Sub-chronic oral toxicity screening of quercetin in mice

Therapeutics of bitter plants from Northeast region of India and their pharmacological and phytochemical perspectives

Natural resources have been used for food and medicine since the beginning of human civilization, and they have always been a low-cost, easily accessible source for individuals. Northeast region of India (NER) represents a significant portion of India's flora and fauna. Marginality, fragility, inaccessibility, ethnicity, and cultural diversity thrived in the region, resulting in the richest reservoir of genetic variation of bioresources. Several bitter plants are used by the locals as both food and medicine to treat a variety of diseases. These medicinal plants are an excellent source of chemically diverse biologically active phytometabolites. There have been few efforts to raise awareness about health benefits of bitter plant resources abound in this region that may provides opportunities for their sustainable utilization. Understanding the structural features of plant derived bitterants in relationship with specific bitter receptor will provide research prospects to identify biomolecules with health benefits. In this context the present review is intended to deliver phyto-pharmacological aspects of bitter plant resources of NER together with detailed understanding of possible association between plant derived phytometabolites as bitter agonists with extraoral bitter receptors.

Antidiabetic Effects of Quercetin and Silk Sericin in Attenuating Dysregulation of Hepatic Gluconeogenesis in Diabetic Rats Through Potential Modulation of PI3K/Akt/FOXO1 Signaling: In Vivo and In Silico Studies

Type 2 diabetes mellitus (T2DM) is an intricate disease correlated with many metabolic deregulations, including disordered glucose metabolism, oxidative stress, inflammation, and cellular apoptosis due to hepatic gluconeogenesis aberrations. However, there is no radical therapy to inhibit hepatic gluconeogenesis disturbances yet. We thus sought to probe the effectiveness and uncover the potential mechanism of quercetin (QCT) and silk sericin (SS) in mitigating hyperglycemia-induced hepatic gluconeogenesis disorder, which remains obscure. Administration of QCT and SS to diabetic male albino rats markedly restored the levels of glucose, insulin, advanced glycation end-products (AGEs), liver function enzymes, alpha-fetoprotein (AFP), globulin, and glycogen, in addition to hepatic carbohydrate metabolizing enzymes and gluconeogenesis in comparison with diabetic rats. Furthermore, treatment with QCT and SS modulated hepatic malondialdehyde (MD), reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), nitric oxide, tumor necrosis factor-alpha (TNF-α), and interleukin-1β (IL-1β), in addition to serum interleukin-6 (IL-6) and cyclooxygenase-2 (COX-2), implying their effectiveness in safeguarding cells against oxidative impairment and inflammation. Remarkably, QCT and SS treatments led to the upregulation of expression of phosphatidylinositol 3-kinases (PI3K), phospho-Akt (p-Akt), and forkhead box-O1 (FOXO1) genes in hepatic tissues compared to diabetic rats, orchestrating these singling pathways for curtailing hyperglycemia and pernicious consequences in hepatic tissues. Importantly, immunohistochemical investigations exhibited downregulation of caspase-3 expression in rats treated with QCT and SS compared to diabetic animals. Beyond that, the histopathological results of hepatic tissues demonstrated notable correlations with biochemical findings. Interestingly, the in silico results supported the in vivo findings, showing notable binding affinities of QCT and SS to PI3K, GPx, and TNF-α proteins. These results imply that QCT and SS could mitigate oxidative stress and inflammation and regulate hepatic gluconeogenesis in diabetic rats. However, QCT revealed greater molecular interactions with the studied proteins than SS. Overall, our results emphasize that QCT and SS have significant therapeutic effects on attenuating hyperglycemia-induced hepatic gluconeogenesis, with QCT showing superior effectiveness.

Therapeutic Efficacy of Quercetin and Its Nanoformulation Both the Mono- or Combination Therapies in the Management of Cancer: An Update with Molecular Mechanisms

Quercetin, a major representative of the flavonol subclass found abundantly in almost all edible vegetables and fruits, showed remarkable therapeutic properties and was beneficial in numerous degenerative diseases by preventing lipid peroxidation. Quercetin is beneficial in different diseases, such as atherosclerosis and chronic inflammation. This study aims to find out the anticancer activities of quercetin and to determine different mechanisms and pathways which are responsible for the anticancer effect. It also revealed the biopharmaceutical, toxicological characteristics, and clinical utilization of quercetin to evaluate its suitability for further investigations as a reliable anticancer drug. All of the relevant data concerning this compound with cancer was collected using different scientific search engines, including PubMed, Springer Link, Wiley Online, Web of Science, SciFinder, ScienceDirect, and Google Scholar. This review demonstrated that quercetin showed strong anticancer properties, including apoptosis, inhibition of cell proliferation, autophagy, cell cycle arrest, inhibition of angiogenesis, and inhibition of invasion and migration against various types of cancer. Findings also revealed that quercetin could significantly moderate and regulate different pathways, including PI3K/AKT-mTORC1 pathway, JAK/STAT signaling system, MAPK signaling pathway, MMP signaling pathway, NF-κB pathway, and p-Camk2/p-DRP1 pathway. However, this study found that quercetin showed poor oral bioavailability due to reduced absorption; this limitation is overcome by applying nanotechnology (nanoformulation of quercetin). Moreover, different investigations revealed that quercetin expressed no toxic effect in the investigated subjects. Based on the view of these findings, it is demonstrated that quercetin might be considered a reliable chemotherapeutic drug candidate in the treatment of different cancers. However, more clinical studies are suggested to establish the proper therapeutic efficacy, safety, and human dose.

Usefulness of Natural Phenolic Compounds in the Fight against Esophageal Cancer: A Systematic Review

Esophageal cancer (EC) is a very common form of cancer in developing countries, and its exponential progression is a cause for concern. Available treatments face the phenomenon of multi-drug resistance, as well as multiple disabling side effects. The number of deaths is expected to double by 2030 if nothing is done. Due to their high representativeness in plants, phenolic compounds are a potential alternative for halting the spread of this disease, which bereaves many thousands of families every year. This study aims to identify phenolic compounds with activity against esophageal cancer, assess their toxicological profiles, and explore future perspectives. To achieve this, the literature search was meticulously carried out in the Google Scholar, Scopus, Web of Sciences, and Pub-Med/Medline databases, in accordance with the PRISMA 2020 guidelines. The results show that proanthocyanidin and curcumin represent promising therapeutic options, given their significant in vitro and in vivo activity, and their safety in human subjects in clinical trials. Moscatilin, Genistein, and pristimerin have anticancer activities (≤10 µM) very close to those of doxorubicin and 5-FU, although their safety has not yet been fully established. The compounds identified in vivo exhibit highly significant activities compared with the results obtained in vitro, and are sometimes more effective than the molecules conventionally used to treat EC. Generally, with the exceptions of plumbagin, lapachol, and β-lapachone, all other molecules are relatively non-toxic to normal human cells and represent a therapeutic avenue to be explored by pharmaceutical companies in the fight against esophageal cancer. However, more detailed toxicological studies of certain molecules remain a priority.

Plant-derived bioactive compounds and their novel role in central nervous system disorder treatment via ATF4 targeting: A systematic literature review

Central nervous system (CNS) disorders exhibit exceedingly intricate pathogenic mechanisms. Pragmatic and effective solutions remain elusive, significantly compromising human life and health. Activating transcription factor 4 (ATF4) participates in the regulation of multiple pathophysiological processes, including CNS disorders. Considering the widespread involvement of ATF4 in the pathological process of CNS disorders, the targeted regulation of ATF4 by plant-derived bioactive compounds (PDBCs) may become a viable strategy for the treatment of CNS disorders. However, the regulatory relationship between PDBCs and ATF4 remains incompletely understood. Here, we aimed to comprehensively review the studies on PDBCs targeting ATF4 to ameliorate CNS disorders, thereby offering novel directions and insights for the treatment of CNS disorders. A computerized search was conducted on PubMed, Embase, Web of Science, and Google Scholar databases to identify preclinical experiments related to PDBCs targeting ATF4 for the treatment of CNS disorders. The search timeframe was from the inception of the databases to December 2023. Two assessors conducted searches using the keywords "ATF4," "Central Nervous System," "Neurological," "Alzheimer's disease," "Parkinson's Disease," "Stroke," "Spinal Cord Injury," "Glioblastoma," "Traumatic Brain Injury," and "Spinal Cord Injury." Overall, 31 studies were included, encompassing assessments of 27 PDBCs. Combining results from in vivo and in vitro studies, we observed that these PDBCs, via ATF4 modulation, prevent the deposition of amyloid-like fibers such as Aβ, tau, and α-synuclein. They regulate ERS, reduce the release of inflammatory factors, restore mitochondrial membrane integrity to prevent oxidative stress, regulate synaptic plasticity, modulate autophagy, and engage anti-apoptotic mechanisms. Consequently, they exert neuroprotective effects in CNS disorders. Numerous PDBCs targeting ATF4 have shown potential in facilitating the restoration of CNS functionality, thereby presenting expansive prospects for the treatment of such disorders. However, future endeavors necessitate high-quality, large-scale, and comprehensive preclinical and clinical studies to further validate this therapeutic potential.

The therapeutic potential of typical plant-derived compounds for the management of metabolic disorders

Obesity and Type 2 diabetes are prevalent metabolic dysfunctions that present significant health challenges worldwide. Available cures for these ailments have constraints with accompanying unwanted effects that persistently exist. Compounds originated from plants have recently been introduced as hopeful remedies to treat metabolic disorders because of their diverse pharmacological activities. This detailed observation gives an introduction into the treatment capacity of plant-derived compounds regarding metabolic syndromes while analyzing various groups alongside their performance in this field despite unique mechanisms designed by nature itself. Interestingly, this study provides some examples including curcumin, resveratrol, quercetin, berberine, epigallocatechin gallate (EGCG), and capsaicin, which highlights potential therapeutic impacts for future testing. However, current clinical trials inspecting human studies investigating efficacies concerning metabolism challenge present limitations. Finally, the review weighs up bad reactions possibly inflicted after administering plant-originated materials though suggestive insights will be provided later. Above all, it outlines the chance to identify novel therapies encapsulated within natural substances based upon recent developments could hold significant promise toward managing misplaced metabolisms globally.

Plant-derived flavonoids are a potential source of drugs for the treatment of liver fibrosis

Liver fibrosis is a dynamic pathological process that can be triggered by any chronic liver injury. If left unaddressed, it will inevitably progress to the severe outcomes of liver cirrhosis or even hepatocellular carcinoma. In the past few years, the prevalence and fatality of hepatic fibrosis have been steadily rising on a global scale. As a result of its intricate pathogenesis, the quest for pharmacological interventions targeting liver fibrosis has remained a formidable challenge. Currently, no pharmaceuticals are exhibiting substantial clinical efficacy in the management of hepatic fibrosis. Hence, it is of utmost importance to expedite the development of novel therapeutics for the treatment of this condition. Various research studies have revealed the ability of different natural flavonoid compounds to alleviate or reverse hepatic fibrosis through a range of mechanisms, which are related to the regulation of liver inflammation, oxidative stress, synthesis and secretion of fibrosis-related factors, hepatic stellate cells activation, and proliferation, and extracellular matrix synthesis and degradation by these compounds. This review summarizes the progress of research on different sources of natural flavonoids with inhibitory effects on liver fibrosis over the last decades. The anti-fibrotic effects of natural flavonoids have been increasingly studied, making them a potential source of drugs for the treatment of liver fibrosis due to their good efficacy and biosafety.

Therapeutic detoxification of quercetin for aflatoxin B1-related toxicity: Roles of oxidative stress, inflammation, and metabolic enzymes

Aflatoxins (AFTs), a type of mycotoxin mainly produced by Aspergillus parasiticus and Aspergillus flavus, could be detected in food, feed, Chinese herbal medicine, grain crops and poses a great threat to public health security. Among them, aflatoxin B1 (AFB1) is the most toxic one. Exposure to AFB1 poses various health risks to both humans and animals, including the development of chronic inflammatory diseases, cardiovascular diseases, neurodegenerative diseases, and cancer. The molecular mechanisms underlying these risks are intricate and dependent on specific contexts. This review primarily focuses on summarizing the protective effects of quercetin, a natural phenolic compound, in mitigating the toxic effects induced by AFB1 in both in vitro experiments and animal models. Additionally, the review explores the molecular mechanisms that underlie these protective effects. Quercetin has been demonstrated to not only have the direct inhibitory action on the production of AFTs from Aspergillus, both also possess potent ameliorative effects against AFB1-induced cytotoxicity, hepatotoxicity, and neurotoxicity. These effects are attributed to the inhibition of oxidative stress, mitochondrial dysfunction, mitochondrial apoptotic pathway, and inflammatory response. It could also directly target several metabolic enzymes (i.e., CYP3As and GSTA1) to reduce the production of toxic metabolites of AFB1 within cells, then reduce AFB1-induced cytotoxicity. In conclusion, this review highlights quercetin is a promising detoxification agent for AFB1. By advancing our understanding of the protective mechanisms offered by quercetin, we aim to contribute to the development of effective detoxification agents against AFB1, ultimately promoting better health outcomes.

Toxicity studies of condensed fuzheng extract in mice and rats

Nutritional supplements have been used to improve immune function. Condensed fuzheng extract (CFE) is a well-known traditional Chinese medicine (TCM) formula that is predominantly made from sheep placenta, Astragalus mongholicus Bunge, and Polygonatum kingianum Collett & Hemsl. However, the toxicological profile of CFE has not been determined. In this study, we investigated the acute (14 days) and sub-chronic (90 days) oral toxicities of CFE in mice and rats and the phytochemical composition of CFE.

Materials and methods

For the assessment of acute toxicity, 80 ICR mice of both sexes were randomly divided into four groups. Three groups were treated with 4500, 2250 and 1125 mg/kg/d bw CFE daily (n = 10/group per sex) for 14 days; a separate group was used as control. To test the sub-chronic toxicity, male and female Sprague Dawley rats were orally administered 8150, 4075 or 2037 mg/kg bw of CFE for 90 days; a control group was included. Hematological, biochemical, and histopathological markers were tested at the end of the experiment. The chemical composition of CFE was determined by UPLC-HRMS method.

Results

In both acute and sub-chronic toxicity studies, no mortalities, indications of abnormality, or treatment-related adverse effects were observed. The LD50 of CFE was higher than 4500 mg/kg. There were no significant changes in the hematological and biochemical data in the treatment group compared with the control group (p > 0.05). Histopathological analyses of the heart, liver, spleen, lungs, kidneys, thymus, testes (male rats) and ovaries (female rats) revealed no anatomical changes of each organ. Phytochemical analysis of CFE revealed the presence of flavonoids (highest abundance), phenols and alkaloids. In conclusion, our results showed that CFE is a safe and non-toxic formula. We also reported phytochemicals in CFE that may possess important pharmacological effects.

Quercetin is a foe in the heart by targeting the hERG potassium channel

Objectives

Quercetin is a plant flavonoid known for its pharmacological activities, such as antioxidant, anti-inflammatory, and anti-cancer properties. However, there is limited information available regarding its potential toxicities. A previous study showed that quercetin can inhibit human ether-a-go-related gene (hERG, also named KCNH2) currents, which may lead to long QT syndrome, torsade de pointes (TdP), and even sudden cardiac death. This study aimed to investigate the effects of quercetin on hERG and its potential mechanism.

Materials and Methods

hERG currents and action potential duration (APD) were assessed using the patch clamp technique. Molecular docking was employed to elucidate the binding sites between quercetin and hERG. Transfection of wild-type or mutant plasmids was used to verify the results of molecular docking. Western blot was performed to determine the expression levels of hERG, transcription factor SP1, molecular chaperones HSP70 and HSP90, phosphorylated E3 ubiquitin ligase p-Nedd4-2, serum- and glucocorticoid-inducible kinase (SGK1), and phosphatidylinositol 3-kinase (PI3K). Immunoprecipitation was conducted to evaluate hERG ubiquitination.

Results

Quercetin acutely blocked hERG current by binding to F656 amino acid residue, subsequently accelerating channel inactivation. Long-term incubation of quercetin accelerates Nedd4-2-mediated ubiquitination degradation of hERG channels by inhibiting the PI3K/SGK1 signaling pathway. Moreover, the APD of human induced pluripotent stem cell-derived cardiomyocytes (hiPS-CMs) is significantly prolonged by 30 μM quercetin.

Conclusion

Quercetin has a potential risk of proarrhythmia, which provided useful information for the usage and development of quercetin as a medication.

Therapeutic considerations of bioactive compounds in Alzheimer's disease and Parkinson's disease: Dissecting the molecular pathways

Leading neurodegenerative diseases Alzheimer's disease (AD) and Parkinson's disease (PD) are characterized by the impairment of memory and motor functions, respectively. Despite several breakthroughs, there exists a lack of disease-modifying treatment strategies for these diseases, as the available drugs provide symptomatic relief and bring along side effects. Bioactive compounds are reported to bear neuroprotective properties with minimal toxicity, however, a detailed elucidation of their modes of neuroprotection is lacking. The review elucidates the neuroprotective mechanism(s) of some of the major phyto-compounds in pre-clinical and clinical studies of AD and PD to understand their potential in combating these diseases. Curcumin, eugenol, resveratrol, baicalein, sesamol and so on have proved efficient in countering the pathological hallmarks of AD and PD. Curcumin, resveratrol, caffeine and so on have reached the clinical phases of these diseases, while aromadendrin, delphinidin, cyanidin and xanthohumol are yet to be extensively explored in pre-clinical phases. The review highlights the need for extensive investigation of these compounds in the clinical stages of these diseases so as to utilize their disease-modifying abilities in the real field of treatment. Moreover, poor pharmacokinetic properties of natural compounds are constraints to their therapeutic yields and this review suggests a plausible contribution of nanotechnology in overcoming these limitations.

Performance and antioxidant traits of broiler chickens fed with diets containing rapeseed or flaxseed oil and optimized quercetin

This study evaluated the effect of quercetin (Q) added to feed mixtures, at concentrations directly optimized for the peroxidability of dietary rapeseed (RO) and flaxseed oil (FLO), on performance and selected biomarkers of oxidative stress of broiler chickens. Ninety-six one-day-old Ross 308 broiler chicken males were randomly assigned to four groups (six replicates per treatment, four birds per cage, n = 24 per group): Group RO received diets containing rapeseed oil (RO) and group FLO received diets containing flaxseed oil (FLO); Group RO_Q and group FLO_Q received these same diets containing RO or FLO oils, supplemented with optimized quercetin (Q). Blood, pectoral muscles, and liver samples of chickens were collected after 35 days to determine: (1) the global indicators of antioxidant capacity: ferric reducing antioxidant power (FRAP), antiradical activity (DPPH·/ABTS·+), total antioxidant status (TAS), and glutathione peroxidase (GSH-Px); (2) the activity of the antioxidant enzymes catalase (CAT) and superoxide dismutase (SOD); and (3) the concentration of malondialdehyde (MDA). Data showed that the FLO diet did not affect the final performance parameters in relation to RO, but the optimized Q tended to improve the total body weight gain and the final body weight of broiler chickens (P = 0.10). The antioxidant traces analyzed in the blood (GSH-Px), plasma (FRAP, ABTS·+, DPPH·, TAS), serum (DPPH·), and pectoral muscles (SOD, CAT) of chickens were not altered by either Oil or Q factor. FLO supplementation increased MDA content in the liver of chickens (P < 0.05) and increased liver CAT activity, which was not improved by optimized Q. Meanwhile, the Oil × Q interaction suggests that optimized Q could reduce the liver burden and negative effects of oxidized lipid by-products associated with FLO diets. Our results indicate that optimizing the addition of natural polyphenols to feed may be a valuable alternative to the application of polyphenolic antioxidants in animal nutrition, allowing for an economical use of the antioxidant additives when customized to the peroxidability of fat sources, which is line to the conception of sustainable development covering 'The European Green Deal' and 'Farm to Fork Strategy'.

Secondary Metabolites Isolated from Artemisia afra and Artemisia annua and Their Anti-Malarial, Anti-Inflammatory and Immunomodulating Properties-Pharmacokinetics and Pharmacodynamics: A Review

There are over 500 species of the genus Artemisia in the Asteraceae family distributed over the globe, with varying potentials to treat different ailments. Following the isolation of artemisinin (a potent anti-malarial compound with a sesquiterpene backbone) from Artemisia annua, the phytochemical composition of this species has been of interest over recent decades. Additionally, the number of phytochemical investigations of other species, including those of Artemisia afra in a search for new molecules with pharmacological potentials, has increased in recent years. This has led to the isolation of several compounds from both species, including a majority of monoterpenes, sesquiterpenes, and polyphenols with varying pharmacological activities. This review aims to discuss the most important compounds present in both plant species with anti-malarial properties, anti-inflammatory potentials, and immunomodulating properties, with an emphasis on their pharmacokinetics and pharmacodynamics properties. Additionally, the toxicity of both plants and their anti-malaria properties, including those of other species in the genus Artemisia, is discussed. As such, data were collected via a thorough literature search in web databases, such as ResearchGate, ScienceDirect, Google scholar, PubMed, Phytochemical and Ethnobotanical databases, up to 2022. A distinction was made between compounds involved in a direct anti-plasmodial activity and those expressing anti-inflammatory and immunomodulating activities or anti-fever properties. For pharmacokinetics activities, a distinction was made between compounds influencing bioavailability (CYP effect or P-Glycoprotein effect) and those affecting the stability of pharmacodynamic active components.

Long Non-Coding RNA Malat1 Increases the Rescuing Effect of Quercetin on TNFα-Impaired Bone Marrow Stem Cell Osteogenesis and Ovariectomy-Induced Osteoporosis

Osteoporosis, a common systematic bone homeostasis disorder related disease, still urgently needs innovative treatment methods. Several natural small molecules were found to be effective therapeutics in osteoporosis. In the present study, quercetin was screened out from a library of natural small molecular compounds by a dual luciferase reporter system. Quercetin was found to upregulate Wnt/β-catenin while inhibiting NF-κB signaling activities, and thereby rescuing osteoporosis-induced tumor necrosis factor alpha (TNFα) impaired BMSCs osteogenesis. Furthermore, a putative functional lncRNA, Malat1, was shown to be a key mediator in quercetin regulated signaling activities and TNFα-impaired BMSCs osteogenesis, as mentioned above. In an ovariectomy (OVX)-induced osteoporosis mouse model, quercetin administration could significantly rescue OVX-induced bone loss and structure deterioration. Serum levels of Malat1 were also obviously rescued in the OVX model after quercetin treatment. In conclusion, our study demonstrated that quercetin could rescue TNFα-impaired BMSCs osteogenesis in vitro and osteoporosis-induced bone loss in vivo, in a Malat1-dependent manner, suggesting that quercetin may serve as a therapeutic candidate for osteoporosis treatment.

Quercetin Improved Muscle Mass and Mitochondrial Content in a Murine Model of Cancer and Chemotherapy-Induced Cachexia

A cachexia diagnosis is associated with a doubling in hospital stay and increased healthcare cost for cancer patients and most cachectic patients do not survive treatment. Unfortunately, complexity in treating cachexia is amplified by both the underlying malignancy and the anti-cancer therapy which can independently promote cachexia. Quercetin, an organic polyphenolic flavonoid, has demonstrated anti-inflammatory and antioxidant properties with promise in protecting against cancer and chemotherapy-induced dysfunction; however, whether quercetin is efficacious in maintaining muscle mass in tumor-bearing animals receiving chemotherapy has not been investigated. C26 tumor-bearing mice were given 5-fluorouracil (5FU; 30 mg/kg of lean mass i.p.) concomitant with quercetin (Quer; 50 mg/kg of body weight via oral gavage) or vehicle. Both C26 + 5FU and C26 + 5FU + Quer had similar body weight loss; however, muscle mass and cross-sectional area was greater in C26 + 5FU + Quer compared to C26 + 5FU. Additionally, C26 + 5FU + Quer had a greater number and larger intermyofibrillar mitochondria with increased relative protein expression of mitochondrial complexes V, III, and II as well as cytochrome c expression. C26 + 5FU + Quer also had increased MFN1 and reduced FIS1 relative protein expression without apparent benefits to muscle inflammatory signaling. Our data suggest that quercetin protected against cancer and chemotherapy-induced muscle mass loss through improving mitochondrial homeostatic balance.