Identifying chondroprotective diet-derived bioactives and investigating their synergism

Isoliquiritigenin, a potential therapeutic agent for treatment of inflammation-associated diseases

ETHNOPHARMACOLOGICAL RELEVANCE

Licorice is a medicinal herb with a 2000-year history of applications in traditional Chinese medicine. Isoliquiritigenin (ISL) is a bioactive chalcone compound isolated from licorice. It has attracted increasing attention in recent years due to its excellent anti-inflammatory activity.

AIM OF THE STUDY

This study is to provide a comprehensive summary of the anti-inflammatory activity of ISL and the underlying molecular mechanisms, and discuss new insights for its potential clinical applications as an anti-inflammation agent.

MATERIALS AND METHODS

We examined literatures published in the past twenty years from PubMed, Research Gate, Web of Science, Google Scholar, and SciFinder, with single or combined key words of "isoliquiritigenin", "inflammation", and "anti-inflammatory".

RESULTS

ISL elicits its anti-inflammatory activity by mediating various cellular processes. It inhibits the upstream of the nuclear factor kappa B (NF-κB) pathway and activates the nuclear factor erythroid related factor 2 (Nrf2) pathway. In addition, it suppresses the NOD-like receptor protein 3 (NLRP3) pathway and restrains the mitogen-activated protein kinase (MAPK) pathway.

CONCLUSIONS

Current studies indicate a great therapeutical potential of ISL as a drug candidate for treatment of inflammation-associated diseases. However, the pharmacokinetics, biosafety, and bioavailability of ISL remain to be further investigated.

Anti-Inflammatory and Chondroprotective Effects Induced by Phenolic Compounds from Onion Waste Extracts in ATDC-5 Chondrogenic Cell Line

Osteoarthritis is a prevalent degenerative condition that is closely related to the destruction and inflammation of cartilage. The high prevalence of this pathology exhorts researchers to search for novel therapeutic approaches. Vegetable-fruit wastes have emerged as a promising origin of anti-inflammatory and antioxidant compounds that, in some cases, may also exert chondroprotective effects. This study aims to decipher the potential of onion waste products in the inhibition of molecular events involved in osteoarthritis. Onion extracts showed a high content of phenolic compounds and antioxidant properties. Cytocompatibility was demonstrated in the chondrogenic cell line ATDC-5, exerting viability percentages higher than 90% and a slight increase in the S phase cycle cell. The induction of inflammation mediated by the lipopolysaccharide and onion extracts' treatment substantially inhibited molecular markers related to inflammation and cartilage degradation, highlighting the promising application of onion extracts in biomedical approaches. The in silico analyses suggested that the results could be attributed to protocatechuic, ellagic, and vanillic acids' greater cell membrane permeability. Our work provides distinctive information about the possible application of waste onion extracts as functional components with anti-inflammatory and chondroprotective characteristics in osteoarthritis.

EDESIA: Plants, Food and Health: A cross-disciplinary PhD programme from crop to clinic

In an era where preventive medicine is increasingly important due to an ageing population and rising obesity, optimised diets are key to improving health and reducing risk of ill health. The Wellcome Trust-funded, EDESIA: Plants, Food and Health: a cross-disciplinary PhD programme from Crop to Clinic (218 467/Z/19/Z) focuses on investigating plant-based nutrition and health, from crop to clinic, drawing on the world-class interdisciplinary research expertise of partner institutions based on the Norwich Research Park (University of East Anglia, John Innes Centre, Quadram Institute and Earlham Institute). Through a rotation-based programme, EDESIA PhD students will train in a wide range of disciplines across the translational pathway of nutrition research, including analyses of epidemiological datasets, assessment of nutritional bioactives, biochemical, genetic, cell biological and functional analyses of plant metabolites, in vitro analyses in tissue and cell cultures, investigation of efficacy in animal models of disease, investigation of effects on composition and functioning of the microbiota and human intervention studies. Research rotations add a breadth of knowledge, outside of the main PhD project, which benefits the students and can be brought into project design. This comprehensive PhD training programme will allow the translation of science into guidelines for healthy eating and the production of nutritionally improved food crops, leading to innovative food products, particularly for prevention and treatment of chronic diseases where age is a major risk factor. In this article, we summarise the programme and showcase the experiences of the first cohort of students as they start their substantive PhD projects after a year of research rotations.

Sambucus nigra flower and berry extracts for food and therapeutic applications: effect of gastrointestinal digestion on in vitro and in vivo bioactivity and toxicity

The bioavailability of natural compounds should be assessed through different perspectives. Studying the behaviour of the extracts after digestion is often overlooked but is crucial for success in the development of active food ingredients. Thus, the bioaccessibility of S. nigra (flower and berry) extracts after in vitro gastrointestinal digestion and their effect on toxicity and bioactive potential were studied. The flower extract had a higher content of phenolic compounds, like rutin, chlorogenic acid and rosmarinic acid, while in the berry extract, rutin, resveratrol, ferulic acid and chlorogenic acid were the main phenolic compounds. The effect of the non-digested and digested extracts was significantly different on different cell lines. The IC₅₀ of the normal cell line (L929) was the highest, indicating low toxicity. The IC₅₀ of the cancerous cell lines (HeLa and HT29) was lower, particularly the extract obtained from the flower upon digestion. In the presence of an oxidant agent - tbHP, only the berry extract was able to significantly reduce the formation of ROS in the L929 cell line, while in the HeLa cells, all the extracts were able to reduce ROS formation. The in vivo Artemia salina lethality bioassay demonstrated a dose-dependent effect of extracts, and the berry digested extract induced the lowest mortality rate. The promising results obtained on the chemical and biological evaluation of the extracts indicate that the natural compounds isolated from S. nigra by-products can be used as potential ingredients for functional food formulations and/or as bio-therapeutic agents.

Nutraceutical Approach to Chronic Osteoarthritis: From Molecular Research to Clinical Evidence

Osteoarthritis (OA) is a degenerative inflammatory condition of the joint cartilage that currently affects approximately 58 million adults in the world. It is characterized by pain, stiffness, and a reduced range of motion with regard to the arthritic joints. These symptoms can cause in the long term a greater risk of overweight/obesity, diabetes mellitus, and falls and fractures. Although the current guidelines for the treatment of OA suggest, as the gold standard for this condition, pharmacological treatment characterized by non-steroidal anti-inflammatory drugs (NSAID), opioids, and cyclooxygenase (COX)-2-specific drugs, a great interest has been applied to nutraceutical supplements, which include a heterogeneous class of molecules with great potential to reduce inflammation, oxidative stress, pain, and joint stiffness and improve cartilage formation. The purpose of this review is to describe the potential application of nutraceuticals in OA, highlighting its molecular mechanisms of actions and data of efficacy and safety (when available).

Sulforaphane protects against oxidative stress‑induced apoptosis via activating SIRT1 in mouse osteoarthritis

Osteoarthritis (OA), the most common form of human joint disease, is characterized by progressive degeneration of the articular cartilage, synovitis and subchondral osteoporosis. Chondrocyte apoptosis is the primary pathogenic mechanism of OA and is considered to be a potential therapeutic target. Sulforaphane (SFN), a dietary isothiocyanate obtained from cruciferous vegetables, has been reported to exert an anti‑apoptotic effect by activating sirtuin 1 (SIRT1). To the best of our knowledge, however, the effects of SFN on apoptotic responses in OA have not been reported. In the present study, SFN was shown to significantly inhibit chondrocyte apoptosis while enhancing expression levels of SIRT1 in a H2O2‑induced OA mouse model. The anti‑apoptotic effect of SFN was reversed by SIRT1 small interfering RNA, implying that SIRT1 exerted a protective role against the effect of SFN on chondrocytes. The expression levels of C/EBP homologous protein, 78‑kDa glucose regulated protein, Bax, Bcl‑2 and cleaved caspase 3 were found to be downregulated in SFN‑treated mice. Furthermore, SFN ameliorated cartilage degradation in the OA mouse model. These findings indicate that SFN exerted an anti‑apoptotic effect on chondrocytes and ameliorated OA in vivo by activating the SIRT1 signaling pathway.

Emerging Natural-Product-Based Treatments for the Management of Osteoarthritis

Osteoarthritis (OA) is a complex degenerative disease in which joint homeostasis is disrupted, leading to synovial inflammation, cartilage degradation, subchondral bone remodeling, and resulting in pain and joint disability. Yet, the development of new treatment strategies to restore the equilibrium of the osteoarthritic joint remains a challenge. Numerous studies have revealed that dietary components and/or natural products have anti-inflammatory, antioxidant, anti-bone-resorption, and anabolic potential and have received much attention toward the development of new therapeutic strategies for OA treatment. In the present review, we provide an overview of current and emerging natural-product-based research treatments for OA management by drawing attention to experimental, pre-clinical, and clinical models. Herein, we review current and emerging natural-product-based research treatments for OA management.

NRF2-Related Epigenetic Modifications in Cardiac and Vascular Complications of Diabetes Mellitus

Diabetes mellitus (DM) is a highly prevalent chronic disease that is accompanied with serious complications, especially cardiac and vascular complications. Thus, there is an urgent need to identify new strategies to treat diabetic cardiac and vascular complications. Nuclear factor erythroid 2-related factor 2 (NRF2) has been verified as a crucial target for the prevention and treatment of diabetic complications. The function of NRF2 in the treatment of diabetic complications has been widely reported, but the role of NRF2-related epigenetic modifications remains unclear. The purpose of this review is to summarize the recent advances in targeting NRF2-related epigenetic modifications in the treatment of cardiac and vascular complications associated with DM. We also discuss agonists that could potentially regulate NRF2-associated epigenetic mechanisms. This review provides a better understanding of strategies to target NRF2 to protect against DM-related cardiac and vascular complications.

Anti-rheumatic effect of quercetin and recent developments in nano formulation

Quercetin is a potential anti-rheumatoid drug. Nano formulation strategies could improve its solubility and efficacy.

Oxidative stress and inflammation in osteoarthritis pathogenesis: Role of polyphenols

Osteoarthritis (OA) is the most prevalent joint degenerative disease leading to irreversible structural and functional changes in the joint and is a major cause of disability and reduced life expectancy in ageing population. Despite the high prevalence of OA, there is no disease modifying drug available for the management of OA. Oxidative stress, a result of an imbalance between the production of reactive oxygen species (ROS) and their clearance by antioxidant defense system, is high in OA cartilage and is a major cause of chronic inflammation. Inflammatory mediators, such as interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) are highly upregulated in OA joints and induce ROS production and expression of matrix degrading proteases leading to cartilage extracellular matrix degradation and joint dysfunction. ROS and inflammation are interdependent, each being the target of other and represent ideal target/s for the treatment of OA. Plant polyphenols possess potent antioxidant and anti-inflammatory properties and can inhibit ROS production and inflammation in chondrocytes, cartilage explants and in animal models of OA. The aim of this review is to discuss the chondroprotective effects of polyphenols and modulation of different molecular pathways associated with OA pathogenesis and limitations and future prospects of polyphenols in OA treatment.

The glucosinolates and their bioactive derivatives in Brassica: a review on classification, biosynthesis and content in plant tissues, fate during and after processing, effect on the human organism and interaction with the gut microbiota

The present study is a systematic review of the scientific literature reporting content, composition and biosynthesis of glucosinolates (GLS), and their derivative compounds in Brassica family. An amended classification of brassica species, varieties and their GLS content, organized for the different plant organs and in uniformed concentration measure unit, is here reported for the first time in a harmonized and comparative manner. In the last years, the studies carried out on the effect of processing on vegetables and the potential benefits for human health has increased rapidly and consistently the knowledge on the topic. Therefore, there was the need for an updated revision of the scientific literature of pre- and post-harvest modifications of GLS content, along with the role of gut microbiota in influencing their bioavailability once they are ingested. After analyzing and standardizing over 100 articles and the related data, the highest GLS content in Brassica, was declared in B. nigra (L.) W. D. J. Koch (201.95 ± 53.36 µmol g^-1), followed by B. oleracea Alboglabra group (180.9 ± 70.3 µmol g^-1). The authors also conclude that food processing can influence significantly the final content of GLS, considering the most popular methods: boiling, blanching, steaming, the latter can be considered as the most favorable to preserve highest level of GLS and their deriviatives. Therefore, a mild-processing strategic approach for GLS or their derivatives in food is recommended, in order to minimize the loss of actual bioactive impact. Finally, the human gut microbiota is influenced by Brassica-rich diet and can contribute in certain conditions to the increasing of GLS bioavailability but further studies are needed to assess the actual role of microbiomes in the bioavailability of healthy glucosinolate derivatives.

The effect of kaempferol and apigenin on allogenic synovial membrane-derived stem cells therapy in knee osteoarthritic male rats

BACKGROUND

Based on the anti-inflammatory and anti-oxidant properties of kaempferol and apigenin, we hypothesized that co-injection of these phytochemicals would increase the effectiveness of cell therapy in knee osteoarthritic rats.

METHODS

Anterior cruciate ligament transection (ACLT) was used to induce osteoarthritis (OA). Animals were treated by weekly intra-articular injections of kaempferol (10 or 20 μM) and/or isolated MSCs from synovial membrane (SMMSCs) (3 × 106 cells), a mixture of apigenin (0.1 μM) and kaempferol alone or SMMSCs, hyaluronic acid or PBS (group size n = 6), for three weeks. After three months, the levels of IL-1β, tumor necrosis factor alpha (TNF-α), superoxide dismutase (SOD) and malondialdehyde (MDA) were measured in the cartilage homogenate. Furthermore, relative expressions of collagen II2a1, aggrecan, IL-1β, TNF-α, inducible nitric oxide synthase (iNOS), SOX-9, MMP-3 and MMP-13 were assessed using real-time PCR. Radiological evaluation, before/after treatments, and histopathological assessments were carried out to evaluate the knees.

RESULTS

Non-toxic concentrations of kaempferol and apigenin determined to be 10, 20 μM and 0.1, 0.3 μM, respectively. In comparison with the OA group, the levels of TNF-α, IL-1β and MDA significantly decreased in OA + MSCs + kaempferol + apigenin group and a significant increase in SOD level was observed. The levels of MMP-13, MMP-3, TNF-α, IL-1β, iNOS were significantly decreased in the groups of OA + MSCs + A0.1 μM + K10 μM and OA + MSCs + K20 μM. Co-treatment of kaempferol and apigenin increased the gene expression levels of collagen IIa1, aggrecan and SOX-9 genes.

CONCLUSION

We showed that kaempferol and apigenin potentially increase the efficiency of OA cell therapy in the rat model of ACLT-induced OA.

Nutraceutical Activity in Osteoarthritis Biology: A Focus on the Nutrigenomic Role

Osteoarthritis (OA) is a disease associated to age or conditions that precipitate aging of articular cartilage, a post-mitotic tissue that remains functional until the failure of major homeostatic mechanisms. OA severely impacts the national health system costs and patients' quality of life because of pain and disability. It is a whole-joint disease sustained by inflammatory and oxidative signaling pathways and marked epigenetic changes responsible for catabolism of the cartilage extracellular matrix. OA usually progresses until its severity requires joint arthroplasty. To delay this progression and to improve symptoms, a wide range of naturally derived compounds have been proposed and are summarized in this review. Preclinical in vitro and in vivo studies have provided proof of principle that many of these nutraceuticals are able to exert pleiotropic and synergistic effects and effectively counteract OA pathogenesis by exerting both anti-inflammatory and antioxidant activities and by tuning major OA-related signaling pathways. The latter are the basis for the nutrigenomic role played by some of these compounds, given the marked changes in the transcriptome, miRNome, and methylome. Ongoing and future clinical trials will hopefully confirm the disease-modifying ability of these bioactive molecules in OA patients.

Targeted and sustained Sox9 expression in mouse hypertrophic chondrocytes causes severe and spontaneous osteoarthritis by perturbing cartilage homeostasis

Sox9 is the master transcription factor essential for cartilage development and homeostasis. To investigate the specific role of Sox9 during chondrocyte hypertrophy, we generated a novel Col10a1-Sox9 transgenic mouse model, in which Sox9 is specifically expressed in hypertrophic chondrocytes driven by a well-characterized 10-kb Col10a1 promoter. These mice were viable and fertile, and appeared normal at birth. However, they developed dwarfism by ten weeks of age. The histological analysis of the growth plates from these transgenic mice demonstrated an abnormal growth plate architecture and a significantly reduced amount of trabecular bone and mineral content in the primary spongiosa. Real-time qPCR analysis revealed the reduced expression of Col10a1, and increased expressions of adipogenic differentiation markers in primary hypertrophic chondrocytes isolated from transgenic mice. Concomitantly, the transgenic mouse chondrocyte cultures had increased lipid droplet accumulation. Unexpectedly, we also observed an increased incidence of spontaneous osteoarthritis (OA) development in the transgenic mice by X-ray analysis, micro-computed tomography scanning, and histological examination of knee joints. The manifestation of OA in Col10a1-Sox9 transgenic mice began by six-months of age, and worsened by eleven-months of age. In conclusion, we provide strong evidence that the proper spatiotemporal expression of Sox9 is necessary for normal adult hypertrophic cartilage homeostasis, and that the aberrant expression of Sox9 might lead to spontaneous OA development.