The effects of flavonoids on bone

Dietary Flavonoid and Subclass Intakes are not Associated with Markers of Bone Health in U.S. Adults Age 50+ Years

BACKGROUND

Dietary flavonoid intakes have been associated with improved markers of bone health in Chinese and Scottish cohorts, but little data exist in middle aged to older adults in the United States.

OBJECTIVES

The objective of our research was to assess if dietary flavonoid intakes are associated with bone mineral density (BMD), bone mineral content (BMC), and bone area of the lumbar spine and femoral neck in a nationally representative population of middle aged to older U.S. adults. We further sought to investigate if relationships of the main flavonoid subgroups (i.e., anthocyanins, flavan-3-ols, flavanones, flavones, flavonols, and isoflavones) exist, as a secondary objective.

METHODS

Cross-sectional data from individuals aged 50+ years enrolled in the 2017-2018 National Health and Nutrition Examination Survey (NHANES) were used in our analyses (N = 2590). Weighted multivariate logistic regression models were used to investigate the relationship between quartiles of flavonoid intake and BMD, BMC, and bone area of the lumbar spine and femoral neck of participants.

RESULTS

Mean age of participants was 63.4 ± 0.52 years and 64.1 ± 0.52 years for men and women, respectively. Average total flavonoid intake was 217 ± 19.4 mg/day and 306 ± 26.9 mg/day for men and women, respectively. Total flavonoid intakes were not significantly associated with BMD, BMC, or bone area of the femoral neck or lumbar spine in male or female participants. Flavonoid subclass intakes were also not consistently associated with improved markers of bone health.

CONCLUSION

Although several limitations exist, this cross-sectional analysis of U.S. adults aged 50+ years provides contradictory evidence to the hypothesis that higher flavonoid and flavonoid subclass intakes beneficially impacts markers of bone health. Large prospective cohort investigations that better capture long-term dietary flavonoid intake and ascertain fractures the primary outcome, as well as randomized controlled trials, are needed to fully elucidate the effects flavonoids on bone health.

Increased Osteoblastic and Osteocytic in Vitro Cell Viability by Yerba Mate (Ilex paraguariensis)

BACKGROUND

Yerba mate (YM, Ilex paraguariensis) consumption beneficially affects the bones. However, whether YM components exert their effect on bone cells directly remains elusive.

METHODS

We evaluated how main YM components affect osteoblastic (MC3T3-E1) and osteocytic (MLO-Y4) cells in vitro when administered separately or in an aqueous extract. MC3T3-E1 and MLO-Y4 cells were exposed to three different experimental conditions: (1) Caffeine, chlorogenic acid, and their combinations; (2) Caffeine, rutin, and their combinations; (3) Aqueous YM extract.

RESULTS

All polyphenol and caffeine concentrations as well as that of their tested combinations significantly increased MC3T3-E1 cell viability from 16.6% to 34.8% compared to the control. In MLO-Y4 cells, the lowest rutin and the two highest caffeine concentrations significantly increased cell viability by 11.9, 14.9, and 13.7%, respectively. While rutin and caffeine combinations tended to increase MLO-Y4 cell viability, different chlorogenic acid and caffeine combinations did not affect it. Finally, the aqueous YM extract significantly increased MLO-Y4, MC3T3-E1, and differentiated MC3T3-E1 cell viability compared to the control without treatment.

CONCLUSIONS

YM components (rutin, chlorogenic acid, and caffeine) positively affected bone cells, mainly pre-osteoblast cells. Moreover, the aqueous YM extract significantly increased MLO-Y4, MC3T3-E1, and differentiated MC3T3-E1 cell viabilities indicating an additional relevant nutritional property of YM infusion. Further studies would be required to elucidate the underlying effector mechanism of YM on the bones and its relationship with previously described in vivo positive effects.

The Potential Use of Vitamin D3 and Phytochemicals for Their Anti-Ageing Effects

Unlike other vitamins, vitamin D3 is synthesised in skin cells in the body. Vitamin D3 has been known as a bone-related hormone. Recently, however, it has been considered as an immune vitamin. Vitamin D3 deficiency influences the onset of a variety of diseases. Vitamin D3 regulates the production of proinflammatory cytokines such as tumour necrosis factor-α (TNF-α) through binding to vitamin D receptors (VDRs) in immune cells. Since blood levels of vitamin D3 (25-OH-D3) were low in coronavirus disease 2019 (COVID-19) patients, there has been growing interest in the importance of vitamin D3 to maintaining a healthy condition. On the other hand, phytochemicals are compounds derived from plants with over 7000 varieties and have various biological activities. They mainly have health-promoting effects and are classified as terpenoids, carotenoids, flavonoids, etc. Flavonoids are known as the anti-inflammatory compounds that control TNF-α production. Chronic inflammation is induced by the continuous production of TNF-α and is the fundamental cause of diseases like obesity, dyslipidaemia, diabetes, heart and brain diseases, autoimmune diseases, Alzheimer's disease, and cancer. In addition, the ageing process is induced by chronic inflammation. This review explains the cooperative effects of vitamin D3 and phytochemicals in the suppression of inflammatory responses, how it balances the natural immune response, and its link to anti-ageing effects. In addition, vitamin D3 and phytochemicals synergistically contribute to anti-ageing by working with ageing-related genes. Furthermore, prevention of ageing processes induced by the chronic inflammation requires the maintenance of healthy gut microbiota, which is related to daily dietary habits. In this regard, supplementation of vitamin D3 and phytochemicals plays an important role. Recently, the association of the prevention of the non-disease condition called "ME-BYO" with the maintenance of a healthy condition has been an attractive regimen, and the anti-ageing effect discussed here is important for a healthy and long life.

Bone Fracture-healing Properties and UPLC-MS Analysis of an Enriched Flavonoid Fraction from Oxystelma esculentum

Oxystelma esculentum has been used as a folk medicine to treat jaundice, throat infections, and skin problems. In the current study, the bone fracture-healing properties of a flavonoid-enriched fraction (Oxy50-60F) of O. esculentum were investigated in Swiss mice using a drill-hole injury model. Oxy50-60F (1 mg/kg/day, 5 mg/kg/day, and 10 mg/kg/day) was administered orally (from the next day) after a 0.6 mm drill-hole injury in mice femur mid-diaphysis for 7 days and 14 days. Parathyroid hormone (40 µg/kg; 5 times/week) was given subcutaneously as the positive control. Confocal imaging for bone regeneration, micro-architecture of femur bones, ex vivo mineralization, hematoxyline and eosin staining, measurement of reactive oxygen species, and gene expression of osteogenic and anti-inflammatory genes were studied. Quercetin, kaempferol, and isorhamnetin glycosides were identified in the active fraction using mass spectrometry techniques. Our results confirm that Oxy50-60F treatment promotes fracture healing and callus formation at drill-hole sites and stimulates osteogenic and anti-inflammatory genes. Oxy50-60F administration to fractured mice exhibited significantly better micro-CT parameters in a dose-dependent manner and promoted nodule mineralization at days 7 and 14 post-injury. Oxy50-60F also prevents ROS generation by increasing expression of the SOD2 enzyme. Overall, this study reveals that Oxy50-60F has bone regeneration potential in a cortical bone defect model, which supports its use in delayed-union and non-union fracture cases.

Fruit and Vegetable Consumption and the Risk of Bone Fracture: A Grading of Recommendations, Assessment, Development, and Evaluations (GRADE)-Assessed Systematic Review and Dose-Response Meta-Analysis

Researchers have examined the link between consuming fruit and vegetables and the incidence of fractures for many years. Nevertheless, their findings have been unclear. Furthermore, the dose-dependent relationship has not been examined, and the level of certainty in the evidence was not evaluated. We carried out a dose-dependent meta-analysis examining the relation between fruit and vegetables intake and fracture incidence. PubMed, Web of Sciences, and Scopus were searched until April 2023 for cohort studies evaluating the relation between fruit and vegetables and fracture incidence. Summary relative risks (RRs) were computed from complied data by applying random effects analysis. To examine the level of evidence, we utilized the approach called the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE). Ten cohort studies comprising 511,716 individuals were entered. There was a nonsignificant relation between fruit and vegetables, as well as only fruit intake and any fracture risk. In contrast, high versus low analysis presented that vegetables consumption was linked to a 16% decrease in any type of fracture incidence (RR 0.84; 95% confidence interval [CI], 0.75 to 0.95; I 2 = 83.1%; n = 6). Also, per one serving/day (200 g/day) increments in vegetables consumption, there was a 14% decline in the fracture risk (RR 0.86; 95% CI, 0.77 to 0.97; I 2 = 84.7%; n = 5; GRADE = moderate). With moderate certainty, a greater consumption of only vegetables, but not total fruit and vegetables or only fruit, might reduce the risk of fracture. These associations were also evident in dose-response analysis. Large intervention trials are demanded to approve our findings. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Hesperidin Anti-Osteoporosis by Regulating Estrogen Signaling Pathways

Osteoporosis (OP) is distinguished by a reduction in bone mass and degradation of bone micro-structure, frequently resulting in fractures. As the geriatric demographic expands, the incidence of affected individuals progressively rises, thereby exerting a significant impact on the quality of life experienced by individuals. The flavonoid compound hesperidin has been subject to investigation regarding its effects on skeletal health, albeit the precise mechanisms through which it operates remain ambiguous. This study utilized network pharmacology to predict the core targets and signaling pathways implicated in the anti-OP properties of hesperidin. Molecular docking and molecular dynamics simulations were employed to confirm the stability of the interaction between hesperidin and the core targets. The effects of hesperidin on osteoblastic cells MC3T3-E1 were assessed using MTT, ELISA, alkaline phosphatase assay, and RT-qPCR techniques. Furthermore, in vivo experiments were conducted to determine the potential protective effects of hesperidin on zebrafish bone formation and oxidative stress response. The results demonstrate that network pharmacology has identified 10 key target points, significantly enriched in the estrogen signaling pathway. Hesperidin exhibits notable promotion of MC3T3-E1 cell proliferation and significantly enhances ALP activity. ELISA measurements indicate an elevation in NO levels and a reduction in IL-6 and TNF-α. Moreover, RT-qPCR analysis consistently reveals that hesperidin significantly modulates the mRNA levels of ESR1, SRC, AKT1, and NOS3 in MC3T3-E1 cells. Hesperidin promotes osteogenesis and reduces oxidative stress in zebrafish. Additionally, we validate the stable and tight binding of hesperidin with ESR1, SRC, AKT1, and NOS3 through molecular dynamics simulations. In conclusion, our comprehensive analysis provides evidence that hesperidin may exert its effects on alleviating OP through the activation of the estrogen signaling pathway via ESR1. This activation leads to the upregulation of SRC, AKT, and eNOS, resulting in an increase in NO levels. Furthermore, hesperidin promotes osteoblast-mediated bone formation and inhibits pro-inflammatory cytokines, thereby alleviating oxidative stress associated with OP.

Biological Properties and Antimicrobial Potential of Cocoa and Its Effects on Systemic and Oral Health

Cocoa is considered a functional food because it is a natural source of macro- and micronutrients. Thus, cocoa is rich in vitamins, minerals, fiber, fatty acids, methylxanthines and flavonoids. In addition to favoring the metabolism of lipids and carbohydrates, the bioactive components of cocoa can have an antioxidant, anti-inflammatory and antimicrobial effect, providing numerous benefits for health. This literature review presents an overview of the effects of cocoa, fruit of the Theobroma cacao tree, on systemic and oral health. Several studies report that cocoa intake may contribute to the prevention of cardiovascular, neurodegenerative, immunological, inflammatory, metabolic and bone diseases, in addition to reducing the risk of vascular alterations and cognitive dysfunctions. On oral health, in vitro studies have shown that cocoa extract exerted an inhibitory effect on the growth, adherence and metabolism of cariogenic and periodontopathogenic bacteria, also inhibiting acid production, glycosyltransferase enzyme activity and the synthesis of insoluble polysaccharides. Additionally, administration of cocoa extract reduced biofilm accumulation and caries development in animals infected with cariogenic species. Clinical studies also reported that the use of mouthwashes containing cocoa extract reduced Streptococcus mutans counts in saliva and dental biofilm formation. In short, these studies highlight the nutritional value of cocoa, considering its clinical applicability, stability and economic accessibility.

Plant-Based Dairy Alternatives Contribute to a Healthy and Sustainable Diet

Plant-based foods are increasing in popularity as more and more people are concerned about personal and planetary health. The consumption of plant-based dairy alternatives (PBDAs) has assumed a more significant dietary role in populations shifting to more sustainable eating habits. Plant-based drinks (PBDs) made from soya and other legumes have ample protein levels. PBDs that are appropriately fortified have adequate levels of important vitamins and minerals comparable to dairy milk. For the PBDs examined, the greenhouse gas emissions were diminished by 59-71% per 250 mL, and the land use and eutrophication impact was markedly less than the levels displayed by dairy milk. The water usage for the oat and soya drinks, but not rice drinks, was substantially lower compared to dairy milk. When one substitutes the 250 mL serving of dairy milk allowed within the EAT Lancet Planetary Health Diet for a fortified plant-based drink, we found that the nutritional status is not compromised but the environmental footprint is reduced. Combining a nutrient density score with an environmental index can easily lead to a misclassification of food when the full nutrition profile is not utilized or only a selection of environmental factors is used. Many PBDAs have been categorized as ultra-processed foods (UPFs). Such a classification, with the implied adverse nutritional and health associations, is inconsistent with current findings regarding the nutritional quality of such products and may discourage people from transitioning to a plant-based diet with its health and environmental advantages.

Catechins and Proanthocyanidins Involvement in Metabolic Syndrome

Recent studies on natural antioxidant compounds have highlighted their potentiality against various pathological conditions. The present review aims to selectively evaluate the benefits of catechins and their polymeric structure on metabolic syndrome, a common disorder characterized by a cluster of three main risk factors: obesity, hypertension, and hyperglycemia. Patients with metabolic syndrome suffer chronic low inflammation state and oxidative stress both conditions effectively countered by flavanols and their polymers. The mechanism behind the activity of these molecules has been highlighted and correlated with the characteristic features present on their basic flavonoidic skelethon, as well as the efficient doses needed to perform their activity in both in vitro and in vivo studies. The amount of evidence provided in this review offers a starting point for flavanol dietary supplementation as a potential strategy to counteract several metabolic targets associated with metabolic syndrome and suggests a key role of albumin as flavanol-delivery system to the different target of action inside the organism.

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.

Diosmetin inhibits subchondral bone loss and indirectly protects cartilage in a surgically-induced osteoarthritis mouse model

Osteoarthritis (OA) is a common degenerative disease characterized by articular cartilage destruction, subchondral bone remodeling, ectopic osteophyte formation and synovitis. It is now recognized that the integrity of the underlying subchondral bone is crucial for the maintenance of the overlying articular cartilage. Therapeutic agents that can prevent subchondral bone loss are demonstrate potential in the prevention and treatment of OA. Diosmetin (DIOS; 3',5,7 -trihydroxy-4'-methoxy flavone), a natural flavonoid, has been shown to exert anti-oxidative, anti-inflammatory, anti-apoptotic and anticancer properties. In this study, we found that diosmetin suppressed the DMM-induced subchondral bone loss and reduced subsequent cartilage degradation in vivo. Cellular-based assays showed that diosmetin inhibited RANKL-induced osteoclast formation and bone resorption,but did not affect IL-1β-induced chondrocyte hypertrophy. Biochemical analyses demonstrated that the anti-osteoclastic effect of diosmetin was at least in part due to the suppression of RANKL-induced activation of the ERK, p38, and JNK MAPK signaling pathways. Collectively, our results show that diosmetin have potential as a therapeutic agent the treatment of abnormal subchondral bone loss and cartilage degradation associated with the onset of OA.

Avicularin Alleviates Osteoporosis in Ovariectomized Mice by Inhibiting Osteoclastogenesis through NF-κB Pathway Inhibition

Osteoporosis (OP) is mainly manifested by bone loss and bone degeneration. OP is considered a risk factor for pathological fractures, as well as impacts the health of middle-aged and elderly individuals. Drug therapy remains the main treatment scheme for OP; however, its efficacy is limited and has been associated with serious side effects. Therefore, it is important to develop new, effective, and safe treatment methods for OP. Avicularin (AL) is a flavonoid and quercetin derivative from various plants. Our study showed that AL disrupts osteoclast activation and resorptive function via inhibition of the RANKL-induced osteoclast differentiation together with the resorption capacity of bone marrow-derived macrophages (BMMs). Hence, AL prevents the activation and resorptive activity of osteoclasts. The results of qPCR showed that genes related to osteoclasts exhibited downregulated expression after AL treatment. Furthermore, AL inhibited RANKL-induced phosphorylation as well as degradation of the inhibitor IκBα of the NF-κB pathway, together with P65 phosphorylation in BMMs. We used an OP mouse model that was established by ovariectomy (OVX). Relative to untreated OP mice, mice that received AL treatment showed a significant increase in bone mineral density; however, the expression of TRAP, NFATC1, mmp9, and CTX-1 was significantly reduced. These results indicate that AL disrupts osteoclastogenesis via inhibition of the NF-κB pathway, which in turn improves OVX-induced OP.

Evaluation of vasodilatory effect and antihypertensive effect of chrysin through in vitro and sub-chronic in vivo study

Chrysin, a bioflavonoid belonging to the flavone, occurs naturally in plants such as the passionflower, honey and propolis. Few studies have demonstrated that chrysin can promote vasorelaxant activities in rats' aorta and mesenteric arteries. To date, no research has explored the signalling system routes that chrysin may utilise to produce its vasorelaxant action. Therefore, this study aimed to investigate the underlying mechanisms involved in chrysin-induced vasorelaxant in rats' aortic rings and assess the antihypertensive effect of chrysin in spontaneously hypertensive rats (SHRs). The findings revealed that chrysin utilised both endothelium-dependent and endothelium-independent mechanisms. The presence of L-NAME (endothelial NO synthase inhibitor), ODQ (sGC inhibitor), methylene blue (cGMP lowering agent), 4-AP (voltage-gated potassium channel inhibitor), atropine (muscarinic receptors inhibitor) and propranolol (β-adrenergic receptors inhibitor) significantly reduced the chrysin's vasorelaxant action. Furthermore, chrysin can reduce intracellular Ca²⁺ levels by limiting the extracellular intake of Ca²⁺ through voltage-operated calcium channels and blocking the intracellular release of Ca²⁺ from the sarcoplasmic reticulum via the IP₃ receptor. These indicate that chrysin-induced vasorelaxants involved NO/sGC/cGMP signalling cascade, muscarinic and β-adrenergic receptors, also the potassium and calcium channels. Although chrysin had vasorelaxant effects in in vitro studies, the in vivo antihypertensive experiment discovered chrysin does not significantly reduce the blood pressure of SHRs following 21 days of oral treatment. This study proved that chrysin utilised multiple signalling pathways to produce its vasorelaxant effect in the thoracic aorta of rats; however, it had no antihypertensive effect on SHRs.

A synthetic peptide from Sipunculus nudus promotes bone formation via Estrogen/MAPK signal pathway based on network pharmacology

The tripeptide Leu-Pro-Lys (LPK), derived from the Sipunculus nudus protein, was synthesized and studied to investigate its potential protective effect on bone formation. The effect and mechanism of LPK were analyzed through network pharmacology, bioinformatics, and experimental pharmacology. The study found that LPK at concentrations of 25 μg/mL and 50 μg/mL significantly increased ALP activity and mineralization in C3H10 cells. LPK also increased the expression of COL1A1 and promoted bone formation in zebrafish larvae. Network pharmacology predicted 148 interaction targets between LPK and bone development, and analysis of the protein-protein interaction network identified 13 hub genes, including ESR1, MAPK8, and EGFR, involved in bone development. Through KEGG enrichment pathways analysis, it was determined that LPK promotes bone development by regulating endocrine resistance, the relaxin signaling pathway, and the estrogen signaling pathway. Molecular docking results showed direct interactions between LPK and ESR1, MAPK8, and MAPK14. Additional verification experiments using western blot assay revealed that LPK significantly upregulated the expression of genes related to bone formation, including COL1A1, OPG, RUNX2, ESR1, phosphorylated MAPK14, and phosphorylated MAPK8 in C3H10 cells. These results suggest that LPK promotes bone formation by activating the estrogen/MAPK signaling pathway.

Evaluation of the osteogenic effect of apigenin on human mesenchymal stem cells by inhibiting inflammation through modulation of NF-κB/IκBα

Background and purpose

Apigenin has stimulatory effects on osteogenic differentiation of human mesenchymal stem cells (hMSCs) as well as anti-inflammatory properties. This study investigated the osteogenic differentiation of hMSCs in inflammatory conditions treated with apigenin focusing on nuclear factor kappa-light-chain-enhancer of activated B (NF-кB), nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha (IκBα) and nucleotide-binding oligomerization domain, leucine-rich repeat and pyrin domain containing 3 (NLRP3) inflammatory pathways.

Experimental approach

Along with osteogenic differentiation of the hMSCs, they became inflamed with lipopolysaccharide (LPS)/palmitic acid (PA) and treated with apigenin. Alizarin red staining, alkaline phosphatase (ALP) activity, and Runt-related transcription factor 2 (RUNX2) gene expression were used to determine the degree of differentiation. Also, gene expression of NLRP3 was performed along with protein expression of interleukin 1-beta (IL-1β), NF-кB, and IκBα.

Findings / Results

Apigenin was shown to be effective in neutralizing the inhibitory impact of LPS/PA on osteogenesis. Apigenin increased MSC osteogenic capacity by inhibiting NLRP3 expression and the activity of caspase-1. It was also associated with a considerable decrease in the protein expression of NF-κB and IκBα, as well as IL-1β, in these cells.

Conclusion and implications

The effects of apigenin on osteogenesis under inflammatory conditions were cautiously observed.

Polyphenolic Compounds Inhibit Osteoclast Differentiation While Reducing Autophagy through Limiting ROS and the Mitochondrial Membrane Potential

Polyphenolic compounds are a diverse group of natural compounds that interact with various cellular proteins responsible for cell survival, differentiation, and apoptosis. However, it is yet to be established how these compounds interact in myeloid cells during their differentiation and the molecular and intracellular mechanisms involved. Osteoclasts are multinucleated cells that originate from myeloid cells. They resorb cartilage and bone, maintain bone homeostasis, and can cause pathogenesis. Autophagy is a cellular mechanism that is responsible for the degradation of damaged proteins and organelles within cells and helps maintain intracellular homeostasis. Imbalances in autophagy cause various pathological disorders. The current study investigated the role of several polyphenolic compounds, including tannic acid (TA), gallic acid (GA), and ellagic acid (EA) in the regulation of osteoclast differentiation of myeloid cells. We demonstrated that polyphenolic compounds inhibit osteoclast differentiation in a dose-dependent manner. Quantitative real-time PCR, immunocytochemistry, and western blotting revealed that osteoclast markers, such as NFATc1, Cathepsin K, and TRAP were inhibited after the addition of polyphenolic compounds during osteoclast differentiation. In our investigation into the molecular mechanisms, we found that the addition of polyphenolic compounds reduced the number of autophagic vesicles and the levels of LC3B, BECN1, ATG5, and ATG7 molecules through the inactivation of Akt, thus inhibiting the autophagy process. In addition, we found that by decreasing intracellular calcium and decreasing ROS levels, along with decreasing mitochondrial membrane potential, polyphenolic compounds inhibit osteoclast differentiation. Together, this study provides evidence that polyphenolic compounds inhibit osteoclast differentiation by reducing ROS production, autophagy, intracellular Ca²⁺ level, and mitochondrial membrane potentials.

S-allylmercapto-N-acetylcysteine protects bone cells from oxidation and improves femur microarchitecture in healthy and diabetic mice

Oxidative stress is involved in the deterioration of bone quality and mechanical strength in both diabetic and aging adults. Therefore, we studied the ability of the antioxidant compound, S-allylmercapto-N-acetylcysteine (ASSNAC) to protect bone marrow stromal cells (BMSCs) from advanced glycation end-products (AGEs) cytotoxicity and improve bone microarchitecture of adult healthy and obese/diabetic (db/db) female mice. ASSNAC effect on AGEs-treated cultured rat BMSCs was evaluated by Neutral Red and XTT cell survival and reactive oxygen species (ROS) level assays. Its effect on healthy (C57BL/6) and obese/diabetic (C57BLKS/J Lepr^db+/+; db/db) female mice femur parameters, such as (1) number of adherent BMSCs, (2) percentage of CD73⁺/CD45^- cells in bone marrow (BM), (3) glutathione level in BM cells, and (4) femur microarchitecture parameters by microcomputed tomography, was studied. ASSNAC treatment protected BMSCs by significantly decreasing AGEs-induced ROS production and increasing their cellular resistance to the cytotoxic effect of AGEs. ASSNAC treatment of healthy female mice (50 mg/kg/day; i.p.; age 12-20 weeks) significantly increased the number of BMSCs (+60%), CD73⁺/CD45^- cells (+134%), and glutathione level (+110%) in the femur bone marrow. Furthermore, it increased the femur length (+3%), cortical diameter (+3%), and cortical areal moment of inertia (Ct.MOI; +10%) a surrogate for biomechanical strength. In db/db mice that demonstrated a compromised trabecular bone and growth plate microarchitecture, ASSNAC treatment restored the trabecular number (Tb.N, +29%), bone volume fraction (Tb.BV/TV, +130%), and growth plate primary spongiosa volumetric bone mineral density (PS-vBMD, +7%) and thickness (PS-Th, +18%). In conclusion, this study demonstrates that ASSNAC protects bone marrow cells from oxidative stress and may improve bone microarchitecture in adult healthy and diabetic female mice.

Therapeutic Potential of Naringenin Nanosuspension: In Vitro and In Vivo Anti-Osteoporotic Studies

Naringenin (NRG) is a flavonoid and has been reported as an anti-osteoporotic agent. However, poor bioavailability may limit the anti-osteoporotic potential of the drug. The purpose of the study was to compare the anti-osteoporotic activity of naringenin nanosuspension (NRG-NS) with the NRG and standard therapeutic drug, raloxifene hydrochloride (RLX). Here, NRG-NS showed anti-osteoporotic activity in MG-63 cells by upregulating the osteocalcin levels. The in vivo anti-osteoporotic activity of NRG-NS was further investigated in an osteoporotic rat model to mimic the post-menopausal condition. The animals were randomized and separated into six groups. The animals were treated with RLX (p.o., 5.4 mg/kg), NRG (p.o., 20 mg/kg), NRG-NS (p.o., 20 mg/kg), and blank-NS for 60 days after completion of a 30-day post-surgery period and compared with control and ovariectomized (OVX) groups. After the treatment, body and uterine weights, biochemical estimation in serum (calcium, phosphorus, acid phosphatase, alkaline phosphatase, osteocalcin), bone parameters (length, diameter, dry weight, density, ash weight, bone mineral content) and bone microarchitecture by histopathology were determined. The results showed the protective effects of NRG-NS on osteoblast-like MG-63 cells. The biochemical estimations confirmed the normalization of parameters viz., alkaline phosphatase, calcium concentrations, and bone density with a decrease in levels of acid phosphatase and inorganic phosphorus with NRG-NS as compared to plain NRG. The results indicated that the oral administration of NRG-NS could be a potential therapeutic formulation for the treatment of osteoporosis.

Therapeutic Effects of Citrus Flavonoids Neohesperidin, Hesperidin and Its Aglycone, Hesperetin, on Bone Health

Flavonoids are natural phytochemicals that have therapeutic effects and act in the prevention of several pathologies. These phytochemicals can be found in seeds, grains, tea, coffee, wine, chocolate, cocoa, vegetables and, mainly, in citrus fruits. Neohesperidin, hesperidin and hesperetin are citrus flavonoids from the flavanones subclass that have anti-inflammatory and antioxidant potential. Neohesperidin, in the form of neohesperidin dihydrochalcone (NHDC), also has dietary properties as a sweetener. In general, these flavanones have been investigated as a strategy to control bone diseases, such as osteoporosis and osteoarthritis. In this literature review, we compiled studies that investigated the effects of neohesperidin, hesperidin and its aglycone, hesperetin, on bone health. In vitro studies showed that these flavanones exerted an antiosteoclastic and anti- inflammatory effects, inhibiting the expression of osteoclastic markers and reducing the levels of reactive oxygen species, proinflammatory cytokines and matrix metalloproteinase levels. Similarly, such studies favored the osteogenic potential of preosteoblastic cells and induced the overexpression of osteogenic markers. In vivo, these flavanones favored the regeneration of bone defects and minimized inflammation in arthritis- and periodontitis-induced models. Additionally, they exerted a significant anticatabolic effect in ovariectomy models, reducing trabecular bone loss and increasing bone mineral density. Although research should advance to the clinical field, these flavanones may have therapeutic potential for controlling the progression of metabolic, autoimmune or inflammatory bone diseases.

Nutrition and Healthy Aging: Prevention and Treatment of Gastrointestinal Diseases

Nutritional well-being is a fundamental aspect for the health, autonomy and, therefore, the quality of life of all people, but especially of the elderly. It is estimated that at least half of non-institutionalized elderly people need nutritional intervention to improve their health and that 85% have one or more chronic diseases that could improve with correct nutrition. Although prevalence estimates are highly variable, depending on the population considered and the tool used for its assessment, malnutrition in the elderly has been reported up to 50%. Older patients are particularly at risk of malnutrition, due to multiple etiopathogenetic factors which can lead to a reduction or utilization in the intake of nutrients, a progressive loss of functional autonomy with dependence on food, and psychological problems related to economic or social isolation, e.g., linked to poverty or loneliness. Changes in the aging gut involve the mechanical disintegration of food, gastrointestinal motor function, food transit, intestinal wall function, and chemical digestion of food. These alterations progressively lead to the reduced ability to supply the body with adequate levels of nutrients, with the consequent development of malnutrition. Furthermore, studies have shown that the quality of life is impaired both in gastrointestinal diseases, but especially in malnutrition. A better understanding of the pathophysiology of malnutrition in elderly people is necessary to promote the knowledge of age-related changes in appetite, food intake, homeostasis, and body composition in order to better develop effective prevention and intervention strategies to achieve healthy aging.

Flavonoids: Classification, Function, and Molecular Mechanisms Involved in Bone Remodelling

Flavonoids are polyphenolic compounds spotted in various fruits, vegetables, barks, tea plants, and stems and many more natural commodities. They have a multitude of applications through their anti-inflammatory, anti-oxidative, anti-carcinogenic properties, along with the ability to assist in the stimulation of bone formation. Bone, a rigid connective body tissue made up of cells embedded in a mineralised matrix is maintained by an assemblage of pathways assisting osteoblastogenesis and osteoclastogenesis. These have a significant impact on a plethora of bone diseases. The homeostasis between osteoblast and osteoclast formation decides the integrity and structure of the bone. The flavonoids discussed here are quercetin, kaempferol, icariin, myricetin, naringin, daidzein, luteolin, genistein, hesperidin, apigenin and several other flavonoids. The effects these flavonoids have on the mitogen activated protein kinase (MAPK), nuclear factor kappa β (NF-kβ), Wnt/β-catenin and bone morphogenetic protein 2/SMAD (BMP2/SMAD) signalling pathways, and apoptotic pathways lead to impacts on bone remodelling. In addition, these polyphenols regulate angiogenesis, decrease the levels of inflammatory cytokines and play a crucial role in scavenging reactive oxygen species (ROS). Considering these important effects of flavonoids, they may be regarded as a promising agent in treating bone-related ailments in the future.

Rosehip Extract-Functionalized Magnesium Hydroxide Nanoparticles and Its Effect on Osteoblastic and Osteoclastic Cells

Considering the role of magnesium in bone metabolism and the increasing relevance of plant-mediated green-synthesis, this work compares the bone cytocompatibility of magnesium hydroxide nanoparticles (NPs) produced by using pure water, Mg(OH)₂, or a rosehip (RH) aqueous extract, Mg(OH)₂RH. The NPs were evaluated for dose- and time-dependent effects on human osteoblastic and osteoclastic response, due to the direct involvement of the two cell types in bone metabolism. Mg(OH)₂ NPs presented nanoplatelet-like morphology (mean diameter ~90 nm) and a crystalline structure (XRD analysis); the RH-mediated synthesis yielded smaller rounded particles (mean diameter <10 nm) with decreased crystallinity. On the ATR-FTIR spectra, both NPs presented the characteristic Mg-OH peaks; Mg(OH)₂RH exhibited additional vibration bands associated with the presence of phytochemicals. On osteoblastic cells, NPs did not affect cell growth and morphology but significantly increased alkaline phosphatase (ALP) activity; on osteoclastic cells, particles had little effect in protein content, tartrate-resistant acid phosphatase (TRAP) activity, percentage of multinucleated cells, and cell area. However, compared with Mg(OH)₂, Mg(OH)₂RH increased osteoblastic differentiation by inducing ALP activity and promoting the expression of Runx2, SP7, Col1a1, and ALP, and had a negative effect on the expression of the osteoclastic genes NFATC1, CA2, and CTSK. These observations suggest the potential usefulness of Mg(OH)₂RH NPs in bone regeneration.

The effect of mild hypothermia plus rutin on the treatment of spinal cord injury and inflammatory factors by repressing TGF-β/smad pathway

Purpose

To probe the mechanism of mild hypothermia combined with rutin in the treatment of spinal cord injury (SCI).

Methods

Thirty rats were randomized into the following groups: control, sham, model, mild hypothermia (MH), and mild hypothermia plus rutin (MH+Rutin). We used modified Allen’s method to injure the spinal cord (T10) in rats, and then treated it with MH or/and rutin immediately. BBB scores were performed on all rats. We used HE staining for observing the injured spinal cord tissue; ELISA for assaying TNF-α, IL-1β, IL-8, Myeloperoxidase (MPO), and Malondialdehyde (MDA) contents; Dihydroethidium (DHE) for measuring the reactive oxygen species (ROS) content; flow cytometry for detecting apoptosis; and both RT-qPCR and Western blot for determining the expression levels of TGF-β/Smad pathway related proteins (TGF-β, Smad2, and Smad3).

Results

In comparison with model group, the BBB score of MH increased to a certain extent and MH+Rutin group increased more than MH group (p < 0.05). After treatment with MH and MH+Rutin, the inflammatory infiltration diminished. MH and MH+Rutin tellingly dwindled TNF-β, MDA and ROS contents (p < 0.01), and minified spinal cord cell apoptosis. MH and MH+Rutin could patently diminished TGF-β1, Smad2, and Smad3 expression (p < 0.01).

Conclusions

MH+Rutin can suppress the activation of TGF-β/Smad pathway, hence repressing the cellular inflammatory response after SCI.

Fusarium solani G6, a novel vitexin-producing endophytic fungus: characterization, yield improvement and osteoblastic proliferation activity

The study aimed to characterize a novel vitexin-producing endophytic fungus Fusarium solani G6 from Cajanus cajan, improve its capability for producing vitexin and evaluate its osteoblastic proliferation activity. A total of 153 endophytic fungi, classified into 6 genera, were isolated from C. cajan. Among them, only one strain, endophyte G6 identified as Fusarium solani, was found to produce vitexin. After the optimization of fermentation conditions, the highest vitexin yield (18.72 mg/L) for the strain was observed in PDB liquid medium containing 20.54 g/L of glucose and 8.90 g/L of ammonium sulfate, at an initial medium pH of 5.1 and at 28 °C for 6 days of cultivation. Moreover, the fungal vitexin exhibited notable osteoblastic proliferation stimulating activity. A novel vitexin-producing endophytic fungus F. solani G6 was characterized from C. cajan for the first time. The findings highlighted its potential use for large-scale production of vitexin and might have a promising use as therapeutic agent for osteoporosis.

The Influence of Ficus deltoidea in Preserving Alveolar Bone in Ovariectomized Rats

Ficus deltoidea has been shown to possess antioxidant properties that could prevent the development of chronic inflammatory bone diseases. In this study, the efficacy of F. deltoidea in preventing alveolar bone resorption in osteoporotic rats induced by ovariectomy (OVX) was investigated. Twenty-four female Wistar rats were divided into four groups (n = 6) consisting of sham-operated (SO), ovariectomized control (OVXN), ovariectomized treated with estrogen (OVXP), and ovariectomized treated with F. deltoidea extract (OVXF). At the beginning of the study, two nonovariectomized, healthy rats were sacrificed to serve as baseline (BL). Treatment of the rats commenced two weeks after ovariectomy—the OVXP rats that served as positive control received Premarin® (64.5 μg/kg body weight), while OVXF rats were given F. deltoidea (800 mg/kg body weight); both agents were administered orally for two months. The negative control group of rats (OVXN) and the SO group received deionized water, also administered via oral gavage. At necropsy, morphometric assessment of the interradicular bone of the first molar was carried out using a micro-CT scanner, while quantification of osteoclasts and osteoblasts was performed histologically. The results showed that no statistically significant differences among the groups (p > 0.05) for bone morphometric assessment. However, trabecular thickness in the OVXF group was similar to BL, while trabecular separation and alveolar bone loss height were lower than those of the OVXN group. Histologically, the OVXF group demonstrated a significantly lower number of osteoclasts and a higher number of osteoblasts compared with OVXN (p=0.008 and p=0.019, respectively; p < 0.05). In conclusion, F. deltoidea has the capacity to prevent alveolar bone loss in ovariectomy-induced osteoporosis rats by potentially preserving trabecular bone microarchitecture and to decrease osteoclast and increase osteoblast cell count.

Flavonoids: nutraceutical potential for counteracting muscle atrophy

Skeletal muscle plays a vital role in the conversion of chemical energy into physical force. Muscle atrophy, characterized by a reduction in muscle mass, is a symptom of chronic disease (cachexia), aging (sarcopenia), and muscle disuse (inactivity). To date, several trials have been conducted to prevent and inhibit muscle atrophy development; however, few interventions are currently available for muscle atrophy. Recently, food ingredients, plant extracts, and phytochemicals have received attention as treatment sources to prevent muscle wasting. Flavonoids are bioactive polyphenol compounds found in foods and plants. They possess diverse biological activities, including anti-obesity, anti-diabetes, anti-cancer, anti-oxidation, and anti-inflammation. The effects of flavonoids on muscle atrophy have been investigated by monitoring molecular mechanisms involved in protein turnover, mitochondrial activity, and myogenesis. This review summarizes the reported effects of flavonoids on sarcopenia, cachexia, and disuse muscle atrophy, thus, providing an insight into the understanding of the associated molecular mechanisms.

Quercetin-Based Nanocomposites as a Tool to Improve Dental Disease Management

The restoration and prosthetic rehabilitation of missing teeth are commonly performed using dental implants, which are extremely effective and long-lasting techniques due to their osteointegration ability with the preimplant tissues. Quercetin is a phytoestrogen-like flavonoid well known for its several positive effects on human health, mostly linked to the anti-inflammatory, antioxidant, and antibacterial activities against both Gram-positive and Gram-negative bacteria. Moreover, many studies in dentistry and the maxillofacial fields have highlighted the positive effects of quercetin on osteogenesis, acting on osteoblast activity and angiogenetic process, and promoting soft and hard tissue regeneration. This review focuses on the role of quercetin on the healing and restoration of bony defects, considering the experimental findings of its application both in vitro and in vivo as a mere compound or in association with scaffolds and dental implants having functionalized surfaces.

Unraveling the anti-influenza effect of flavonoids: Experimental validation of luteolin and its congeners as potent influenza endonuclease inhibitors

The biological effects of flavonoids on mammal cells are diverse, ranging from scavenging free radicals and anti-cancer activity to anti-influenza activity. Despite appreciable effort to understand the anti-influenza activity of flavonoids, there is no clear consensus about their precise mode-of-action at a cellular level. Here, we report the development and validation of a screening assay based on AlphaScreen technology and illustrate its application for determination of the inhibitory potency of a large set of polyols against PA N-terminal domain (PA-Nter) of influenza RNA-dependent RNA polymerase featuring endonuclease activity. The most potent inhibitors we identified were luteolin with an IC₅₀ of 72 ± 2 nM and its 8-C-glucoside orientin with an IC₅₀ of 43 ± 2 nM. Submicromolar inhibitors were also evaluated by an in vitro endonuclease activity assay using single-stranded DNA, and the results were in full agreement with data from the competitive AlphaScreen assay. Using X-ray crystallography, we analyzed structures of the PA-Nter in complex with luteolin at 2.0 Å resolution and quambalarine B at 2.5 Å resolution, which clearly revealed the binding pose of these polyols coordinated to two manganese ions in the endonuclease active site. Using two distinct assays along with the structural work, we have presumably identified and characterized the molecular mode-of-action of flavonoids in influenza-infected cells.

Therapeutic and Mechanistic Approaches of Tridax Procumbens Flavonoids for the Treatment of Osteoporosis

Homeostasis of bone is closely regulated by the balanced activities between the bone resorbing activity of osteoclast cells and bone-forming ability of osteoblast cells. Multinucleated osteoclasts degrade bone matrix and involve in the dynamic bone remodelling in coordination with osteoblasts. Disruption of this regulatory balance between these cells or any imbalance in bone remodelling caused by a higher rate of resorption over construction of bone results in a decrease of bone matrix including bone mineral density (BMD). These osteoclast-dominant effects result in a higher risk of bone crack and joint demolition in several bone-related diseases, including osteoporosis and rheumatoid arthritis (RA). Tridax procumbens is a very interesting perennial plant and its secondary metabolites called here T. procumbens flavonoids (TPFs) are well-known phytochemical agents owing to various therapeutic practices such as anti-inflammatory, anti-anaemic and anti-diabetic actions. This review designed to focus the systematic convention concerning the medicinal property and mechanism of actions of TPFs for the management of bone-related diseases. Based on the current literature, the review offers evidence-based information of TPFs for basic researchers and clinicians for the prevention and treatment of bone related diseases, including osteoporosis. It also emphasizes the medical significance for more research to comprehend the cellular signalling pathways of TPFs for the regulation of bone remodelling and discusses the possible promising ethnobotanical resource that can convey the preclinical and clinical clues to develop the next generation therapeutic agents for the treatment of bonerelated disorders.

Fermentation Improves Calcium Bioavailability in Moringa oleifera leaves and Prevents Bone Loss in Calcium-deficient Rats

Nowadays, there is an increasing demand of healthier plant calcium supplements. Moringa oleifera leaves (MOL) are rich in calcium and thus are promising candidates for developing efficient calcium supplements. Here, using fermentation-based approaches, we developed a Moringa oleifera leaf ferment (MOLF), which contents higher levels of calcium. The therapeutic potential of the MOLF was also examined both in vitro and in vivo. Nine lactic acid bacteria and four yeasts were tested for better fermentation of MOL. Calcium-deficient rats were used for evaluating the therapeutic effects of MOLF. The results of liquid fermentation showed that the mixture of Lactobacillus reuteri, Lactobacillus acidophilus , and Candida utilis elevated the content of MOL calcium most strikingly, with the content of calcium increased nearly 2.4-fold (from 2.08% to 4.90%). The resulting MOLF was then subjected to cell experiments and animal experiments. The results showed that calcium absorption in Caco-2 cells in MOLF group was higher than that in CaCl2 group significantly. Interestingly, in calcium-deficient rats, MOLF treatment significantly increased the thickness of cortical bone, rat body weight, wet weight of the femur, and the femur bone density, whereas it decreased osteoclast numbers. These results indicate that microbial fermentation increased calcium bioavailability of MOL, promote the growth and development of calcium-deficient rats, bone calcium deposition, and bone growth; enhance bone strength; reduce bone resorption; and prevent calcium deficiency.

The Role of Diet in Osteoporotic Fracture Healing: a Systematic Review

PURPOSE OF REVIEW

Summarize the in vivo evidences on the association between nutrition and osteoporosis fracture healing.

RECENT FINDINGS

Osteoporotic fractures constitute a considerable public health burden. The healing capacity of fractures is influenced by local factors related to the fracture and by general factors (e.g., age, sex, osteoporosis, muscular mass, smoking, alcohol, drugs, and diet). The systematic review was conducted according to PRISMA statement. From the literature search on PubMed and Web of Science, from January 2016 to October 2019, twelve studies were selected and resulted highly variable in samples, exposure, methods, outcomes, and outcome assessment. Eleven studies were conducted on laboratory animals. Only one study aimed to investigate the impact of nutritional status on fracture healing in osteoporotic patients. In this review, the role of calcium/vitamin D supplementation remained controversial, while sialoglycoprotein supplementation, phytoestrogen-rich herb extract, flavonoids, and phosphorylated peptides showed a positive effect on osteoporotic fracture healing.

Rutin promotes osteogenic differentiation of periodontal ligament stem cells through the GPR30-mediated PI3K/AKT/mTOR signaling pathway

Rutin is one of the flavonoids found in fruits and vegetables. Recent reports have revealed that rutin is a major player in proliferation and bone development. However, data on how rutin regulates the proliferation of periodontal ligament stem cells (PDLSCs), as well as the differentiation of osteogenic cells are scanty. Here, our findings showed that rutin enhanced PDLSCs proliferation, increased ALP activity, and matrix mineralization. Moreover, rutin significantly promoted the expression of osteogenic genes and elevated phosphorylated AKT and mTOR. Treatment with LY294002 reversed these effects by inhibiting PI3K. We also found that the expression levels of GPR30 were increased by rutin. Interestingly, this upregulation was not altered after the addition of LY294002. In addition, G15, a selective antagonist of GPR30, could reduce the beneficial effects induced by rutin and interfere with the modulation of PI3K/AKT/mTOR signal transduction. Collectively, our findings revealed that rutin increased proliferation and osteogenic differentiation of PDLSCs through GPR30-mediated PI3K/AKT/mTOR signal transduction. Therefore, it could be deduced that rutin as a certain flavonoid possesses therapeutic value for periodontal bone regeneration and tissue engineering.

Impact statement

In our study, the effects and mechanisms of rutin on the osteogenic differentiation and proliferation of PDLSCs were investigated. Our findings might provide basic knowledge and guidance to understand and use rutin in the bioengineering of the periodontal tissues and regeneration of bones. The following is a short description of the main findings: rutin promotes the osteogenic differentiation and proliferation of PDLSCs; PI3K/AKT/mTOR signal pathway mediates the effects of rutin on PDLSCs; rutin activates PI3K/AKT/mTOR signal pathway via GPR30.

Recent Advances in Nanoencapsulation Systems Using PLGA of Bioactive Phenolics for Protection against Chronic Diseases

Plant-derived polyphenolic compounds have gained widespread recognition as remarkable nutraceuticals for the prevention and treatment of various disorders, such as cardiovascular, neurodegenerative, diabetes, osteoporosis, and neoplastic diseases. Evidence from the epidemiological studies has suggested the association between long-term consumption of diets rich in polyphenols and protection against chronic diseases. Nevertheless, the applications of these phytochemicals are limited due to its low solubility, low bioavailability, instability, and degradability by in vivo and in vitro conditions. Therefore, in recent years, newer approaches have been attempted to solve the restrictions related to their delivery system. Nanoencapsulation of phenolic compounds with biopolymeric nanoparticles could be a promising strategy for protection and effective delivery of phenolics. Poly(lactic-co-glycolic acid) (PLGA) is one of the most successfully developed biodegradable polymers that has attracted considerable attention due to its attractive properties. In this review, our main goal is to cover the relevant recent studies that explore the pharmaceutical significance and therapeutic superiority of the advance delivery systems of phenolic compounds using PLGA-based nanoparticles. A summary of the recent studies implementing encapsulation techniques applied to polyphenolic compounds from plants confirmed that nanoencapsulation with PLGA nanoparticles is a promising approach to potentialize their therapeutic activity.

Alcohol intake, specific alcoholic beverages, and risk of hip fractures in postmenopausal women and men age 50 and older

BACKGROUND

Although a number of studies have examined the association between alcohol intake and hip fractures, few have considered specific alcoholic beverages separately.

OBJECTIVES

We prospectively assessed total alcohol and specific alcoholic beverage consumption and risk of hip fractures in US men and women.

METHODS

Health, lifestyle information, and hip fractures were self-reported on biennial questionnaires between 1980 and 2014 in 75,180 postmenopausal women from the Nurses' Health Study, and between 1986 and 2014 in 38,398 men aged ≥50 y from the Health Professionals Follow-Up Study. Diet was assessed approximately every 4 y with a semiquantitative FFQ. RRs were computed for hip fracture using Cox proportional hazards models, adjusting for potential confounders.

RESULTS

We ascertained 2360 incident low trauma hip fractures in women and 709 in men. Among women, RRs for low trauma hip fractures compared with nondrinkers were 0.89 (95% CI: 0.80, 0.99) for an average daily consumption of <5.0 g, 0.81 (95% CI: 0.70, 0.94) for 5.0 to <10.0 g, 0.83 (95% CI: 0.71, 0.96) for 10.0 to <20.0 g, and 0.93 (95% CI: 0.78, 1.10) for ≥20.0 g. Among men, risk declined linearly with higher alcohol consumption (P-trend = 0.002). Multivariable RR compared with nondrinkers was 0.77 (95% CI: 0.59, 1.01), 0.69 (0.49, 0.96), and 0.67 (0.48, 0.95) for an average intake of 10 g/d to <20 g/d, 20 g/d to <30 g/d, and 30.0 g/d or more, respectively. In women, the alcoholic beverage most significantly associated with hip fracture risk was red wine (RR per serving = 0.59; 95% CI: 0.45, 0.79). In men, there was no clear association with specific alcoholic beverages.

CONCLUSION

In these 2 US cohorts, low to moderate alcohol consumption, when compared with no consumption, was associated with a lower risk of hip fractures, particularly with red wine consumption among women.

Piceatannol attenuates RANKL-induced osteoclast differentiation and bone resorption by suppressing MAPK, NF-κB and AKT signalling pathways and promotes Caspase3-mediated apoptosis of mature osteoclasts

Osteoclasts are multinuclear giant cells that have unique ability to degrade bone. The search for new medicines that modulate the formation and function of osteoclasts is a potential approach for treating osteoclast-related bone diseases. Piceatannol (PIC) is a natural organic polyphenolic stilbene compound found in diverse plants with a strong antioxidant and anti-inflammatory effect. However, the effect of PIC on bone health has not been scrutinized systematically. In this study, we used RAW264.7, an osteoclast lineage of cells of murine macrophages, to investigate the effects and the underlying mechanisms of PIC on osteoclasts. Here, we demonstrated that PIC treatment ranging from 0 to 40 µM strongly inhibited osteoclast formation and bone resorption in a dose-dependent manner. Furthermore, the inhibitory effect of PIC was accompanied by the decrease of osteoclast-specific genes. At the molecular level, PIC suppressed the phosphorylation of c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase (ERK1/2), NF-κB p65, IκBα and AKT. Besides, PIC promoted the apoptosis of mature osteoclasts by inducing caspase-3 expression. In conclusion, our results suggested that PIC inhibited RANKL-induced osteoclastogenesis and bone resorption by suppressing MAPK, NF-κB and AKT signalling pathways and promoted caspase3-mediated apoptosis of mature osteoclasts, which might contribute to the treatment of bone diseases characterized by excessive bone resorption.

Grapefruit juice exerts anti-osteoporotic activities in a prednisolone-induced osteoporosis rat femoral fracture model, possibly via the RANKL/OPG axis

This study aimed to shed light on the protective and therapeutic anti-osteoporotic effects and mechanisms of action of grapefruit juice (GFJ) on prednisolone-induced osteoporosis a rat femoral fracture model. We found that treating rats with GFJ before and/or after prednisolone-induced osteoporosis resulted in increased bone density, total mineral content, and calcium content to counteract the osteoporotic effects of prednisolone. In parallel, the histological and ultrastructural results of the GFJ-treated groups correlated well with enhanced breaking strength of femurs subjected to a constant load. Furthermore, GFJ treatment before and after prednisolone-induced osteoporosis decreased plasma alkaline phosphatase and tartrate-resistant acid phosphatase activities and increased the level of insulin-like growth factor 1. Mechanistically, our immunohistochemistry study showed that GFJ ameliorated prednisolone-induced osteocalcin depletion, decreased receptor activator of nuclear factor kappa-B ligand (RANKL) expression, and increased osteoprotegerin (OPG) expression. GFJ showed a beneficial anti-osteoporotic effect against prednisolone-induced osteoporosis in rats, possibly via the RANKL/OPG axis, suggesting that GFJ might be a good candidate for developing anti-osteoporotic drugs.

Chocolate and chocolate constituents influence bone health and osteoporosis risk

Bone loss resulting in increased risk for osteoporosis is a major health issue worldwide. Chocolate is a rich source of antioxidant and antiinflammatory flavonoids and dietary minerals with the potential to benefit bone health. However, other chocolate constituents such as cocoa butter, sugar, and methylxanthines may be detrimental to bone. Human studies investigating the role of chocolate consumption on serum bone markers and bone mineral density (BMD) have been inconsistent. A contributing factor is likely the different composition and thereby the nutrient and bioactive content among chocolate types. White and milk chocolate are high in sugar and low in flavonoids and most minerals. Dark chocolate (45-85% cocoa solids) is high in flavonoids, most minerals, and low in sugar with ≥70% cocoa solids resulting in higher fat and methylxanthine content. The aim of this review was to examine the relationship between chocolate consumption and its constiuents, including flavonoid content, on bone health and osteoporosis risk. Studies showed postmenopausal women had no bone effects at moderate chocolate intakes, whereas adolescents consuming chocolate had greater longitudinal bone growth. Based on flavonoid and mineral content, unsweetened cocoa powder appeared to be the best option followed by dark chocolate with higher cocoa content in terms of supporting and preserving bone health. Determining dietary recommendations for chocolate consumption relative to bone health is important because of the growing popularity of chocolate, particularly dark chocolate, and an expected increase in consumption owing to suggestions of health benefits against various degenerative diseases.

Effects of Taxifolin on Osteoclastogenesis in vitro and in vivo

Osteoporosis is a highly prevalent disease which has been a major public health problem and considered to be associated with chronic low-grade systemic inflammation and oxidative damage. Taxifolin is a natural flavonoid and possesses many pharmacological activities including antioxidant and anti-inflammatory. Because flavonoids have been confirmed to fight osteoporosis and promote bone health, the aim of this study was to investigate the effects of taxifolin on the formation and function of osteoclast. In this study, we examined the effects of taxifolin on osteoclast using both in vitro and in vivo studies. Taxifolin suppressed the activation of nuclear factor-κB, C-Fos and mitogen-activated protein kinase, and also decreased osteoclast-specific genes expression, including Trap, Mmp-9, Cathepsin K, C-Fos, Nfatc1, and Rank. Taxifolin also prevented reactive oxygen species (ROS) production following RANKL stimulation. In addition, taxifolin alleviated ovariectomized-induced bone loss by repressing osteoclast activity and decreasing serum levels of tumor necrosis factor-α, interleukin-1β, interleukin-6 and receptor activator of nuclear factor-κB ligand (RANKL) in vivo. Our results indicated that taxifolin inhibits osteoclastogenesis via regulation of modulation of several RANKL signaling pathways. Therefore, taxifolin may be considered as a potential alternative therapeutic agent for treating osteoclast-related diseases.

Quercitrin Nanocoated Implant Surfaces Reduce Osteoclast Activity In Vitro and In Vivo

In this study, the effect on osteoclast activity in vitro and in vivo of titanium implants that were coated with quercitrin was evaluated. Titanium surfaces were covalently coated with the flavonoid quercitrin. The effect of the surfaces on osteoclastogenesis was first tested in vitro on RAW264.7 cells that were supplemented with receptor activator of nuclear factor kappa-B ligand (RANKL) to generate osteoclast-like cells by tartrate-resistant acid phosphatase (TRAP) inmunostaining after five days of culture, and by analysis of the mRNA expression levels of markers related to bone resorption after seven days of culture. A rabbit tibial model was used to evaluate the in vivo biological response to the implant surfaces after eight weeks of healing, analyzing the lactate dehydrogenase (LDH) and the alkaline phosphatase (ALP) activities in the wound fluid that were present at the implant interface and the peri-implant bone mRNA expression levels of several markers related to inflammation, bone resorption and osteoblast-osteoclast interaction. No differences between groups and control surfaces were found in the wound fluid analyses. Moreover, quercitrin implant surfaces significantly decreased the expression of osteoclast related genes in vitro (Trap, CalcR, Ctsk, H⁺ATPase, Mmp9) and in vivo (Ctsk, H⁺ATPase, Mmp9) as well as the expression of RankL in vivo. Moreover, quercitrin surfaces were not cytotoxic for the cells. Thus, quercitrin implant surfaces were biocompatible and decreased osteoclastogenesis in vitro and in vivo. This could be used to improve the performance of dental implants.

Dietary flavonoid kaempferol inhibits glucocorticoid-induced bone loss by promoting osteoblast survival

OBJECTIVE

Kaempferol, a dietary flavonoid found in fruits and vegetables, has been reported to reverse osteopenic condition in ovariectomized rats. Because kaempferol is endowed with osteogenic activity, the aim of this study was to determine whether it has a beneficial effect on glucocorticoid (GC)-induced bone loss.

METHODS

Adult female rats were divided into four groups as control (vehicle; distilled water), methylprednisolone (MP; 5 mg•kg•d, subcutaneously), MP + kaempferol (5 mg•kg•d, oral), and MP + human parathyroid 1-34 (30 µg/kg, 5 times/wk, subcutaneously) and treated for 4 wk. To study the antagonizing effect of kaempferol on GC-induced inhibition of fracture healing, drill-hole injury was performed on control and GC-treated rats. An oral dose of kaempferol was given for 14 d to observe the effect on callus formation at the site of injury. After treatment, bones were collected for further analysis.

RESULTS

GC was associated with a decreased bone mineral density and impaired bone microarchitecture parameters. Consumption of kaempferol induced bone-sparing effects in GC-induced osteopenic condition. Additionally, improved callus formation at site of drill injury in femur diaphysis was observed with kaempferol consumption in animals on GC. Consistent with the in vivo data, kaempferol elicited a higher expression of osteogenic markers in vitro and antagonized the apoptotic effect of dexamethasone on calvarial osteoblasts.

CONCLUSION

These results suggested that kaempferol reduced GC-induced bone loss and enhanced bone regeneration at fractured site, thus emphasizing the positive role of flavonoids on bone health.

Rutin Isolated from Chrozophora tinctoria Enhances Bone Cell Proliferation and Ossification Markers

Osteoporosis is a chronic disease in which the skeleton loses a weighty proportion of its mineralized mass and mechanical pliability. Currently available antiosteoporotic agents suffer adverse effects that include elevated risk of thrombosis and cancer. Phytochemicals may constitute a safer and effective option. In the current work, six flavonoids were obtained from Chrozophora tinctoria and identified as amentoflavone (1), apigenin-7-O-β-d-glucopyranoside (2), apigenin-7-O-6′′-E-p-coumaroyl-β-d-glucopyranoside (3), acacetin-7-O-β-d-[α-l-rhamnosyl(1→6)]3′′-E-p-coumaroyl glucopyranoside (4), apigenin-7-O-(6′′-Z-p-coumaroyl)-β-d-glucopyranoside (5), and rutin (6). An extensive review of the literature as well as NMR and mass spectral techniques was employed in order to elucidate the compound structures. Proliferation was enhanced in MCF7, MG-63, and SAOS-2 cells after exposure to subcytotoxic levels of the tested flavonoids. Rutin was chosen for subsequent studies in SAOS-2 cells. Rutin was not found to cause any alteration in the index of proliferation of these cells, when examining the cell cycle distribution by DNA flowcytometric analysis. Rutin was, however, found to increase osteocyte and osteoblast-related gene expression and lower the expression of RUNX suppressor and osteoclast genes. When examining the influence of rutin on vitamin D levels and the activity of alkaline phosphatase enzyme, it was found to enhance both, while decreasing acid phosphatase which is a marker of osteoporosis. Thus, rutin enhances proliferation and ossification markers in bone cells.

Dihydromyricetin Protects against Bone Loss in Ovariectomized Mice by Suppressing Osteoclast Activity

Dihydromyricetin (DMY), the main flavonoid component of Ampelopsis grossedentata, possesses pharmacological activities useful for treatment of diseases associated with inflammation and oxidative damage. Because osteoclasts are often involved in chronic low-grade systemic inflammation and oxidative damage, we hypothesized that DMY may be an effective treatment for osteoclast-related diseases. The effects of DMY on osteoclast formation and activity were examined in vitro. Female C57BL/6 mice were ovariectomized to mimic menopause-induced bone loss and treated with DMY, and femur samples were subjected to bone structure and histological analysis, serum biochemical indicators were also measured. DMY suppressed the activation of nuclear factor-κB, c-Fos and mitogen-activated protein kinase, and prevented production of reactive oxygen species. DMY decreased expression of osteoclast-specific genes, including Trap, Mmp-9, Cathepsin K, C-Fos, Nfatc1, and Rank. In addition, DMY prevented bone loss and decreased serum levels of tumor necrosis factor-α, interleukin-1β, and interleukin-6, and with a decrease in the ratio between receptor activator of nuclear factor-κB (RANK) ligand (RANKL) and osteoprotegerin (OPG) in vivo. These findings demonstrate that DMY attenuates bone loss and inhibits osteoclast formation and activity through modulation of multiple pathways both upstream and downstream of RANKL signaling. DMY may thus be a useful option for treatment of osteoclast-related diseases such as rheumatoid arthritis and osteoporosis.

Safflower bud inhibits RANKL-induced osteoclast differentiation and prevents bone loss in ovariectomized mice

BACKGROUND

The powder and extract of safflower seeds are known to be effective in the prevention of bone loss in ovariectomized animals. However, the inhibitory effect and molecular mechanisms of safflower bud (SB), the germinated safflower, on bone destruction is unclear.

PURPOSE

The present study was designed to investigate the inhibitory effect and molecular mechanism of SB on osteoclastic differentiation and on bone loss in ovarietomized (OVX) mice.

METHODS

Osteoclastogenesis was determined by TRAP staining, F-actin ring formation, and bone resorption assay. NF-κB and MAPKs activation was analyzed by transfection assay and Western blot, respectively. Real-time PCR was performed to examine the expression of osteoclastogenesis-related genes. Histological changes, increases in TRAP-positive cells, and cathepsin K expression were examined in the metaphysis of OVX mice. Density of bone marrow was evaluated by µCT.

RESULTS

SB inhibited the RANKL-induced differentiation of BMDMs into osteoclasts in a dose-dependent manner. F-actin ring formation and bone resorption were also reduced by SB in RANKL-treated BMDMs. In addition, SB decreased the activation of NF-κB and MAPKs and the expression of osteoclastogenesis-related genes in BMDMs treated with RANKL. Feeding of SB-included diet prevented bone loss in OVX mice. The number of TRAP-positive cells and level of protein expression of cathepsin K was reduced and bone mineral density was increased in the metaphysis of mice fed SB compared with OVX mice.

CONCLUSION

These findings suggest that SB can be a preventive and therapeutic candidate for destructive bone diseases.