidant/pro-oxidant effect as potential anticancer remedy

Recently, there is growing interest in the natural bioactive components having anticancer activity. Thymoquinone (TQ), the principle active constituent of black seed (Nigella sativa), has promising properties including anticancer and chemosensitizing peculiarities. The anticancer power of TQ is accomplished by several aspects; including promotion of apoptosis, arrest of cell cycle and ROS generation. In addition, it boosts the immune system and lessens the side effects associated with traditional anticancer therapy. TQ also controls angiogenesis and cancer metastasis. This review focuses on the potential aspects and mechanisms by which TQ acquires its actions.

Could Polyphenols Help in the Control of Rheumatoid Arthritis?

Rheumatoid arthritis (RA) is a chronic, systemic, joint-invading, autoimmune inflammatory disease, which causes joint cartilage breakdown and bone damage, resulting in functional impairment and deformation of the joints. The percentage of RA patients has been rising and RA represents a substantial burden for patients around the world. Despite the development of many RA therapies, because of the side effects and low effectiveness of conventional drugs, patients still need and researchers are seeking new therapeutic alternatives. Polyphenols extracted from natural products are effective on several inflammatory diseases, including RA. In this review polyphenols are classified into four types: flavonoids, phenolic acids, stilbenes and others, among which mainly flavonoids are discussed. Researchers have reported that anti-RA efficacies of polyphenols are based mainly on three mechanisms: their anti-inflammatory, antioxidant and apoptotic properties. The main RA factors modified by polyphenols are mitogen-activated protein kinase (MAPK), interleukin-1β (IL-1β), IL-6, tumor necrosis factor-α (TNF-α), nuclear factor κ light chain enhancer of activated B cells (NF-κB) and c-Jun N-terminal kinases (JNK). Polyphenols could be potent alternative RA therapies and sources for novel drugs for RA by affecting its key mechanisms.

In vitro and in vivo assessment of the proresolutive and antiresorptive actions of resolvin D1: relevance to arthritis

BACKGROUND

Resolvin D1 (RvD1), an important member of resolvins, exerts a wide spectrum of biological effects, including resolution of inflammation, tissue repair, and preservation of cell viability. The aim of the present study is to investigate the anti-arthritic potential and clarify the bone protective actions of RvD1 in vitro and in vivo.

METHODS

RAW264.7 cells were treated with 50 ng/ml LPS for 72 h in the presence or absence of RvD1 (0-500 nM). Primary human monocytes were treated with M-CSF + RANKL for 14 days ± RvD1 (0-500 nM) with or without siRNA against RvD1 receptor FPR2. Expressions of inflammatory mediators, degrading enzymes, osteoclasts (OC) formation, and bone resorption were analyzed. The therapeutic effect of RvD1 (0-1000 ng) was carried out in murine collagen antibody-induced arthritis. Arthritis scoring, joint histology, and inflammatory and bone turnover markers were measured.

RESULTS

RvD1 is not toxic and inhibits OC differentiation and activation. It decreases bone resorption, as assessed by the inhibition of TRAP and cathepsin K expression, hydroxyapatite matrix resorption, and bone loss. In addition, RvD1 reduces TNF-α, IL-1β, IFN-γ, PGE₂, and RANK and concurrently enhances IL-10 in OC. Moreover, in arthritic mice, RvD1 alleviates clinical score, paw inflammation, and bone and joint destructions. Besides, RvD1 reduces inflammatory mediators and markedly decreases serum markers of bone and cartilage turnover.

CONCLUSION

Our results provide additional evidence that RvD1 plays a key role in preventing bone resorption and other pathophysiological changes associated with arthritis. The study highlights the clinical relevance of RvD1 as a potential compound for the treatment of inflammatory arthritis and related bone disorders.

Nicorandil abates arthritic perturbations induced by complete Freund's adjuvant in rats via conquering TLR4-MyD88-TRAF6 signaling pathway

BACKGROUND AND PURPOSE

Rheumatoid arthritis (RA) is a chronic, systemic autoimmune inflammatory disease which poses a need to explore effective yet safe pharmacotherapeutic options. The current work aimed to study the therapeutic role of nicorandil in controlling RA.

EXPERIMENTAL APPROACH

Complete Freund's adjuvant (CFA)-induced arthritis model was applied by injecting 400 μL of CFA in the right hind paw at day 0 and day 7. Four groups of rats were used as follows: normal-control (CTRL), CFA-induced arthritis (ART), CFA-induced arthritis treated with diclofenac (DIC) and CFA-induced arthritis treated with nicorandil (NIC). Both NIC and DIC were administered at day 14 for two weeks. Paw volume, knee joint diameter, pain behavior assessment as well as body weight were all periodically recorded throughout the experimental period. Following the sacrifice of animals at day 28, gene expressions of TLR-4, MyD88 and TRAF6 as well as extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), nuclear factor Kappa B (NF-κB) were quantified in hind paws tissue. Finally, the serum levels of the inflammatory biomarkers (tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6) together with the histopathological examination of sections in the rat hind paw were recorded.

RESULTS

Both NIC and DIC proved promising anti-arthritic potential mediated, at least in part through switching off TLR4-MyD88-TRAF6 axis as well as downstream TRAF6 dependent activated MAP kinases and NF-κB.

CONCLUSION AND IMPLICATIONS

Nicorandil, via interfering with TLR4 signaling, sheds light on a potential clinical role of the drug in pursuit for safe and effective regimens for RA.

Thymoquinone reduces cardiac damage caused by hypercholesterolemia in apolipoprotein E-deficient mice

BACKGROUND

Hypercholesterolemia is a well-established risk factor for cardiac damage, which can lead to cardiovascular diseases. Many studies have shown that thymoquinone protected rats from doxorubicin-induced cardiotoxicity and cardiac damage. The aim of this study was to investigate the possible protective effects of thymoquinone against cardiac damage in apolipoprotein E knockout (ApoE-/-) mice.

METHODS

Eight-week-old male ApoE-/- mice were randomly divided into three groups: control group fed a normal diet (ND group), a high cholesterol diet (HD group) or HD mixed with thymoquinone (HD + TQ group). All groups were fed the different diets for 8 weeks. Blood samples were obtained from the inferior vena cava and collected in serum tubes. The samples were then stored at - 80 °C until used. Coronal sections of heart tissues were fixed in 10% formalin and then embedded in paraffin for histological evaluation. The remainder of the heart tissues was snap-frozen in liquid nitrogen for mRNA or immunohistochemical analysis.

RESULTS

The metabolic characteristics of total cholesterol (TC), low-density lipoprotein-cholesterol (LDL-c), and high-sensitivity C-reactive protein (hs-CRP) were lower in ApoE-/-HD + TQ mice than in ApoE-/- HD mice. Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) gene and protein expression was lower in the heart tissue of ApoE-/-HD + TQ mice than in those of ApoE-/-HD mice. Furthermore, the levels of macrophages and pro-inflammatory cytokines were lower in the cardiac tissues of ApoE-/-HD + TQ mice than in those of ApoE-/-HD mice.

CONCLUSIONS

These results indicate that thymoquinone may provide a potential therapeutic target for cardiac damage caused by hypercholesterolemia.

Nigella sativa fixed oil as alternative treatment in management of pain in arthritis rheumatoid

BACKGROUND

N. sativa seeds is the source of fixed oil, which contain fatty acids and thymoquinone. N. sativa fixed oil topically or orally is used traditionally for management of pain in back, joints, musculoskeletal organs and arthritis rheumatoid.

PURPOSE

The aim of this review article was to evaluate the potential effects of N. sativa fixed oil in pain and inflammation, especially in arthritis rheumatoid.

METHODS

All information was extracted from accessible and inaccessible sources (books, electronic sources, thesis and etc.).

RESULTS

The results of our investigation showed N. sativa fixed oil, especially thymoquinone content had valuable anti-inflammatory and analgesic effects via different pathways. The efficacy of thymoquinone as potential treatment was confirmed in different animal model of arthritis and the clinical studies confirmed the oral (n = 4) and topical use (n = 1) of N. sativa fixed oil without adverse effects in patients suffering from arthritis rheumatoid.

CONCLUSION

The larger multicenter clinical trials for comparing the efficacy of topical, oral administrations and current treatment may help to understand better the efficacy of valuable fixed oil.

Anti-cancer properties and mechanisms of action of thymoquinone, the major active ingredient of Nigella sativa

Over the past two decades, studies have documented the wide-range anti-cancer effects of Nigella sativa, known as black seed or black cumin. Thymoquinone (TQ), its major active ingredient, has also been extensively studied and reported to possess potent anti-cancer properties. Herein, we provide a comprehensive review of the findings related to the anti-cancer activity of TQ. The review focuses on analyzing experimental studies performed using different in vitro and in vivo models to identify the anti-proliferative, pro-apoptotic, anti-oxidant, cytotoxic, anti-metastatic, and NK-dependent cytotoxic effects exerted by TQ. In addition, we pinpoint the molecular mechanisms underlying these effects and the signal transduction pathways implicated by TQ. Our analysis show that p53, NF-κB, PPARγ, STAT3, MAPK, and PI3K/AKT signaling pathways are among the most significant pathways through which TQ mediates its anti-cancer activity. Experimental findings and recent advances in the field highlight TQ as an effective therapeutic agent for the suppression of tumor development, growth and metastasis for a wide range of tumors.

Nigella sativa oil modulates the therapeutic efficacy of mesenchymal stem cells against liver injury in irradiated rats

Stem cell transplantation is a novel strategy for regenerative medicine in liver disease. This study was conducted to explore the modulatory effect of Nigella sativa oil (NSO) on the therapeutic potential of mesenchymal stem cells (MSCs) against irradiation-induced liver damage in rats. Liver damage was induced by a total body exposure to a single dose of 7Gy. NSO (2mg/kg/day) was then given orally for 4 consecutive weeks starting 24h after irradiation with or without a single intravenous MSCs administration, then rats were sacrificed four weeks after exposure to γ radiation. Data revealed that irradiation elevated aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities in serum, increased hepatic malondialdehyde (MDA) content and reduced hepatic superoxide dismutase (SOD) activity. Furthermore, it caused elevation in pro-inflammatory mediators such as interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) associated with reduction in anti-inflammatory cytokine interleukin-10 (IL-10) and it increased fibrogenic marker transforming growth factor-β (TGF-β) in liver tissues. It was observed that combined NSO/MSCs therapy provided more beneficial tissue repair comparable to MSCs alone as demonstrated by modulating the tested parameters. Finally, these results were confirmed by histopathological examination. In conclusion, dual therapy with NSO and MSCs could serve as a promising approach for alleviating radiation-induced liver injury in patients with radiotherapy.

Therapeutic Potential and Pharmaceutical Development of Thymoquinone: A Multitargeted Molecule of Natural Origin

Thymoquinone, a monoterpene molecule is chemically known as 2-methyl-5-isopropyl-1, 4-benzoquinone. It is abundantly present in seeds of Nigella sativa L. that is popularly known as black cumin or black seed and belongs to the family Ranunculaceae. A large number of studies have revealed that thymoquinone is the major active constituent in N. sativa oil this constituent is responsible for the majority of the pharmacological properties. The beneficial organoprotective activities of thymoquinone in experimental animal models of different human diseases are attributed to the potent anti-oxidant and anti-inflammatory properties. Thymoquinone has also been shown to alter numerous molecular and signaling pathways in many inflammatory and degenerative diseases including cancer. Thymoquinone has been reported to possess potent lipophilicity and limited bioavailability and exhibits light and heat sensitivity. Altogether, these physiochemical properties encumber the successful formulation for the delivery of drug in oral dosages form and restrict the pharmaceutical development. In recent past, many efforts were undertaken to improve the bioavailability for clinical usage by manipulating the physiochemical parameters. The present review aimed to provide insights regarding the physicochemical characteristics, pharmacokinetics and the methods to promote pharmaceutical development and endorse the clinical usage of TQ in future by overcoming the associated physiochemical obstacles. It also enumerates briefly the pharmacological and molecular targets of thymoquinone as well as the pharmacological properties in various diseases and the underlying molecular mechanism. Though, a convincing number of experimental studies are available but human studies are not available with thymoquinone despite of the long history of use of black cumin in different diseases. Thus, the clinical studies including pharmacokinetic studies and regulatory toxicity studies are required to encourage the clinical development of thymoquinone.

Phytochemicals as potential antidotes for targeting NF-κB in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune destructive arthropathy prevalent among people in the age group of 40-70 years. RA induces severe pain, swelling and stiffness of joints resulting in bone damage. RA leads to reduced life expectancy when left untreated. RA is characterized by synovial hyperplasia, infiltration of inflammatory cells resulting in formation of pannus. Synovial hyperplasia is mediated by proinflammatory cytokines, notably IL-1 and TNF-α. NF-κB is a predominant transcription factor in amplifying the inflammatory response. The translocation of activated NF-κB into the nucleus triggers the transcription of several genes that induce proinflammatory cytokine production. The inhibition of NF-κB translocation aids blocking the activation of proinflammatory cascades. The quest for more effective and side-effect free treatment for RA unveiled phytochemicals as efficacious and promising. Phytochemicals have been a source of therapeutic substances for many ailments from ancient times. Their therapeutic ability helps in developing potent and safe drugs targeting immune inflammatory diseases driven by NF-κB including RA. This review highlights the importance of NF-κB inflammatory cascade in RA so as to elucidate the crucial role of phytochemicals that inhibit the activity of NF-κB.

Natural antioxidants in the treatment and prevention of diabetic nephropathy; a potential approach that warrants clinical trials

Diabetic nephropathy is the major cause of end-stage renal disease and effective and new therapeutic approaches are needed in diabetic nephropathy and chronic kidney diseases. Oxidative stress and inflammatory process are important factors contributing to kidney damage by increasing production of oxidants. KEAP1/Nrf2/ARE pathway regulates the transcription of many antioxidant genes and modulation of the pathway up regulates antioxidants. NFB controls the expression of genes involved in the inflammatory response. Natural substances have antioxidant and anti-inflammatory activities and have an impact on NFB and KEAP1/Nrf2/ARE pathways. The preclinical studies explored the effectiveness of whole herbs, plants or seeds and their active ingredients in established diabetic nephropathy. They ameliorate oxidative stress induced kidney damage, enhance antioxidant system, and decrease inflammatory process and fibrosis; most likely by activating KEAP1/Nrf2/ARE pathway and by deactivating NFB pathway. Whole natural products contain balanced antioxidants that might work synergistically to induce beneficial therapeutic outcome. In this context, more clinical studies involving whole plants or herbal products or mixtures of different herbs and plants and their active ingredients might change our strategies for the management of diabetic nephropathy. The natural products might be useful as preventive interventions and studies are required in this field.

Thymoquinone reduces kidney damage in apolipoprotein E-deficient mice fed a high-cholesterol diet

Hypercholesterolemia is a well-established risk factor for kidney injury that can lead to chronic kidney disease (CKD). Thymoquinone may be a potential therapeutic agent for kidney damage from hypercholesterolemia.

Mitigation of cadmium-induced lung injury by Nigella sativa oil

Induction of oxidative stress and inflammation are considered the primary mechanism of cadmium (Cd) toxicity. Nigella sativa (NS) seeds and their oil (NSO) have been reported to possess antioxidant and anti-inflammatory potential. This study was conducted to assess the protective effect of NSO on Cd-induced lung damage in rat. Forty adult male Wistar rats were divided equally into 4 groups. Animals in groups I, II, and III received 1 ml of isotonic saline intraperitoneally (IP), 2 mg/kg of cadmium chloride (CdCl₂) dissolved in isotonic saline IP, and 1 ml/kg of NSO by gastric gavage, respectively. Group IV rats received NSO an hour prior to CdCl₂ administration via the same routes and doses as previously described. All animals were treated for 28 days. At the end of the study, animals were sacrificed; lungs were harvested for histopathological studies using light and electron microscopy. Saline-treated and NSO-treated rats showed normal lung parenchyma. However, CdCl₂-treated rats showed massive degenerative changes in alveolar epithelial lining, disrupted interalveolar septa, and hemolytic debris in alveoli. Rats treated with both NSO and CdCl₂ (group IV) showed amelioration of most Cd-induced lung damage with minimal histopathological changes in lung architecture. This study elucidates the protective effects of NSO on Cd-induced lung injury in rats and highlights the possibility of using NSO as a protective agent in individuals at high risk of Cd-induced lung toxicity.

Recent advances on the anti-cancer properties of Nigella sativa, a widely used food additive

The use of naturally-occurring agents to regulate tumorigenesis is on the rise. Several herbal extracts, pure plant-derived active constituents, and food additives have been reported to possess potent anti-cancer properties and cancer-ameliorating effects. The wide-range anti-cancer effects of Nigella sativa, also known as black seed or black cumin, have been extensively studied using different in vitro and in vivo models. Here, we provide a comprehensive, analytical review of the reported anti-cancer properties of N. sativa seed extracts. This review focuses on analyzing experimental findings related to the ability of N. sativa to exert anti-proliferative, pro-apoptotic, anti-oxidant, cytotoxic, anti-mutagenic, anti-metastatic, and NK cytotoxic activity enhancing effects against various primary cancer cells and cancer cell lines. Moreover, we underline the molecular mechanisms of action and the signal transduction pathways implicated in the suppression of tumorigenesis by N. sativa. The major signaling pathway utilized by N. sativa to manifest its anti-cancer activity is the iNOS signaling pathway. This review underscores the recent developments that highlight an effective therapeutic potential of N. sativa to suppress tumor development, reduce tumor incidence, and ameliorate carcinogenesis. In sum, experimental findings reported in the last two decades strongly suggest that N. sativa fractions could serve, alone or in combination with known chemotherapeutic drugs, as effective agents to control tumor initiation, growth, and metastasis, and hence, treatment of a wide range of cancers.

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N. sativa exerts cytotoxic, pro-apoptotic, anti-proliferative, anti-oxidant, anti-mutagenic, and anti-metastatic effects.

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Augmentation of NK cytotoxic activity is a one molecular mechanism by which N. sativa manifests its anti-cancer activity.

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The anti-cancer effects of N. sativa are primarily mediated via iNOS, p53, and caspase signaling pathways.

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N. sativa extracts can potentially be employed in the development of effective anti-cancer therapeutic agents.

A mechanistic review on medicinal plants used for rheumatoid arthritis in traditional Persian medicine

Objectives

Rheumatoid arthritis (RA) is a chronic, inflammatory, autoimmune disease, which affects synovial tissue in multiple joints. Although conventional treatments of RA commonly alleviate the symptoms, high incidence of adverse reactions leads to research tendency towards complementary and alternative medicine. As various medicinal plants are traditionally used for the management of symptomatologies associated with RA in Persian medicine, we reviewed medicinal literature to confirm their efficacy in the management of RA.

Key findings

Scientific evidence revealed that traditional medicaments exert beneficial effects on RA through several cellular mechanisms including downregulation of pro-inflammatory cytokines such as TNF-α, IL-6 and NF-κB, suppression of oxidative stress, inhibition of cartilage degradation with destructive metalloproteinases and enhancement of antioxidant performance. Various active constituents from different chemical categories including flavonols, lignans, coumarins, terpenes, glycosylflavons, dihydroflavonols, phytoestrogens, sesquiterpene lactones, anthraquinones, alkaloids and thymoquinones have been isolated from the medicinal plants.

Summary

The pharmacological mechanisms of the medicinal plants traditionally used for RA in Persian medicine are discussed in the current review. Further investigations are mandatory to focus on bioefficacy of these phytochemicals for finding novel natural drugs.