Non-flavonoid polyphenols in osteoporosis: preclinical evidence

Osteoarthritis in the Elderly Population: Preclinical Evidence of Nutrigenomic Activities of Flavonoids

Osteoarthritis (OA) is a degenerative joint disease that is age-related and progressive. It causes the destruction of articular cartilage and underlying bone, often aggravated by inflammatory processes and oxidative stresses. This pathology impairs the quality of life of the elderly, causing pain, reduced mobility, and functional disabilities, especially in obese patients. Phytochemicals with anti-inflammatory and antioxidant activities may be used for long-term treatment of OA, either in combination with current anti-inflammatories and painkillers, or as an alternative to other products such as glucosamine and chondroitin, which improve cartilage structure and elasticity. The current systematic review provides a comprehensive understanding of the use of flavonoids. It highlights chondrocyte, cartilage, and subchondral bone activities, with a particular focus on their nutrigenomic effects. The molecular mechanisms of these molecules demonstrate how they can be used for the prevention and treatment of OA in the elderly population. However, clinical trials are still needed for effective use in clinical practice.

Multi-Anticancer Activities of Phytoestrogens in Human Osteosarcoma

Phytoestrogens are plant-derived bioactive compounds with estrogen-like properties. Their potential health benefits, especially in cancer prevention and treatment, have been a subject of considerable research in the past decade. Phytoestrogens exert their effects, at least in part, through interactions with estrogen receptors (ERs), mimicking or inhibiting the actions of natural estrogens. Recently, there has been growing interest in exploring the impact of phytoestrogens on osteosarcoma (OS), a type of bone malignancy that primarily affects children and young adults and is currently presenting limited treatment options. Considering the critical role of the estrogen/ERs axis in bone development and growth, the modulation of ERs has emerged as a highly promising approach in the treatment of OS. This review provides an extensive overview of current literature on the effects of phytoestrogens on human OS models. It delves into the multiple mechanisms through which these molecules regulate the cell cycle, apoptosis, and key pathways implicated in the growth and progression of OS, including ER signaling. Moreover, potential interactions between phytoestrogens and conventional chemotherapy agents commonly used in OS treatment will be examined. Understanding the impact of these compounds in OS holds great promise for developing novel therapeutic approaches that can augment current OS treatment modalities.

Oxidative Stress and Inflammation in Osteoporosis: Molecular Mechanisms Involved and the Relationship with microRNAs

Osteoporosis is characterized by the alteration of bone homeostasis due to an imbalance between osteoclastic bone resorption and osteoblastic bone formation. Estrogen deficiency causes bone loss and postmenopausal osteoporosis, the pathogenesis of which also involves oxidative stress, inflammatory processes, and the dysregulation of the expression of microRNAs (miRNAs) that control gene expression at post-transcriptional levels. Oxidative stress, due to an increase in reactive oxygen species (ROS), proinflammatory mediators and altered levels of miRNAs enhance osteoclastogenesis and reduce osteoblastogenesis through mechanisms involving the activation of MAPK and transcription factors. The present review summarizes the principal molecular mechanisms involved in the role of ROS and proinflammatory cytokines on osteoporosis. Moreover, it highlights the interplay among altered miRNA levels, oxidative stress, and an inflammatory state. In fact, ROS, by activating the transcriptional factors, can affect miRNA expression, and miRNAs can regulate ROS production and inflammatory processes. Therefore, the present review should help in identifying targets for the development of new therapeutic approaches to osteoporotic treatment and improve the quality of life of patients.

Bioactivity, Molecular Mechanism, and Targeted Delivery of Flavonoids for Bone Loss

Skeletal disabilities are a prominent burden on the present population with an increasing life span. Advances in osteopathy have provided various medical support for bone-related diseases, including pharmacological and prosthesis interventions. However, therapeutics and post-surgery complications are often reported due to side effects associated with modern-day therapies. Thus, therapies utilizing natural means with fewer toxic or other side effects are the key to acceptable interventions. Flavonoids constitute a class of bioactive compounds found in dietary supplements, and their pharmacological attributes have been well appreciated. Recently, flavonoids' role is gaining renowned interest for its effect on bone remodeling. A wide range of flavonoids has been found to play a pivotal role in the major bone signaling pathways, such as wingless-related integration site (Wnt)/β-catenin, bone morphogenetic protein (BMP)/transforming growth factor (TGF)-β, mitogen-activated protein kinase (MAPK), etc. However, the reduced bioavailability and the absorption of flavonoids are the major limitations inhibiting their use against bone-related complications. Recent utilization of nanotechnological approaches and other delivery methods (biomaterial scaffolds, micelles) to target and control release can enhance the absorption and bioavailability of flavonoids. Thus, we have tried to recapitulate the understanding of the role of flavonoids in regulating signaling mechanisms affecting bone remodeling and various delivery methods utilized to enhance their therapeutical potential in treating bone loss.

Flavonoids from Dalbergia cochinchinensis: Impact on osteoclastogenesis

Background/purpose

Dalbergia cochinchinensi has been widely used in traditional medicine because of its flavonoids. This study examined which components in D. cochinchinensis were capable of reducing or even stimulating the formation of bone-resorbing osteoclasts.

Materials and methods

We have isolated subfamilies of chalcones (isoliquiritigenin, butein), flavones (7-hydroxy-6-methoxyflavone) and neoflavanoids (5-methoxylatifolin), and performed an in vitro bioassay on osteoclastogenesis. The flavonoids were tested for their potential to change the expression of tartrate-resistant acid phosphatase (TRAP) and cathepsin K (CTSK) in murine bone marrow cultures being exposed to RANKL, M-CSF and TGF-β1 using RT-PCR, histochemistry and immunoassay.

Results

We could confirm that isoliquiritigenin and butein significantly lower the expression of TRAP and CTSK in this setting. Moreover, histochemistry supported the decrease of TRAP by the chalcones. We further observed a trend towards an increase of osteoclastogenesis in the presence of 5-methoxylatifolin and 7-hydroxy-6-methoxyflavone, particular in bone marrow cultures being exposed to RANKL and M-CSF. Consistently, the anti-inflammatory activity was restricted to isoliquiritigenin and butein in murine RAW 264.7 inflammatory macrophages stimulated by lipopolysaccharide (LPS). With respect to osteoblastogenesis, neither of the flavonoids but butyrate, a short chain fatty acid, increased the osteogenic differentiation marker alkaline phosphatase activity in ST2 murine mesenchymal cells.

Conclusion

We have identified two flavonoids from D. cochinchinensis with a potential pro-osteoclastogenic activity and confirm the anti-osteoclastogenic activity of isoliquiritigenin and butein.

Recent Advances in Natural Polyphenol Research

Polyphenols are secondary metabolites produced by plants, which contribute to the plant's defense against abiotic stress conditions (e.g., UV radiation and precipitation), the aggression of herbivores, and plant pathogens. Epidemiological studies suggest that long-term consumption of plant polyphenols protects against cardiovascular disease, cancer, osteoporosis, diabetes, and neurodegenerative diseases. Their structural diversity has fascinated and confronted analytical chemists on how to carry out unambiguous identification, exhaustive recovery from plants and organic waste, and define their nutritional and biological potential. The food, cosmetic, and pharmaceutical industries employ polyphenols from fruits and vegetables to produce additives, additional foods, and supplements. In some cases, nanocarriers have been used to protect polyphenols during food processing, to solve the issues related to low water solubility, to transport them to the site of action, and improve their bioavailability. This review summarizes the structure-bioactivity relationships, processing parameters that impact polyphenol stability and bioavailability, the research progress in nanocarrier delivery, and the most innovative methodologies for the exhaustive recovery of polyphenols from plant and agri-waste materials.

Effect of moderate beer consumption (with and without ethanol) on osteoporosis in early postmenopausal women: Results of a pilot parallel clinical trial

Introduction

Osteoporosis is a chronic progressive bone disease characterized by low bone mineral density (BMD) and micro-architectural deterioration of bone tissue, leading to an increase in bone fragility and the risk of fractures. A well-known risk factor for bone loss is postmenopausal status. Beer may have a protective effect against osteoporosis associated with its content of silicon, polyphenols, iso-α-acids and ethanol, and its moderate consumption may therefore help to reduce bone loss in postmenopausal women.

Methods

Accordingly, a 2-year controlled clinical intervention study was conducted to evaluate if a moderate daily intake of beer with (AB) or without alcohol (NAB) could have beneficial effects on bone tissue. A total of 31 postmenopausal women were assigned to three study groups: 15 were administered AB (330 mL/day) and six, NAB (660 mL/day), whereas, the 10 in the control group refrained from consuming alcohol, NAB, and hop-related products. At baseline and subsequent assessment visits, samples of plasma and urine were taken to analyze biochemical parameters, and data on medical history, diet, and exercise were collected. BMD and the trabecular bone score (TBS) were determined by dual-energy X-ray absorptiometry. Markers of bone formation (bone alkaline phosphatase [BAP] and N-propeptide of type I collagen [PINP]) and bone resorption (N-telopeptide of type I collagen [NTX] and C-telopeptide of type I collagen [CTX]) were determined annually.

Results

Bone formation markers had increased in the AB and NAB groups compared to the control after the 2-year intervention. However, the evolution of BMD and TBS did not differ among the three groups throughout the study period.

Discussion

Therefore, according to the findings of this pilot study, moderate beer intake does not seem to have a protective effect against bone loss in early post-menopausal women.

Polyphenols: Chemoprevention and therapeutic potentials in hematological malignancies

Polyphenols are one of the largest plant-derived natural product and they play an important role in plants' defense as well as in human health and disease. A number of them are pleiotropic molecules and have been shown to regulate signaling pathways, immune response and cell growth and proliferation which all play a role in cancer development. Hematological malignancies on the other hand, are cancers of the blood. While current therapies are efficacious, they are usually expensive and with unwanted side effects. Thus, the search for newer less toxic agents. Polyphenols have been reported to possess antineoplastic properties which include cell cycle arrest, and apoptosis via multiple mechanisms. They also have immunomodulatory activities where they enhance T cell activation and suppress regulatory T cells. They carry out these actions through such pathways as PI3K/Akt/mTOR and the kynurenine. They can also reverse cancer resistance to chemotherapy agents. In this review, i look at some of the molecular mechanism of action of polyphenols and their potential roles as therapeutic agents in hematological malignancies. Here i discuss their anti-proliferative and anti-neoplastic activities especially their abilities modulate signaling pathways as well as immune response in hematological malignancies. I also looked at clinical studies done mainly in the last 10-15 years on various polyphenol combination and how they enhance synergism. I recommend that further preclinical and clinical studies be carried out to ensure safety and efficacy before polyphenol therapies be officially moved to the clinics.

Association of ESR1 and ESR2 Polymorphisms with Osteoporosis: A Meta-Analysis from 36 Studies

BACKGROUND

Recently, the roles of ESR1 and ESR2 polymorphisms in osteoporosis have been extensively reported, with conflicting findings. Therefore, we performed this present study to evaluate the potential associations between ESR1 and ESR2 polymorphisms and osteoporosis risk.

METHODOLOGY

All included literatures published up to April 2021 were identified by searching Pubmed, Embase, Web of Science, Cochrane Library, Chinese National Knowledge Infrastructure (CNKI) and Wanfang databases. Pooled odds ratio (OR) and 95% confidence interval (CI) were calculated the associations using a fixed or random effects model.

RESULTS

36 observational studies involving five gene polymorphisms (ESR1 PvuII, ESR1 XbaI, ESR1 G2014A, ESR2 AluI and ESR2 RsaI) covering 12507 cases and 18487 controls were included. The results of our meta-analysis demonstrated the variant A allele of ESR2 RsaI polymorphism might play a remarkable protective role in developing osteoporosis under all genetic models. However, no associations were observed between ESR1 PvuII, ESR1 XbaI, ESR1 G2014A and ESR2 AluI polymorphisms with the risk of osteoporosis under all genetic models.

CONCLUSIONS

Our meta-analysis suggests that genetic polymorphism in ESR2 RsaI may lead to decreased risk for osteoporosis. Further larger studies are needed to confirm this conclusion.

Two Important Anticancer Mechanisms of Natural and Synthetic Chalcones

ATP-binding cassette subfamily G and tubulin pharmacological mechanisms decrease the effectiveness of anticancer drugs by modulating drug absorption and by creating tubulin assembly through polymerization. A series of natural and synthetic chalcones have been reported to have very good anticancer activity, with a half-maximal inhibitory concentration lower than 1 µM. By modulation, it is observed in case of the first mechanism that methoxy substituents on the aromatic cycle of acetophenone residue and substitution of phenyl nucleus by a heterocycle and by methoxy or hydroxyl groups have a positive impact. To inhibit tubulin, compounds bind to colchicine binding site. Presence of methoxy groups, amino groups or heterocyclic substituents increase activity.

Modulation of Inflammation by Plant-Derived Nutraceuticals in Tendinitis

Tendinitis (tendinopathy) is a pro-inflammatory and painful tendon disease commonly linked with mechanical overuse and associated injuries, drug abuse, and lifestyle factors (including poor diet and physical inactivity) that causes significant healthcare expenditures due to its high incidence. Nuclear factor kappa B (NF-κB) is one of the major pro-inflammatory transcription factors, along with other inflammation signaling pathways, triggered by a variety of stimuli, including cytokines, endotoxins, physical and chemical stressors, hypoxia, and other pro-inflammatory factors. Their activation is known to regulate the expression of a multitude of genes involved in inflammation, degradation, and cell death. The pathogenesis of tendinitis is still poorly understood, whereas efficient and sustainable treatment is missing. Targeting drug suppression of the key inflammatory regulators represents an effective strategy for tendinitis therapy, but requires a comprehensive understanding of their principles of action. Conventional monotherapies are often ineffective and associated with severe side effects in patients. Therefore, agents that modulate multiple cellular targets represent therapeutic treatment potential. Plant-derived nutraceuticals have been shown to act as multi-targeting agents against tendinitis via various anti-oxidant and anti-inflammatory mechanisms, whereat they were able to specifically modulate numerous signaling pathways, including NF-κB, p38/MAPK, JNK/STAT3, and PI3K/Akt, thus down-regulating inflammatory processes. This review discusses the utility of herbal nutraceuticals that have demonstrated safety and tolerability as anti-inflammatory agents for the prevention and treatment of tendinitis through the suppression of catabolic signaling pathways. Limitations associated with the use of nutraceuticals are also described.

ncRNAs and polyphenols: new therapeutic strategies for hypertension

Polyphenols have gained significant attention in protecting several chronic diseases, such as cardiovascular diseases (CVDs). Accumulating evidence indicates that polyphenols have potential protective roles for various CVDs. Hypertension (HTN) is among the hazardous CVDs accounting for nearly 8.5 million deaths worldwide. HTN is a complex and multifactorial disease and a combination of genetic susceptibility and environmental factors play major roles in its development. However, the underlying regulatory mechanisms are still elusive. Polyphenols have shown to cause favourable and beneficial effects in the management of HTN. Noncoding RNAs (ncRNAs) as influential mediators in modulating the biological properties of polyphenols, have shown significant footprints in CVDs. ncRNAs control basic functions in virtually all cell types relevant to the cardiovascular system and, thus, a direct link with blood pressure (BP) regulation is highly probable. Recent evidence suggests that a number of ncRNAs, including main small ncRNAs, microRNAs (miRNAs) and long ncRNAs (lncRNAs), play crucial roles with respect to the antihypertensive effects of polyphenols. Indeed, targeting lncRNAs by polyphenols will be a novel and promising strategy in the management of HTN. Herein, we reviewed the effects of polyphenols in HTN. Additionally, we emphasized on the potential effects of polyphenols on regulations of main ncRNAs, which imply the role of polyphenols in regulating ncRNAs in order to exert protective effects and thus proposing them as new targets for HTN treatment.Abbreviations : CVD: cardiovascular disease; BP: blood pressure; HTN: hypertension, lncRNAs: long noncoding RNAs; p38-MAPK: p38-mitogenactivated protein kinase; OPCs: oligomeric procyanidins; GTP: guanosine triphosphate; ROS: reactive oxygen species; cGMP: cyclic guanosine monophosphate; SGC: soluble guanylate cyclase; PI3K: phosphatidylinositol 3-kinase; cGMP: Cyclic GMP; eNOS: endothelial NO synthase; ERK ½: extracellular signal-regulated kinase ½; L-Arg: L-Arginine; MAPK: mitogen-activated protein kinases; NO: Nitric oxide; P: Phosphorus; PDK1: Phosphoinositide-dependent kinase 1; PI3-K: Phosphatidylinositol 3-kinase; PIP2: Phosphatidylinositol diphosphate; ncRNAs: non-protein-coding RNA; miRNAs: microRNAs; OPCs: oligomeric procyanidins; RES: resveratrol; GE: grape extract; T2DM: type 2 diabetes mellitus; IL: interleukin; TNF-α: tumour necrosis factor-alpha; NF-κB: nuclear factor NF-kappa-B; ALP: alkaline phosphatase; PARP1: poly [ADP-ribose] polymerase 1; HIF1a: Hypoxia-inducible-factor 1A; NFATc2: nuclear factor of activated T cells 2; PAD: peripheral artery disease; SHR: spontaneously hypertensive rat; RAAS: renin-angiotensin-aldosterone system; AT₁R: angiotensin type-1 receptor; Nox: NADPH oxidase; HO-1: haem oxygenase-1; JAK/STAT: Janus kinase/signal transducers/activators of the transcription; PNS: panax notoginseng saponin; snoRNA: small nucleolar RNA; hnRNA: heterogeneous nuclear RNA; VSMCs: vascular smooth muscle cells; irf7: interferon regulatory factor 7; limo2: LIM only domain 2; GWAS: genome-wide association study; GAS5: Growth arrest-specific 5; Asb3, Ankyrin repeat and SPCS box containing 3; Chac2: cation transport regulator homolog 2; Pex11b: peroxisomal membrane 11B; Sp5: Sp5 transcription factor; EGCG: epigallocatechin gallate; ApoE: Apo lipoprotein E; ERK-MAP kinase: extracellular signal-regulated kinases-mitogen-activated protein kinase; PAH: pulmonary artery hypertension; PAP: pulmonary arterial pressure; HIF1a: hypoxia-inducible-factor 1A; NFATc2: nuclear factor of activated T cells 2; HMEC-1: Human microvascular endothelial cells; stat2: signal transducers and activators of transcription 2; JNK: c-Jun N-terminal kinase; iNOS: inducible NO synthase. SNP: single nucleotide polymorphism; CAD: coronary artery disease.

Multiple Effects of Resveratrol on Osteosarcoma Cell Lines

Osteosarcoma (OS) is the most common primary bone sarcoma affecting the life of pediatric patients. The clinical treatment faces numerous difficulties, including the adverse effects of chemotherapies, chemoresistance, and recurrences. In this study, the effects of resveratrol (RSV), a natural polyphenol, on OS cell lines were investigated to evaluate its action as an adjuvant therapy to the current chemotherapy regimens. RSV exhibited multiple tumor-suppressing activities on OS cell lines, inducing a series of critical events. We found (1) a cell growth inhibition due to an increase in cell distress, which was, in part, due to the involvement of the AKT and caspase-3 pathways, (2) an increase in cellular differentiation due to major gene expression levels of the osteoblastic differentiation genes, (3) an inhibition of IL-6 secretion due to an epigenetic effect on the IL-6 promoter, and (4) an inhibition of OS cells migration related to the decrease in IL-8 secretion levels due to an epigenetic effect on its promoter. Finally, the cotreatment of RSV with doxorubicin and cisplatin increased their cytotoxic effect on OS cells. Although further investigations are mandatory, it seems RSV might be a promising therapeutic adjuvant agent for OS cell treatment, exerting an antitumor effect when combined with chemotherapy.

Effects and Mechanisms of Rhus chinensis Mill. Fruits on Suppressing RANKL-Induced Osteoclastogenesis by Network Pharmacology and Validation in RAW264.7 Cells

Rhus chinensis Mill. fruits are a kind of widely distributed edible seasoning, which have been documented to possess a variety of biological activities. However, its inhibitory effect on osteoclast formation has not been determined. The objective of this study was to evaluate the effect of the fruits on osteoclast differentiation of RAW264.7 cells, induced by receptor activator of nuclear factor-κB ligand (RANKL) and to illuminate the potential mechanisms using network pharmacology and western blots. Results showed that the extract containing two organic acids and twelve phenolic substances could effectively inhibit osteoclast differentiation in RANKL-induced RAW264.7 cells. Network pharmacology examination and western blot investigation showed that the concentrate essentially decreased the expression levels of osteoclast-specific proteins, chiefly through nuclear factor kappa-B, protein kinase B, and mitogen-activated protein kinase signaling pathways, particularly protein kinase B α and mitogen-activated protein kinase 1 targets. Moreover, the extract likewise directly down regulated the expression of cellular oncogene Fos and nuclear factor of activated T-cells cytoplasmic 1 proteins. Citric acid, quercetin, myricetin-3-O-galactoside, and quercetin-3-O-rhamnoside were considered as the predominant bioactive ingredients. Results of this work may provide a scientific basis for the development and utilization of R. chinensis fruits as a natural edible material to prevent and/or alleviate osteoporosis-related diseases.

Antioxidant and Bone; Protect Your Future: A Brief Review

The global campaign of osteoporosis has been organized by the International Osteoporosis Foundation (IOF) and them introducing World Osteoporosis Day (WOD) in 1997. The day is celebrated on October 20^th each year and aimed to improve the awareness of the population about disease prevention. We present some aspects of bone health and the prevention of osteoporosis related to the use of vitamins. The presenting mini-review covers a variety of sources including PubMed, Embase, Scopus, and directory of open access journals (DOAJ) from 10 years ago (Oct 2009 to Oct 2019) for recent developments in the prevention of bone loss. The search was performed by using combinations of the following keywords and or their equivalents; osteoporosis, bones health, bone loss, and vitamin to find related articles about the prevention of osteoporosis by nutritional factors. The factors affecting bone are various and could begin from fetal periods to the end of life. Some of them are not changeable including age, and genetic; however, it is possible to modify some others such as poor nutrition and vitamin deficiency. Beyond vitamin D deficiency, consumption of other vitamins also is beneficial to maintain bone health. By considering the nutritional factors especially vitamins that affect bones, it is possible to have stronger bones to enjoy life in the elderly and protect your future.

Terpenoid treatment in osteoporosis: this is where we have come in research

Lower bone resistance to load is due to the imbalance of bone homeostasis, where excessive bone resorption, compared with bone formation, determines a progressive osteopenia, leading to a high risk of fractures and consequent pain and functional limitations. Terpenoids, with their activities against bone resorption, have recently received increased attention from researchers. They are potentially more suitable for long-term use compared with traditional therapeutics. In this review of the literature of the past 5 years, we provide comprehensive information on terpenoids, with their anti-osteoporotic effects, highlighting molecular mechanisms that are often in epigenetic key and a possible pharmacological use in osteoporosis prevention and treatment.

Emerging roles of circular RNAs in osteoporosis

Osteoporosis is one bone disease characterized with skeletal impairment, bone strength reduced and fracture risk enhanced. The regulation processes of bone metabolism are associated with several factors such as mechanical stimulation, epigenetic regulation and hormones. However, the mechanism of osteoporosis remains unsatisfactory. Increasing high‐throughput RNA sequencing and circular RNAs (circRNAs) microarray studies indicated that circRNAs are differentially expressed in osteoporosis. Growing functional studies further pinpointed specific deregulated expressed circRNAs (e.g., circ_28313, circ_0016624, circ_0006393, circ_0076906 and circ_0048211) for their functions involved in bone metabolism, including bone marrow stromal cells (BMSCs) differentiation, proliferation and apoptosis. Moreover, CircRNAs (circ_0002060, Circ_0001275 and Circ_0001445) may be acted as diagnostic biomarkers for osteoporosis. This review discussed recent progresses in the circRNAs expression profiling analyses and their potential functions in regulating BMSCs differentiation, proliferation and apoptosis.