Anabolic activity of ursolic acid in bone: Stimulating osteoblast differentiation in vitro and inducing new bone formation in vivo

Anti-osteoporosis effects of triterpenoids from the fruit of sea buckthorn (Hippophae rhamnoides) through the promotion of osteoblast differentiation in mesenchymal stem cells, C3H10T1/2

In a previous study, we discovered that the ethanolic extract of sea buckthorn (Hippophae rhamnoides) fruits exhibited anti-osteoporosis effects both in vitro and in vivo. Through bioassay-guided fractionation, we identified the hexane fraction (HRH) as the active fraction, which was further fractionated using preparative HPLC. Among the resulting six fractions, HRHF4 showed significant activity. In the present study, we focused on the bioassay-guided isolation of bioactive compounds from the HRHF4 fraction. We successfully identified the active HRHF43 fraction, which led us to the isolation of potential bioactive compounds (1-6). The chemical structures of these compounds were determined using NMR data, LC-MS analysis, and HR-ESI-MS data as four triterpenes, ursolic acid (1), uvaol (2), oleanolic aldehyde (3), and ursolic aldehyde (4), together with two fatty acids, methyl linoleate (5) and ethyl oleate (6). To evaluate the efficacy of promoting osteoblast differentiation and the expression of mRNA biomarkers related to osteogenesis, we tested the isolated compounds in the mouse mesenchymal stem cell line, C3H10T1/2. Alkaline phosphate staining demonstrated that triterpenes (1-4) displayed osteogenic activity. Particularly noteworthy, ursolic aldehyde (4) exhibited the most potent effect, showing an 11.2-fold higher activity at a concentration of 10 μg/mL compared to the negative control. Moreover, ursolic aldehyde (4) upregulated the gene expression of bone formation-related biomarkers, including Runx2, Osterix, Alp, and Osteopontin. These findings suggest that the fruit extract of H. rhamnoides may have potential as a nutraceutical for promoting bone health, with ursolic aldehyde (4) identified as an active constituent.

Dissolving microneedle transdermal patch loaded with Risedronate sodium and Ursolic acid bipartite nanotransfersomes to combat osteoporosis: Optimization, characterization, in vitro and ex vivo assessment

Osteoporosis is a fatal bone-wearing malady and a substantial reason behind the impermanence of human life and economic burden. Risedronate Sodium along with Ursolic acid has been studied to ameliorate osteoporosis. To bypass problems associated with bioavailability, we have developed a microneedle transdermal patch loaded with optimized formulation nanotransfersomes. It was optimized using three factor, three-level Central composite design with independent variables namely, the concentration of phospholipid, surfactant, and sonication time on dependent variables (vesicle size, entrapment efficiency and Polydispersity index). Vesicles of size 271.9 ± 8.45 nm with PDI 0.184 ± 0.01, having entrapment efficiency of 86.12 ± 5.20% and 85.65 ± 4.88% for RIS and UA respectively were observed. In vitro release study showed the sustained release pattern with 78.16 ± 1.12% and 75.72 ± 1.01% release of RIS and UA respectively. Dissolving MN patch prepared from gelatin was found to have good strength and folding endurance with uniform drug content (98.68 ± 0.004%). Ex vivo permeation study revealed that up to 80% of the drug can be permeated within 24 h. CLSM analysis was also performed to show penetration of RU-NTRs. From the results obtained, we can conclude that dissolving MN patch loaded with RU-NTRs has great potential than its conventional counterpart.

Ursolic acid alleviates steroid-induced avascular necrosis of the femoral head in mouse by inhibiting apoptosis and rescuing osteogenic differentiation

Steroid-induced avascular necrosis of femoral head (SANFH) is a common disorder worldwide with high disability. Overdose of glucocorticoid (GC) is the most common non-traumatic cause of SANFH. Up until now, there are limited therapeutic strategies for curing SANFH, and the mechanisms underlying SANFH progression remain unclear. Nevertheless, Osteogenic dysfunction is considered to be one of the crucial pathobiological mechanisms in the development of SANFH, which involves mouse bone marrow mesenchymal stem cells (BMSCs) apoptosis and osteogenic differentiation disorder. Ursolic acid (UA), an important component of the Chinese medicine formula Yougui Yin, has a wide range of pharmacological properties such as anti-tumor, anti-inflammatory and bone remodeling. Due to the positive effect of Yougui Yin on bone remodeling, the purpose of this study was to investigate the effects of UA on dexamethasone (DEX)-induced SANFH in vitro and vivo. In vitro, we demonstrated that UA can promote mouse BMSCs proliferation and resist DEX-induced apoptosis by CCK8, Western blotting, TUNEL and so on. In addition, vitro experiments such as ALP and Alizarin red staining assay showed that UA had a beneficial effect on the osteogenic differentiation of mouse BMSCs. In vivo, the results of H&E staining, immunohistochemistry staining, Elisa and micro-CT analysis showed that UA had a bone repair-promoting effect in SANFH model. Moreover, the results of Western blot and TUNEL experiments showed that UA could delay the disease progression of SANFH in mice by inhibiting apoptosis. Overall, our study suggests that UA is a potential compound for the treatment of SANFH.

A new osteogenic protein isolated from Dioscorea opposita Thunb accelerates bone defect healing through the mTOR signaling axis

Delayed bone defect repairs lead to severe health and socioeconomic impacts on patients. Hence, there are increasing demands for medical interventions to promote bone defect healing. Recombinant proteins such as BMP-2 have been recognized as one of the powerful osteogenic substances that promote mesenchymal stem cells (MSCs) to osteoblast differentiation and are widely applied clinically for bone defect repairs. However, recent reports show that BMP-2 treatment has been associated with clinical adverse side effects such as ectopic bone formation, osteolysis and stimulation of inflammation. Here, we have identified one new osteogenic protein, named 'HKUOT-S2' protein, from Dioscorea opposita Thunb. Using the bone defect model, we have shown that the HKUOT-S2 protein can accelerate bone defect repair by activating the mTOR signaling axis of MSCs-derived osteoblasts and increasing osteoblastic biomineralization. The HKUOT-S2 protein can also modulate the transcriptomic changes of macrophages, stem cells, and osteoblasts, thereby enhancing the crosstalk between the polarized macrophages and MSCs-osteoblast differentiation to facilitate osteogenesis. Furthermore, this protein had no toxic effects in vivo. We have also identified HKUOT-S2 peptide sequence TKSSLPGQTK as a functional osteogenic unit that can promote osteoblast differentiation in vitro. The HKUOT-S2 protein with robust osteogenic activity could be a potential alternative osteoanabolic agent for promoting osteogenesis and bone defect repairs. We believe that the HKUOT-S2 protein may potentially be applied clinically as a new class of osteogenic agent for bone defect healing.

Effect of the Composition of Leuzea and Cranberry Meal Extracts on Metabolic Processes in Norm and Pathology

This study was conducted to evaluate the effects of long-term administration of a new herbal composition of leuzea and cranberry meal extracts at a dose of 70:500 mg/kg in healthy and pathological mice. After 4 weeks of daily composition administration to healthy CD-1 mice and C57BL/6 mice with diet-induced metabolic syndrome, oral glucose tolerance test (OGTT), serum biochemical examination and histology of internal organs were performed. Additionally, histological examination of white and brown adipose tissue was performed to evaluate the ability of the composition to prevent abdominal obesity in C57BL/6Ay (agouti yellow) mice. The results showed that the composition increased tissue sensitivity to glucose in healthy CD-1 mice; at the same time, it did not worsen the course of pathological processes in pathological mice. In both cases, the application of the developed composition was safe and contributed to the restoration of metabolic parameters.

Equisetum arvense Inhibits Alveolar Bone Destruction in a Rat Model with Lipopolysaccharide (LPS)-Induced Periodontitis

Background and Aims

Equisetum arvense extract (EA) exerts various biological effects, including anti-inflammatory activity. The effect of EA on alveolar bone destruction has not been reported; therefore, we aimed to determine whether EA could inhibit alveolar bone destruction associated with periodontitis in a rat model in which periodontitis was induced using lipopolysaccharide from Escherichia coli (E. coli-LPS).

Methods

Physiological saline or E. coli-LPS or E. coli-LPS/EA mixture was topically administered into the gingival sulcus of the upper molar region of the rats. After 3 days, periodontal tissues of the molar region were collected. Immunohistochemistry was performed for cathepsin K, receptor activator of NF-κB ligand (RANKL), and osteoprotegerin (OPG). The cathepsin K-positive osteoclasts along the alveolar bone margin were counted. EA effects on the expression of the factors regulating osteoclastogenesis in osteoblasts with E. coli-LPS-stimulation were also examined in vitro.

Results

Treatment with EA significantly reduced the number of osteoclasts by decreasing the RANKL-expression and increasing OPG-expression in the periodontal ligament in the treatment group compared to the E. coli-LPS group. The in vitro study showed that the upregulation of p-IκB kinase α and β (p-IKKα/β), p-NF-κB p65, TNF-α, interleukin-6, and RANKL and downregulation of semaphorin 3A (Sema3A), β-catenin, and OPG in the osteoblasts with E. coli-LPS-stimulation improved with EA-treatment.

Conclusion

These findings demonstrated that topical EA suppressed alveolar bone resorption in the rat model with E. coli-LPS-induced periodontitis by maintaining a balance in RANKL/OPG ratio via the pathways of NF-κB, Wnt/β-catenin, and Sema3A/Neuropilin-1. Therefore, EA possesses the potential to prevent bone destruction through inhibiting osteoclastogenesis attributed to cytokine burst under plaque accumulation.

Research on the Mechanism of Liuwei Dihuang Decoction for Osteoporosis Based on Systematic Biological Strategies

Background

Osteoporosis is an important health problem worldwide. Liuwei Dihuang Decoction (LDD) and its main ingredients may have a good clinical effect on osteoporosis. Meanwhile, its mechanism for treating osteoporosis needs to be further revealed in order to provide a basis for future drug development.

Methods

A systematic biological methodology was utilized to construct and analyze the LDD-osteoporosis network. After that, the human transcription data of LDD intervention in patients with osteoporosis and protein arrays data of LDD intervention in osteoporosis rats were collected. The human transcription data analysis, protein arrays data analysis, and molecular docking were performed to validate the findings of the prediction network (LDD-osteoporosis PPI network). Finally, animal experiments were conducted to verify the prediction results of systematic pharmacology.

Results

(1) LDD-osteoporosis PPI network shows the potential compounds, potential targets (such as ALB, IGF1, SRC, and ESR1), clusters, biological processes (such as positive regulation of calmodulin 1-monooxygenase activity, estrogen metabolism, and endothelial cell proliferation), and signaling and Reactome pathways (such as JAK-STAT signaling pathway, osteoclast differentiation, and degradation of the extracellular matrix) of LDD intervention in osteoporosis. (2) Human transcriptomics data and protein arrays data validated the findings of the LDD-osteoporosis PPI network. (3) The animal experiments showed that LDD can improve bone mineral density (BMD), increase serum estradiol (E2) and alkaline phosphatase (ALP) levels, and upregulate Wnt3a and β-catenin mRNA expression (P < 0.05). (4) Molecular docking results showed that alisol A, dioscin, loganin, oleanolic acid, pachymic acid, and ursolic acid may stably bind to JAK2, ESR1, and CTNNB1.

Conclusion

LDD may have a therapeutic effect on osteoporosis through regulating the targets (such as ALB, IGF1, SRC, and ESR1), biological processes (such as positive regulation of calmodulin 1-monooxygenase activity, estrogen metabolism, and endothelial cell proliferation), and pathways (such as JAK-STAT signaling pathway, osteoclast differentiation, and degradation of the extracellular matrix) found in this research.

23-Hydroxyursolic acid from Viburnum lutescens inhibits osteoclast differentiation in vitro and lipopolysaccharide-induced bone loss in vivo by suppressing c-Fos and NF-κB signalling

Bone homeostasis is maintained by a combination of osteoclast-mediated bone resorption and osteoblast-mediated bone formation. Excessive osteoclast activity is linked to several bone-related disorders, including osteoporosis and rheumatoid arthritis. Pharmacological therapy might have a number of adverse effects. Therefore, the development of natural anti-osteoclastogenic drugs with greater efficacy and fewer adverse effects is desirable. In this study, the anti-osteoclastogenic effects of 23-hydroxyursolic acid (HUA), a triterpene isolated from Viburnum lutescens, were investigated in vitro and in vivo. HUA significantly inhibited receptor activator of nuclear factor kappa-B ligand (RANKL)-induced mature osteoclast differentiation by reducing the number of tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts and F-actin ring formation. It also inhibited the expression of osteoclast-specific marker genes such OSCAR, MMP-9, TRAP, DC-STAMP, and CtsK, as well as transcription factors, c-Fos and nuclear factor of activated T cells cytoplasmic 1 (NFATc1) in response to RANKL. Mice orally administered with HUA (25 and 50 mg/kg) exhibited significant protection against bone loss and osteoclast formation induced by lipopolysaccharide (LPS). HUA suppressed RANKL-induced nuclear factor kappa B (NF-κB) activation and phosphorylation of JNK and ERK mitogen-activated protein kinases (MAPKs). These results suggest that HUA attenuates osteoclast formation in vitro and in vivo by suppressing the RANKL-mediated AP1, NF-κB, and NFATc1 pathways. Therefore, HUA may be a lead compound for the prevention or treatment of osteolytic bone disorders.

Traditional Chinese Medicine Compound-Loaded Materials in Bone Regeneration

Bone is a dynamic organ that has the ability to repair minor injuries via regeneration. However, large bone defects with limited regeneration are debilitating conditions in patients and cause a substantial clinical burden. Bone tissue engineering (BTE) is an alternative method that mainly involves three factors: scaffolds, biologically active factors, and cells with osteogenic potential. However, active factors such as bone morphogenetic protein-2 (BMP-2) are costly and show an unstable release. Previous studies have shown that compounds of traditional Chinese medicines (TCMs) can effectively promote regeneration of bone defects when administered locally and systemically. However, due to the low bioavailability of these compounds, many recent studies have combined TCM compounds with materials to enhance drug bioavailability and bone regeneration. Hence, the article comprehensively reviewed the local application of TCM compounds to the materials in the bone regeneration in vitro and in vivo. The compounds included icariin, naringin, quercetin, curcumin, berberine, resveratrol, ginsenosides, and salvianolic acids. These findings will contribute to the potential use of TCM compound-loaded materials in BTE.

Evolving Roles of Natural Terpenoids From Traditional Chinese Medicine in the Treatment of Osteoporosis

Osteoporosis (OP) is a systemic metabolic skeletal disease which can lead to reduction in bone mass and increased risk of bone fracture due to the microstructural degradation. Traditional Chinese medicine (TCM) has been applied in the prevention and treatment of osteoporosis for a long time. Terpenoids, a class of natural products that are rich in TCM, have been widely studied for their therapeutic efficacy on bone resorption, osteogenesis, and concomitant inflammation. Terpenoids can be classified in four categories by structures, monoterpenoids, sesquiterpenoids, diterpenoids, and triterpenoids. In this review, we comprehensively summarize all the currently known TCM-derived terpenoids in the treatment of OP. In addition, we discuss the possible mechanistic-of-actions of all four category terpenoids in anti-OP and assess their therapeutic potential for OP treatment.

Ursolic Acid Loaded-Mesoporous Hydroxylapatite/ Chitosan Therapeutic Scaffolds Regulate Bone Regeneration Ability by Promoting the M2-Type Polarization of Macrophages

PURPOSE

Mesoporous hydroxylapatite (MHAP) might be important for bone regeneration, and ursolic acid (UA) has anti-inflammatory effects. Accordingly, we developed, for the first time, ursolic acid-loaded MHAP-chitosan (MHAP-CS-UA) scaffolds to treat bone defects.

METHODS

In vitro, we synthesize biomaterial scaffolds. By SEM, XRD, EDS and FTIR, we test the performance of the hybrid scaffolds. By drug release, flow cytometry, immunofluorescence, alizarin red staining, and Western blotting, we test the anti-inflammatory and osteo-inductive properties of scaffolds. In vivo, we verify osseointegration ability and bone regeneration.

RESULTS

The MHAP is a rod-shaped structure with a length of 100~300nm and a diameter of 40~60nm. The critical structure gives the micro-scaffold a property of control release due to the pore sizes of 1.6~4.3 nm in hydroxyapatite and the hydrogen bonding between the scaffolds and UA drugs. The released UA drugs could notably inhibit the polarization of macrophages to pro-inflammatory macrophages (M1 type) and promote the expression of osteogenic-related genes (COL1, ALP and OPG) and osteogenic-related proteins (BMP-2, RUNX2 and COL1).

CONCLUSION

The MHAP-CS-UA scaffolds have good anti-inflammatory, osseointegration, osteo-inductivity and bone regeneration. And they will be the novel and promising candidates to cure the bone disease.

In Silico Network Analysis of Ingredients of Cornus officinalis in Osteoporosis

BACKGROUND Cornus officinalis (CO), also known as 'Shanzhuyu', is one of the most common traditional Chinese herbs used against osteoporosis. Although previous studies have found that CO has beneficial effects in alleviating osteoporosis, its mechanisms remain unclear. MATERIAL AND METHODS In this study, we applied system bioinformatic approaches to investigate the possible therapeutic mechanisms of CO against osteoporosis. We collected the active ingredients of CO and their targets from the TCMSP, BATMAN-TCM, and ETCM databases. Next, we obtained the osteoporosis targets from differentially expressed mRNAs from the Gene Expression Omnibus (GEO) gene series (GSE35958). Next, the shared genes of the CO pharmacological targets and osteoporosis-related targets were selected to construct the protein-protein interaction network, based on the results from the STRING database. Subsequently, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were carried out by using the clusterProfiler package in R software. RESULTS In all, there were 58 unique CO compounds and 518 therapeutic targets. Based on the GO and KEGG enrichment results of 98 common genes, we selected the top 25 terms, based on the terms' P values. We found that the anti-osteoporotic effect of CO may mostly involve the regulation of calcium metabolism and reactive oxygen species, and the estrogen signaling pathway and osteoclast differentiation pathway. CONCLUSIONS We found the possible mechanisms of CO in treating osteoporosis may be based on multiple targets and pathways. We also provided a theoretical basis and promising direction for investigating the exact anti-osteoporotic mechanisms of CO.

In vivo behavior of bioactive glass-based composites in animal models for bone regeneration

This review presents the recent advances and the current state-of-the-art of bioactive glass-based composite biomaterials intended for bone regeneration. Composite materials comprise two (or more) constituents at the nanometre scale, in which typically, one constituent is organic and functions as the matrix phase and the other constituent is inorganic and behaves as the reinforcing phase. Such materials, thereby, more closely resemble natural bio-nanocomposites such as bone. Various glass compositions in combination with a wide range of natural and synthetic polymers have been evaluated in vivo under experimental conditions ranging from unloaded critical-sized defects to mechanically-loaded, weight-bearing sites with highly favourable outcomes. Additional possibilities include controlled release of anti-osteoporotic drugs, ions, antibiotics, pro-angiogenic substances and pro-osteogenic substances. Histological and morphological evaluations suggest the formation of new, highly vascularised bone that displays signs of remodelling over time. With the possibility to tailor the mechanical and chemical properties through careful selection of individual components, as well as the overall geometry (from mesoporous particles and micro-/nanospheres to 3D scaffolds and coatings) through innovative manufacturing processes, such biomaterials present exciting new avenues for bone repair and regeneration.

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.

Establishment of extraction design space for ursolic acid from Paulowniae Flos based on the concept of quality by design

INTRODUCTION

The application of quality by design (QbD) concept needs to be strengthened in the field of traditional Chinese medicine research. The extraction process has an important influence on the effectiveness of the drug, and the combination of QbD and the extraction process of the active ingredient helps to improve the effectiveness of the drug.

OBJECTIVE

To establish the extraction design space for ursolic acid (UA) from Paulowniae Flos based on the concept of QbD.

METHODS

The extraction yield of the target component UA was taken as critical quality attributes (CQAs), extraction time, extraction temperature, ethanol concentration and liquid-solid ratio, as critical process parameters (CPPs). Box-Behnken design (BBD) was applied to optimise the design space and the chromatographic conditions were performed on a Shimadzu C18 reversed-phase column with 0.1% (v/v) acetic acid aqueous water-acetonitrile (7:13, v/v) as the mobile phase at a 1 mL/min flow rate, using UA standard as a control and detection at 210 nm.

RESULTS

The single factor investigation and BBD experiment were used to construct the design space, while verification experiments and methodological validation were used to demonstrate that the space was robust and analytical methods were appropriate. The operating space of ethanol concentration 93-98%, liquid-solid ratio 28-37 mL/g and extraction temperature 70-78.3°C was recommended.

CONCLUSION

The proposed methodology can help to promote the quality control of the Chinese medicine extraction process and facilitate the production operation of the enterprise easier.

N16 suppresses RANKL-mediated osteoclatogenesis by down-regulating RANK expression

N16 is an active protein existing in Pinctada martensi. Our previous studies have demonstrated that N16 inhibited osteoclast differentiation in vitro. To better understand how N16 regulates osteoclast differentiation, RAW264.7 cells, a murine monocytic cell line and murine bone marrow-derived macrophages (BMMs) were adopted. Treatment of RAW264.7 cells with RANKL activated osteoclastogenesis and N16 inhibited the formation of multinucleated osteoclasts and TRAP activity. The suppression occurred at the early stage of osteoclastogenesis. Moreover, we found that N16 inhibited PU.1 and MITF expressions, mirroring the inhibition of RANK expressions, indicating that N16 inhibited RANK expression by down-regulating the expressions of MITF and PU.1, thus preventing osteoclastogenesis.

Betulin Promotes Differentiation of Human Osteoblasts In Vitro and Exerts an Osteoinductive Effect on the hFOB 1.19 Cell Line Through Activation of JNK, ERK1/2, and mTOR Kinases

Although betulin (BET), a naturally occurring pentacyclic triterpene, has a variety of biological activities, its osteogenic potential has not been investigated so far. The aim of this study was to assess the effect of BET on differentiation of human osteoblasts (hFOB 1.19 and Saos-2 cells) in vitro in osteogenic (with ascorbic acid as an osteogenic supplement) and osteoinductive (without an additional osteogenic supplement) conditions. Osteoblast differentiation was evaluated based on the mRNA expression (RT-qPCR) of Runt-related transcription factor 2 (RUNX2), alkaline phosphatase (ALP), type I collagen-α1 (COL1A1), and osteopontin (OPN). Additionally, ALP activity and production of COL1A1 (western blot analysis) and OPN (ELISA) were evaluated. The level of mineralization (calcium accumulation) was determined with Alizarin red S staining. BET upregulated the mRNA level of RUNX2 and the expression of other osteoblast differentiation markers in both cell lines (except the influence of BET on ALP expression/activity in the Saos-2 cells). Moreover, it increased mineralization in both cell lines in the osteogenic conditions. BET also increased the mRNA level of osteoblast differentiation markers in both cell lines (except for ALP in the Saos-2 cells) in the osteoinductive conditions, which was accompanied with increased matrix mineralization. The osteoinductive activity of BET in the hFOB 1.19 cells was probably mediated via activation of MAPKs (JNK and ERK1/2) and mTOR, as the specific inhibitors of these kinases abolished the BET-induced osteoblast differentiation. Our results suggest that BET has the potential to enhance osteogenesis.

Ursolic acid loaded-mesoporous bioglass/chitosan porous scaffolds as drug delivery system for bone regeneration

Bioglass scaffolds have great application potentials in orthopedics, and Ursolic acid (UA) can effectively promote in vivo new bone formation. Herein, we for the first time developed the mesoporous bioglass/chitosan porous scaffolds loaded with UA (MBG/CS/UA) for enhanced bone regeneration. The MBG microspheres with particle sizes of ~300 nm and pore sizes of ~3.9 nm were uniformly dispersed on the CS films. The mesoporous structure within the MBG microspheres and the hydrogen bonding between the scaffolds and UA drugs made the MBG/CS/UA scaffolds have controlled drug release performances. The as-released UA drugs from the scaffolds increased remarkably the alkaline phosphatase activity, osteogenic differentiation related gene type I collagen, runt-related transcription factor 2 expression, and osteoblast-associated protein expression. Moreover, the results of micro-CT images, histomorphological observations demonstrated that the MBG/CS/UA scaffolds improved new bone formation ability. Therefore, the MBG/CS/UA porous scaffolds can be used as novel bone tissue engineering materials.

Ursolic Acid Prevents Retinoic Acid-Induced Bone Loss in Rats

OBJECTIVE

To examine the effects of ursolic acid (UA) on mitigating retinoic acid (RA)-induced osteoporosis in rats.

METHODS

Fifty female Sprague-Dawley rats were randomly divided into the control group (n=10) and the osteoporosis group (n=40). The 40 osteoporosis rats were induced by 75 mg/(kg•d) RA once daily for 2 weeks, and then were randomly assigned to vehicle control (model), low-, middle-, and high-dose UA [(UA-L, UA-M, UA-H; 30, 60, 120 mg/(kg•d), respectively] groups (10 rats each). UA were administered once daily to the rats from the 3rd weeks for up to 4 weeks by gavage. Bone turnover markers [serum alkaline phosphatase (ALP), osteocalcin (OCN), urine deoxypyridinoline (DPD)] and other parameters, including serum calcium (S-Ca), serum phosphorus (S-P), urine calcium (U-Ca), urine phosphorus (U-P), and bone mineral density (BMD) of the femur, 4th lumbar vertebra and tibia, bone biomechanical properties and trabecular microarchitecture, were measured.

RESULTS

The osteoporosis in rats was successfully induced by RA. Compared with the model group, UA-M and UA-H significantly reversed the RA-induced changes in S-P, U-Ca, U-P, ALP, OCN and urine DPD ratio and markedly enhanced the BMD of right femur, 4th lumbar vertebra and tibia (Plt;0.05 or Plt;0.01). Further, biomechanical test and microcomputed tomography evaluation also showed that UA-H drastically improved biomechanical properties and trabecular microarchitecture (Plt;0.05 or Plt;0.01).

CONCLUSION

UA could promote bone formation, increase osteoblastic activity and reduce osteoclastic activity in rats, indicating that UA might be a potential therapeutic of RA-induced acute osteoporosis.

Oleanolic Acid and Ursolic Acid Improve Bone Properties and Calcium Balance and Modulate Vitamin D Metabolism in Aged Female Rats

Oleanolic acid (OA) and ursolic acid (UA) are the major chemical constituents in Fructus Ligustri Lucidi (FLL), a kidney-tonifying Chinese herb that is previously shown to improve bone properties and enhance calcium balance in aged female rats. The present study was designed to study if OA and UA act as the active ingredients in FLL to exert the positive effects on bone and mineral metabolism in aged rats. Aged (13-month-old) Sprague-Dawley female rats were randomly assigned to four groups with oral administration of drug or vehicle treatment for 12 weeks: medium calcium diet (MCD, 0.6% calcium), high calcium diet (HCD, 1.2% calcium), MCD + FLL (700 mg/kg/day), MCD + OA (23.6 mg/kg/day) + UA (8.6 mg/kg/day). A group of mature (3-month-old) female rats fed with MCD was included as positive control. The results demonstrated that FLL and OA+UA increased bone mineral density and improved microarchitectural properties of aged female rats. The osteoprotective effects of FLL and OA+UA might be, at least in part, associated with their actions on enhancing calcium balance and suppressing age-induced secondary hyperparathyroidism in aged female rats. FLL and OA+UA also significantly induced renal CYP27B1 protein expression and OA+UA treatment decreased CYP24A1 mRNA and protein expressions in aged female rats. In addition, FLL and OA+UA significantly increased the promoter activity, mRNA and protein expressions of renal CYP27B1 in vitro in human proximal tubule HKC-8 cells. The present findings suggest that OA+UA can be regarded as the active ingredients of FLL and might be a potential drug candidate for prevention and treatment of osteoporosis.

Both Oleanolic Acid and a Mixture of Oleanolic and Ursolic Acids Mimic the Effects of Fructus ligustri lucidi on Bone Properties and Circulating 1,25-Dihydroxycholecalciferol in Ovariectomized Rats

Background

Oleanolic acid (OA) and ursolic acid (UA) are major chemical constituents found in Fructus ligustri lucidi (FLL), a Chinese herb previously shown to increase bone properties and modulate calcium-vitamin D metabolism in rats. OA and UA have been reported to exert osteoprotective effects in vitro.

Objective

The present study was designed to determine whether OA or OA + UA mimicked the effects of FLL on bone and calcium homeostasis using ovariectomized rats.

Methods

Three-month-old ovariectomized Sprague-Dawley rats were stabilized for 2 mo and randomly assigned to 4 groups offered the same amount (15-17 g/d) of a control diet or experimental diets containing FLL (18.8 g/kg), OA (0.67 g/kg), or OA (0.67 g/kg) + UA (0.22 g/kg) for 6 wk. Serum was obtained for measurement of 1,25-dihydroxycholecalciferol [1,25(OH)2D3] and bones were collected for micro-CT analysis. Calcium balance was measured at weeks 1 and 6. A calcium kinetic study using 45Ca was conducted at week 6 and modeled using WinSAAM software.

Results

Compared with the control group, rats fed the FLL-, OA-, and OA + UA-enriched diets had better bone properties and 51%, 31%, and 27% higher serum 1,25(OH)2D3 concentrations at week 6, respectively. These variables did not differ between the treatments. Calcium balance was not affected by diet at either week 1 or week 6. Kinetic modeling predicted that FLL and OA + UA diet-fed rats had 9% and 15% less endogenous excretion of calcium, respectively, compared with the control group. All 3 treatments resulted in a higher calcium mass of compartment 3 because of changes in transfer rate between compartments 2 and 3, and were positively associated with the serum 1,25(OH)2D3 concentration (R2 = 0.28; P < 0.01).

Conclusion

Similar to FLL, OA and OA + UA increase bone properties, serum 1,25(OH)2D3 concentration, and calcium use in ovariectomized rats, suggesting their potential role in management of osteoporosis.

New secoiridoids from the fruits of Ligustrum lucidum

Three new secoiridoids, nuezhenelenoliciside (1), isojaslanceoside B (2), 6'-O-trans-cinnamoyl-secologanoside (3), were isolated from the dried fruits of Ligustrum lucidum. Their structures were elucidated by comprehensive spectroscopic analysis. Among them, 1 featured a rare rearrangement product of secoiridoid, which underwent the cleavage of chemical bond between C-1 and O-2, and the reformation of a new iridoid ring between C-8 and O-2. In addition, all compounds were tested for their osteogenic activity on pre-osteoblastic MC3T3-E1 cells. As a result, 1 and 3 exhibited potent effects on promoting cell proliferation of pre-osteoblast cells.

Fructus Ligustri Lucidi in Osteoporosis: A Review of its Pharmacology, Phytochemistry, Pharmacokinetics and Safety

Background: Fructus Ligustri Lucidi (FLL) has now attracted increasing attention as an alternative medicine in the prevention and treatment of osteoporosis. This study aimed to provide a general review of traditional interpretation of the actions of FLL in osteoporosis, main phytochemical constituents, pharmacokinetics, pharmacology in bone improving effect, and safety. Materials and Methods: Several databases, including PubMed, China National Knowledge Infrastructure, National Science and Technology Library, China Science and Technology Journal Database, and Web of Science were consulted to locate publications pertaining to FLL. The initial inquiry was conducted for the presence of the following keywords combinations in the abstracts: Fructus Ligustri Lucidi, osteoporosis, phytochemistry, pharmacokinetics, pharmacology, osteoblasts, osteoclasts, salidroside. About 150 research papers and reviews were consulted. Results: FLL is assumed to exhibit anti-osteoporotic effects by improving liver and kidney deficiencies and reducing lower back soreness in Traditional Chinese Medicine (TCM). The data from animal and cell experiments demonstrate that FLL is able to improve bone metabolism and bone quality in ovariectomized, growing, aged and diabetic rats through the regulation of PTH/FGF-23/1,25-(OH)₂D₃/CaSR, Nox4/ROS/NF-κB, and OPG/RANKL/cathepsin K signaling pathways. More than 100 individual compounds have been isolated from this plant. Oleanolic acid, ursolic acid, salidroside, and nuzhenide have been reported to exhibit the anti-osteoporosis effect. The pharmacokinetics data reveals that salidroside is one of the active constituents, and that tyrosol is hard to detect under physiological conditions. Acute and subacute toxicity studies show that FLL is well tolerated and presents no safety concerns. Conclusions: FLL provides a new option for the prevention and treatment of osteoporosis, which attracts rising interests in identifying potential anti-osteoporotic compounds and fractions from this plant. Further scientific evidences are expected from well-designed clinical trials on its bone protective effects and safety.

Guava fruit extract and its triterpene constituents have osteoanabolic effect: Stimulation of osteoblast differentiation by activation of mitochondrial respiration via the Wnt/β-catenin signaling

The aim of this study was to evaluate the skeletal effect of guava triterpene-enriched extract (GE) in rats and identify osteogenic compounds thereof, and determine their modes of action. In growing female rats, GE at 250 mg/kg dose increased parameters of peak bone mass including femur length, bone mineral density (BMD) and biomechanical strength, suggesting that GE promoted modeling-directed bone growth. GE also stimulated bone regeneration at the site of bone injury. In adult osteopenic rats (osteopenia induced by ovariectomy, OVX) GE completely restored the lost bones at both axial and appendicular sites, suggesting a strong osteoanabolic effect. Serum metabolomics studies showed changes in several metabolites (some of which are related to bone metabolism) in OVX compared with ovary-intact control and GE treatment to OVX rats reversed those. Out of six abundantly present triterpenes in GE, ursolic acid (UA) and 2α-hydroxy ursolic acid (2α-UA) induced osteogenic differentiation in vitro as did GE by activating Wnt/β-catenin pathway assessed by phosphorylation of GSK-3β. Over-expressing of constitutively active GSK-3β (caGSK-3β) in osteoblasts abolished the differentiation-promoting effect of GE, UA and 2α-UA. All three increased both glycolysis and mitochondrial respiration but only rotenone (inhibitor of mitochondrial electron transfer) and not 2-deoxyglucose (to block glycolysis) inhibited osteoblast differentiation. In addition, caGSK-3β over-expression attenuated the enhanced mitochondrial respiration caused by GE, UA and 2α-UA. We conclude that GE has osteoanabolic effect which is contributed by UA and 2α-UA, and involve activation of canonical Wnt signaling which in turn modulates cellular energy metabolism leading to osteoblast differentiation.

Comparison of the interaction between lactoferrin and isomeric drugs

The binding properties of pentacyclic triterpenoid isomeric drugs, i.e. ursolic acid (UA) and oleanolic acid (OA), to bovine lactoferrin (BLF) have been studied by molecule modeling, fluorescence spectroscopy, UV-visible absorbance spectroscopy and infrared spectroscopy (IR). Molecular docking, performed to reveal the possible binding mode or mechanism, suggested that hydrophobic interaction and hydrogen bonding play important roles to stabilize the complex. The results of spectroscopic measurements showed that the two isomeric drugs both strongly quenched the intrinsic fluorescence of BLF through a static quenching procedure although some differences between UA and OA binding strength and non-radiation energy transfer occurred within the molecules. The number of binding sites was 3.44 and 3.10 for UA and OA, respectively, and the efficiency of Förster energy transfer provided a distance of 0.77 and 1.21nm for UA and OA, respectively. The conformation transformation of BLF affected by the drugs conformed to the "all-or-none" pattern. In addition, the changes of the ratios of α-helices, β-sheets and β-turns of BLF during the process of the interaction were obtained. The results of the experiments in combination with the calculations showed that there are two modes of pentacyclic triterpenoid binding to BLF instead of one binding mode only governed by the principle of the lowest bonding energy.

Therapeutic Role of Punica Granatum (Pomegranate) Seed Oil Extract on Bone Turnover and Resorption Induced in Ovariectomized Rats

CONTEXT

Postmenopausal osteoporosis is mostly caused by increased bone remodeling resulting from estrogen deficiency. Hormone replacement therapy (HRT) is used to prevent osteoporosis, but it increases the risk for breast cancer, thromboembolism, strokes, and heart attacks. Pomegranate seed oil extract (SOE) is rich in phytoestrogen and antioxidant compounds.

OBJECTIVES

To evaluate the therapeutic role of SOE against bone turnover, resorption and osteoporosis induced in ovariectomized rats as a postmenopausal model and comparing the results with those from Generic CycloProgynova drug (D).

DESIGN

The study used western albino rats undergo bilaterally ovariectomization as a model for postmenopausal.

SETTING

The study took part in a laboratory setting.

ANIMALS

Forty female western albino rats (age: 3-4 months) weighing 150-180 gm.

MEASUREMENTS

Rats were divided into four groups, 10 rats each; SC-group: Sham control = untreated and unovariectomized rats; OVX-group = ovariectomized rats; (OVX-SOE) and (OVX-D) groups = OVX rats were treated with SOE and D, respectively. Bone markers (BMs) especially osteocalcin (BGP), alkaline phosphatase (ALP), tartarate resistance acid phosphatase (TRAcP), bone weight, bone calcium concentration, serum electrolytes (calcium, sodium and potassium) and serum estradiol (E2) level and histopathological examination of bones were determined. Also lipid profile, uric acid, prothrombin time (INR) and liver and kidney functions were measured to evaluate the adverse effects of SOE and D.

RESULTS

In OVX group the activities of ALP and TRAcP and the levels of BGP, serum calcium, sodium and body weight were significantly higher (p≤0.05) than SC-group, while bone calcium concentration, bone mass, serum E2 and potassium level as well as uterus mass were significantly lower (p≤0.05). Also histopathological results revealed that the outer cortical bone became thinner, while the cancellous bone trabeculae lost their normal architecture. Moreover in OVX group lipid profile and uric acid levels were significantly higher (p≤0.05) than SC group, but there were no significant changes (p≤0.05) in INR level, liver and kidney functions. Treatment of OVX rats with SOE or D for 12 weeks improved both the architecture of bones as shown from the histopathological results and BMs, serum electrolytes and E2 levels (p≤0.05) which approached SC-group. Moreover after treatment of OVX rats with SOE the levels of lipid profile and uric acid were improved and approached SC-group, while liver function became significant lower (p≤0.05) than SC-group. Also there were no significant changes (p≤0.05) in kidney functions and INR of (OVX-SOE), OVX and SC groups. In contrast in (OVX-D) group the levels of lipid profile, liver and kidney functions, uric acid and INR were significantly higher (p≤0.05) than those of OVX and SC groups.

CONCLUSION

The results of this study show that SOE has therapeutic effects on osteoporosis, while it has no adverse effects on lipid profile, uric acid, liver and kidney functions when compared to HRT. SOE offers a promising alternative in the design of new strategies in nutritional management of age-related bone complications.

Natural Products from Chinese Medicines with Potential Benefits to Bone Health

Osteoporosis is a progressive, systemic bone disorder characterized by loss of bone mass and microstructure, leading to reduced bone strength and increased risk of fracture. It is often associated with reduced quality of life and other medical complications. The disease is common in the aging population, particularly among postmenopausal women and patients who receive long-term steroidal therapy. Given the rapid growth of the aging population, increasing life expectancy, the prevalence of bone loss, and financial burden to the healthcare system and individuals, demand for new therapeutic agents and nutritional supplements for the management and promotion of bone health is pressing. With the advent of global interest in complementary and alternative medicine and natural products, Chinese medicine serves as a viable source to offer benefits for the improvement and maintenance of bone health. This review summarizes the scientific information obtained from recent literatures on the chemical ingredients of Chinese medicinal plants that have been reported to possess osteoprotective and related properties in cell-based and/or animal models. Some of these natural products (or their derivatives) may become promising leads for development into dietary supplements or therapeutic drugs.

Ligustrum lucidum and its Constituents: A Mini-Review on the Anti-Osteoporosis Potential

Osteoporosis is a metabolic bone disorder commonly occurred in aging populations, particularly postmenopausal women and patients who undergo long-term steroid or anti-estrogen therapies. Given the rapid growth of the aging population, the prevalence of bone loss, and the huge medical and healthcare cost involved, demand for alternative approaches for the promotion of bone health is pressing. With the advent of global interest in complementary and alternative medicine and natural products, Chinese medicine serves as a viable source that offers benefits to improve and maintain bone health. This review summarizes the scientific information on the Chinese medicinal herb Ligustrum lucidum and its chemical components as potential therapy for osteoporosis.

Ursolic Acid--A Pentacyclic Triterpenoid with a Wide Spectrum of Pharmacological Activities

Ursolic acid (UA) is a natural terpene compound exhibiting many pharmaceutical properties. In this review the current state of knowledge about the health-promoting properties of this widespread, biologically active compound, as well as information about its occurrence and biosynthesis are presented. Particular attention has been paid to the application of ursolic acid as an anti-cancer agent; it is worth noticing that clinical tests suggesting the possibility of practical use of UA have already been conducted. Amongst other pharmacological properties of UA one can mention protective effect on lungs, kidneys, liver and brain, anti-inflammatory properties, anabolic effects on skeletal muscles and the ability to suppress bone density loss leading to osteoporosis. Ursolic acid also exhibits anti-microbial features against numerous strains of bacteria, HIV and HCV viruses and Plasmodium protozoa causing malaria.

Osteoprotective Effect of Echinocystic Acid, a Triterpone Component from Eclipta prostrata, in Ovariectomy-Induced Osteoporotic Rats

Echinocystic acid (EA) is a natural triterpone enriched in various herbs and has been used for medicinal purposes in China. In the present study, we systematically examined the effects of EA on ovariectomy-induced osteoporosis in rats for the first time. Three-month-old female ovariectomy (OVX) Sprague-Dawley rats were used to evaluate the osteoprotective effect of EA. Results showed that administration of EA (5 or 15 mg/kg/day) for 12 weeks prevented lower levels of maximum stress and Young's modulus of femur induced by OVX. EA also recovered bone metabolic biomarkers levels in OVX rats, including osteocalcin, alkaline phosphatese, deoxypyridinoline, and urinary calcium and phosphorus. EA (5 and 15 mg/kg/day) could prevent the alteration of total bone mineral density in the femur caused by OVX. However, only high dose (15 mg/kg/day) of EA significantly improved trabecular architecture, as evidenced by higher levels of bone volume/tissue volume, trabecula number, and trabecula thickness, and lower levels of trabecula separation and structure model index compared with OVX rats. In addition, EA treatment decresed the serum levels of IL-1β and TNF-α in OVX rats. In conclusion, EA could prevent reduction of bone mass and strength and improve the cancellous bone structure and biochemical properties in OVX rats. Hence, EA may serve as a new candidate or a leading compound for anti-osteoporosis.

Effect of Fructus Ligustri Lucidi on osteoblastic like cell-line MC3T3-E1

Fructus Ligustri Lucidi, fruits of Ligustrum lucidum Ait. (Oleaceae), has the effects of tonifying the liver and the kidney and strengthening the bones and muscles. In ancient times, Fructus Ligustri Lucidi can be prepared in ethanol or in water. Some active compounds have been found in Fructus Ligustri Lucidi, like Oleanolic acid and Ursolic acid, and Ursolic acid were proved to have osteogenic effects.

METHODS AND RESULTS

To prove that Fructus Ligustri Lucidi water extract have osteogenic effects on MC3T3-E1 cells and how these effects work, we used CCK-8 (cell counting kit-8), ELISA (enzyme-linked immunosorbent assay), FQ-PCR (realtime fluorescence quantitative PCR) and western blot assays. After treatment with Fructus Ligustri Lucidi for 48h, 72h, 96h, the cell viability was marked increased, on concentration-dependently and time-dependently pattern. High and low concentrations of Fructus Ligustri Lucidi promoted differentiation of cells. Fructus Ligustri Lucidi could up-regulate OPG and RANKL protein in supernatant at 48h and 72h except for highest concentration (10(-1)mg/ml). Fructus Ligustri Lucidi promote OPG and RANKL mRNA expression at 48h and 72h, while the level of promoting at 72 was higher than 48h. 10(-5)mg/ml of Fructus Ligustri Lucidi up-regulates OPG protein expression and down-regulates RANKL protein expression. After treatment with Fructus Ligustri Lucidi water extract, inhibitors, Fructus Ligustri Lucidi water extract with inhibitors for 72h, inhibitors PD 98059, SB 203580, SP600125 and LY 294002 showed Fructus Ligustri Lucidi-induced cell proliferation and the leakage of OPG proteins effects. Fructus Ligustri Lucidi promoted the protein levels of ERK, p-ERK, p-JNK, p38, pp38, AKT and p-AKT, and inhibited the protein levels of JNK.

CONCLUSIONS

Fructus Ligustri Lucidi water extract promoted cell proliferation and differentiation, mRNA and protein expression of OPG and RANKL on MC3T3-E1 cells. The effects of cell proliferation and leakage of OPG related to MAPK and AKT signaling pathways in different ways.

Anxiolytic-like effects of ursolic acid in mice

Ursolic acid is a pentacyclic triterpenoid that possesses several biological and neuropharmacological effects including antidepressant-like activity. Anxiety disorders represent common and disability psychiatric conditions that are often associated with depressive symptoms. This work investigated the anxiolytic-like effects of ursolic acid administration in different behavioral paradigms that evaluate anxiety in mice: open field test, elevated plus maze test, light/dark box test and marble burying test. To this end, mice were administered with ursolic acid (0.1, 1 and 10mg/kg, p.o.) or diazepam (2mg/kg, p.o.), positive control, and submitted to the behavioral tests. The results show that ursolic acid (10mg/kg) elicited an anxiolytic-like effect observed by the increased total time in the center and decreased number of rearings responses in the open field test and an increased percentage of entries and total time spent in the open arms of elevated plus maze, similarly to diazepam. No significant effects of ursolic acid were shown in the light/dark box and marble burying test. These data indicate that ursolic acid exhibits anxiolytic-like effects in the open field and elevated plus maze test, but not in the light/dark box and marble burying test, showing the relevance of testing several behavioral paradigms in the evaluation of anxiolytic-like actions. Of note, the results extend the understanding on the effects of ursolic acid in the central nervous system and suggest that it may be a novel approach for the management of anxiety-related disorders.

CB(2) and TRPV(1) receptors oppositely modulate in vitro human osteoblast activity

In the current study, we have investigated the effect of CB2 and TRPV1 receptor ligands on in vitro osteoblasts from bone marrow of human healthy donors. A pivotal role for the endocannabinoid/endovanilloid system in bone metabolism has been highlighted. We have demonstrated a functional cross-talk between CB2 and TRPV1 in human osteoclasts, suggesting these receptors as new pharmacological target for the treatment of bone resorption disease as osteoporosis. Moreover, we have shown the presence of these receptors on human mesenchimal stem cells, hMSCs. Osteoblasts are mononucleated cells originated from hMSCs by the essential transcription factor runt-related transcription factor 2 and involved in bone formation via the synthesis and release of macrophage colony-stimulating factor, receptor activator of nuclear factor kappa-B ligand and osteoprotegerin. For the first time, we show that CB2 and TRPV1 receptors are both expressed on human osteoblasts together with enzymes synthesizing and degrading endocannabinoids/endovanilloids, and oppositely modulate human osteoblast activity in culture in a way that the CB2 receptor stimulation improves the osteogenesis whereas TRPV1 receptor stimulation inhibits it.

Inhibitory effects of ursolic acid on osteoclastogenesis and titanium particle-induced osteolysis are mediated primarily via suppression of NF-κB signaling

Ursolic acid (UA), a pentacyclic triterpenoid found in a variety of plants, has attracted considerable attention because of its important biological and pharmacological activities. However, its effect on osteoclasts and mechanism of action require further investigation. In this study, we evaluated the effects of UA on osteoclastogenesis and osteoclast-mediated osteolysis in vitro and in vivo, and explored its possible mechanism of action. The results indicated that UA could inhibit receptor activator of nuclear factor-κB ligand (RANKL)-mediated osteoclastogenesis and the bone resorptive function of osteoclasts in a concentration-dependent manner in vitro. Further, UA effectively inhibited the mRNA and protein expression of NFATc1, primarily via the suppression of nuclear factor-κB (NF-κB) signaling, and partly through the suppression of c-Jun N-terminal kinase (JNK) signaling. Additionally, UA treatment downregulated the expression of NFATc1-regulated osteoclast marker genes. Likewise, UA induced dose-dependent attenuation of titanium (Ti) particle-induced mouse calvarial bone loss, and decreased the number of tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts. In conclusion, these results demonstrate that UA protects against wear particle-induced osteolysis by suppressing osteoclast formation and function. These effects are associated with the inhibition of the NF-κB- and JNK-related signaling pathways.

Salvia miltiorrhiza: an ancient Chinese herbal medicine as a source for anti-osteoporotic drugs

ETHNOPHARMACOLOGICAL RELEVANCE

Red sage (Salvia miltiorrhiza Bunge), also known as Danshen in Chinese, has been used historically and is currently exploited in combination with other herbs to treat skeletal diseases in traditional Chinese medicine (TCM). With the advance of modern analytical technology, a multitude of bone-targeting, pharmaceutically active, compounds has been isolated and characterized from various sources of TCM including those produced in Salvia miltiorrhiza root. The aim of the review is to provide a comprehensive overview about the historical TCM interpretation of the action of Salvia miltiorrhiza in osteoporosis, its use clinical trials, its main phytochemical constituents, and its action on bone-resorptive and bone formation-stimulating mechanisms in in vitro and in vivo studies.

MATERIALS AND METHODS

Literature sources used were Pubmed, CNKI.net, Cqvip.com, PubChem, and the Web of Science. For the inquiry, keywords such as Salvia, danshen, osteoporosis, bone, osteoclast and osteoblast were used in various combinations. About 130 research papers and reviews were consulted.

RESULTS

In TCM, the anti-osteopororotic effect of Salvia miltiorrhiza is ascribed to its action on liver and blood stasis as main therapeutic targets defining osteoporosis. 36 clinical trials were identified which used Salvia miltiorrhiza in combination with other herbs and components to treat post-menopausal, senile, and secondary osteoporosis. On average the trials were characterized by high efficacy (>80%) and low toxicity problems. However, various limitations such as small patient samples, short treatment duration, frequent lack of detailed numerical data, and no clear endpoints must be taken into consideration. To date, more than 100 individual compounds have been isolated from this plant and tested in various animal models and biochemical assays. Compounds display anti-resorptive and bone formation-stimulating features targeting different pathways in the bone remodeling cycle. Pathways affected include the activation of osteoblasts, the modulation of osteoclastogenesis, and the inhibition of collagen degradation by cathepsin K.

CONCLUSIONS

The inclusion of Salvia miltiorrhiza in more than 30% of all herbal clinical trials successfully targeting osteoporosis has stimulated significant interest in the identification and characterization of individual constituents of this herb. The review highlights the anti-osteoporotic potential of Salvia miltiorrhiza in clinical applications and the potential of the herb to provide potent compounds targeting specific pathways in bone resorption and bone formation.

Tryptophan hydroxylase 1 (Tph-1)-targeted bone anabolic agents for osteoporosis

Tryptophan hydroxylase 1 (Tph-1), the principal enzyme for peripheral serotonin biosynthesis, provides a novel target to design anabolic agents for osteoporosis. Here, we present a design, synthesis of a novel series of ursolic acid derivatives under the guidance of docking technique, and bioevaluation of the derivatives using RBL2H3 cells and ovariectomized (OVX) rats. Of the compounds, 9a showed a potent inhibitory activity on serotonin biosynthesis. Further investigations revealed that 9a, as an efficient Tph-1 binder identified by SPR (estimated KD: 6.82 μM), suppressed the protein and mRNA expressions of Tph-1 and lowered serotonin contents in serum and gut without influence on brain serotonin. Moreover, oral administration of 9a elevated serum level of N-terminal propeptide of procollagen type 1 (P1NP), a bone formation marker, and improved bone microarchitecture without estrogenic side effects in ovariectomized rats. Collectively, 9a may serve as a new candidate for bone anabolic drug discovery.

Fructus ligustri lucidi ethanol extract improves bone mineral density and properties through modulating calcium absorption-related gene expression in kidney and duodenum of growing rats

Optimizing peak bone mass in early life is one of key preventive strategies against osteoporosis. Fructus ligustri lucidi (FLL), the fruit of Ligustrum lucidum Ait., is a commonly prescribed herb in many kidney-tonifying traditional Chinese medicinal formulas to alleviate osteoporosis. Previously, FLL extracts have been shown to have osteoprotective effect in aged or ovariectomized rats. In the present study, we investigated the effects of FLL ethanol extract on bone mineral density (BMD) and mechanical properties in growing male rats and explored the underlying mechanisms. Male weaning Sprague-Dawley rats were randomized into four groups and orally administrated for 4 months an AIN-93G formula-based diet supplementing with different doses of FLL ethanol extract (0.40, 0.65, and 0.90 %) or vehicle control, respectively. Then calcium balance, serum level of Ca, P, 25(OH)2D3, 1,25(OH)2D3, osteocalcin (OCN), C-terminal telopeptide of type I collagen (CTX-I), and parathyroid hormone, bone microarchitecture, and calcium absorption-related genes expression in duodenum and kidney were analyzed. The results demonstrated that FLL ethanol extract increased BMD of growing rats and improved their bone microarchitecture and mechanical properties. FLL ethanol extract altered bone turnover, as evidenced by increasing a bone formation maker, OCN, and decreasing a bone resorption maker, CTX-I. Intriguingly, both Ca absorption and Ca retention rate were elevated by FLL ethanol extract treatment, possibly through the mechanisms of up-regulating the transcriptions of calcitropic genes in kidney (1α-hydroxylase) and duodenum (vitamin D receptor, calcium transporter calbindin-D9k, and transient receptor potential vanilloid 6). In conclusion, FLL ethanol extract increased bone mass gain and improved bone properties via modulating bone turnover and up-regulating calcium absorption-related gene expression in kidney and duodenum, which could then activate 1,25(OH)2D3-dependent calcium transport in male growing rats.

Inhibitory effects of the leaves of loquat (Eriobotrya japonica) on bone mineral density loss in ovariectomized mice and osteoclast differentiation

The loquat, Eriobotrya japonica Lindl. (Rosaceae), is a small tree native to Japan and China that is widely cultivated for its succulent fruit. Its leaves are used as an ingredient of a tasty tea called "Biwa cha" in Japanese. The anti-osteoporosis effects of the leaves of loquat in vitro and in vivo have been investigated. After 15 days of feeding normal diet or diet supplemented with 5% loquat leaves, the body weight, viscera weights, and bone mineral density (BMD) of both groups of eight ovariectomized (OVX) mice were compared. The result showed that the loss of BMD in loquat-fed mice was significantly prevented in three parts of the body, especially in the trabecular bone of the head (P < 0.05), abdomen (P < 0.01), and lumbar (P < 0.05) compared to the control group. No hypertrophy in the uterus by the loquat leaves diet was observed. The effect of the extract (447.25 g) prepared from the dried leaves of loquat (2.36 kg) was further studied on RANKL-induced osteoclast differentiation and cell viability. The extract suppressed the differentiation of osteoclasts under 50, 125, 250, and 500 μg/mL. Through bioactivity-guided fractionation, ursolic acid (1) was isolated and inhibited osteoclast differentiation under 4 and 10 μg/mL. It was concluded that loquat leaves possess the potential to suppress ovariectomy-induced bone mineral density deterioration.

Microbial transformation of ursolic acid by Syncephalastrum racemosum (Cohn) Schroter AS 3.264

Biotransformation of ursolic acid by the filamentous fungus Syncephalastrum racemosum (Cohn) Schroter AS 3.264 yielded five metabolites. Their structures were identified as 3β,21β-dihydroxy-urs-11-en-28-oic acid-13-lactone, 3β,7β,21β-trihydroxy-urs-11-en-28-oic acid-13-lactone, 1β,3β-dihydroxy-urs-12-en-21-one-28-oic acid, 1β,3β,21β-trihydroxy-urs-12-en-28-oic acid and 11,26-epoxy-3β,21β-dihydroxy-urs-12-en-28-oic acid based on NMR and MS spectroscopic analyses. The condensation reactions to form 28-oic acid-13-lactone ring and 11,26-epoxy ring are not frequently seen for the biotransformation of triterpenoids. One compound showed moderate inhibitory activity against protein tyrosine phosphatase 1B (PTP1B).

The "bone morphogenic proteins" pathways in bone and joint diseases: translational perspectives from physiopathology to therapeutic targets

A large body of evidence supports an important role of bone morphogenic proteins (BMPs) pathways in skeletal development in the embryo. BMPs are also involved in skeletal homeostasis and diseases in the adult. They were first identified as major bone anabolic agents and recent advances indicate that they also regulate osteoclastogenesis and joint components via multiple cross-talks with other signaling pathways. This review attempts to integrate these data in the pathogenesis of bone and joints diseases, such as osteoporosis, fracture healing, osteoarthritis, inflammatory arthritis, or bone metastasis. The use of recombinant BMPs in bone tissue engineering and in the treatment of skeletal diseases, or future therapeutic strategies targeting BMPs signal and its regulators, will be discussed based on these considerations.

Alternative therapies for the prevention and treatment of osteoporosis

Osteoporosis is a medical condition that affects millions of men and women. People with this condition have low bone mass, which places them at increased risk for bone fracture after minor trauma. The surgeries and treatments required to repair and heal bone fractures involve long recovery periods and can be expensive. Because osteoporosis occurs frequently in the elderly, the financial burden it places on society is likely to be large. In the United States, the Food and Drug Administration has approved several drugs for use in the prevention and treatment of osteoporosis. However, all of the currently available agents have severe side effects that limit their efficacy and underscore the urgent need for new treatment options. One promising approach is the development of alternative (nonpharmaceutical) strategies for bone maintenance, as well as for the prevention and treatment of osteoporosis. This review examines the currently available nonpharmaceutical alternatives that have been evaluated in in vitro and in vivo studies. Certain plants from the following families have shown the greatest benefits on bone: Alliceae, Asteraceae, Thecaceae, Fabaceae, Oleaceae, Rosaceae, Ranunculaceae, Vitaceae, Zingiberaceae. The present review discusses the most promising findings from studies of these plant families.

Development of a liquid chromatography-mass spectrometry method for the determination of ursolic acid in rat plasma and tissue: application to the pharmacokinetic and tissue distribution study

A fast and sensitive liquid chromatography-mass spectrometry method was developed for the determination of ursolic acid (UA) in rat plasma and tissues. Glycyrrhetinic acid was used as the internal standard (IS). Chromatographic separation was performed on a 3.5 μm Zorbax SB-C18 column (30 mm × 2.1 mm) with a mobile phase consisting of methanol and aqueous 10 mM ammonium acetate using gradient elution. Quantification was performed by selected ion monitoring with (m/z)(-) 455 for UA and (m/z)(-) 469 for the IS. The method was validated in the concentration range of 2.5 - 1470 ng mL(-1) for plasma samples and 20 - 11760 ng g(-1) for tissue homogenates. The intra- and inter-day assay of precision in plasma and tissues ranged from 1.6% to 7.1% and 3.7% to 9.0%, respectively, and the intra- and inter-day assay accuracy was 84.2 - 106.9% and 82.1 - 108.1%, respectively. Recoveries in plasma and tissues ranged from 83.2% to 106.2%. The limits of detections were 0.5 ng mL(-1) or 4.0 ng g(-1). The recoveries for all samples were >90%, except for liver, which indicated that ursolic acid may metabolize in liver. The main pharmacokinetic parameters obtained were T(max) = 0.42 ± 0.11 h, C(max) = 1.10 ± 0.31 μg mL(-1), AUC = 1.45 ± 0.21 μg h mL(-1) and K(a) = 5.64 ± 1.89 h(-1). The concentrations of UA in rat lung, spleen, liver, heart, and cerebellum were studied for the first time. This method is validated and could be applicable to the investigation of the pharmacokinetics and tissue distribution of UA in rats.

Chrysoeriol isolated from Eurya cilliata leaves protects MC3T3-E1 cells against hydrogen peroxide-induced inhibition of osteoblastic differentiation

Chrysoeriol is a flavonoid compound found in several tropical medicinal plants. To elucidate the protective effects of chrysoeriol isolated from Eurya cilliata on the response of osteoblasts to oxidative stress, osteoblastic MC3T3-E1 cells were incubated with chrysoeriol and/or H₂O₂, and markers of osteoblast function and oxidative damage were examined. Chrysoeriol treatment significantly (P < 0.05) reversed the cytotoxic effect of H₂O₂ and increased collagen content, alkaline phosphatase activity and calcium deposition of osteoblasts in the presence of H₂O₂. These effects were blocked by ICI182780, suggesting that chrysoeriol's effect might be partly involved in estrogen action. Moreover, H₂O₂-induced reduction of osteocalcin was recovered in the presence of chrysoeriol. Chrysoeriol significantly (P < 0.05) decreased the production of receptor activator of nuclear factor-κB ligand, interleukin-6, protein carbonyl and malondialdehyde of MC3T3-E1 cells in the presence of H₂O₂. These results demonstrate that chrysoeriol isolated from E. cilliata can protect osteoblasts from oxidative stress-induced toxicity.