Nigella Plants - Traditional Uses, Bioactive Phytoconstituents, Preclinical and Clinical Studies

Exploring ethnobotanical remedies: Medicinal plants for snakebite envenoming treatments in the Oued Righ region (Northern Algerian Sahara)

Snakebites present a significant health risk in the Sahara, where access to modern medical facilities is limited, leading local populations to rely on traditional remedies. The medicinal plants used by indigenous communities in the Oued Righ region of the Northern Algerian Sahara are vital for treating envenomation from snakebites. This study provides an ethnobotanical inventory of medicinal plants used by local communities in the Oued Righ region for snakebite treatment and evaluates their therapeutic potential. Ethnobotanical data were collected through structured surveys of 200 local residents, herbalists, and healers. Data were analyzed using ethnobotanical indices, including relative citation frequency (RFC), use value (UV), and family importance value (FIV). A total of 41 plant species from 23 families were identified, and their uses for snake envenomation were documented. The most frequently used plants were Citrullus colocynthis (14.95%) and Nigella sativa (10.74%), with Asteraceae being the most represented family. The remedies are predominantly prepared using aerial parts and seeds in various forms, such as poultices and decoctions. The ethnobotanical indices highlight the cultural importance and pharmacological potential of these plants. This study documents traditional knowledge on snakebite treatments, creating a foundational database for future pharmacological studies. The identified plant species hold significant potential for developing new antivenom therapies.

Unleashing of cytotoxic effects of thymoquinone-bovine serum albumin nanoparticles on A549 lung cancer cells

This research examines the cytotoxic consequences of thymoquinone-loaded bovine serum albumin nanoparticles (TQ-BSA NPs) on the A549 lung cancer cell line. UV-visible (UV-Vis) spectroscopy, Fourier transform infrared spectrophotometer (FT-IR), scanning electron microscopy (SEM), and dynamic light scattering (DLS) were employed to verify the biogenic TQ-BSA NPs' size, shape, and distribution. UV-Vis spectrophotometry indicated peaks at 200-300 nm, 500-600 nm, and a prominent peak at 700-800 nm, confirming the presence of TQ-BSA NPs. The polydispersity index, as confirmed by DLS, indicated a solvent distribution in water, accompanied by a zeta potential value of 126.2 ± 46.8 mV. The average size of TQ-BSA NPs was confirmed to be 187 ± 8 nm by SEM. TQ-BSA NPs reduce colony formation in the A549 lung cancer cell line in a dose-dependent manner relative to the control group. Protein expression analysis indicated that TQ-BSA NPs promoted programmed cell death by increasing pro-apoptotic levels and decreasing anti-apoptotic levels. TQ-BSA NPs demonstrated inhibition of cancer cell proliferation and promotion of apoptosis and exhibited significant efficacy against cancer cells at low concentrations. As a result, they have the makings of a promising chemotherapeutic agent for low-dose, long-term administration.

Antimicrobial Properties and Therapeutic Potential of Bioactive Compounds in Nigella sativa: A Review

Nigella sativa (N. sativa; Ranunculaceae), commonly referred to as black cumin, is one of the most widely used medicinal plants worldwide, with its seeds having numerous applications in the pharmaceutical and food industries. With the emergence of antibiotic resistance in pathogens as an important health challenge, the need for alternative microbe-inhibitory agents is on the rise, whereby black cumin has gained considerable attention from researchers for its strong antimicrobial characteristics owing to its high content in a wide range of bioactive compounds, including thymoquinone, nigellimine, nigellidine, quercetin, and O-cymene. Particularly, thymoquinone increases the levels of antioxidant enzymes that counter oxidative stress in the liver. Additionally, the essential oil in N. sativa seeds effectively inhibits intestinal parasites and shows moderate activity against some bacteria, including Bacillus subtilis and Staphylococcus aureus. Thymoquinone exhibits minimum inhibitory concentrations (MICs) of 8-16 μg/mL against methicillin-resistant Staphylococcus aureus (MRSA) and exhibits MIC 0.25 µg/mL against drug-resistant mycobacteria. Similarly, quercetin shows a MIC of 2 mg/mL against oral pathogens, such as Streptococcus mutans and Lactobacillus acidophilus. Furthermore, endophytic fungi isolated from N. sativa have demonstrated antibacterial activity. Therefore, N. sativa is a valuable medicinal plant with potential for medicinal and food-related applications. In-depth exploration of the corresponding therapeutic potential and scope of industrial application warrants further research.

Astragalus membranaceus, Nigella sativa, and Perilla frutescens as Immunomodulators-Molecular Mechanisms and Clinical Effectiveness in Allergic Diseases

Plants are the source of numerous remedies in modern medicine, and some of them have been studied due to their potential immunomodulatory activity. Astragalus membranaceus Fisch. ex Bunge (A. membranaceus), Nigella sativa L. (N. sativa), and Perilla frutescens (L.) Britton (P. frutescens) are plant species used in traditional medicine for the treatment of various diseases. Their potential to act as immunomodulatory, anti-inflammatory, and anti-allergic agents makes them interesting for investigating their clinical potential in alleviating the symptoms of allergic diseases. Allergy affects a large number of people; according to some sources more than 30% of the world population suffer from some type of allergic reaction, with pollen allergy as the most common type. Treatment is usually pharmacological and may not be completely effective or have side effects. Thus, we are seeking traditional medicine, mostly medicinal plants, with promising potential for alleviating allergy symptoms. A literature overview was conducted employing databases such as Scopus, PubMed, Web of Science, Springer, and Google Scholar. This manuscript summarizes recent in vivo preclinical and clinical studies on three species with immunomodulatory activity, provides a comparison of their anti-allergic effects, and underlines the potential of their application in clinical practice. The obtained results confirmed their efficacy in the in vivo and clinical studies, but also emphasize the problem of phytochemical characterization of the species and difference between tested doses. More clinical trials with standardized protocols (defined active molecules, dosage, side effects) are required to obtain safe and effective herbal drugs.

Effect of cyclodextrin-complexed lyophilized nanosuspension of Nigella sativa seeds oleoresin on chronic unpredictable mild stress (CUMS)-induced depression in mice

Depression is a prevalent global health concern necessitating alternative approaches to conventional antidepressant medications due to its associated adverse effects. Nigella sativa (NS) is recognized for its potential as an antidepressant, offering a promising solution with fewer side effects. This study investigated the antidepressant efficacy of cyclodextrin-complexed lyophilized nanosuspension of NS oleoresin (NSOR) in a murine model of chronic unpredictable mild stress (CUMS)-induced depression. This study sought to evaluate and contrast the antidepressant potential of the nano-NSOR with that of the NS ethanolic extract (NSEE). The prepared nano-NSOR was characterized physicochemically and evaluated for in vitro drug release and in vivo antidepressant activity. The particle size of nano-NSOR was determined to be 164.6 nm. In vitro drug release studies suggested the higher drug release from nano-NSOR (90.15 % after 72 h) compared to the native NSOR (59.55 % after 72 h). Furthermore, nano-NSOR exhibited a more pronounced antidepressant effect than NSEE in the context of CUMS-induced depression. This study highlights a potential alternative for managing depression, addressing the need for improved antidepressant treatments with reduced side effects. These results suggest that nano-NSOR ameliorates CUMS-induced depression by modulating neurotransmitter levels, reducing inflammation, and enhancing neuroprotection.

Phytochemical Analysis and Anti-Biofilm Potential That Cause Dental Caries from Black Cumin Seeds (Nigella sativa Linn.)

The oral cavity is an excellent place for various microorganisms to grow. Spectrococcus mutans and Spectrococcus sanguinis are Gram-negative bacteria found in the oral cavity as pioneer biofilm formers on the tooth surface that cause caries. Caries treatment has been done with antibiotics and therapeutics, but the resistance level of S. mutans and S. sanguinis bacteria necessitates the exploration of new drug compounds. Black cumin (Nigella sativa Linn.) is known to contain secondary metabolites that have antioxidant, antibacterial, anti-biofilm, anti-inflammatory and antifungal activities. The purpose of this review article is to present data on the potential of Nigella sativa Linn seeds as anti-biofilm. This article will discuss biofilm-forming bacteria, the resistance mechanism of antibiotics, the bioactivity of N. sativa extracts and seed isolates together with the Structure Activity Relationship (SAR) review of N. sativa compound isolates. We collected data from reliable references that will illustrate the potential of N. sativa seeds as anti-biofilm drug.

Nigella sativa and its chemical constituents: pre-clinical and clinical evidence for their potential anti-SARS-CoV-2 effects

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused over 500 million reported cases of COVID-19 worldwide with relatively high morbidity and mortality. Although global vaccination drive has helped control the pandemic, the newer variant of the virus still holds the world in ransom. Several medicinal herbs with antiviral properties have been reported, and one such promising herb is Nigella sativa (NS). Recent molecular docking, pre-clinical, and clinical studies have shown that NS extracts may have the potential to prevent the entry of coronaviruses into the host cell as well as to treat and manage COVID-19 symptoms. Several active compounds from NS, such as nigelledine, α-hederin, dithymoquinone (DTQ), and thymoquinone (TQ), have been proposed as excellent ligands to target angiotensin-converting enzyme 2 (ACE2 receptors) and other targets on host cells as well as the spike protein (S protein) on SARS-CoV-2. By binding to these target proteins, these ligands could potentially prevent the binding between ACE2 and S protein. Though several articles have been published on the promising therapeutic role of NS and its constituents against SARS-CoV-2 infection, in this review, we consolidate the published information on NS and SARS-CoV-2, focusing on pre-clinical in silico studies as well as clinical trials reported between 2012 and 2023.

Phytocompounds screening of Nigella sativa in terms of human cancer by targeting sphingosine kinase-1 and pyruvate kinase-M2: a study based on in silico analysis

Cancer is a multifactorial disease that can cause morbidity and mortality in humans. An altered gene expression in cancer leads to a change in the overall activity of the human cell. Overexpression of cancer protein may give a piece of wide information about the specific type of tumor. Sphingosine kinase-1 (SK-1) is a metabolic enzyme that is mainly overexpressed in several types of cancer and other inflammatory diseases. Similarly, pyruvate kinase-M2 (PK-M2) is an important oncogenic ATP-producing glycolytic enzyme that is upregulated in most cancer cells. The phytocompound of medicinal plants such as Nigella sativa contains a variety of micronutrients that inhibit the proliferation and activity of tumor cells. In this study, the role of phytocompounds in combating cancer was studied against the model kinase proteins, that is, PK-M2 and SK-1. In silico tool like the PASS-Way2Drug server was used to predict the anticancer properties of phytocompounds. Moreover, the CLC-Pred web server provided the cytotoxicity prediction of chemical compounds against several human cancer cell lines. The pharmacokinetics and toxicity profiles were predicted by the SwissADME and pkCSM software. The binding energies were obtained by molecular docking to confirm the intermolecular interaction of selected phytocompounds with proteins. Consequently, molecular dynamics (MD) simulation confirmed the stability, conformational changes, and dynamic behavior of the kinase proteins complexed with the lead phytocompounds, that is, epicatechin, apigenin, and kaempferol.Communicated by Ramaswamy H. Sarma.

Thymoquinone mitigates obesity and diabetic parameters through regulation of major adipokines, key lipid metabolizing enzymes and AMPK/p-AMPK in diet-induced obese rats

The present study was designed to evaluate the anti-obesity and anti-hyperglycemic activity of Thymoquinone (ThyQ) isolated from Nigella sativa seeds. Male Wistar rats were randomly divided into five groups and fed either normal pellet diet or high-fat diet (HFD) for 18 weeks and water ad-libitum. Group I: normal pellet diet (NPD)-fed, Group II: high-fat diet (HFD)-fed, Group III: HFD-fed-ThyQ (20 mg)-treated, Group IV: HFD-fed-ThyQ (40 mg)-treated and Group V: HFD-fed-Orlistat (5 mg)-treated group. Intervention with ThyQ started from 12th week onwards to HFD-fed rats of group III and IV. ThyQ administration significantly (p < 0.01) mitigated body weight gain, blood glucose, insulin level, serum and liver lipids (except HDL) and improved glucose tolerance and insulin sensitivity as evaluated by oral glucose tolerance test (OGTT), homeostasis model assessment-insulin resistance (HOMA-IR) and insulin tolerance test (ITT). Furthermore, ThyQ significantly (p < 0.01) diminished serum aspartate transaminase (AST), alanine transaminase (ALT), acetyl-CoA carboxylase (ACC), plasma leptin, resistin and visfatin levels but enhanced lipoprotein lipase (LPL) and adiponectin levels. RT-PCR analysis demonstrated down-regulated mRNA expression of sterol regulatory element-binding proteins-1c (SREBP-1c), CCAAT/enhancer-binding protein-α (C/EBP-α) and fatty acid synthase (FAS) but upregulation of Insulin receptor substrate-1 (IRS-1).Western blot analysis displayed phosphorylation of adenosine monophosphate activated protein kinase (AMPK) in ThyQ-treated rats. Liver microtome sections of HFD-fed rats showed degenerated hepatocytes with high lipid stores while that of adipose tissue sections displayed large, fat-laden adipocytes, however, these histological changes were considerably attenuated in ThyQ-treated groups. Together these findings demonstrate that ThyQ can be a valuable therapeutic compound to potentially alleviate diet-induced obesity, hyperglycemia and insulin resistance.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-023-03847-x.

Thymoquinone: A comprehensive review of its potential role as a monotherapy for metabolic syndrome

Metabolic syndrome (MetS) is a widespread global epidemic that affects individuals across all age groups and presents a significant public health challenge. Comprising various cardio-metabolic risk factors, MetS contributes to morbidity and, when inadequately addressed, can lead to mortality. Current therapeutic approaches involve lifestyle changes and the prolonged use of pharmacological agents targeting the individual components of MetS, posing challenges related to cost, compliance with medications, and cumulative side effects. To overcome the challenges associated with these conventional treatments, herbal medicines and phytochemicals have been explored and proven to be holistic complements/alternatives in the management of MetS. Thymoquinone (TQ), a prominent bicyclic aromatic compound derived from Nigella sativa emerges as a promising candidate that has demonstrated beneficial effects in the treatment of the different components of MetS, with a good safety profile. For methodology, literature searches were conducted using PubMed and Google Scholar for relevant studies until December 2023. Using Boolean Operators, TQ and the individual components of MetS were queried against the databases. The retrieved articles were screened for eligibility. As a result, we provide a comprehensive overview of the anti-obesity, anti-dyslipidaemic, anti-hypertensive, and anti-diabetic effects of TQ including some underlying mechanisms of action such as modulating the expression of several metabolic target genes to promote metabolic health. The review advocates for a paradigm shift in MetS management, it contributes valuable insights into the multifaceted aspects of the application of TQ, fostering an understanding of its role in mitigating the global burden of MetS.

A Scoping Review of the Clinical Evidence for the Health Benefits of Culinary Doses of Herbs and Spices for the Prevention and Treatment of Metabolic Syndrome

Metabolic syndrome (MetS) is a growing global health problem. Evidence suggests that diets rich in phytochemical-containing herbs and spices can contribute to reducing the risk of chronic diseases. This review assesses the scope of evidence supporting the use of herbs and spices in the diet for the prevention or treatment of MetS and its associated health conditions. A search of the PubMed, Scopus and Google Scholar databases was carried out to assess the available clinical evidence for culinary doses of commonly used herbs and spices. Trials that were measuring health factors related to metabolic disorders in healthy individuals, or the health of individuals with MetS or associated diseases, were included. Out of a total of 1738 papers identified, there were 142 relevant studies on black pepper, chilli, cardamom, cinnamon, coriander, cumin, fennel, fenugreek, garlic, ginger, nigella seed, rosemary, sage and turmeric. No relevant research was found for cloves, mint, oregano, parsley or thyme. Cinnamon, fenugreek and ginger were the herbs/spices with the most published trials on them and that showed promise for glycaemic control. Cardamom appears to have potential to reduce inflammatory markers, and cinnamon, ginger and turmeric to reduce blood lipids. Patients with type 2 diabetes were the population most likely to be included in studies, but the preventative benefits of herbs/spices in healthy populations were also investigated, particularly for chilli, ginger and cinnamon. There is evidence for the beneficial effect of culinary doses of many common herbs/spices in the prevention and treatment of MetS and associated disorders.

Mechanism of the antidiabetic action of Nigella sativa and Thymoquinone: a review

Introduction

Long used in traditional medicine, Nigella sativa (NS; Ranunculaceae) has shown significant efficacy as an adjuvant therapy for diabetes mellitus (DM) management by improving glucose tolerance, decreasing hepatic gluconeogenesis, normalizing blood sugar and lipid imbalance, and stimulating insulin secretion from pancreatic cells. In this review, the pharmacological and pharmacokinetic properties of NS as a herbal diabetes medication are examined in depth, demonstrating how it counteracts oxidative stress and the onset and progression of DM.

Methods

This literature review drew on databases such as Google Scholar and PubMed and various gray literature sources using search terms like the etiology of diabetes, conventional versus herbal therapy, subclinical pharmacology, pharmacokinetics, physiology, behavior, and clinical outcomes.

Results

The efficiency and safety of NS in diabetes, notably its thymoquinone (TQ) rich volatile oil, have drawn great attention from researchers in recent years; the specific therapeutic dose has eluded determination so far. TQ has anti-diabetic, anti-inflammatory, antioxidant, and immunomodulatory properties but has not proved druggable. DM's intimate link with oxidative stress, makes NS therapy relevant since it is a potent antioxidant that energizes the cell's endogenous arsenal of antioxidant enzymes. NS attenuates insulin resistance, enhances insulin signaling, suppresses cyclooxygenase-2, upregulates insulin-like growth factor-1, and prevents endothelial dysfunction in DM.

Conclusion

The interaction of NS with mainstream drugs, gut microbiota, and probiotics opens new possibilities for innovative therapies. Despite its strong potential to treat DM, NS and TQ must be examined in more inclusive clinical studies targeting underrepresented patient populations.

Thymoquinone induces apoptosis and protective autophagy in gastric cancer cells by inhibiting the PI3K/Akt/mTOR pathway

Gastric cancer (GC) is often diagnosed in the advanced stages with a poor prognosis. Thymoquinone (TQ) is known for its antitumor activity; however, the specific mechanism in GC remains unknown. In our study, TQ inhibited GC cell proliferation and induced apoptosis and autophagy in a concentration-dependent manner. Transmission electron microscopy showed increased autophagosome formation in GC cells treated with TQ. Meanwhile, the LC3B puncta and LC3BII protein levels were significantly increased in GC cells, while p62 expression was significantly decreased. The autophagy inhibitor, Bafilomycin A1 enhanced TQ-inhibited proliferation and TQ-induced apoptosis, suggesting that TQ-induced autophagy has a protective effect on GC cells. Furthermore, TQ decreased the phosphorylation levels of phosphatidylinositol-4,5-bisphosphate 3 kinase (PI3K), protein kinase B (Akt), and mechanistic target of rapamycin (mTOR). The PI3K agonist partially rescued TQ-induced autophagy and apoptosis. Finally, in vivo experiments showed that TQ could inhibit tumor growth and promote apoptosis and autophagy. This study provides new insights into the specific mechanism for the anti-GC effect of TQ. TQ inhibits the proliferation of GC cells and induces apoptosis and protective autophagy by inhibiting the PI3K/Akt/mTOR pathway. The results suggest that the combination of TQ and autophagy inhibitors might be a potential chemotherapeutic strategy for GC.

Autophagy Induction by Scutellaria Flavones in Cancer: Recent Advances

In parallel with a steady rise in cancer incidence worldwide, the scientific community is increasingly focused on finding novel, safer and more efficient modalities for managing this disease. Over the past decades, natural products have been described as a significant source of new structural leads for novel drug candidates. Scutellaria root is one of the most studied natural products because of its anticancer potential. Besides just describing the cytotoxic properties of plant constituents, their molecular mechanisms of action in different cancer types are equally important. Therefore, this review article focuses on the role of the Scutellaria flavones wogonin, baicalein, baicalin, scutellarein and scutellarin in regulating the autophagic machinery in diverse cancer models, highlighting these molecules as potential lead compounds for the fight against malignant neoplasms. The knowledge that autophagy can function as a dual-edged sword, acting in both a pro- and antitumorigenic manner, further complicates the issue, revealing an amazing property of flavonoids that behave either as anti- or proautophagic agents.

Biological Properties, Phenolic Profile, and Botanical Aspect of Nigella sativa L. and Nigella damascena L. Seeds: A Comparative Study

The use of Nigella seeds in the food, pharmaceutical, and cosmetic fields is common, since the iniquity and the virtues of these plants are directly related to their characteristic phytochemical composition. This investigation focused on the comparative study of the botanical aspect, phenolic profile, and in vitro and in vivo biological activities of Nigella sativa L. (NS) and Nigella damascena L. (ND) seeds. The macro- and micro-morphological properties of these seeds were studied, and the key dissimilarities between them were clearly illustrated. The phytochemical contents and phenolic profiles were determined, and the in vitro antioxidant activity was assessed using four methods. The in vivo antioxidant and biochemical parameters of the blood of supplemented mice were determined. The results of the macro- and micro-structure analysis revealed differences between the two plants. Here, ND is characterized by higher phytochemical contents and the best antioxidant activities. The HPLC analysis indicated the presence of nine compounds, namely seven phenolic acids, particularly hydroxybenzoic and caffeic acids, and two flavonoids. The administration of ND extract to mice for 21 days at a concentration of 500 mg/kg allowed a substantial amelioration of plasma antioxidant properties. In addition, the extracts ameliorate blood parameters (cholesterol, triglycerides, glycemia, and urea). Furthermore, the antimicrobial activity of extracts demonstrated their effects on Staphylococcus and Aspergillus. Nigella seeds, in particular ND, expressed considerable in vitro antioxidant properties and demonstrated significant amelioration of mice blood properties. Consequently, these species can serve as a valuable source of compounds with various applications.

Phytochemical Profiles and Biological Studies of Selected Botanical Dietary Supplements Used in the United States

Based on their current wide bioavailability, botanical dietary supplements have become an important component of the United States healthcare system, although most of these products have limited scientific evidence for their use. The most recent American Botanical Council Market Report estimated for 2020 a 17.3% increase in sales of these products when compared to 2019, for a total sales volume of $11,261 billion. The use of botanical dietary supplements products in the United States is guided by the Dietary Supplement Health and Education Act (DSHEA) from 1994, enacted by the U.S. Congress with the aim of providing more information to consumers and to facilitate access to a larger number of botanical dietary supplements available on the market than previously. Botanical dietary supplements may be formulated for and use only using crude plant samples (e.g., plant parts such as the bark, leaves, or roots) that can be processed by grinding into a dried powder. Plant parts can also be extracted with hot water to form an "herbal tea." Other preparations of botanical dietary supplements include capsules, essential oils, gummies, powders, tablets, and tinctures. Overall, botanical dietary supplements contain bioactive secondary metabolites with diverse chemotypes that typically are found at low concentration levels. These bioactive constituents usually occur in combination with inactive molecules that may induce synergy and potentiation of the effects observed when botanical dietary supplements are taken in their different forms. Most of the botanical dietary supplements available on the U.S. market have been used previously as herbal remedies or as part of traditional medicine systems from around the world. Their prior use in these systems also provides a certain level of assurance in regard to lower toxicity levels. This chapter will focus on the importance and diversity of the chemical features of bioactive secondary metabolites found in botanical dietary supplements that are responsible for their applications. Many of the active principles of botanical dietary substances are phenolics and isoprenoids, but glycosides and some alkaloids are also present. Biological studies on the active constituents of selected botanical dietary supplements will be discussed. Thus, the present chapter should be of interest for both members of the natural products scientific community, who may be performing development studies of the products available, as well as for healthcare professionals who are directly involved in the analysis of botanical interactions and evaluation of the suitability of botanical dietary supplements for human consumption.

Potential health benefits of Nigella sativa on diabetes mellitus and its complications: A review from laboratory studies to clinical trials

This review aims to gather and summarize up-to-date information on the potential health benefits of Nigella sativa (NS) on diabetes mellitus (DM) and its complications from different animal models, clinical trials and in vitro studies. DM is one of the most prevalent metabolic disorders resulting from chronic hyperglycaemia due to problems in insulin secretion, insulin action or both. It affects people regardless of age, gender and race. The main consequence of DM development is the metabolic dysregulation of glucose homeostasis. Current treatments for DM include pharmacological therapy, insulin and diabetic therapy targeting β cells. Some of these therapeutic approaches are promising; however, their safety and effectiveness remain elusive. Since ancient times, medicinal plants have been used and proven effective against diseases. These plants are believed to be effective and benefit physiological and pathological processes, as they can be used to prevent, reduce or treat multiple diseases. Nigella sativa Linn. is an annual indigenous herbaceous plant belonging to Ranunculaceae, the buttercup family. NS exhibits multifactorial activities; it could ameliorate oxidative, inflammatory, apoptotic and insulinotropic effects and inhibit carbohydrate digestive enzymes. Thus, this review demonstrates the therapeutic potential of NS that could be used as a complement or adjuvant for the management of DM and its complications. However, future research should be able to replicate and fill in the gaps of the study conducted to introduce NS safely to patients with DM.

Effect of hydroalcoholic seed extract of Nigella sativa on hepatic and pancreatic factors of Nrf2 and FGF21 in the regulation of insulin transcription factors of MafA and PDX-1 in streptozotocin-treated diabetic rats

Introduction

Nigella sativa (N. sativa), one of the most commonly used medicinal herbs with antioxidant properties, increases blood insulin levels and lowers fasting blood sugar. Nuclear Erythroid Factor-Related Factor 2 (Nrf2) and Fibroblast Growth Factor 21 (FGF21) are two antioxidant factors that are increased by oxidative stress and hyperglycemia. The present study investigated how hydroalcoholic extract of N. sativa seed (HENS) increases blood insulin levels, taking into account changes in antioxidant factors and expression of insulin transcription factors.

Materials and methods

Two groups of male diabetic wistar rats were treated orally with HESN at doses of 200 and 400 mg/kg-body weight for one month. Fasting blood sugar (FBS) and insulin were measured using standard kits by photometric and ELISA methods, respectively. The expression levels of the Nrf2, FGF21 and β-Klotho genes as well as the insulin gene-stimulating transcription factors of MafA and PDX-1 were evaluated using real-time PCR. Oxidative stress was assessed by assessing serum total oxidation status (TOS), malondialdehyde (MDA), and total antioxidant capacity (TAC).

Results

HSEN showed a significant reducing effect on FBS and oxidative biomarkers and an increasing effect on serum insulin levels in treated diabetic rats compared to untreated diabetics (P < 0.05). The elevated levels of NRF2 and FGF21 in the liver and pancreas of the diabetic control group were significantly reduced after treatment with both HESN doses (P < 0.05). Following the ameliorative effects of HENS on pancreatic tissue and the reduction of oxidative stress, the expression level of MafA and PDX1 genes approached the level of these factors in healthy rats (P < 0.05).

Conclusion

This study showed the therapeutic effects of HENS on diabetic pancreas by reducing oxidative stress and tissue damage, modifying the expression levels of PDX-1 and MafA genes, and regulating insulin secretion and blood glucose levels.    

Natural Antioxidant Compounds as Potential Pharmaceutical Tools against Neurodegenerative Diseases

Natural antioxidants are a very large diversified family of molecules classified by activity (enzymatic or nonenzymatic), chemical-physical properties (e.g., hydrophilic or lipophilic), and chemical structure (e.g., vitamins, polyphenols, etc.). Research on natural antioxidants in various fields, such as pharmaceutics, nutraceutics, and cosmetics, is among the biggest challenges for industry and science. From a biomedical point of view, the scavenging activity of reactive oxygen species (ROS) makes them a potential tool for the treatment of neurodegenerative diseases including Alzheimer's disease, Parkinson's disease, Huntington's disease, dementia, and amyotrophic lateral sclerosis (ALS). In addition to the purified phytochemical compounds, a variety of natural extracts characterized by a complex mixture of antioxidants and anti-inflammatory molecules have been successfully exploited to rescue preclinical models of these diseases. Extracts derived from Ginkgo biloba, grape, oregano, curcumin, tea, and ginseng show multitherapeutic effects by synergically acting on different biochemical pathways. Furthermore, the reduced toxicity associated with many of these compounds limits the occurrence of side effects. The support of nanotechnology for improving brain delivery, controlling release, and preventing rapid degradation and excretion of these compounds is of fundamental importance. This review reports on the most promising results obtained on in vitro systems, in vivo models, and in clinical trials, by exploiting natural-derived antioxidant compounds and extracts, in their free form or encapsulated in nanocarriers.

Pharmacologically Active Phytomolecules Isolated from Traditional Antidiabetic Plants and Their Therapeutic Role for the Management of Diabetes Mellitus

Diabetes mellitus is a chronic complication that affects people of all ages. The increased prevalence of diabetes worldwide has led to the development of several synthetic drugs to tackle this health problem. Such drugs, although effective as antihyperglycemic agents, are accompanied by various side effects, costly, and inaccessible to the majority of people living in underdeveloped countries. Medicinal plants have been used traditionally throughout the ages to treat various ailments due to their availability and safe nature. Medicinal plants are a rich source of phytochemicals that possess several health benefits. As diabetes continues to become prevalent, health care practitioners are considering plant-based medicines as a potential source of antidiabetic drugs due to their high potency and fewer side effects. To better understand the mechanism of action of medicinal plants, their active phytoconstituents are being isolated and investigated thoroughly. In this review article, we have focused on pharmacologically active phytomolecules isolated from medicinal plants presenting antidiabetic activity and the role they play in the treatment and management of diabetes. These natural compounds may represent as good candidates for a novel therapeutic approach and/or effective and alternative therapies for diabetes.

The ethnobotany, phytochemistry, and biological properties of Nigella damascena - A review

This review is a systematic scientific work on medicinal and traditional use, on the chemical composition of specialized metabolites, volatile and non-volatile, on aspects related to toxicology and phytotherapy of Nigella damascena L. The genus Nigella (Ranunculaceae) is distributed throughout the Mediterranean basin, extending to northern India, and has been divided into three sections. Nigella damanscena L. is traditionally used as an ingredient in food, for example, as flavouring agents in bread and cheese, but is also known in folk medicine, used to regulate menstruation; for catarrhal affections and amenorrhea; as a diuretic and sternutatory; as an analgesic, anti-oedematous, and antipyretic; and for vermifuge and its disinfectant effects. This paper reviews the most dated to the latest scientific research on this species, highlighting the single isolated metabolites and exploring their biological activity. Fifty-seven natural compounds have been isolated and characterised from the seeds, roots, and aerial parts of the plant. Among these constituents, alkaloids, flavonoids, diterpenes, triterpenes, and aromatic compounds are the main constituents. The isolated compounds and the various extracts obtained with solvents of different polarities presented a diverse spectrum of biological activities such as antibacterial, antifungal, antitumour, antioxidant, anti-inflammatory, antipyretic, anti-oedema, and antiviral activities. Various in vitro and in vivo tests have demonstrated the pharmacological potential of β-elemene and alkaloid damascenin. Unfortunately, the largest number of biological studies on this species and its metabolites have been conducted in vitro; therefore, further investigation is necessary to evaluate the toxicological aspects and real mechanisms of action of crude extracts to confirm the therapeutic potential of N. damascena.

Nigella sativa L. and COVID-19: A Glance at The Anti-COVID-19 Chemical Constituents, Clinical Trials, Inventions, and Patent Literature

COVID-19 has had an impact on human quality of life and economics. Scientists have been identifying remedies for its prevention and treatment from all possible sources, including plants. Nigella sativa L. (NS) is an important medicinal plant of Islamic value. This review highlights the anti-COVID-19 potential, clinical trials, inventions, and patent literature related to NS and its major chemical constituents, like thymoquinone. The literature was collected from different databases, including Pubmed, Espacenet, and Patentscope. The literature supports the efficacy of NS, NS oil (NSO), and its chemical constituents against COVID-19. The clinical data imply that NS and NSO can prevent and treat COVID-19 patients with a faster recovery rate. Several inventions comprising NS and NSO have been claimed in patent applications to prevent/treat COVID-19. The patent literature cites NS as an immunomodulator, antioxidant, anti-inflammatory, a source of anti-SARS-CoV-2 compounds, and a plant having protective effects on the lungs. The available facts indicate that NS, NSO, and its various compositions have all the attributes to be used as a promising remedy to prevent, manage, and treat COVID-19 among high-risk people as well as for the therapy of COVID-19 patients of all age groups as a monotherapy or a combination therapy. Many compositions of NS in combination with countless medicinal herbs and medicines are still unexplored. Accordingly, the authors foresee a bright scope in developing NS-based anti-COVID-19 composition for clinical use in the future.

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.

Analgesic and antiinflammatory effects of Nigella orientalis L. seeds fixed oil: Pharmacological potentials and molecular mechanisms

Nigella species have been widely used in traditional medicine. The aim of this study was to evaluate the antiinflammatory and analgesic potentials of Nigella orientalis L. seeds fixed oil (NOO). The acetic acid writhing test and the formaldehyde-induced licking paw were performed to assess the analgesic activity of the oil. The antiinflammatory activity was first evaluated in vitro by the erythrocyte membrane stabilization then in vivo by xylene- and carrageenan-induced ear and paw edema, respectively. To further understand the molecular mechanism of action of the Nigella extract, lipopolysaccharide-activated RAW 264.7 macrophages were used. Nitric oxide (NO) production was measured by Griess reaction and cell viability by MTT assay. The gene and protein expression of inflammatory mediators were assessed by RT-PCR and western blot, respectively. NOO exerted a potent analgesic effect in in vivo models of writhing test and induced edema. The analyzed molecular mechanisms revealed a role for NO and prostaglandins as molecules mediating the pharmacological effects of the extract through a mechanism involving nuclear factor-κB and mitogen-activated protein kinases. This study demonstrates, for the first time, that the fixed oil of N. orientalis has strong antinociceptive and antiinflammatory properties and might be a promising agent for the treatment of certain inflammation-related diseases.

Anti-Inflammatory Effects of Thymoquinone in Atherosclerosis: A Mini Review

Atherosclerosis poses serious health problems and increases the risk of various cardiovascular diseases, including myocardial infarction, heart failure, ischemic stroke, and peripheral arterial disease. Atherosclerosis patients require long-term medications to prevent complications, some of which are costly and may result in unwanted adverse reactions. Natural products have emerged as potential sources of bioactive compounds that provide health benefits in cardiovascular diseases. Increased inflammation and vascular remodeling have been associated with atherosclerosis pathogenesis. The molecules involved in signaling pathways are considered valuable targets for new treatment approaches. Therefore, this review aimed to summarize the available evidence of the anti-inflammatory effects of thymoquinone, the major active compound isolated from Nigella sativa L., via inflammatory signaling pathways in atherosclerosis. Specifically, nuclear factor-κB and mitogen-activated protein kinase signaling pathways were considered. Furthermore, the potential toxic effects elicited by thymoquinone were addressed. These findings suggest a potential role of thymoquinone in managing atherosclerosis, and further studies are required to ascertain its effectiveness and safety profile.

The role of thymoquinone, a major constituent of Nigella sativa, in the treatment of inflammatory and infectious diseases

Nigella sativa (N. sativa) is an annual flowering plant that has been used as a traditional remedy for many centuries. The seed possesses a large variety of compounds with thymoquinone (TQ) considered its major but not sole bioactive constituent. Supercritical fluid extraction, geographical location, and oxidative status of N. sativa produces the highest yield of essential oil content including TQ. Thymoquinone is lipophilic, heat and light sensitive with low oral bioavailability and rapid elimination that have significantly inhibited its pharmacological development. Novel developments in nanoparticulate-based oral administration, nasal spray and transdermal delivery may allow the clinical development of N. sativa and TQ as therapeutic agents. Animal and human studies indicate a potential role of N. sativa seed oil and TQ for a diverse range of disease processes including hypertension, dyslipidaemia, type 2 diabetes mellitus, arthritis, asthma, bacterial and viral infections, neurological and dermatological disorders, as it belongs to the group of pan-assay interference compounds. This review outlines the pharmacological properties of N. sativa and TQ and their potential wide application for a large variety of human diseases. The paper will focus on recent studies of the anti-inflammatory and antiviral properties that make N. sativa and TQ promising therapeutic agents targeting contemporary inflammatory and infectious diseases including Covid 19.