Eriodictyol inhibits IL-1β-induced inflammatory response in human osteoarthritis chondrocytes

Bacterial biosynthesis of flavonoids: Overview, current biotechnology applications, challenges, and prospects

Flavonoids are secondary metabolites present in plant organs and tissues. These natural metabolites are the most prevalent and display a wide range of beneficial physiological effects, making them usually intriguing in several scientific fields. Due to their safety for use and protective attributes, including antioxidant, anti-inflammatory, anticancer, and antimicrobial functions, flavonoids are broadly utilized in foods, pharmaceuticals, and nutraceuticals. However, conventional methods for producing flavonoids, such as plant extraction and chemical synthesis, entailed dangerous substances, and laborious procedures, with low product yield. Recent studies have documented the ability of microorganisms, such as fungi and bacteria, to synthesize adequate amounts of flavonoids. Bacterial biosynthesis of flavonoids from plant biomass is a viable and environmentally friendly technique for producing flavonoids on a larger scale and has recently received much attention. Still, only a few bacteria species, particularly Escherichia coli, have been extensively studied. The most recent developments in bacterial biosynthesis of flavonoids are reviewed and discussed in this article, including their various applications as natural food biocontrol agents. In addition, the challenges currently faced in bacterial flavonoid biosynthesis and possible solutions, including the application of modern biotechnology approaches for developing bacterial strains that could successfully produce flavonoids on an industrial scale, were elucidated.

The Multifaceted Protective Role of Nuclear Factor Erythroid 2-Related Factor 2 in Osteoarthritis: Regulation of Oxidative Stress and Inflammation

Osteoarthritis (OA) is a chronic degenerative joint disease characterized by the degradation of joint cartilage, subchondral bone sclerosis, synovitis, and structural changes in the joint. Recent research has highlighted the role of various genes in the pathogenesis and progression of OA, with nuclear factor erythroid 2-related factor 2 (NRF2) emerging as a critical player. NRF2, a vital transcription factor, plays a key role in regulating the OA microenvironment and slowing the disease's progression. It modulates the expression of several antioxidant enzymes, such as Heme oxygenase-1 (HO-1) and NAD(P)H oxidoreductase 1 (NQO1), among others, which help reduce oxidative stress. Furthermore, NRF2 inhibits the nuclear factor kappa-B (NF-κB) signaling pathway, thereby decreasing inflammation, joint pain, and the breakdown of cartilage extracellular matrix, while also mitigating cell aging and death. This review discusses NRF2's impact on oxidative stress, inflammation, cell aging, and various cell death modes (such as apoptosis, necroptosis, and ferroptosis) in OA-affected chondrocytes. The role of NRF2 in OA macrophages, and synovial fibroblasts was also discussed. It also covers NRF2's role in preserving the cartilage extracellular matrix and alleviating joint pain. The purpose of this review is to provide a comprehensive understanding of NRF2's protective mechanisms in OA, highlighting its potential as a therapeutic target and underscoring its significance in the development of novel treatment strategies for OA.

Natural products in osteoarthritis treatment: bridging basic research to clinical applications

Osteoarthritis (OA) is the most prevalent degenerative musculoskeletal disease, severely impacting the function of patients and potentially leading to disability, especially among the elderly population. Natural products (NPs), obtained from components or metabolites of plants, animals, microorganisms etc., have gained significant attention as important conservative treatments for various diseases. Recently, NPs have been well studied in preclinical and clinical researches, showing promising potential in the treatment of OA. In this review, we summed up the main signaling pathways affected by NPs in OA treatment, including NF-κB, MAPKs, PI3K/AKT, SIRT1, and other pathways, which are related to inflammation, anabolism and catabolism, and cell death. In addition, we described the therapeutic effects of NPs in different OA animal models and the current clinical studies in OA patients. At last, we discussed the potential research directions including in-depth analysis of the mechanisms and new application strategies of NPs for the OA treatment, so as to promote the basic research and clinical transformation in the future. We hope that this review may allow us to get a better understanding about the potential bioeffects and mechanisms of NPs in OA therapy, and ultimately improve the effectiveness of NPs-based clinical conservative treatment for OA patients.

Eriodictyol inhibits the motility, angiogenesis and tumor growth of hepatocellular carcinoma via NLRP3 inflammasome inactivation

NLRP3 involves in the development of hepatocellular carcinoma (HCC). Eriodictyol has shown its inhibitory effect on HCC cell proliferation. However, the underlying mechanism of eriodictyol in HCC is still unclear. This study aimed to explore the effect of and mechanism of eriodictyol on HCC. In this study, compared with eriodictyol (0 μM) group, eriodictyol significantly suppressed HepG2 cells (eriodictyol of 25, 50 and 100 μM) and Huh-7 cells (eriodictyol of 50 and 100 μM) viability, invasion, tube formation, metastasis-related genes MMP3, MMP16 and angiogenesis regulator VEGFA expressions with IC50 of 45.63 μM and 78.26 μM in vitro, respectively. Besides, eriodictyol significantly repressed NLRP3 expression, and reduced the protein levels of NLRP3 inflammasome-related proteins, adapter protein ASC, caspase-1, interleukin (IL)-18, and IL-1β in HepG2 (eriodictyol of 25, 50 and 100 μM) and Huh-7 cells (eriodictyol of 50 and 100 μM), respectively. Meanwhile, compared with control group, NLRP3 overexpression reversed the anti-metastatic effects of 100 μM eriodictyol on HCC cells invasion, tube formation, and metastasis-related genes MMP3, MMP16 and angiogenesis regulator VEGFA expressions, whereas NLRP3 knockdown enhanced the anti-metastatic effects of 100 μM eriodictyol on HCC cells. In vivo, compared with control group, eriodictyol significantly reduced the tumor growth, liver damage, inhibited the activation of NLRP3 inflammasome, and improved liver function, whereas NLRP3 overexpressing neutralized the anti-tumor effects of eriodictyol and degraded liver function. Hence, eriodictyol inhibited HCC cell viability, motility, angiogenesis and tumor growth via NLRP3 inflammasome inactivation both in vitro and in vivo.

Activation of NRF2 by celastrol increases antioxidant functions and prevents the progression of osteoarthritis in mice

Excessive oxidative stress impairs cartilage matrix metabolism balance, significantly contributing to osteoarthritis (OA) development. Celastrol (CSL), a drug derived from Tripterygium wilfordii, has recognized applications in the treatment of cancer and immune system disorders, yet its antioxidative stress mechanisms in OA remain underexplored. This study aimed to substantiate CSL's chondroprotective effects and unravel its underlying mechanisms. We investigated CSL's impact on chondrocytes under both normal and inflammatory conditions. In vitro, CSL mitigated interleukin (IL)-1β-induced activation of proteinases and promoted cartilage extracellular matrix (ECM) synthesis. In vivo, intra-articular injection of CSL ameliorated cartilage degeneration and mitigated subchondral bone lesions in OA mice. Mechanistically, it was found that inhibiting nuclear factor erythroid 2-related factor 2 (NRF2) abrogated CSL-mediated antioxidative functions and exacerbated the progression of OA. This study is the first to elucidate the role of CSL in the treatment of OA through the activation of NRF2, offering a novel therapeutic avenue for arthritis therapy.

Active components and mechanisms of total flavonoids from Rhizoma Drynariae in enhancing cranial bone regeneration: An investigation employing serum pharmacochemistry and network pharmacology approaches

ETHNOPHARMACOLOGICAL RELEVANCE

Rhizoma Drynariae, as the dried rhizome of Drynaria fortunei (Kunze ex Mett.) J. Sm., is a traditional Chinese medicine for treating the injury and bone broken of falling and beating. Total flavonoids is considered as the major and effective compounds for the therapeutic efficacy of Rhizoma Drynariae.

AIM OF THE STUDY

To explore the effect of total flavonoids from Rhizoma Drynariae (TFRD) on bone regeneration and the underlying mechanisms.

MATERIALS AND METHODS

The effect of TFRD in various doses on bone reconstruction in cranial bone defect rats was explored in vivo. The active ingredients in TFRD-medicated serum were characterized by serum pharmacochemistry and integrated by network pharmacology analysis and target prediction. To elucidate the underlying mechanism of TFRD on bone regeneration, experimental validation in vitro was executed to assess the influence of different concentrations of TFRD-medicated serum on osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs).

RESULTS

Micro-CT, histological examination, immunohistochemical analysis, and ELSA demonstrated that administration of TFRD could promote bone reconstruction in a rat cranial defect model. We identified 27 active components of TFRD using ultra-high-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS). Results from CCK8, ALP, and Alizarin Red S staining revealed that TFRD-medicated serum notably enhanced BMSCs proliferation and osteogenic differentiation. qRT-PCR and Western blot harvested results consistent with those predicted by network pharmacology, providing further evidence that TFRD activated the TGF-β signaling pathway to benefit bone regeneration.

CONCLUSION

The active components of TFRD modulate the TGF-β signaling pathway to facilitate osteogenesis, thereby repairing cranial bone defects.

Ruscogenin attenuates cartilage destruction in osteoarthritis through suppressing chondrocyte ferroptosis via Nrf2/SLC7A11/GPX4 signaling pathway

Osteoarthritis (OA) is a common joint degenerative disease, and chondrocyte injury is the main pathological and physiological change. Ruscogenin (Rus), a bioactive compound isolated from Radix Ophiopogon japonicus, exhibits various pharmacological effects. The aim of this research was to test the role and mechanism of Rus on OA both in vivo and in vitro. Destabilized medial meniscus (DMM)-induced OA model was established in vivo and IL-1β-stimulated mouse chondrocytes was used to explore the role of Rus on OA in vitro. In vivo, Rus exhibited protective effects against DMM-induced OA model. Rus could inhibit MMP1 and MMP3 expression in OA mice. In vitro, IL-1β-induced inflammation and degradation of extracellular matrix were inhibited by Rus, as confirmed by the inhibition of PGE2, NO, MMP1, and MMP3 by Rus. Also, IL-1β-induced ferroptosis was suppressed by Rus, as confirmed by the inhibition of MDA, iron, and ROS, as well as the upregulation of GSH, GPX4, Ferritin, Nrf2, and SLC7A11 expression induced by Rus. Furthermore, the suppression of Rus on IL-1β-induced inflammation, MMPs production, and ferroptosis were reversed when Nrf2 was knockdown. In conclusion, Rus attenuated OA progression through inhibiting chondrocyte ferroptosis via Nrf2/SLC7A11/GPX4 signaling pathway.

Nrf2: A promising therapeutic target in bone-related diseases

Nuclear factor erythroid-2-related factor 2 (Nrf2) plays an important role in maintaining cellular homeostasis, as it suppresses cell damage caused by external stimuli by regulating the transcription of intracellular defense-related genes. Accumulating evidence has highlighted the crucial role of reduction-oxidation (REDOX) imbalance in the development of bone-related diseases. Nrf2, a transcription factor linked to nuclear factor-erythrocyte 2, plays a pivotal role in the regulation of oxidative stress and induction of antioxidant defenses. Therefore, further investigation of the mechanism and function of Nrf2 in bone-related diseases is essential. Considerable evidence suggests that increased nuclear transcription of Nrf2 in response to external stimuli promotes the expression of intracellular antioxidant-related genes, which in turn leads to the inhibition of bone remodeling imbalance, improved fracture recovery, reduced occurrence of osteoarthritis, and greater tumor resistance. Certain natural extracts can selectively target Nrf2, potentially offering therapeutic benefits for osteogenic arthropathy. In this article, the biological characteristics of Nrf2 are reviewed, the intricate interplay between Nrf2-regulated REDOX imbalance and bone-related diseases is explored, and the potential preventive and protective effects of natural products targeting Nrf2 in these diseases are elucidated. A comprehensive understanding of the role of Nrf2 in the development of bone-related diseases provides valuable insights into clinical interventions and can facilitate the discovery of novel Nrf2-targeting drugs.

Protective effect of eriodictyol against hyperglycemia-induced diabetic nephropathy in rats entails antioxidant and anti-inflammatory effects mediated by activating Nrf2

The pathogenesis of diabetic nephropathy (DN) involves cellular activation of oxidative stress and inflammation. Eriodictyol is a citrus-derived flavonoid with multiple pharmacological and protective effects in various conditions. The protective role of Eriodictyol against diabetes and diabetic nephropathy is less investigated. The current research aimed to explore the role of eriodictyol in protecting against DN prompted by streptozotocin in male rats and investigate some possible mechanisms of action. Diabetes was brought about in rats by an i.p injection of a lone dose (65 mg/kg). Five groups of rats were included (n = 8 each) as control (non-diabetic), eriodictyol (20 mg/kg, orally), STZ-diabetic, STZ + eriodictyol (20 mg/kg, orally), and STZ + eriodictyol (20 mg/kg, orally) + ML385 (30 µg/kg, i.p.). Kidney histology and the levels of some markers of kidney function, renal oxidative stress, and renal inflammation were analyzed in all groups of rats. Treatment with eriodictyol prevented the damage in the renal glomeruli and tubules and reduced renal immune cell infiltration in STZ-treated animals. It also spiked urinary creatinine excretion and reduced urine volume and urinary levels of albumin, monocyte chemoattractant protein 1 (MCP-1), urinary kidney injury molecule-1 (KIM-1), and nephrin in these diabetic rats. In addition, eriodictyol stimulated the nuclear protein accumulation of Nrf2 and boosted the expression of superoxide dismutase (SOD), glutathione (GSH), heme oxygenase-1 (HO-1), and catalase (CAT) in the diabetic rat kidneys. In concomitance, it reduced the nuclear levels of NF-κB and levels of interleukine-6 (IL-6), malondialdehyde (MDA), and tumor necrosis factor-α (TNF-α) and attenuated the reduction in renal ATP levels and the increase in the mitochondria transition pore opening (mtTPT). However, the administration of eriodictyol did not affect rats' body weights and fasting glucose and insulin levels but significantly reduced serum levels of cholesterol, triglycerides, LDL-c, and oxidized LDL-c (ox-LDL-c). In conclusion, eriodictyol prevents STZ-induced nephropathy by a hypolipidemic effect and concomitant antioxidant and anti-inflammatory effects mediated by activating Nrf2/NF-κB/antioxidant axis.

Anti-Inflammatory Study and Phytochemical Characterization of Zingiber officinale Roscoe and Citrus limon L. Juices and Their Formulation

Zingiber officinale and Citrus limon, well known as ginger and lemon, are two vegetals widely used in traditional medicine and the culinary field. The juices of the two vegetals were evaluated based on their inflammation, both in vivo and in vitro. High-performance liquid chromatography (HPLC) was used to characterize different juices from Zingiber officinale Roscoe and Citrus limon. After the application of the HPLC method, different compounds were identified, such as 6-gingerol and 6-gingediol from the ginger juice and isorhamnetin and hesperidin from the lemon juice. In addition, the two juices and their formulation were assessed for their anti-inflammatory activity, in vitro by utilizing the BSA denaturation test, in vivo using the carrageenan-induced inflammation test, and the vascular permeability test. Important and statistically significant anti-inflammatory activities were observed for all juices, especially the formulation. The results of our work showed clearly that the Zingiber officinale and Citrus limon juices protect in vivo the development of the rat paw edema, especially the formulation F composed of the Zingiber officinale and Citrus limon juices, which shows an anti-inflammatory activity equal to -35.95% and -44.05% using 10 and 20 mg/kg of the dose, respectively. Our work also showed that the formulation was the most effective tested extract since it inhibits the vascular permeability by -37% and -44% at the doses of 200 and 400 mg/kg, respectively, and in vitro via the inhibition of the denaturation of BSA by giving a synergetic effect with the highest IC50 equal to 684.61 ± 7.62 μg/mL corresponding to the formulation F. This work aims to develop nutraceutical preparations in the future and furnishes the support for a new investigation into the activities of the various compounds found in Zingiber officinale Roscoe and Citrus limon.

Pelargonidin ameliorates inflammatory response and cartilage degeneration in osteoarthritis via suppressing the NF-κB pathway

Pelargonidin (PG), a derivative of anthocyanins, has anti-oxidant and anti-inflammatory properties. Herein, the protective effect and the mechanism of PG in counteract the osteoarthritis (OA) progression were needed to further evaluate. In the current study, C57BL/6 mice was induced by destabilization of medial meniscus (DMM) surgery to establish the OA model. Primary chondrocytes were acquired from the knee cartilage of newborn mice. Then, PG was administrated to OA mice and IL-1β-stimulated chondrocytes to evaluate its protective effects, respectively. Results uncovered that no conspicuous cytotoxic effects were observed when chondrocytes were treated with PG at a concentration lower than 40 μM for 24-72h. Thus, 10 μM, 20 μM, and 40 μM PG were chosen for subsequent experiments in vitro. Then, we observed that 10, 20, and 40 μM PG reduced the levels of IL-6, TNF-α, COX-2 and iNOS in chondrocytes. In line, PG inhibited the IL-1β-induced ECM catabolism in chondrocytes, as evidenced by deepening toluidine blue staining, increased expression of Collagen II, and decreased expressions of ADAMTS5 and MMP13. Moreover, PG also reduced the IL-1β-stimulated p-p65 overexpression and nuclear translocation of p65 in chondrocytes. In vivo, Safranin O/Fast green and HE staining showed that articular cartilage surface morphology was basically smooth and complete after PG treatment for 8 weeks. Similarly, OARSI scores and MMP13 expression were apparently decreased, whereas Aggrecan expression was elevated in PG-treated mice 8 weeks after DMM surgery. In conclusion, PG can effectively ameliorate inflammatory reactions and cartilage degeneration via suppressing the NF-κB pathway, thereby restraining the OA progression.

Natural compounds protect against the pathogenesis of osteoarthritis by mediating the NRF2/ARE signaling

Osteoarthritis (OA), a chronic joint cartilage disease, is characterized by the imbalanced homeostasis between anabolism and catabolism. Oxidative stress contributes to inflammatory responses, extracellular matrix (ECM) degradation, and chondrocyte apoptosis and promotes the pathogenesis of OA. Nuclear factor erythroid 2-related factor 2 (NRF2) is a central regulator of intracellular redox homeostasis. Activation of the NRF2/ARE signaling may effectively suppress oxidative stress, attenuate ECM degradation, and inhibit chondrocyte apoptosis. Increasing evidence suggests that the NRF2/ARE signaling has become a potential target for the therapeutic management of OA. Natural compounds, such as polyphenols and terpenoids, have been explored to protect against OA cartilage degeneration by activating the NRF2/ARE pathway. Specifically, flavonoids may function as NRF2 activators and exhibit chondroprotective activity. In conclusion, natural compounds provide rich resources to explore the therapeutic management of OA by activating NRF2/ARE signaling.

System pharmacology analysis to decipher the effect and mechanism of active ingredients combination from Duhuo Jisheng decoction on osteoarthritis in rats

ETHNOPHARMACOLOGY RELEVANCE

Duhuo Jisheng decoction is a traditional Chinese formula that has been widely used in clinical practice to treat osteoarthritis, which has the effects of removing invaded cold and dampness, relieving joint pain. However, it is difficult to determine the effective substances and mechanisms due to assorted herbs and components, and further research is needed.

AIM OF THE STUDY

This study was designed to explore and verify the mechanism and targets of DHJSD in the treatment of OA via network analysis and experiments.

METHOD

In this study, the active ingredients of DHJSD were qualitatively analyzed by UPLC-QDA. Network analysis was used to identify common targets and pathways. Next, we explored the therapeutic mechanism of DHJSD through a rat model of knee osteoarthritis. HE staining was used to judge the establishment of the animal model. ELISA and Western blotting were used to verify the expression of key pathway proteins.

CONCLUSION

In this study, seventeen chemical constituents in DHJSD were identified. According to the network analysis, we obtained the potential associated pathways of action. Then, molecular docking and SPR experiments showed that the sixteen identified components had high binding energies to IL-6. HE staining showed that the high-dose group of DHJSD had an obvious therapeutic effect on model rats. Compared with the model group, the levels of IL-1β, TNF-α, IL-6, MMP3, MMP13, ADAMTS4 and ADAMTS5 in serum and the expression of STAT3 and p-STAT3 protein in administration groups were significantly decreased. This result indicated that the IL-6/STAT3 signaling pathway was one of the important pathways regulated by DHJSD to improve OA.

Syringaresinol attenuates osteoarthritis via regulating the NF-κB pathway

Osteoarthritis (OA) is a now regarded as a worldwide whole joint disease with synovial inflammation, cartilage degeneration, and subchondral sclerosis. Non-steroidal anti-inflammatory drugs (NSAIDs) are commonly used drugs for OA treatment which only relieve the symptoms and restrain the progression of OA. However, various severe adverse effects often occur in patients with long-term NSAIDs use, which heavily burdens the healthcare system and impacts the quality of life. Therefore, it is much imperative to identify alternative drugs with increased efficacy. Syringaresinol (Syr), a naturally occurring phytochemical which belonging to the lignan group of polyphenols, shows anti-tumor and anti-oxidant activities, which to benefit human health. Studies has shown Syr can regulate the inflammatory response by modulating the secretion and expression level of cytokines IL-6, IL-8, and tumor necrosis factor (TNF)-α. it also shows the inhibitory effect on NF-κB pathway in mouse cells. In the present study, we aimed to demonstrate the anti-inflammatory effects of Syr in OA. In vitro Syr treatment in IL-1β-activated mouse chondrocytes significantly restrained the expression of NO, PGE2, IL-6, TNF-α, INOS, COX-2 and MMP-13. Moreover, it considerably ameliorated the degradation of aggrecan and collagen II. Furthermore, the phosphorylation of the NF-kB signaling pathway was significantly suppressed by Syr. Moreover, in vivo, the cartilage degeneration was attenuated and the increased Osteoarthritis Research Society International (OARSI) scores were reversed in the DMM + Syr group, comprared to those in the DMM group. In sum, our study demonstrated that Syr can attenuate the inflammation in vitro and further verified its effect on OA in vivo. Thus, Syr might be a potent therapeautic alternative for OA treatment.

Role of Plant-Derived Compounds in the Molecular Pathways Related to Inflammation

Inflammation is the primary response to infection and injury. Its beneficial effect is an immediate resolution of the pathophysiological event. However, sustained production of inflammatory mediators such as reactive oxygen species and cytokines may cause alterations in DNA integrity and lead to malignant cell transformation and cancer. More attention has recently been paid to pyroptosis, which is an inflammatory necrosis that activates inflammasomes and the secretion of cytokines. Taking into consideration that phenolic compounds are widely available in diet and medicinal plants, their role in the prevention and support of the treatment of chronic diseases is apparent. Recently, much attention has been paid to explaining the significance of isolated compounds in the molecular pathways related to inflammation. Therefore, this review aimed to screen reports concerning the molecular mode of action assigned to phenolic compounds. The most representative compounds from the classes of flavonoids, tannins, phenolic acids, and phenolic glycosides were selected for this review. Our attention was focused mainly on nuclear factor-κB (NF-κB), nuclear factor erythroid 2-related factor 2 (Nrf2), and mitogen-activated protein kinase (MAPK) signaling pathways. Literature searching was performed using Scopus, PubMed, and Medline databases. In conclusion, based on the available literature, phenolic compounds regulate NF-κB, Nrf2, and MAPK signaling, which supports their potential role in chronic inflammatory disorders, including osteoarthritis, neurodegenerative diseases, cardiovascular, and pulmonary disorders.

Potential of Tamarind Shell Extract against Oxidative Stress In Vivo and In Vitro

Tamarind shell is rich in flavonoids and exhibits good biological activities. In this study, we aimed to analyze the chemical composition of tamarind shell extract (TSE), and to investigate antioxidant capacity of TSE in vitro and in vivo. The tamarind shells were extracted with 95% ethanol refluxing extraction, and chemical constituents were determined by ultra-performance chromatography-electrospray tandem mass spectrometry (UPLC-MS/MS). The free radical scavenging activity of TSE in vitro was evaluated using the oxygen radical absorbance capacity (ORAC) method. The antioxidative effects of TSE were further assessed in 2,2-azobis (2-amidinopropane) dihydrochloride (AAPH)-stimulated ADTC5 cells and tert-butyl hydroperoxide (t-BHP)-exposed zebrafish. A total of eight flavonoids were detected in TSE, including (+)-catechin, taxifolin, myricetin, eriodictyol, luteolin, morin, apigenin, and naringenin, with the contents of 5.287, 8.419, 4.042, 6.583, 3.421, 4.651, 0.2027, and 0.6234 mg/g, respectively. The ORAC assay revealed TSE and these flavonoids had strong free radical scavenging activity in vitro. In addition, TSE significantly decreased the ROS and MDA levels but restored the SOD activity in AAPH-treated ATDC5 cells and t-BHP-exposed zebrafish. The flavonoids also showed excellent antioxidative activities against oxidative damage in ATDC5 cells and zebrafish. Overall, the study suggests the free radical scavenging capacity and antioxidant potential of TSE and its primary flavonoids in vitro and in vivo and will provide a theoretical basis for the development and utilization of tamarind shell.

The protective activity of natural flavonoids against osteoarthritis by targeting NF-κB signaling pathway

Osteoarthritis (OA) is a typical joint disease associated with chronic inflammation. The nuclear factor-kappaB (NF-κB) pathway plays an important role in inflammatory activity and inhibiting NF-κB-mediated inflammation can be a potential strategy for treating OA. Flavonoids are a class of naturally occurring polyphenols with anti-inflammatory properties. Structurally, natural flavonoids can be divided into several sub-groups, including flavonols, flavones, flavanols/catechins, flavanones, anthocyanins, and isoflavones. Increasing evidence demonstrates that natural flavonoids exhibit protective activity against the pathological changes of OA by inhibiting the NF-κB signaling pathway. Potentially, natural flavonoids may suppress NF-κB signaling-mediated inflammatory responses, ECM degradation, and chondrocyte apoptosis. The different biological actions of natural flavonoids against the NF-κB signaling pathway in OA chondrocytes might be associated with the differentially substituted groups on the structures. In this review, the efficacy and action mechanism of natural flavonoids against the development of OA are discussed by targeting the NF-κB signaling pathway. Potentially, flavonoids could become useful inhibitors of the NF-κB signaling pathway for the therapeutic management of OA.

Calycosin mitigates chondrocyte inflammation and apoptosis by inhibiting the PI3K/AKT and NF-κB pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Shaoyao Gancao Decoction (SG-Tang), originated from the Treatise on Febrile Diseases, is often used to treat OA pain symptoms. Whereas its efficacy has been verified by several clinical studies, the underlying mechanism remained unclear. Network pharmacology and UPLC-QTOF-MS analysis found that calycosin could be regarded as the active components of SG-Tang in treating OA. However, the effect of calycosin on cartilage destruction and the pathogenesis of OA are not known. Therefore, we evaluated the benefits of calycosin for OA and revealed the underlying mechanisms.

AIM OF STUDY

Using network pharmacology, UPLC-QTOF-MS analysis and experiments, the active components of SG-Tang were analyzed to explore their potential therapeutic mechanism in OA.

MATERIALS AND METHODS

The components of SG-Tang were detected by UPLC-QTOF-MS, and the possible active components and mechanism of SG-Tang in the treatment of OA were screened by network pharmacology. The OA mouse model was constructed by DMM. In total, 30 mice were randomly divided into three groups: Sham, DMM, and DMM + Calycosin. H&E, safranin O/fast green staining and the OARSI scores were used to evaluate joint injury in mice. In addition, OA models were established using chondrocytes treated with 10 ng/mL IL-1β. Treatment groups were treated with 100, 200 or 400 μM calycosin. CCK-8 assay was used for assessing the cytotoxic effects of calycosin. TUNEL staining and Western blotting were used to detect chondrocyte apoptosis. In addition, PI3K/Akt and NF-κB signaling pathway-related markers and cartilage matrix-related indicators were also detected.

RESULTS

In vivo studies showed that calycosin inhibited IL-1β-induced IL-6 and TNF-α production, as well as iNOS and COX-2 expression. Meanwhile, calycosin could inhibit IL-1β-induced degradation of cartilage matrix, including downregulation of MMP3, MMP-13, collagen II and aggrecan. NF-κB and PI3K/AKT were also inhibited by calycosin in OA chondrocytes. Furthermore, calycosin inhibited IL-1β-induced apoptosis in mouse chondrocytes. In a mouse model of OA, our results suggest that calycosin has a chondroprotective effect.

CONCLUSIONS

According to this study, calycosin may act as a protective agent against OA by inhibiting the PI3K/AKT and NF-κB pathways. Furthermore, this study suggested that calycosin is a potential candidate for the treatment of OA.

Bioassay-Guided Isolation of Anti-Inflammatory Constituents of the Subaerial Parts of Cyperus articulatus (Cyperaceae)

Based on data from a previous ethnobotanical study in northern Angola, phytochemical investigations into the methanolic rhizomes and roots extract of Cyperus articulatus, monitored by in vitro assays, resulted in the recovery of 12 sesquiterpenes, 3 stilbenes, 2 phenolic acids, 1 monoterpene, and 1 flavonoid. Among them, 14 compounds were isolated for the first time from this species. Their inhibitory potential against nitric oxide (NO) production, as well as inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression, was evaluated in LPS-treated J774A.1 murine macrophages. Especially, both stilbene dimer trans-scirpusin B and trimer cyperusphenol B showed promising inhibitory activity against the production of the inflammatory mediator, NO, in a concentration-dependent manner (10−1 µM). The obtained data are the first results confirming the anti-inflammatory potential of C. articulatus and support its indigenous use as a traditional remedy against inflammation-related disorders.

Chicoric acid attenuates tumor necrosis factor-α-induced inflammation and apoptosis via the Nrf2/HO-1, PI3K/AKT and NF-κB signaling pathways in C28/I2 cells and ameliorates the progression of osteoarthritis in a rat model

Osteoarthritis (OA) is the most common arthritis, and is characterized by inflammation and cartilage degradation. Chicoric acid (CA), a bioactive caffeic acid derivative isolated from the root of Taraxacum mongolicumHand. - Mazz., has been reported to have anti-inflammatory effects. However, the therapeutic effects of CA on chondrocyte inflammation remain unknown. Our study aimed to explore the effect of CA on OA both in vivo and in vitro. In vitro, CA treatment significantly suppressed the overproduction of nitric oxide (NO), prostaglandin E2 (PGE2), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), interleukin-1 beta (IL-1β), interleukin-6 (IL-6), and IL-12 in tumor necrosis factor alpha (TNF-α)-induced human C28/I2 chondrocytes. Moreover, CA attenuated TNF-α induced degradation of the extracellular matrix (ECM) by upregulating the expression of collagen Ⅱ and aggrecan, and downregulating ADAMTS-5 and matrix metalloproteinases (MMPs). Additionally, CA treatment inhibited apoptosis in C28/I2 cells by upregulating of Bcl-2 levels, downregulating Bax and ROS levels, and activating the Nrf2/HO-1 pathway. Mechanistically, CA exerted an anti-inflammatory effect by inhibiting the PI3K/AKT and NF-κB signaling pathways, enhancing Nrf-2/HO-1 to limit the activation of NF-κB. In vivo experiments also proved the therapeutic effects of CA on OA in rats. These findings indicate that CA may become a new drug for the treatment of OA.

Eriodictyol mediated selective targeting of the TNFR1/FADD/TRADD axis in cancer cells induce apoptosis and inhibit tumor progression and metastasis

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Eriodictyol induces Selective Cytotoxicity to tumor cells.

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Eriodictyol enhances TNFR1 expression in cancer cells.

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Eriodictyol targets TNFR1 to selectively mediate apoptosis and cytotoxicity to cancer cells.

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Eriodictyol reduces tumour burden in experimentally induced lung metastasis in vivo.

While the anti-inflammatory activities of Eriodictyol, a plant-derived flavonoid is well-known, reports on its anti-cancer efficacy and selective cytotoxicity in cancer cells are still emerging. However, little is known regarding its mechanism of selective anti-cancer activities. Here, we show the mechanism of selective cytotoxicity of Eriodictyol towards cancer cells compared to normal cells. Investigation reveals that Eriodictyol significantly upregulates TNFR1 expression in tumor cells (HeLa and SK-RC-45) while sparing the normal cells (HEK, NKE and WI-38), which display negligible TNFR1 expression, irrespective of the absence or presence of Eriodictyol. Further investigation of the molecular events reveal that Eriodictyol induces apoptosis through expression of the pro-apoptotic DISC components leading to activation of the caspase cascade. In addition, CRISPR-Cas9 mediated knockout of TNFR1 completely blocks apoptosis in HeLa cells in response to Eriodictyol, confirming that Eriodictyol induced cancer cell apoptosis is indeed TNFR1-dependent. Finally, in vivo data demonstrates that Eriodictyol not only impedes tumor growth and progression, but also inhibits metastasis in mice implanted with 4T1 breast cancer cells. Thus, our study has identified Eriodictyol as a compound with high selectivity towards cancer cells through TNFR1 and suggests that it can be further explored for its prospect in cancer therapeutics.

The Protective Effect of Evodiamine in Osteoarthritis: An In Vitro and In Vivo Study in Mice Model

Osteoarthritis (OA) is a chronic disease with high economic burden characterized by cartilage degradation and joint inflammation. Evodiamine (EV), which can be extracted from Evodia rutaecarpa (Rutaceae), is a traditional Chinese medicine to treat inflammation, cardiovascular disorders, infection, and obesity. Studies have shown that EV can suppress the activation of immune cells and restrain the secretion of pro-inflammatory cytokines. However, it is still not well known about its role in the treatment of OA. In this study, we utilized interleukin-1β (IL-1β)–stimulated mouse chondrocytes in vitro and the destabilization of the medial meniscus (DMM) model in vivo to demonstrate the anti-inflammatory properties of EV in OA. The results suggested that EV decreased the generation of NO, IL-6, TNF-α, and PGE2. Meanwhile, the increased expression of iNOS, COX-2, and MMP-13 and the degradation of aggrecan and Col-II were significantly alleviated by EV in IL-1β–activated mouse chondrocytes. Moreover, EV can inhibit the considerable IL-1β–stimulated phosphorylation of the NF-κB signaling pathway and nuclear translocation of p65, compared with the control group. Furthermore, EV alleviated cartilage degeneration and reversed the increased Osteoarthritis Research Society International (OARSI) scores in the OA model in vivo. Our study demonstrates that EV can suppress inflammation in vitro and cartilage degeneration in vivo in OA, which implies that EV may be a potential candidate for the treatment of OA.

A multi-targeted approach to identify potential flavonoids against three targets in the SARS-CoV-2 life cycle

The advent and persistence of the Severe Acute Respiratory Syndrome Coronavirus - 2 (SARS-CoV-2)-induced Coronavirus Disease (COVID-19) pandemic since December 2019 has created the largest public health emergency in over a century. Despite the administration of multiple vaccines across the globe, there continues to be a lack of approved efficacious non-prophylactic interventions for the disease. Flavonoids are a class of phytochemicals with historically established antiviral, anti-inflammatory and antioxidative properties that are effective against cancers, type 2 diabetes mellitus, and even other human coronaviruses. To identify the most promising bioactive flavonoids against the SARS-CoV-2, this article screened a virtual library of 46 bioactive flavonoids against three promising targets in the SARS-CoV-2 life cycle: human TMPRSS2 protein, 3CLpro, and PLpro. By examining the effects of glycosylation and other structural-activity relationships, the presence of sugar moiety in flavonoids significantly reduces its binding energy. It increases the solubility of flavonoids leading to reduced toxicity and higher bioavailability. Through protein-ligand contact profiling, it was concluded that naringin formed more hydrogen bonds with TMPRSS2 and 3CLpro. In contrast, hesperidin formed a more significant number of hydrogen bonds with PLpro. These observations were complimented by the 100 ns molecular dynamics simulation and binding free energy analysis, which showed a considerable stability of docked bioflavonoids in the active site of SARS-CoV-2 target proteins. Finally, the binding affinity and stability of the selected docked complexes were compared with the reference ligands (camostat for TMPRSS2, GC376 for 3CLpro, and GRL0617 for PLpro) that strongly inhibit their respective SARS-COV-2 targets. Overall analysis revealed that the selected flavonoids could be potential therapeutic agents against SARS-CoV-2. Naringin showed better affinity and stability for TMPRSS2 and 3CLpro, whereas hesperidin showed a better binding relationship and stability for PLpro.

Eriodictyol Inhibits the Production and Gene Expression of MUC5AC Mucin via the IκBα-NF-κB p65 Signaling Pathway in Airway Epithelial Cells

In this study, we investigated whether eriodictyol exerts an effect on the production and gene expression of MUC5AC mucin in human pulmonary epithelial NCI-H292 cells. The cells were pretreated with eriodictyol for 30 min and then stimulated with phorbol 12-myristate 13-acetate (PMA) for 24 h. The effect of eriodictyol on PMA-induced nuclear factor kappa B (NF-κB) signaling pathway was also investigated. Eriodictyol suppressed the MUC5AC mucin production and gene expression induced by PMA via suppression of inhibitory kappa Bα degradation and NF-κB p65 nuclear translocation. These results suggest that eriodictyol inhibits mucin gene expression and production in human airway epithelial cells via regulation of the NF-κB signaling pathway.

Discovery of natural 15-LOX small molecule inhibitors from Chinese herbal medicine using virtual Screening, biological evaluation and molecular dynamics studies

Chinese herbal medicines (CHM) are frequently used to treat different types of inflammatory diseases and 15-Lipoxygenase (15-LOX) is a critical target enzyme for treating various inflammatory diseases. In this study, natural 15-LOX inhibitors were identified in CHM using an approach of virtual screening combined with the biological assays. First, an in-house Chinese medicine database containing 360 compounds was screened using a virtual screening approach based on pharmacophore and molecular docking to uncover several novel potential 15-LOX inhibitors. Secondly, the inhibitory effect of virtual screening hits against the 15-LOX enzyme was validated in an in vitro enzyme inhibition assay. Then, a tumor necrosis factor-α (TNF-α) release assay was carried out to explore the anti-inflammatory response of the active compounds. Furthermore, molecular dynamics (MD) simulation and binding free energy calculation were applied to analyze the process of inhibitors binding and also compared the mode of binding of the inhibitors by using the Molecular Mechanics-Generalized Born Surface Area (MM/GBSA) method. Finally, licochalcone B and eriodictyol were confirmed as inhibitors of the 15-LOX enzyme with IC₅₀ values of 9.67 and 18.99 μM, respectively. In vitro cell-based assay showed that licochalcone B and eriodictyol inhibited the release of TNF-α factor in RAW264.7 cells stimulated by lipopolysaccharides (LPS) in a dose-dependent manner. Molecular dynamics and binding free energy analysis showed that the two 15-LOX-ligand systems immediately attained equilibrium with almost 1 Å fluctuation, the calculated binding free energies were found around -18.89 and -12.96 kcal/mol for licochalcone B and eriodictyol, respectively. Thr412, Arg415, Val420, Thr429, Ile602 and Trp606 were the main amino acid residues for the inhibition of 15-LOX enzyme activity. The current study confirms that licochalcone B and eriodictyol are 15-LOX inhibitors and can suppress the release of the TNF-α factor in RAW264.7 cells stimulated by LPS, thus providing a basis for the follow-up research and development for 15-LOX inhibitors.

Decursin alleviates the aggravation of osteoarthritis via inhibiting PI3K-Akt and NF-kB signal pathway

Osteoarthritis (OA) is a common joint disease that takes joint degeneration or aging as its pathological basis, and joint swelling, pain or dysfunction as its main clinical manifestations. Decursin (DE), the major active component isolated from Angelica gigas Nakai, has been demonstrated to possess anti-inflammatory effect in many diseases. But, the specific physiological mechanism of DE on OA is not clear yet. Therefore, the object of this study was to assess the therapeutic effect of DE on OA, and to explore its potential anti-inflammatory mechanisms. In vitro cell experiments, the inflammatory response in chondrocytes is mediated via interleukin-1β (IL-1β), which led to abnormal secretion of pro-inflammatory factors, such as prostaglandin E2 (PGE₂), interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), cyclooxygenase-2 (COX-2), nitric oxide (NO) and inducible nitric oxide synthase (iNOS). These cytokines were all decreased by the preconditioning of DE in a dose-dependent form of 1, 5, and 10 µM. Moreover, DE could restrain IL-1β-mediated inflammatory reaction and the collapse of extracellular matrix (ECM) via reducing the secretion of ADAMTS (a disintegrin and metalloproteinase with thrombospondin motifs) and MMPs (matrix metalloproteinases). In short, DE restrained IL-1β-mediated abnormal excitation of PI3K/AKT/NF-κB axis. Furthermore, molecular docking analysis showed that DE has a strong binding affinity with the inhibitory targets of PI3K. In vivo animal studies, DE treatment could helped to improve destruction of articular cartilage and decreased the serum inflammatory factor levels in an operationally induced mouse OA model. To sum up, these data obtained from the experiment indicate that DE has good prospects for the treatment of osteoarthritis.

Apple Fermented Products: An Overview of Technology, Properties and Health Effects

As an easily adapted culture, with overloaded production in some parts of the globe, apples and their by-products are being redirected to pharmaceutical, canning and beverages industries, both alcoholic and non-alcoholic. Fermentation is generally considered to increase the bioavailability of bioactive compounds found in apple, by impacting, through a high degree of changes, the product’s properties, including composition and health-promoting attributes, as well as their sensory profile. Probiotic apple beverages and apple vinegar are generally considered as safe and healthy products by the consumers. Recently, contributions to human health, both in vivo and in vitro studies, of non-alcoholic fermented apple-based products have been described. This review highlighted the advances in the process optimization of apple-based products considering vinegar, cider, pomace, probiotic beverages and spirits’ technologies. The different processing impacts on physical-chemical, nutritional and sensory profiles of these products are also presented. Additionally, the harmful effects of toxic compounds and strategies to limit their content in cider and apple spirits are illustrated. New trends of fermented apple-based products applicability in tangential industries are summarized.

Molecular mechanisms of mechanical load-induced osteoarthritis

INTRODUCTION

Mechanical loading enhances the progression of osteoarthritis. However, its molecular mechanisms have not been established.

OBJECTIVE

The aim of this review was to summarize the probable mechanisms of mechanical load-induced osteoarthritis.

METHODS

A comprehensive search strategy was used to search PubMed and EMBASE databases (from the 15th of January 2015 to the 20th of October 2020). Search terms included "osteoarthritis", "mechanical load", and "mechanism".

RESULTS

Abnormal mechanical loading activates the interleukin-1β, tumour necrosis factor-α, nuclear factor kappa-B, Wnt, transforming growth factor-β, microRNAs pathways, and the oxidative stress pathway. These pathways induce the pathological progression of osteoarthritis. Mechanical stress signal receptors such as integrin, ion channel receptors, hydrogen peroxide-inducible clone-5, Gremlin-1, and transient receptor potential channel 4 are present in the articular cartilages.

CONCLUSION

This review highlights the molecular mechanisms of mechanical loading in inducing chondrocyte apoptosis and extracellular matrix degradation. These mechanisms provide potential targets for osteoarthritis prevention and treatment.

Pharmacological Activity of Eriodictyol: The Major Natural Polyphenolic Flavanone

Eriodictyol is a flavonoid that belongs to a subclass of flavanones and is widespread in citrus fruits, vegetables, and medicinally important plants. Eriodictyol has been anticipated to explain the method of its activity via multiple cellular signaling cascades. Eriodictyol is an effective natural drug source to maintain higher health standards due to its excellent therapeutic roles in neuroprotection, cardioprotective activity, hepatoprotective activity, antidiabetes and obesity, and skin protection and having highly analgesic, antioxidant, and anti-inflammatory effects, antipyretic and antinociceptive actions, antitumor activity, and much more. This review aims to highlight the modes of action of eriodictyol against various diseases via multiple cellular signaling pathways.

In silico pharmacokinetic and molecular docking studies of natural flavonoids and synthetic indole chalcones against essential proteins of SARS-CoV-2

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is distinctly infective and there is an ongoing effort to find a cure for this pandemic. Flavonoids exist in many diets as well as in traditional medicine, and their modern subset, indole-chalcones, are effective in fighting various diseases. Hence, these flavonoids and structurally similar indole chalcones derivatives were studied in silico for their pharmacokinetic properties including absorption, distribution, metabolism, excretion, toxicity (ADMET) and anti-SARS-CoV-2 properties against their proteins, namely, RNA dependent RNA polymerase (rdrp), main protease (Mpro) and Spike (S) protein via homology modelling and docking. Interactions were studied with respect to biology and function of SARS-CoV-2 proteins for activity. Functional/structural roles of amino acid residues of SARS-CoV-2 proteins and, the effect of flavonoid and indole chalcone interactions which may cause disease suppression are discussed. The results reveal that out of 23 natural flavonoids and 25 synthetic indole chalcones, 30 compounds are capable of Mpro deactivation as well as potentially lowering the efficiency of Mpro function. Cyanidin may inhibit RNA polymerase function and, Quercetin is found to block interaction sites on the viral spike. These results suggest flavonoids and their modern pharmaceutical cousins, indole chalcones are capable of fighting SARS-CoV-2. The in vitro anti-SARS-CoV-2 activity of these 30 compounds needs to be studied further for complete understanding and confirmation of their inhibitory potential.

Polyphenolic Profiling of Forestry Waste by UPLC-HDMSE

Polyphenols constitute a diverse array of naturally occurring secondary metabolites found in plants which, when consumed, have been shown to promote human health. Greater consumption may therefore aid in the fight against diseases such as obesity, diabetes, heart disease, cancer, etc. Tree bark is polyphenol-rich and has potential to be used in food supplements. However, it is important to gain insight into the polyphenol profile of different barks to select the material with greatest concentration and diversity. Ultra-performance liquid chromatography (UPLC) was coupled with an ion mobility time-of-flight high-definition/high-resolution mass spectrometer (UPLC-HDMSE) to profile ethanol extracts of three common tree barks (Pinus contorta, Pinus sylvestris, Quercus robur) alongside a commercial reference (Pycnogenol® extracted from Pinus pinaster). Through the use of Progenesis QI informatics software, 35 high scoring components with reported significance to health were tentatively identified across the three bark extracts following broadly the profile of Pycnogenol®. Scots Pine had generally higher compound abundances than in the other two extracts. Oak bark extract showed the lowest abundances but exhibited higher amounts of naringenin and 3-O-methylrosmarinic acid. We conclude that forestry bark waste provides a rich source of extractable polyphenols suitable for use in food supplements and so can valorise this forestry waste stream.

Resveratrol alleviates the interleukin-1β-induced chondrocytes injury through the NF-κB signaling pathway

BACKGROUND

Osteoarthritis (OA) is a regular age-related disease that affects millions of people. Resveratrol (RSV) is a flavonoid with a stilbene structure with different pharmacological effects. The purpose of the experiment was to evaluate the protective role of RSV against the human OA chondrocyte injury induced by interleukin-1β (IL-1β).

METHODS

Chondrocytes were isolated from OA patients and identified by type II collagen, safranin O staining, and toluidine blue staining. Differentially expressed genes in chondrocytes treated RSV were identified by RNA sequencing. Kyoto encyclopedia of genes and genomes (KEGG) pathway as well as gene ontology (GO) were further conducted through Metascape online tool. A cell counting kit-8 (CCK-8) assay was applied to discover the viability of chondrocytes (6, 12, 24, and 48 μM). Many genes associated with inflammation and matrix degradation are evaluated by real-time PCR (RT-PCR) as well as western blot (WB). The mechanism of RSV for protecting IL-1β induced chondrocytes injury was further measured through immunofluorescence and WB assays.

RESULTS

A total of 845 differentially expressed genes (upregulated = 499, downregulated = 346) were found. These differentially expressed genes mainly enriched into negative regulation of catabolic process, autophagy, and cellular catabolic process, intrinsic apoptotic, apoptotic, and regulation of apoptotic signaling pathway, cellular response to abiotic stimulus, external stimuli, stress, and radiation. These differentially expressed genes were obviously enriched in NF-kB signaling pathway. RSV at the concentration of 48 μM markedly weakened the viability of the cells after 24 h of treatment (87% vs 100%, P < 0.05). No obvious difference was observed between the 6, 12, and 24 μM groups (106% vs 100%, 104% vs 100%, 103% vs 100%, P > 0.05). RSV (24 μM) also markedly depressed the levels of PGE2 and NO induced by IL-1β by 25% and 29% respectively (P < 0.05). Our experiment pointed out that RSV could dramatically inhibit the inflammatory response induced by IL-1β, including the MMP-13, MMP-3, and MMP-1 in human OA chondrocytes by 50%, 35%, and 33% respectively. On the other hand, RSV inhibited cyclooxygenase-2 (COX-2), matrix metalloproteinase-1 (MMP-1), MMP-3, MMP-13, and inducible nitric oxide synthase (iNOs) expression (P < 0.05), while increased collagen-II and aggrecan levels (P < 0.05). From a mechanistic perspective, RSV inhibited the degradation of IκB-α as well as the activation of nuclear factor-kappa B (NF-κB) induced by IL-1β.

CONCLUSION

In summary, RSV regulates the signaling pathway of NF-κB, thus inhibiting inflammation and matrix degradation in chondrocytes. More studies should be focused on the treatment efficacy of RSV for OA in vivo.

The pharmacological and biological roles of eriodictyol

Eriodictyol is a flavonoid in the flavanones subclass. It is abundantly present in a wide range of medicinal plants, citrus fruits, and vegetables that are considered to have potential health importance. Having the considerable medicinal properties, eriodictyol has been predicted to clarify the mode of action in various cellular and molecular pathways. Evidence for the existing therapeutic roles of eriodictyol includes antioxidant, anti-inflammatory, anti-cancer, neuroprotective, cardioprotective, anti-diabetic, anti-obesity, hepatoprotective, and miscellaneous. Therefore, this review aims to present the recent evidence regarding the mechanisms of action of eriodictyol in different signaling pathways in a specific disease condition. In view of the immense therapeutic effects, eriodictyol may serve as a potential drug source to enhance community health standards.

Green and Sustainable Valorization of Bioactive Phenolic Compounds from Pinus By-Products

In Europe, pine forests are one of the most extended forests formations, making pine residues and by-products an important source of compounds with high industrial interest as well as for bioenergy production. Moreover, the valorization of lumber industry residues is desirable from a circular economy perspective. Different extraction methods and solvents have been used, resulting in extracts with different constituents and consequently with different bioactivities. Recently, emerging and green technologies as ultrasounds, microwaves, supercritical fluids, pressurized liquids, and electric fields have appeared as promising tools for bioactive compounds extraction in alignment with the Green Chemistry principles. Pine extracts have attracted the researchers’ attention because of the positive bioproperties, such as anti-inflammatory, antimicrobial, anti-neurodegenerative, antitumoral, cardioprotective, etc., and potential industrial applications as functional foods, food additives as preservatives, nutraceuticals, pharmaceuticals, and cosmetics. Phenolic compounds are responsible for many of these bioactivities. However, there is not much information in the literature about the individual phenolic compounds of extracts from the pine species. The present review is about the reutilization of residues and by-products from the pine species, using ecofriendly technologies to obtain added-value bioactive compounds for industrial applications.

Adipose tissue as a possible therapeutic target for polyphenols: A case for Cyclopia extracts as anti-obesity nutraceuticals

Obesity is a significant contributor to increased morbidity and premature mortality due to increasing the risk of many chronic metabolic diseases such as type 2 diabetes, cardiovascular disease and certain types of cancer. Lifestyle modifications such as energy restriction and increased physical activity are highly effective first-line treatment strategies used in the management of obesity. However, adherence to these behavioral changes is poor, with an increased reliance on synthetic drugs, which unfortunately are plagued by adverse effects. The identification of new and safer anti-obesity agents is thus of significant interest. In recent years, plants and their phenolic constituents have attracted increased attention due to their health-promoting properties. Amongst these, Cyclopia, an endemic South African plant commonly consumed as a herbal tea (honeybush), has been shown to possess modulating properties against oxidative stress, hyperglycemia, and obesity. Likewise, several studies have reported that some of the major phenolic compounds present in Cyclopia spp. exhibit anti-obesity effects, particularly by targeting adipose tissue. These phenolic compounds belong to the xanthone, flavonoid and benzophenone classes. The aim of this review is to assess the potential of Cyclopia extracts as an anti-obesity nutraceutical as underpinned by in vitro and in vivo studies and the underlying cellular mechanisms and biological pathways regulated by their phenolic compounds.

Eriodictyol inhibits high glucose-induced extracellular matrix accumulation, oxidative stress, and inflammation in human glomerular mesangial cells

Diabetic nephropathy (DN) is one of the major complications of diabetes mellitus. The progression of DN has been found to be associated with high glucose (HG)-induced oxidative stress and inflammation in diabetes mellitus. Eriodictyol is a flavonoid that possesses antioxidant and anti-inflammatory effects. However, the effect of eriodictyol on DN remains unknown. In the present study, we evaluated the role of eriodictyol in mesangial cells (MCs) in response to HG condition. The results showed that eriodictyol repressed cell proliferation of HG-stimulated MCs. Treatment with eriodictyol attenuated oxidative stress, which was evidenced by increased superoxide dismutase activity as well as decreased production of reactive oxygen species (ROS) and malondialdehyde. Besides, eriodictyol suppressed the expressions of two NADPH oxidase (NOX) isoforms, NOX2 and NOX4, which are responsible for the generation of ROS. Eriodictyol suppressed the production of extracellular matrix proteins including fibronectin and Collagen IV, as well as the secretion of inflammatory cytokines including TNF-α, IL-1β, and IL-6 in HG-induced MCs. Moreover, the HG-induced activation of Akt/NF-κB pathway was mitigated by eriodictyol. In conclusion, eriodictyol protected MCs from HG stimulation though inhibition of Akt/NF-κB pathway.

Sinomenine contributes to the inhibition of the inflammatory response and the improvement of osteoarthritis in mouse-cartilage cells by acting on the Nrf2/HO-1 and NF-κB signaling pathways

Pathological changes, such as articular cartilage degeneration, destruction, and hyperosteogeny, are regarded as the main features of osteoarthritis (OA). Sinomenine (SIN) is a monomeric component purified from the plant Sinomenium acutum which has been found to have anti-inflammatory effects, however, the mechanism of action of SIN on OA is not clear. In this study, we evaluated whether SIN could regulate the inflammatory response induced by interleukin (IL)-1β and improve outcomes in the instability model of OA (medial meniscus mice (DMM)) by acting on the Nrf2/HO-1 and NF-κ B signaling pathways in chondrocytes. From our experiments, which include Griess reaction, ELISA, Western blot, and immunofluorescence, we found that SIN not only down-regulated the expression of pro-inflammatory factors induced by IL-1β, including; inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), nitricoxide (NO), prostaglandin E2 (PGE2), tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6), but also decreased the production of IL-1β-induced cartilage matrix catabolic enzymes including; ADAMTS-5 and MMPs, in mouse chondrocytes. In addition, the degradation of aggrecan and type II collagen protein in the extracellular matrix (ECM) stimulated by IL-1β was reversed. Most importantly, we have revealed for the first time that in OA, SIN inhibited the inflammatory response and ECM degradation by activating the Nrf2/HO-1 signaling pathways and inhibiting NF-κB activity in mouse-cartilage cells. In in vivo experiments, SIN treatment helped to improve the cartilage destruction in OA model mice. In conclusion, this study has demonstrated that SIN inhibits the IL-1β-induced inflammatory response and cartilage destruction by activating the Nrf2/HO-1 signaling pathway and inhibiting the NF-κB signaling pathway in mouse chondrocytes, suggesting a new use for SIN in the treatment of OA.

Chondroprotective Effects of Genistein against Osteoarthritis Induced Joint Inflammation

Genistein is an isoflavone extracted from soybean (Glycine max). This compound has anti-inflammatory, anti-oxidative, and anti-cancer effects; however, the mechanism underlying the effects of genistein on IL-1β-stimulated human osteoarthritis (OA) chondrocytes remains unknown. Our objectives in this study were to explore the anti-inflammatory effects of genistein on IL-1β-stimulated human OA chondrocytes and to investigate the potential mechanisms which underlie them. Our results from an in-vitro model of osteoarthritis indicate that genistein inhibits the IL-1β-induced expression of the catabolic factors nitric oxide synthase 2 (NOS2), cyclooxygenase 2 (COX-2), and matrix metalloproteinases (MMPs). Genistein was shown to stimulate Ho-1 expression, which has been associated with Nrf-2 pathway activation in human chondrocytes. In a rat model, genistein was also shown to attenuate the progression of traumatic osteoarthritis. Taken together, these results demonstrate the effectiveness of genistein in mediating the inflammation associated with joint disorders. Our results also indicate that genistein could potentially serve as an alternative therapeutic treatment for OA.

A comprehensive study of eriocitrin metabolism in vivo and in vitro based on an efficient UHPLC-Q-TOF-MS/MS strategy

Eriocitrin, a main flavonoid in lemons, possesses strong antioxidant, lipid-lowering and anticancer activities and has long been used in food, beverages and wine. However, its metabolism in vivo and in vitro is still unclear. In this study, an efficient strategy was developed to detect and identify metabolites of eriocitrin by using ultra-high-performance liquid chromatography coupled with hybrid triple quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS) based on online data acquisition and multiple data processing techniques. A total of 32 metabolites in vivo and 27 metabolites in vitro were obtained based on the above method. Furthermore, the main metabolic pathways of eriocitrin included reduction, hydrogenation, N-acetylation, ketone formation, oxidation, methylation, sulfate conjugation, glutamine conjugation, glycine conjugation, desaturation and demethylation to carboxylic acid. This study will lay a foundation for further studies on the metabolic mechanisms of eriocitrin.

41 metabolites of eriocitrin in vivo and in vitro was identified based on the efficient UHPLC-Q-TOF-MS/MS strategy.

Transient receptor potential ankyrin 1 (trpa1) mediates il-1β-induced apoptosis in rat chondrocytes via calcium overload and mitochondrial dysfunction

Background

Chondrocyte apoptosis is a central feature in the progression of osteoarthritis (OA), and would be triggered by sustained elevation of intracellular calcium ion (Ca²⁺), also known as a cellular second messenger. Transient receptor potential ankyrin 1 (TRPA1) is a membrane-associated cation channel, and the activation of which causes an influx of cation ions, in particularly Ca²⁺, into the activated cells. Therefore, we investigate the potential role of TRPA1 in mediating Ca²⁺ influx to promote chondrocyte apoptosis in OA.

Methods

The expression of TRPA1 in interleukin (IL)-1β-treated rat chondrocytes was assessed by Polymerase chain reaction (PCR) and Western blot (WB), and the functionality of TRPA1 channel by Ca²⁺ influx measurements. Meanwhile, the chondrocyte apoptosis in IL-1β-treated cells was measured by TUNEL assay and flow cytometry. The measurement of mitochondrial membrane potential and apoptosis-associated proteins after inhibition of TRPA1 were also performed in IL-1β-treated rat chondrocytes.

Results

After being induced by IL-1β, the gene and protein expression of TRPA1 was increased in the dose-dependent manner. Meanwhile, Ca²⁺ influx mediated by TRPA1 in rat chondrocytes was also enhanced. Pharmacological inhibition of TRPA1 downregulated the apoptotic rate in IL-1β-treated rat chondrocytes. In addition, the membrane potential depolarization was improved and significantly increased expression of apoptosis-associated proteins also reduced by the TRPA1 antagonist.

Conclusions

We found the IL-1β caused the increased functional expression of TRPA1, the activation of which involved IL-1β-induced apoptosis in rat chondrocytes. The potential mechanism may be linked to the intracellular calcium overload mediated by TRPA1 and attendant mitochondrial dysfunction.