Natural products as alternative treatments for metabolic bone disorders and for maintenance of bone health

Advances in additive manufacturing for bone tissue engineering: materials, design strategies, and applications

The growing annual demand for bone grafts and artificial implants emphasizes the need for effective solutions to repair or replace injured bones. Additive manufacturing technology offers unique merits for advancing bone tissue engineering (BTE), enabling the creation of scaffolds and implants with customized shapes and designs, interconnected architecture, controlled mechanical properties and compositions, and broadening its range of applications. It overcomes the limitations of traditional manufacturing methods such as electrospinning, salt leaching, freeze drying, solvent casting etc. This review highlights additive manufacturing technologies and their applications in BTE, as well as materials and scaffold architectures to widen the potential of the biomedical sector. The selection of optimal printing methods for BTE requires careful consideration of the advantages and disadvantages against the needs for degradation, strength, and biocompatibility. Material extrusion and powder bed fusion techniques are the most widely used additive manufacturing processes in BTE. The comprehensive review also revealed that parametric designs such as triply periodic minimal surface (TPMS) and Voronoi hold better characteristics for their application in BTE. Voronoi designs exhibit exceptional randomness whereas TPMS structures feature high permeability with continuous surfaces. Topology optimized and gradient models exhibited superior physical and mechanical properties compared to uniform lattices. Future research should focus on the development of novel biomaterials, multi-material printing, assessing long-term impacts, and enhancing 3D printing technologies.

Salidroside alleviates simulated microgravity-induced bone loss by activating the Nrf2/HO-1 pathway

BACKGROUND

Bone loss caused by microgravity exposure presents a serious threat to the health of astronauts, but existing treatment strategies have specific restrictions. This research aimed to investigate whether salidroside (SAL) can mitigate microgravity-induced bone loss and its underlying mechanism.

METHODS

In this research, we used hindlimb unloading (HLU) and the Rotary Cell Culture System (RCCS) to imitate microgravity in vivo and in vitro.

RESULTS

The results showed that salidroside primarily enhances bone density, microstructure, and biomechanical properties by stimulating bone formation and suppressing bone resorption, thereby preserving bone mass in HLU rats. In MC3T3-E1 cells cultured under simulated microgravity in rotary wall vessel bioreactors, the expression of osteogenic genes significantly increased after salidroside administration, indicating that salidroside can promote osteoblast differentiation under microgravity conditions. Furthermore, the Nrf2 inhibitor ML385 diminished the therapeutic impact of salidroside on microgravity-induced bone loss. Overall, this research provides the first evidence that salidroside can mitigate bone loss induced by microgravity exposure through stimulating the Nrf2/HO-1 pathway.

CONCLUSION

These findings indicate that salidroside has great potential for treating space-related bone loss in astronauts and suggest that Nrf2/HO-1 is a viable target for counteracting microgravity-induced bone damage.

Indication-Specific Effect of a Phytotherapeutic Remedy on Human Fetal Osteoblastic Cells: An in vitro Analysis

BACKGROUND

Impaired fracture healing is a recurring interdisciplinary medical challenge. Alternative treatment concepts, apart from conventional medicine, are popular, but scientific evidence on their effects is still lacking. Plant-derived substances are widely assumed to support bone homeostasis. To clarify the effects on bone healing mechanisms, a commercially available, homeopathic-spagyric remedy, containing inter alia two herbal substances with assumed osteogenic potential, equisetum arvense and bellis perennis, was analyzed.

METHODS

Human fetal osteoblastic (hFOB) 1.19 cells were incubated with the test substance in serial dilutions from 10 to 0.00001%. Cell viability has been evaluated through ATP level (CTG assay) and MTT tetrazolium reduction. Cell proliferation was analyzed by BrdU incorporation and cell migration by wound healing assay (WHA) via image analysis. Additionally, determination of the expression of key genes via real-time PCR and proteins via proteome array for inflammation, cell proliferation, and angiogenesis were performed.

RESULTS

An incubation of hFOB 1.19 cells with the test substance for 24/72 h showed no reduction in cell number, viability, or proliferation. Cell migration was unimpaired. The test substance induced inflammatory genes and growth factors along with genes of osseous regeneration (ALP, Col1, IL-1α, IL-6, IL-8, IL-10, Osteocalcin, Osteonectin, RUMX2, TGF, VEGFA). Increased protein expression was found in multiple cytokines, chemokines, and acute phase proteins.

CONCLUSION

The test substance did not impair cell vitality parameters (MTT, CTG, BrdU, and WHA). A tendency to activate growth factors, bone regeneration genes, and proteins was shown for osteoblasts, indicating a possible positive effect on osteogenic processes.

Hintergrund

Störungen des komplexen Prozesses der Knochenheilung stellen auch heutzutage noch eine interdisziplinäre Herausforderung dar. Es existieren zahlreiche alternative Therapiekonzepte, deren Evidenz jedoch häufig nicht belegt ist. Es wird davon ausgegangen, dass pflanzliche Substanzen die Knochenheilung unterstützen können. Wir analysierten die Wirkung eines kommerziellen, homeopathisch-spagyrischen Heilmittels, welches unter anderen zwei Pflanzenstoffe enthält, denen ein osteogenes Potential zugeschrieben wird (Equisetum arvense und Bellis perennis).

Methoden

Es erfolgte eine Inkubation humaner fetaler Osteoblastenzellen (hFOB 1.19) mit der Testsubstanz in absteigender Verdünnung von 10 bis 0.00001%. Die Zellvitalität wurde anhand der Zellzahlbestimmung durch ATP-abhängige metabolische Aktivität mittels CellTiter-Glo® (CTG) Test sowie durch Tetrazolium Reduktion (MTT) evaluiert. Die Zellproliferation wurde durch Inkorporation von Bromdesoxyuridin (BrdU) in die DNA aktiver Zellen analysiert. Der Wound Healing Assay (WHA) diente der Quantifizierung der Zellmigration. Zusätzlich wurde die Expression bestimmter Schlüsselgene mittels real-time PCR und die Proteinexpression via proteom array für Inflammation, Zellproliferation und Angiogenese erhoben.

Ergebnisse

Die Inkubation von hFOB 1.19 mit der Testsubstanz für 24/72 Stunden führte zu keiner Reduktion von Zellzahl, -vitalität oder -proliferation. Auch die Zellmigration war unbeeinträchtigt. Es zeigte sich eine Induktion inflammatorischer Gene, Wachstumsfaktoren sowie Genen der knöchernen Regeneration (ALP, Col1, IL-1α, IL-6, IL-8, IL-10, Osteocalcin, Osteonectin, RUMX2, TGF, VEGFA). Verschiedene Zytokine, Chemokine und Akute Phase Proteine wurden vermehrt exprimiert.

Schlussfolgerung

Die Testsubstanz hatte keine negativen Auswirkungen auf die gemessenen Zellvitalitätsparameter (MTT, CTG, BrdU and WHA). Es zeigte sich eine Aktivierungstendenz für Wachstumsfaktoren, Gene und Proteine der Knochenregeneration, die auf einen möglichen positiven Effekt der Substanz auf den Prozess des Knochenheilung hinweisen.

Piperlongumine, a Piper longum-derived amide alkaloid, protects mice from ovariectomy-induced osteoporosis by inhibiting osteoclastogenesis via suppression of p38 and JNK signaling

Postmenopausal osteoporosis (PMOP) is a metabolic bone disease that results from overproduction and hyperactivation of osteoclasts caused by insufficient estrogen in women after menopause. Current therapeutic strategies are mainly focused on treating PMOP patients who have already developed severe bone loss or even osteoporotic fractures. Obviously, a better strategy is to prevent PMOP from occurring in the first place. However, such reagents are largely lacking. Piperlongumine (PLM), an amide alkaloid extracted from long pepper Piper longum, exhibits the anti-osteoclastogenic effect in normal bone marrow macrophages (BMMs) and the protective effect against osteolysis induced by titanium particles in mice. This study examined the preventive effect of PLM on PMOP and explored the potential mechanism of this effect using both ovariectomized mice and their primary cells. The result showed that PLM (5 and 10 mg kg-1) administered daily for 6 weeks ameliorated ovariectomy-induced bone loss and osteoclast formation in mice. Further cell experiments showed that PLM directly suppressed osteoclast formation, F-actin ring formation, and osteoclastic resorption pit formation in BMMs derived from osteoporotic mice, but did not obviously affect osteogenic differentiation of bone marrow stromal cells (BMSCs) from these mice. Western blot analysis revealed that PLM attenuated maximal activation of p38 and JNK pathways by RANKL stimulation without affecting acute activation of NF-κB, AKT, and ERK signaling. Furthermore, PLM inhibited expression of key osteoclastogenic transcription factors NFATc1/c-Fos and their target genes (Dcstamp, Atp6v0d2, Acp5, and Oscar). Taken together, our findings suggest that PLM inhibits osteoclast formation and function by suppressing RANKL-induced activation of the p38/JNK-cFos/NFATc1 signaling cascade, thereby preventing ovariectomy-induced osteoporosis in mice. Thus, PLM can potentially be used as an anti-resorption drug or dietary supplement for the prevention of PMOP.

Garcinone C attenuates RANKL-induced osteoclast differentiation and oxidative stress by activating Nrf2/HO-1 and inhibiting the NF-kB signaling pathway

Osteoporosis is the result of osteoclast formation exceeding osteoblast production, and current osteoporosis treatments targeting excessive osteoclast bone resorption have serious adverse effects. There is a need to fully understand the mechanisms of osteoclast-mediated bone resorption, identify new drug targets, and find better drugs to treat osteoporosis. Gar C (Gar C) is a major naturally occurring phytochemical isolated from mangosteen, and is a derivative of the naturally occurring phenolic antioxidant lutein. We used an OP mouse model established by ovariectomy (OVX). We found that treatment with Gar C significantly increased bone mineral density and significantly decreased the expression of TRAP, NFATC1 and CTSK relative to untreated OP mice. We found that Garcinone C could disrupt osteoclast activation and resorption functions by inhibiting RANKL-induced osteoclast differentiation as well as inhibiting the formation of multinucleated osteoclasts. Immunoblotting showed that Gar C downregulated the expression of osteoclast-related proteins. In addition, Gar C significantly inhibited RANKL-induced ROS production and affected NF-κB activity by inhibiting phosphorylation Formylation of P65 and phosphorylation and degradation of ikba. These data suggest that Gar C significantly reduced OVX-induced osteoporosis by inhibiting osteoclastogenesis and oxidative stress in bone tissue. Mechanistically, this effect was associated with inhibition of the ROS-mediated NF-κB pathway.

Ethanol Extract of Radix Asteris Suppresses Osteoclast Differentiation and Alleviates Osteoporosis

Radix Asteris, the root of Aster tataricus L. f., is historically significant in East Asian medicine for treating respiratory conditions. Yet, its implications on bone health remain uncharted. This research investigated the impact of an aqueous ethanol extract of Radix Asteris (EERA) on osteoclast differentiation and its prospective contribution to osteoporosis management. We discerned that EERA retards osteoclast differentiation by inhibiting receptor activator of nuclear factor kappa-B ligand (RANKL) expression and obstructing RANKL-induced osteoclastogenesis. EERA markedly suppressed RANKL-induced expression of NFATc1, a pivotal osteoclastogenic factor, via modulating early RANK signaling. EERA's therapeutic potential was underscored by its defense against trabecular bone degradation and its counteraction to increased body and perigonadal fat in ovariectomized mice, mirroring postmenopausal physiological changes. In the phytochemical analysis of EERA, we identified several constituents recognized for their roles in regulating bone and fat metabolism. Collectively, our findings emphasize the potential of EERA in osteoclast differentiation modulation and in the management of osteoporosis and associated metabolic changes following estrogen depletion, suggesting its suitability as an alternative therapeutic strategy for postmenopausal osteoporosis intertwined with metabolic imbalances.

Synthesis and characterization of mesoporous bioactive glass nanoparticles loaded with peganum harmala for bone tissue engineering

Globally, there is an increase in a number of bone disorders including osteoarthritis (OA), osteomyelitis, bone cancer, and etc., which has led to a demand for bone tissue regeneration. In order to take use of the osteogenic potential of natural herbs, mesoporous bioactive glass nanoparticles (MBGNs) have the ability to deliver therapeutically active chemicals locally. MBGNs influence bioactivity and osteointegration of materials making them suitable for bone tissue engineering (BTE). In the present study, we developed Peganum Harmala (P. harmala) loaded MBGNs (PH-MBGNs) synthesized via modified Stöber process. The MBGNs were analyzed in terms of surface morphology, chemical make-up, amorphous nature, chemical interaction, pore size, and surface area before and after loading with P. harmala. A burst release of drug from PH-MBGNs was observed within 8 h immersion in phosphate buffer saline (PBS). PH-MBGNs effectively prevented Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) from spreading. Furthermore, PH-MBGNs developed a hydroxyapatite (HA) layer in the presence of simulated body fluid (SBF) after 21 days, which confirmed the in-vitro bioactivity of MBGNs. In conclusion, PH-MBGNs synthesized in this work are potential candidate for scaffolding or a constituent in the coatings for BTE applications.

Ginsenoside Rb3 inhibits osteoclastogenesis via ERK/NF-κB signaling pathway in vitro and in vivo

OBJECTIVE

The objective of the study was to determine the anti-osteoclastogenic potential of ginsenoside Rb3 for the treatment of periodontitis.

METHODS

The anti-osteoclastogenic effect was determined using RANKL-induced RAW264.7 cells and murine bone marrow-derived macrophages followed by TRAP and phalloidin staining. Expression of osteoclastogenesis-related genes and proteins were examined by qPCR and WB. Activation of signaling pathways was detected by WB and IHC techniques. Experimental periodontitis rat model was built up by gingival injections of P. gingivalis LPS. After 21 days of Rb3 treatment, rats were sacrificed for micro-CT, IHC, H&E, and TRAP staining analyses.

RESULTS

Rb3 dramatically inhibits RANKL-induced osteoclastogenesis. Nfatc1, Mmp9, Ctsk, Acp5 mRNA, and MMP9, CTSK proteins were dose-dependently downregulated by Rb3 pretreatment. WB results revealed that Rb3 suppressed activations of p38 MAPK, ERK, and p65 NF-κB, and the inhibition of ERK was most pronounced. Consistently, IHC analysis revealed that p-ERK was highly expressed in alveolar bone surface, blood vessels, odontoblasts, and gingival epithelia, which were notably suppressed by Rb3 treatment. H&E staining and micro-CT analyses showed that Rb3 significantly attenuated gingivitis and alveolar bone resorption in rats.

CONCLUSION

Rb3 inhibits RANKL-induced osteoclastogenesis and attenuates P. gingivalis LPS-induced gingivitis and alveolar bone resorption in rats via ERK/NF-κB signaling pathway.

Isolation and Characterization of an Anti-Osteoporotic Compound from Melia toosendan Fructus

Melia toosendan fructus, traditionally employed in traditional Chinese and Korean herbal medicine, exhibits diverse biological properties encompassing anti-tumor, anti-inflammatory, and anti-viral effects. However, its influence on bone metabolism remains largely unexplored. In this study, we investigated the impact of an ethanolic extract of Melia toosendan fructus (MTE) on osteoclast differentiation and characterized its principal active constituent in osteoclast differentiation and function, as well as its effects on bone protection. Our findings demonstrate that MTE effectively inhibits the differentiation of osteoclast precursors induced by receptor activator of nuclear factor κB ligand (RANKL). Utilizing a bioassay-guided fractionation approach coupled with UHPLC-MS/MS analysis, we isolated and identified the triterpenoid compound toosendanin (TSN) as the active constituent responsible for MTE's anti-osteoclastogenic activity. TSN treatment downregulated the expression of nuclear factor of activated T cells c1, a pivotal osteoclastogenic transcription factor, along with molecules implicated in osteoclast-mediated bone resorption, including tumor necrosis factor receptor-associated factor 6, carbonic anhydrase II, integrin beta-3, and cathepsin K. Furthermore, treatment of mature osteoclasts with TSN impaired actin ring formation, acidification, and resorptive function. Consistent with our in vitro findings, TSN administration mitigated trabecular bone loss and reduced serum levels of the bone resorption marker, C-terminal cross-linked telopeptides of type I collagen, in a mouse bone loss model induced by intraperitoneal injections of RANKL. These results suggest that TSN, as the principal active constituent of MTE with inhibitory effects on osteoclastogenesis, exhibits bone-protective properties by suppressing both osteoclast differentiation and function. These findings imply the potential utility of TSN in the treatment of diseases characterized by excessive bone resorption.

Water Extract of Angelica dahurica Inhibits Osteoclast Differentiation and Bone Loss

Angelica dahurica radix has a long history of traditional use in China and Korea for treating headaches, cold-damp pain and skin diseases. Despite various pharmacological studies on A. dahurica, its impact on bones remains unclear. Hence, this study investigated the inhibitory effect of A. dahurica's radix water extract (WEAD) on osteoclast differentiation. In vitro experiments showed that WEAD effectively suppresses osteoclast differentiation. Treatment of an osteoclast precursor with WEAD significantly suppressed the expression of nuclear factor of activated T-cells 1 (NFATc1), essential transcription factor for osteoclastogenesis, while increasing the expression of negative regulators, interferon regulatory factor 8 (Irf8) and v-maf musculoaponeurotic fibrosarcoma oncogene homolog B (MafB). Consistent with the in vitro findings, the oral administration of WEAD (100 and 300 mg/kg/day) to mice subjected to surgical ovariectomy for a duration of six weeks alleviated bone loss, while also mitigating weight gain and liver fat accumulation. In addition, we also identified phytochemicals present in WEAD, known to regulate osteoclastogenesis and/or bone loss. These results suggest the potential use of WEAD for treating various bone disorders caused by excessive bone resorption.

Eucalyptol induces osteoblast differentiation through ERK phosphorylation in vitro and in vivo

Eucalyptol (EU) is monoterpene oxide that is the main component of the essential oil extracted from aromatic plants such as Eucalyptus globules. EU has therapeutic effects such as antibacterial, anti-inflammatory and antioxidant in chronic diseases including inflammation disorder, respiratory disease, and diabetic disease. However, the effects of EU on osteoblast differentiation and bone diseases such as osteoporosis have not been studied. The present study investigated the effects of EU on osteoblast differentiation and bone formation. EU induces mRNA and protein expression of osteogenic genes in osteoblast cell line MC3T3-E1 and primary calvarial osteoblasts. EU also promoted alkaline phosphatase (ALP) activity and mineralization. Here, the osteoblast differentiation effect of EU is completely reversed by ERK inhibitor. These results demonstrate that osteoblast differentiation effect of EU is mediated by ERK phosphorylation. The efficacy of EU on bone formation was investigated using surgical bone loss-induced animal models. EU dose-dependently promoted bone regeneration in zebrafish caudal fin rays. In the case of ovariectomized mice, EU increased ERK phosphorylation and ameliorated bone loss of femurs. These results indicate that EU ameliorates bone loss by promoting osteoblast differentiation through ERK phosphorylation. We suggest that EU, plant-derived monoterpenoid, may be useful for preventing bone loss. KEY MESSAGES: Eucalyptol (EU) increases osteoblast differentiation in pre-osteoblasts. EU up-regulates the osteogenic genes expression via ERK phosphorylation. EU promotes bone regeneration in partially amputated zebrafish fin rays. Oral administration of EU improves ovariectomy-induced bone loss and increases ERK phosphorylation.

Vanillic acid mitigates hyperinsulinemia induced ER stress mediated altered calcium homeostasis, MAMs distortion and surplus lipogenesis in HepG2 cells

Hyperinsulinemia (HI) induced insulin resistance (IR) and associated pathologies are the burning and unsolvable issues in diabetes treatment. The cellular, molecular and biochemical events associated with HI are not yet elucidated. Similarly, no focused research on designing therapeutic strategies with natural products for attenuation of HI are seen in literature. Keeping this in mind we planned the present study to evaluate the alterations occurring at ER/Ca²⁺ homeostasis/mitochondria associated endoplasmic reticulum membranes (MAMs) in HepG2 cells during HI and to evaluate the possible beneficial effect of vanillic acid (VA) to mitigate the complications. An in vitro model of HI was established by treating HepG2 cells with human insulin (1 μM) for 24 h. Then, ER stress, Ca²⁺ homeostasis, MAMs, IR and hepatic lipogenesis were studied at protein level. Various proteins critical to ER, Ca²⁺ homeostasis and MAMs such as p-IRE-1α, ATF6, p-PERK, p-eIF2α, CHOP, XBP1, p-CAMKII, InsP3R, SERCA, JNK, GRP78, VDAC, Cyp D, GRP75, MFN2, PTEN and mTORC were studied and found altered significantly causing ER stress, defect in Ca²⁺ movements and distortion of MAMs. The decreased expression of IRS2 and an unaltered expression of IRS1 confirmed the development of selective insulin resistance in hepatocytes during HI and this was the crucial factor for the progression of the hepatic lipid accumulation. We found simultaneous treatment of VA is beneficial up to a certain extent to protect HepG2 cells from the adverse effect of HI via its antioxidant, antilipogenic, mitochondrial and ER protection properties.

Blackcurrants Reduce the Risk of Postmenopausal Osteoporosis: A Pilot Double-Blind, Randomized, Placebo-Controlled Clinical Trial

Beneficial effects of blackcurrant supplementation on bone metabolism in mice has recently been demonstrated, but no studies are available in humans. The current study aimed to examine the dose-dependent effects of blackcurrant in preventing bone loss and the underlying mechanisms of action in adult women. Forty peri- and early postmenopausal women were randomly assigned into one of three treatment groups for 6 months: (1) a placebo (control group, n = 13); (2) 392 mg/day of blackcurrant powder (low blackcurrant, BC, group, n = 16); and (3) 784 mg/day of blackcurrant powder (high BC group, n = 11). The significance of differences in outcome variables was tested by repeated-measures ANOVA with treatment and time as between- and within-subject factors, respectively. Overall, blackcurrant supplementation decreased the loss of whole-body bone mineral density (BMD) compared to the control group (p < 0.05), though the improvement of whole-body BMD remained significant only in the high BC group (p < 0.05). Blackcurrant supplementation also led to a significant increase in serum amino-terminal propeptide of type 1 procollagen (P1NP), a marker of bone formation (p < 0.05). These findings suggest that daily consumption of 784 mg of blackcurrant powder for six months mitigates the risk of postmenopausal bone loss, potentially through enhancing bone formation. Further studies of larger samples with various skeletal conditions are warranted to confirm these findings.

Chemical profiling and identification of anti-osteoporosis chemical-markers of Cinnamomum cassia (L.) presl extracts using GC-MS and spectrum-activity analyses

Cinnamomum cassia (L.) Presl (cinnamon), an important folk medicine is widely used to prevent osteoporosis for long time in China. Our study aimed to investigate the anti-osteoporosis activity and mechanisms of cinnamon extracts obtained by supercritical CO₂ extraction (SFE) and identify activity associated chemical components by gas chromatography-mass spectrometry. The cinnamon SFE exhibited superior anti-osteoporosis efficacy in an ovariectomised mice model to common alcohol extracts. It could induce calcified nodules and ALP activity, upregulate the mRNA expression of ALP, BMP-2, and RUNX2 in MC3T3-E1 cells. The major chemical classes of cinnamon extracts were alcohol esters (28.2%), and terpenes (16.1%). The spectrum-activity analysis indicated that the potential chemical-markers of extracts could be (E)-Cinnamaldehyde, γ-Sitosterol, and (Z, Z)-9,12-Octadecadienoic acid, which could induce the proliferation and ALP activity in MC3T3-E1 cells. Our study revealed the promising applications of the cinnamon SFE in prevention of osteoporosis, and identified its anti-osteoporosis associated compounds.

Estrogen Receptor 1 (ESR1) and the Wnt/β-Catenin Pathway Mediate the Effect of the Coumarin Derivative Umbelliferon on Bone Mineralization

Bone physiology is regulated by osteoblast and osteoclast activities, both involved in the bone remodeling process, through deposition and resorption mechanisms, respectively. The imbalance between these two phenomena contributes to the onset of bone diseases. Among these, osteoporosis is the most common metabolic bone disorder. The therapies currently used for its treatment include antiresorptive and anabolic agents associated with side effects. Therefore, alternative therapeutic approaches, including natural molecules such as coumarin and their derivatives, have recently shown positive results. Thus, our proposal was to investigate the effect of the coumarin derivative umbelliferon (UF) using an interesting model of human osteoblasts (hOBs) isolated from osteoporotic patients. UF significantly improved the activity of osteoporotic-patient-derived hOBs via estrogen receptor 1 (ESR1) and the downstream activation of β-catenin pathway. Additionally, hOBs were co-cultured in microgravity with human osteoclasts (hOCs) using a 3D system bioreactor, able to reproduce the bone remodeling unit in bone loss conditions in vitro. Notably, UF exerted its anabolic role by reducing the multinucleated cells. Overall, our study confirms the potential efficacy of UF in bone health, and identified, for the first time, a prospective alternative natural compound useful to prevent/treat bone loss diseases such as osteoporosis.

A Review on the Molecular Mechanisms of Action of Natural Products in Preventing Bone Diseases

The drugs used for treating bone diseases (BDs), at present, elicit hazardous side effects that include certain types of cancers and strokes, hence the ongoing quest for the discovery of alternatives with little or no side effects. Natural products (NPs), mainly of plant origin, have shown compelling promise in the treatments of BDs, with little or no side effects. However, the paucity in knowledge of the mechanisms behind their activities on bone remodeling has remained a hindrance to NPs’ adoption. This review discusses the pathological development of some BDs, the NP-targeted components, and the actions exerted on bone remodeling signaling pathways (e.g., Receptor Activator of Nuclear Factor κ B-ligand (RANKL)/monocyte/macrophage colony-stimulating factor (M-CSF)/osteoprotegerin (OPG), mitogen-activated protein kinase (MAPK)s/c-Jun N-terminal kinase (JNK)/nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), Kelch-like ECH-associated protein 1 (Keap-1)/nuclear factor erythroid 2–related factor 2 (Nrf2)/Heme Oxygenase-1 (HO-1), Bone Morphogenetic Protein 2 (BMP2)-Wnt/β-catenin, PhosphatidylInositol 3-Kinase (PI3K)/protein kinase B (Akt)/Glycogen Synthase Kinase 3 Beta (GSK3β), and other signaling pathways). Although majority of the studies on the osteoprotective properties of NPs against BDs were conducted ex vivo and mostly on animals, the use of NPs for treating human BDs and the prospects for future development remain promising.

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.

Arctiin elevates osteogenic differentiation of MC3T3-E1 cells by modulating cyclin D1

Osteoporosis is a systemic disorder of bone metabolism. This study aimed to investigate the impacts and possible mechanisms of Arctiin, a lignin isolated from Arctium lappa on MC3T3-E1 osteoblast differentiation. In this study, after treatment with different concentrations of Arctiin, reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blotting were used to estimate the expression of osteogenesis markers. Then, the activity of alkaline phosphatase (ALP) was detected by an ALP assay kit and calcium nodules staining was evaluated by alizarin red staining (ARS). Additionally, the regulatory effects of Arctiin on cyclin D1 (Ccnd1) was assessed by measurement of protein expression. Subsequently, the functions of Ccnd1 silencing on the osteogenic differentiation was examined in Arctiin-treated MC3T3-E1 cells. Results indicated that Arctiin dose-dependently upregulated the expression of runt-related transcription factor 2 (RUNX2), collagen type 1 (COL1A1), osteocalcin (OCN) and osteopontin (OPN). Elevated ALP activity and calcification degree was prominently observed in the Arctiin-treated groups. Moreover, Ccnd1 expression was notably enhanced after Arctiin intervention. Importantly, Ccnd1-knockdown abrogated the impacts of Arctiin on osteogenic differentiation of MC3T3-E1. To conclude, findings in this study suggested that Arctiin could regulate MC3T3-E1 osteoblast differentiation via up-regulating Ccnd1, supporting that Arctiin might be a therapeutic target for osteoporosis.

New bone-generative effect of Salvia officinalis L. in the expanded midpalatal suture : An in vivo and in vitro study

PURPOSE

The aims of this study were to evaluate the effects of systemic administration of Salvia officinalis Linnaeus (L.) leaf extract on new bone formation in the expanded premaxillary suture in rats in vivo and to examine the antioxidant effects and phenolic profile of Salvia officinalis (SO) leaf and root extracts in vitro.

METHODS

Fourteen male Sprague Dawley rats were allocated to two groups: SO group (n = 7) and control group (n = 7). An open-loop spring was attached to the upper incisors of each rat to expand the premaxillae. A 5-day expansion period followed by a 12-day retention period was observed. The rats in the SO group received systemic administration of 20 mg SO/kg/day via the orogastric route for 17 days. Histomorphometric examinations were carried out to examine the amount of new bone formation, number of capillaries, and intensity of inflammatory cell response. Immunohistochemical analysis was conducted to examine the number of osteoblasts and osteoclasts. Leaf and root extracts of SO were also analyzed for antioxidant activity and phenolic compounds in vitro.

RESULTS

Statistical analysis showed that the following were higher in the SO group than in the control group: new bone formation, number of osteoblasts and osteoclasts, intensity of inflammatory cell response (neutrophils, lymphocytes, and macrophages), and number of capillaries. The major compound identified in SO leaf extract was rosmarinic acid, while luteolin derivatives, salvianolic acid F, and medioresinol were also present.

CONCLUSIONS

Salvia officinalis L. from leaf extract provided antioxidant effects and stimulated enhanced new bone formation in the expanded midpalatal suture after maxillary expansion in rats.

The Effects of Polyphenol, Tannic Acid, or Tannic Acid in Combination with Pamidronate on Human Osteoblast Cell Line Metabolism

Background: This study investigates the effect of tannic acid (TA) combined with pamidronate (PAM) on a human osteoblast cell line. Methods: EC₅₀ for TA, PAM, and different combination ratios of TA and PAM (25:75, 50:50, 75:25) were measured by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. The combination index value was utilized to analyze the degree of drug interaction, while trypan blue assay was applied to analyze the cells proliferation effect. The mineralization and detection of bone BSP and Osx genes were determined via histochemical staining and PCR test, respectively. Results: The EC₅₀ of osteoblasts treated with TA and a 75:25 ratio of TA and PAM were more potent with lower EC₅₀ at 0.56 µg/mL and 0.48 µg/mL, respectively. The combination of TA and PAM (75:25) was shown to have synergistic interaction. On Day 7, both TA and PAM groups showed significantly increased proliferation compared with control and combination groups. On Day 7, both the TA and combination-treated groups demonstrated a higher production of calcium deposits than the control and PAM-treated groups. Moreover, on Day 7, the combination-treated group showed a significantly higher expression of BSP and Osx genes than both the TA and PAM groups. Conclusion: Combination treatment of TA and PAM at 75:25 ameliorated the highest enhancement of osteoblast proliferation and mineralization as well as caused a high expression of BSP and Osx genes.

Network Pharmacology-Based Analysis on the Action Mechanism of Oleanolic Acid to Alleviate Osteoporosis

Oleanolic acid (OA) is a triterpenoid commonly found in plants and has shown extensive pharmaceutical activities. This study aimed to investigate the underlying mechanism of antiosteoporosis (OP) action of OA by utilizing the network pharmacology approach and molecular docking methods. First, the targets of OA were identified using the GeneCards, Stitch, and Swisstarget databases, and the targets related to OP were mined using the NCBI, Genecards, and DisGeNet databases. The overlapped targets of OA and OP were regarded as candidate targets, and the String database was used to obtain the protein-protein interactions among the targets. Then, Gene Ontology (GO) functional enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) metabolic pathway enrichment pathways of the candidate targets were performed using the DAVID database. In addition, the top 16 targets in the protein interaction network were used for molecular docking. Finally, an animal model constructed using d-galactose-induced oxidative stress and a low-calcium diet with accelerated bone loss was used to verify the in vivo effects of OA on osteoporotic mice. A total of 42 candidate targets for OA to treat OP were obtained. According to the protein-protein interaction network, MAPK1 showed the highest connectivity with other proteins. Additionally, GO analysis identified the top 20 biological processes, 9 cellular components, and top 20 molecular functions. Moreover, the candidate targets were mainly involved in 13 signaling pathways such as TNF signaling pathway, insulin resistance, MAPK signaling pathway, apoptosis, and PI3K-Akt signaling pathways. Furthermore, molecular docking revealed that OA has a high degree of connections with 16 key proteins. In addition, the anti-OP effects of OA are further validated through the in vivo model. Altogether, our study elucidated the candidate targets for OA to alleviate OP, explored the protein-protein interactions and related signaling pathways of the targets, and validated the anti-OP effects of OA. It could provide a better understanding of the action mechanism in OA to treat OP.

Protective Effects of Water Extract of Fructus Ligustri Lucidi against Oxidative Stress-Related Osteoporosis In Vivo and In Vitro

Fructus Ligustri Lucidi (FLL) is the fruit of Ligustrum lucidum Ait and is a component of many kidney-tonifying traditional Chinese medicine formulae for treating osteoporosis. Accumulating evidence has linked oxidative stress with the progression of bone diseases. The present study aimed to identify the effects of FLL on oxidative stress-related osteoporosis in vivo and in vitro. To construct animal models, we utilized d-galactose (D-gal) injection to induce oxidative stress combined with a low calcium (the exact percentage in the diet was 0.1%) diet. Thirteen-week-old Kunming female mice were gavaged with water extract of FLL for 20 days. Then, eight-month-old Kunming female mice were treated with FLL under standard administration and diet as the aged group. In vitro, MC3T3-E1 cells stimulated by H₂O₂ were treated with FLL for 24 h. The micro-CT results showed that the modeling approach combining oxidative stress with a low calcium diet caused low conversion type osteoporosis in mice. FLL exerted a prominent effect on preventing osteoporosis by inhibiting oxidative stress, increasing bone mineral density (BMD), improving bone microstructure, and promoting osteoblast proliferation and osteoprotegerin (OPG) protein expression; however, FLL had no therapeutic effect on bone loss in aged mice. In conclusion, FLL showed outstanding anti-bone loss ability both in vivo and in vitro and could probably be developed as a prophylactic agent for osteoporosis.

Pro-Osteogenic Properties of Violina pumpkin (Cucurbita moschata) Leaf Extracts: Data from In Vitro Human Primary Cell Cultures

Traditional medicines rely mainly on use of plant extracts to mitigate or treat a wide range of disorders, including those that affect skeletal homeostasis. In this study, we investigated for the first time the potential pro-osteogenic effects of hexane, acetone and methanol extracts of the leaves of Cucurbita moschata, a very popular pumpkin cultivar in Western countries. We found that in Cucurbita moschata leaves, there are acetone-extractable substances—in particular, fatty acids such as 13-OH-9Z,11E,15E-octadecatrienoic acid (PU-13OH-FA), which is capable of both stimulating the function of human primary osteoblasts, which are responsible for bone formation, and inhibiting the differentiation of human osteoclasts, which are responsible for bone resorption. This dual effect was monitored by analyzing Runx2 expression, deposition of mineralized matrix, ALP activity, TRAP and actin ring staining respectively. This study suggests that bioactive chemicals from Cucurbita moschata leaves are potentially suitable as therapeutics for managing metabolic bone disorders such as osteoporosis and rheumatoid arthritis, and promoting tissue healing and functional recovery after bone fractures. The data we obtained increase knowledge on the biological activities of Cucurbita moschata, and in particular underline the potential benefits of consuming leaves which are a part of the plant currently little considered in the Western world.

Natural medicine delivery from biomedical devices to treat bone disorders: A review

With an increasing life expectancy and aging population, orthopedic defects and bone graft surgeries are increasing in global prevalence. Research to date has advanced the understanding of bone biology and defect repair mechanism, leading to a marked success in the development of synthetic bone substitutes. Yet, the quest for functionalized bone grafts prompted the researchers to find a viable alternative that regulates cellular activity and supports bone regeneration and healing process without causing serious side-effects. Recently, researchers have introduced natural medicinal compounds (NMCs) in bone scaffold that enables them to release at a desirable rate, maintains a sustained release allowing sufficient time for tissue in-growth, and guides bone regeneration process with minimized risk of tissue toxicity. According to World Health Organization (WHO), NMCs are gaining popularity in western countries for the last two decades and are being used by 80% of the population worldwide. Compared to synthetic drugs, NMCs have a broader range of safety window and thus suitable for prolonged localized delivery for bone regeneration. There is limited literature focusing on the integration of bone grafts and natural medicines that provides detailed scientific evidences on NMCs, their toxic limits and particular application in bone tissue engineering, which could guide the researchers to develop functionalized implants for various bone disorders. This review will discuss the emerging trend of NMC delivery from bone grafts, including 3D-printed structures and surface-modified implants, highlighting the significance and potential of NMCs for bone health, guiding future paths toward the development of an ideal bone tissue engineering scaffold. STATEMENT OF SIGNIFICANCE: To date, additive manufacturing technology provids us with many advanced patient specific or defect specific bone constructs exhibiting three-dimensional, well-defined microstructure with interconnected porous networks for defect-repair applications. However, an ideal scaffold should also be able to supply biological signals that actively guide tissue regeneration while simultaneously preventing post-implantation complications. Natural biomolecules are gaining popularity in tissue engineering since they possess a safer, effective approach compared to synthetic drugs. The integration of bone scaffolds and natural biomolecules exploits the advantages of customized, multi-functional bone implants to provide localized delivery of biochemical signals in a controlled manner. This review presents an overview of bone scaffolds as delivery systems for natural biomolecules, which may provide prominent advancement in bone development and improve defect-healing caused by various musculoskeletal disorders.

Essential Oils for Bone Repair and Regeneration-Mechanisms and Applications

Although bone possesses a remarkable capacity for self-remodeling and self-healing of small defects, the continuously increasing growth of bone diseases in the elderly population is becoming a significant burden, affecting individual life quality and society. Conventional treatment options involve surgical procedures for repair and reconstruction, local debridement, autografts or allografts, bone transport, Masquelet's two-stage reconstructions, and vascularized bone transplants. However, as such approaches often lead to disruptions of bone-regeneration processes and microbial contaminations and are often inefficient, researchers focus on developing bone-regenerative strategies and identifying novel therapeutic agents that could aid the bone-healing process. In this regard, plant-derived biocompounds, especially essential oils (EOs), have received great scientific attention in recent years, owing to their antioxidant, anti-inflammatory, and antimicrobial effects. Current studies focus on either the direct application of EOs on bone tissue or the introduction of EOs as bioactive compounds in bone scaffolds or as coatings for bone implants. Some of the EOs investigated involve St. John's wort, rosemary, thyme, ylang, white poplar, eucalyptus, lavender, and grape seed. In this context, the present paper aims to provide an overview of the main mechanisms involved in bone repair and regeneration and the potential of EOs to address and enhance these mechanisms.

Bioactive Herbal Extracts of Traditional Chinese Medicine Applied with the Biomaterials: For the Current Applications and Advances in the Musculoskeletal System

Traditional Chinese medicine (TCM) has demonstrated superior therapeutic effect for musculoskeletal diseases for thousands of years. Recently, the herbal extracts of TCM have received rapid advances in musculoskeletal tissue engineering (MTE). A literature review collecting both English and Chinese references on bioactive herbal extracts of TCM in biomaterial-based approaches was performed. This review provides an up-to-date overview of application of TCMs in the field of MTE, involving regulation of multiple signaling pathways in osteogenesis, angiogenesis, anti-inflammation, and chondrogenesis. Meanwhile, we highlight the potential advantages of TCM, opening the possibility of its extensive application in MTE. Overall, the superiority of traditional Chinese medicine turns it into an attractive candidate for coupling with advanced additive manufacturing technology.

Scopolin Prevents Adipocyte Differentiation in 3T3-L1 Preadipocytes and Weight Gain in an Ovariectomy-Induced Obese Mouse Model

Obesity is prevalent in modern human societies. We examined the anti-obesity effects of scopolin on adipocyte differentiation in preadipocyte 3T3-L1 cells and weight loss in an ovariectomy (OVX)-induced obese mouse model. Scopolin inhibited adipocyte differentiation and lipid accumulation in the preadipocyte cells by suppressing the transcription of adipogenic-related factors, including adiponectin (Adipoq), peroxisome proliferator-activated receptor gamma (Pparg), lipoprotein lipase (Lpl), perilipin1 (Plin1), fatty acid-binding protein 4 (Fabp4), glucose transporter type 4 (Slc2a4), and CCAAT/enhancer-binding protein alpha (Cebpa). In OVX-induced obese mice, administration of scopolin promoted the reduction of body weight, total fat percentage, liver steatosis, and adipose cell size. In addition, the scopolin-treated OVX mice showed decreased serum levels of leptin and insulin. Taken together, these findings suggest that the use of scopolin prevented adipocyte differentiation and weight gain in vitro and in vivo, indicating that scopolin may be a potential bioactive compound for the treatment and prevention of obesity in humans.

Arctiin abrogates osteoclastogenesis and bone resorption via suppressing RANKL-induced ROS and NFATc1 activation

Osteoporosis, characterized by disrupted bone resorption and formation, is viewed as a global health challenge. Arctiin (ARC) is a main component of Arctium lappa L, which exerts chemopreventive effects against various tumor cells. However, the role of ARC in bone remodeling is still unclear. Here, we first demonstrated that ARC inhibits osteoclast formation and bone resorption function induced by the receptor activator of nuclear factor-κB ligand (RANKL) in a dose- and time-dependent manner without exerting cytotoxic effects. Mechanistic analysis revealed that ARC not only suppresses RANKL-induced mitogen-activated protein kinase (MAPK) and calcium signaling pathways, but also enhances the expression of cytoprotective enzymes that are involved in scavenging reactive oxygen species (ROS). Further, ARC inhibits the activation of the major transcription factor nuclear factor of activated T cells 1 (NFATc1) during RANKL-induced osteoclast formation. Preclinical studies showed that ARC protects bone loss in an ovariectomy (OVX) mouse model. Conclusively, our data confirmed that ARC could potentially inhibit osteoclastogenesis by abrogating RANKL-induced MAPK, calcium, and NFATc1 signaling pathway, as well as by promoting the expression of ROS scavenging enzymes in Nrf2/Keap1/ARE signaling pathway, thereby2 preventing OVX-induced bone loss. Thus, ARC may serve as a novel therapeutic agent for the treatment of osteoporosis.

Effect of echinalkamide identified from Echinacea purpurea (L.) Moench on the inhibition of osteoclastogenesis and bone resorption

Plant cell cultures have been exploited to provide stable production and new secondary metabolites for better pharmacological activity. Fractionation of adventitious root cultures of Echinacea purpurea resulted in the isolation of eleven constituents, including three new compounds. The structures of the three new compounds were determined to be an alkylamide (1), a polyacetylene (2) and a lignan (3) on the basis of combined spectroscopic analysis. To discover new types of antiresorptive agents, we screened for new compounds that regulate osteoclast differentiation, and survival. Among three new compounds, echinalkamide (compound 1) had considerably inhibitory effects on RANKL-induced osteoclast differentiation, and on proliferation of osteoclasts and efficiently attenuated osteoclastic bone resorption without toxicity. In addition, echinalamide treatment inhibited the osteoclast—specific gene expression level. Echinalkamide achieved this inhibitory effect by disturbing phosphorylation of MAPK and activation of osteoclast transcription factors c-Fos and NFATc1. Conclusionally, our study investigated that echinalkamide remarkably inhibited osteoclast differentiation and osteoclast specific gene expression through repression of the MAPK–c-Fos–NFATC1 cascade.

Natural Medicinal Compounds in Bone Tissue Engineering

Recent advances in 3D printing have provided unprecedented opportunities in bone tissue engineering applications for producing a variety of complex patient-specific implants for the treatment of critical-sized bone defects. Natural medicinal compounds (NMCs) with osteogenic potential can be incorporated into these 3D-printed parts to improve bone formation and therefore enhance implant performance. Using NMCs to treat bone-related disorders may prove to be a healthy preventive choice as they are considered safe, have lesser or no side effects, and are more suitable for prolonged use than synthetic drugs. In this review paper, the current challenges of bone tissue engineering are addressed briefly, highlighting the immense potential of NMCs integrated within tissue engineering scaffolds for orthopedic and dental applications.

Rosmarinus plants: Key farm concepts towards food applications

Rosmarinus species are aromatic plants that mainly grow in the Mediterranean region. They are widely used in folk medicine, food, and flavor industries and represent a valuable source of biologically active compounds (e.g., terpenoids, flavonoids, and phenolic acids). The extraction of rosemary essential oil is being done using three main methods: carbon dioxide supercritical extraction, steam distillation, and hydrodistillation. Furthermore, interesting antioxidant, antibacterial, antifungal, antileishmanial, anthelmintic, anticancer, anti-inflammatory, antidepressant, and antiamnesic effects have also been broadly recognized for rosemary plant extracts. Thus the present review summarized data on economically important Rosmarinus officinalis species, including isolation, extraction techniques, chemical composition, pharmaceutical, and food applications.

Hederagenin protects mice against ovariectomy-induced bone loss by inhibiting RANKL-induced osteoclastogenesis and bone resorption

AIMS

Postmenopausal osteoporosis and other osteolytic bone diseases are often caused by the elevation in osteoclastogenesis and/or increased osteoclastic bone resorption, leading to excessive bone loss. Hederagenin (Hed) is a pentacyclic triterpenoid saponin extracted from various natural medicinal plants and exhibits numerous biological activities and may offer benefits against bone-related conditions. We evaluated the effects of Hed on osteoclast formation and bone resorption in vitro and the in vivo therapeutic benefits in the mouse model of ovariectomy (OVX)-induced bone loss.

MAIN METHODS

In vitro, osteoclast formation were determined by TRAcp staining; bone resorption were examined using Hydroxyapatite resorption assay and Podosomal actin belt formation assay; Related molecular mechanisms were determined by western blot assay. Construction of OVX mice by bilateral oophorectomy to simulate bone loss in vivo.

KEY FINDINGS

In vitro cellular assays showed that Hed inhibited RANKL-induced osteoclast formation and osteoclast bone (hydroxyapatite) resorption as well as marker gene expression from BMM culture. Mechanistically, Hed attenuated RANKL-induced intracellular reactive oxygen species (ROS) production, and MAPK signaling pathway (ERK and p38) activation which curbed the downstream induction of c-Fos and NFATc1. Consistent with the in vitro findings, Hed administration effectively protected OVX mice from bone loss by reducing osteoclast number and activity on bone surface.

SIGNIFICANCE

Our data provided promising evidence for the potential use of Hederagenin in the treatment of osteoclast-mediated osteolytic bone diseases such as postmenopausal osteoporosis.

Magnesium lithospermate B inhibits titanium particles-induced osteoclast formation by c-fos and inhibiting NFATc1 expression

Purpose: Titanium particle-induced osteolysis is one of the important causes of aseptic loosening of artificial joints. Previous studies have shown the potential of natural compounds in preventing Ti particle-induced bone resorption. In this study, we observed the effects of magnesium lithospermate B (MLB) on titanium particle-induced osteoclast activity in vitro. Materials and Methods: RAW264.7 cells were treated with titanium particles (0.1 mg/mL) in the presence or absence of MLB (200 nmol/L). We evaluated the osteoclast formation, bone pits formation and tartrate-resistant acid phosphatase 5b (Tracp5b) levels. Reverse transcription polymerase chain reaction (RT-PCR) and Western blot were used to evaluate osteoclast differentiation-related genes (TRAF6, NFATc1, and c-fos) and protein expression. Results: The number of osteoclasts, pit formation and Tracp5b levels were all the group treated with titanium particles compared to the control group (all p < 0.05). Titanium particles also promoted the expression of the TRAF6, NFATc1 and c-fos genes and protein expression. MLB significantly abolished the titanium particle-enhanced osteoclast and pits formation, and Traf6, NFATc1, and c-fos expression. Conclusions: Our data demonstrated that MLB can suppress titanium-induced osteoclast activity via inhibiting c-fos and NFATc1 expression.

Proliferation study and microscopy evaluation on the effects of tannic acid in human fetal osteoblast cell line (hFOB 1.19)

Tannic acid (TA) is a phenolic compound that might act directly on osteoblast metabolism. The study was performed to investigate the effects of TA on the proliferation, mineralization, and morphology of human fetal osteoblast cells (hFOB 1.19). The cells were divided into TA-treated, untreated, and pamidronate-treated (control drug) groups. Half maximal effective concentration (EC₅₀ ) values for TA and pamidronate were measured using MTT assay. The EC₅₀ of hFOB 1.19 cells treated with TA was 2.94 M. This concentration was more effective compared to the pamidronate (15.27 M). Cell proliferation assay was performed to compare cell viability from Day 1 until Day 14. The morphology of hFOB 1.19 was observed via inverted microscope and scanning electron microscope. Calcium (Ca) and phosphate (P) were assessed using energy-dispersive X-ray (EDX) analysis. Furthermore, the mineralization of hFOB 1.19 was determined by von Kossa staining (P depositions) and Alizarin Red S staining (Ca depositions). The number of cells treated with TA was significantly higher than the two control groups at Day 10 and Day 14. The morphology of cells treated with TA was uniformly fusiform-shaped with filopodia extensions. Besides, globular-like structures of deposited minerals were observed in the TA-treated group. In line with other findings, EDX spectrum analysis confirmed the presence of Ca and P. The cells treated with TA had significantly higher percentage of both minerals at Day 3 and Day 10 compared to the two control groups. In conclusion, TA enhances cell proliferation and causes cell morphology changes, as well as improved mineralization.

Bone Health and Natural Products- An Insight

Bone metabolism involves a complex balance between matrix deposition, mineralization, and resorption. Numerous evidences have revealed that dietary components and phytoconstituents can influence these processes, through inhibition of bone resorption, thus exhibiting beneficial effects on the skeleton. Various traditional herbal formulae in ayurvedic and Chinese medicine have shown demonstrable benefits in pharmacological models of osteoporosis. The present review discusses normal bone metabolism and disorders caused by bone disruption, with particular reference to osteoporosis and current therapeutic treatment. Furthermore the effects of constituents from natural products on bone tissue are explained, with relevant evidences of efficacy in various experimental models.

In vitro assessments of bone microcomputed tomography in an aged male rat model supplemented with Panax ginseng

Recent research has confirmed that Panax ginseng (P. ginseng) has effect on cultured osteoblast of the mouse. In this study we aim to validate the usefulness of tibia quantification by correlating micro-computed tomographic (microCT) images with histology analysis in the aged male rats. A total of thirty - old male WISTAR rats were used and divided into ten 8 weeks rats and ten 112 weeks aged rats with vehicle and ten 112 weeks aged rats with P. ginseng (300 mg/kg/day). Daily oral administration of P. ginseng lasted for 8 weeks. Bone histomorphometric parameters and the trabecular bone microarchitectural properties of tibia were determined by microCT scan. MicroCT analysis showed significantly lower bone mineral density (BMD) and trabecular bone number in the aged group. Ginseng prevented total BMD decrease in the tibia induced by natural aging, which was accompanied by a significant decrease in skeletal remodeling. Furthermore, the aged group with ginseng was found to have a significantly higher osteoblast. In the blood biochemistry results, serum phosphorus, calcium, osteocalcin, T3, and T4 remained unchanged. The present study indicated that P. ginseng might be a potential alternative medicine for the prevention and treatment of natural aging-induced osteoporosis in human.

The Natural Product 6-Gingerol Inhibits Inflammation-Associated Osteoclast Differentiation via Reduction of Prostaglandin E₂ Levels

The natural product 6-gingerol, a major bioactive component of the rhizome of ginger (Zingiber officinale), is known to have several beneficial effects on health, including anti-inflammatory activity. The present study aimed to investigate the effects of 6-gingerol on osteoclast differentiation associated with inflammation. 6-Gingerol inhibited osteoclast differentiation in co-cultures of osteoblasts and osteoclast precursor cells in response to the pro-inflammatory cytokine, interleukin (IL)-1. However, it did not affect osteoclast precursor differentiation into osteoclasts induced by the receptor activator of nuclear factor-κB ligand (RANKL), a key cytokine causing osteoclast differentiation. 6-Gingerol inhibited IL-1-induced RANKL expression in osteoblasts, and the addition of RANKL to the co-cultures overcame 6-gingerol-mediated inhibition of osteoclast differentiation. It also suppressed IL-1-induced prostaglandin E₂ (PGE₂) production in osteoblasts, and the addition of exogenous PGE₂ reversed 6-gingerol-mediated inhibition of IL-induced RANKL expression in osteoblasts and osteoclast differentiation in the co-cultures. We found that 6-gingerol reduced PGE₂ levels by suppressing enzymatic activities of cyclooxygenase and PGE synthase, which cooperatively catalyze the conversion of arachidonic acid to PGE₂. Our findings demonstrate that 6-gingerol inhibits IL-1-induced osteoclast differentiation via suppression of RANKL expression in osteoblasts though reduction of PGE₂ levels, suggesting its potential use in treating inflammatory bone destruction associated with excessive PGE₂ production.

Protective effect of grape or apple juices in bone tissue of rats exposed to cadmium: role of RUNX-2 and RANK/L expression

The aim of this study was to investigate if grape or apple juices are able to protect bone tissue of rats exposed to cadmium. For this purpose, histopathological analysis and immunohistochemistry for RUNX-2 and RANK-L were investigated in this setting. A total of 20 adult Wistar rats were distributed into four groups (n = 5), as follows: control group, cadmium group, cadmium and grape juice group, and Cadmium and apple juice group. Control group received a single intraperitoneal (i.p.) water injection. Cadmium group received a single i.p. injection of cadmium chloride (1.2 mg/kg body weight) diluted in water. Cadmium and grape juice and cadmium and apple juice groups received a single i.p. injection of cadmium chloride (1.2 mg/kg body), and after 15 days, the rats were treated with grape or apple juices for 15 days, by gavage. All animals were euthanized 30 days after the beginning of experiment. Histopathological analysis in rat femur revealed extensive bone loss in rats intoxicated with cadmium. Grape or apple juices were able to increase bone formation. Cadmium inhibited RUNX-2 immunoexpression whereas cadmium increased RANK-L immunoexpression in rat bone cells. Grape or apple juices increased RUNX-2 and decreased RANK-L immunoexpression after cadmium intoxication. Taken together, our results demonstrate that grape or apple juices are able to exert therapeutic activity following cadmium intoxication in rat bone tissue as result of stimulatory effect of bone formation by RUNX-2 upregulation and RANK-L downregulation.

In vitro evaluation of the potential therapeutic role of Dendropanax morbifera extract in ameliorating osteoporosis and resultant bone impairment using MC3T3-E1 cells

Osteoporosis is a widespread musculoskeletal deformity that affects thousands of older people every year, leading to bone abnormalities and ultimately increasing the risk of bone fractures in both genders. It is considered a lethal disease causing death in thousands of people at the late stage of life. Dendropanax morbifera Leveille is a subtropical broad-leaved prevalent species in Korea. Extracts of the leaves, stems, roots, and seeds of D. morbifera have been used in traditional medicine for the treatment of numerous diseases such as diabetes, atherogenesis, skin disorders, and headaches. However, the anti-osteoporosis effects of D. morbifera have not been examined. The primary objectives of this study were to elucidate the anti-osteoporosis effect of D. morbifera extract through an in vitro study using pre-osteoblastic MC3T3-E1 cells. We found that D. morbifera strongly increased the expression of bone metabolic markers such as alkaline phosphatase (ALP) activity, type I collagen (Col-I) level, and mineralization. Additionally, D. morbifera extract also upregulated the mRNA expression levels of osteogenic genes including ALP, osteocalcin (OCN), osterix (Osx), and runt-related transcription factor 2 (Runx2) in MC3T3-E1 cells via upregulation of bone morphogenetic protein 2 (BMP-2)/p38 MAPK/JNK and Smad1/5/8 signaling pathways. Moreover, addition of D. morbifera significantly suppressed the inhibitory effect of SB203580 (p38 inhibitor). In conclusion, the current study demonstrated that D. morbifera extract significantly increased osteoblast differentiation and mineralization in MC3T3-E1 cells by regulating BMP-2/p38/JNK and Smad1/5/8. Our study might be helpful in the discovery and development of new anti-osteoporosis therapeutic agents.

Dried and free flowing granules of Spinacia oleracea accelerate bone regeneration and alleviate postmenopausal osteoporosis

OBJECTIVE

The aim of this study was to demonstrate the efficacy of extract derived from Spinacia oleracea extract (SOE) in reversing bone loss induced by ovariectomy and bone healing properties in a drill-hole fracture model in rats.

METHODS

SOE was administered orally for 12 weeks in adult ovariectomized Sprague Dawley rats after inducing osteopenic condition. Bone micro-architecture, expressions of osteogenic and resorptive gene markers, biomechanical strength, new bone formation, and bone turnover markers were studied. Uterine histomorphometry was used to assess estrogenicity. Bone regeneration potential of SOE was assessed in a drill-hole fracture model. Fracture healing was assessed by calcein intensity and micro-CT analysis of callus at fracture region.

RESULTS

SOE prevented ovariectomy-induced bone loss as evident from 122% increase in bone volume/tissue volume (BV/TV) and 29% decline in Tb.Sp in femoral trabecular micro-architecture. This was corroborated by the more than twofold stimulation in the expression of osteogenic genes runt-related transcription factor 2, osterix, osteocalcin, bone morphogenetic protein 2, collagen-1. Furthermore in the fracture healing model, we observed a 25% increase in BV/TV and enhancement in calcein intensity at the fractured site. The extract when converted into dried deliverable Spinaceae oleracea granule (SOG) form accelerated bone regeneration at fracture site, which was more efficient as evident by a 39% increase in BV/TV. Transforming SOE into dried granules facilitated prolonged systemic availability, thus providing enhanced activity for a period of 14 days.

CONCLUSIONS

SOE treatment effectively prevents ovariectomy-induced bone loss and stimulated fracture healing in adult rats. The dried granular form of the extract of Spinaceae oleracea was effective in fracture healing at the same dose.

Regulatory/modulatory effect of prune essence concentrate on intestinal function and blood lipids

CONTEXT

Prunus domestica Linn (Rosaceae) has been considered a functional food, owing to its various pharmacological activities, including antioxidant, anti-inflammatory, antidiabetic and anticancer.

OBJECTIVE

This placebo-controlled, randomized study was framed to check the beneficial activity of prune essence concentrates (PEC) in corroboration with intestinal function and lipid profile in mildly hypercholesterolemic subjects.

MATERIALS AND METHODS

Sixty healthy mild hypercholesterolemic subjects were randomly chosen and segregated into three groups as placebo (consume 50 mL of simulated prune drink), PEC I (consume 50 mL of PEC/day) and PEC II (consume 100 mL of PEC/day) for 4 weeks with 2 weeks of follow-up without PEC consumption.

RESULTS

Intake of PEC (I and II) for 4 weeks substantially ameliorated (p < 0.05) the colony number of Bifidobacterium spp. (1.18- and 1.19-fold) and Lactobacillus spp. (1.07- and 1.16-fold), but markedly lowered (p < 0.05) the colony number of Clostridium perfringens (5.97 and 8.35%) and Escherichia coli (6.25 and 9.38%). Meanwhile, the total cholesterol (TC; 5.90 and 6.99%) levels and LDL-c (6.68 and 6.53%) were significantly reduced (p < 0.05), but no change in other lipid parameters. Whereas, the antioxidant capacity was also concomitantly elevated (p < 0.05) upon administration with PEC.

DISCUSSION AND CONCLUSION

Overall, the results suggest that the use of PEC may positively regulate the intestinal microflora and thereby effectively lower the TC levels and thus act as a hypocholesterolemic agent.

Ginsenoside Re Inhibits Osteoclast Differentiation in Mouse Bone Marrow-Derived Macrophages and Zebrafish Scale Model

Ginsenosides, which are the active materials of ginseng, have biological functions that include anti-osteoporotic effects. Aqueous ginseng extract inhibits osteoclast differentiation induced by receptor activator of NF-κB ligand (RANKL). Aqueous ginseng extract produces chromatography peaks characteristic of ginsenosides. Among these peaks, ginsenoside Re is a major component. However, the preventive effects of ginsenoside Re against osteoclast differentiation are not known. We studied the effect of ginsenoside Re on osteoclast differentiation, RANKL-induced tartrate-resistant acid phosphatase (TRAP) activity, and formation of multinucleated osteoclasts in vitro. Ginsenoside Re hampered osteoclast differentiation in a dose-dependent manner. In an in vivo zebrafish model, aqueous ginseng extract and ginsenoside Re had anti-osteoclastogenesis effects. These findings suggest that both aqueous ginseng extract and ginsenoside Re prevent bone resorption by inhibiting osteoclast differentiation. Ginsenoside Re could be important for promoting bone health.

Fructus Ligustri Lucidi ethanol extract inhibits osteoclastogenesis in RAW264.7 cells via the RANKL signaling pathway

Fructus ligustri Lucidi (FLL) is the fruit of Ligustrum lucidum Ait and a traditional Chinese medicine, primarily known for its role in osteoporosis prevention and treatment. The present study aimed to elucidate the effect and underlying mechanism of action of ethanol extract of FLL on osteoclast differentiation and bone resorption, and to identify the active compounds within it. RAW264.7 murine monocyte/macrophage cells were stimulated with the receptor activator of nuclear factor κB ligand (RANKL) to induce osteoclast differentiation in vitro. The present study demosntrated that FLL extract and its two primary components, oleanolic acid (OA) and ursolic acid (UA), significantly suppressed RANKL‑induced tartrate resistant acid phosphatase (TRAP) activity and multinucleate osteoclast formation without inducing cytotoxicity; however, no effect was observed on the apoptosis of mature osteoclasts. Additionally, RANKL‑induced mRNA expression levels of the key transcription factors, tumor necrosis factor receptor associated factor‑6, nuclear factor of activated T cell‑c1 and c‑Fos, and the osteoclast markers, TRAP, cathepsin K and matrix metalloproteinase‑9 were suppressed by FLL, OA and UA. However, no effect was observed on RANKL‑induced mRNA expression levels of Src. These results demonstrated that FLL may inhibit osteoclastogenesis in RAW264.7 cells via RANKL signaling pathways. OA and UA are active compounds in inducing this effect; however, their specific roles remain to be elucidated.

Salvia plebeia R.Br. inhibits signal transduction of IL-6 and prevents ovariectomy-induced bone loss by suppressing osteoclastogenesis

The interleukin-6 (IL-6) family of cytokines plays a key role in the pathogenesis of rheumatoid arthritis and osteoporosis through the regulation of bone formation and resorption. In this study, it was observed that ethanol extract of Salvia plebeia R.Br. (S.P-EE) inhibited IL-6-induced signaling cascade including phosphorylation of JAK2/STAT3 and ERK. Subsequently, it was examined whether S.P-EE treatment could recover bone loss in ovariectomized (OVX) mice. Indeed, S.P-EE exhibited both preventive and therapeutic effect on OVX-induced bone loss in trabecular microarchitecture along with significant increase in bone mineral density and content. To understand the mechanism of action of S.P-EE in bone metabolism, the effect of S.P-EE on osteoclast differentiation and activity was investigated. S.P-EE significantly inhibited RANKL-induced osteoclast differentiation by suppressing phosphorylation of MAPK and Akt, and expression of NFATc1 and osteoclast marker genes. S.P-EE also inhibited bone-resorbing activity of osteoclasts. Furthermore, isolation and identification of the active compounds which are responsible for the inhibitory effect of S.P-EE on osteoclast differentiation was carried out. Six major flavonoids and plebeiolide A-C were isolated and examined their effects on osteoclast differentiation. Luteolin and hispidulin, and plebeiolide A and C, not B exhibited potent inhibitory activity on RANKL-induced osteoclast formation.