A novel flavonoid isolated from the steam-bark of Ulmus Wallichiana Planchon stimulates osteoblast function and inhibits osteoclast and adipocyte differentiation

Discovery and optimized extraction of the anti-osteoclastic agent epicatechin-7-O-β-D-apiofuranoside from Ulmus macrocarpa Hance bark

Ulmus macrocarpa Hance bark (UmHb) has been used as a traditional herbal medicine in East Asia for bone concern diseases for a long time. To find a suitable solvent, we, in this study, compared the efficacy of UmHb water extract and ethanol extract which can inhibit osteoclast differentiation. Compared with two ethanol extracts (70% and 100% respectively), hydrothermal extracts of UmHb more effectively inhibited receptor activators of nuclear factor κB ligand-induced osteoclast differentiation in murine bone marrow-derived macrophages. We identified for the first time that (2R,3R)-epicatechin-7-O-β-D-apiofuranoside (E7A) is a specific active compound in UmHb hydrothermal extracts through using LC/MS, HPLC, and NMR techniques. In addition, we confirmed through TRAP assay, pit assay, and PCR assay that E7A is a key compound in inhibiting osteoclast differentiation. The optimized condition to obtain E7A-rich UmHb extract was 100 mL/g, 90 °C, pH 5, and 97 min. At this condition, the content of E7A was 26.05 ± 0.96 mg/g extract. Based on TRAP assay, pit assay, PCR, and western blot, the optimized extract of E7A-rich UmHb demonstrated a greater inhibition of osteoclast differentiation compared to unoptimized. These results suggest that E7A would be a good candidate for the prevention and treatment of osteoporosis-related diseases.

Maternal omega-3 LC-PUFA supplementation programs an improved bone mass in the offspring with a more pronounced effect in females than males at adulthood

Early balanced nutrition is vital in achieving optimal skeletal mass and its maintenance. Although a lower omega-6 (n-6): omega-3 (n-3) long-chain polyunsaturated fatty acid (LC-PUFA) ratio is strongly linked with bone health, its maternal effect in the programming of the offspring's skeleton remains to be elucidated. Plugged C57BL/6 mice were fed either n-3 LC-PUFA Enriched Diet (LED) or a control diet (C) throughout their gestation and lactation. Offspring born to both the groups were weaned onto C till 6, 12, and 24 weeks of their age. Offspring's skeleton metabolism and serum fatty acid composition was studied. In humans, seventy-five mother-female newborns pairs from term gestation were tested for their maternal LC-PUFA status relationships to venous cord blood bone biomarkers. Offspring of maternal LED supplemented mice exhibited a superior bone phenotype over C, more prominent in females than males. A lower serum n-6/n-3 LC-PUFA in the LED group offspring was strongly associated with blood biomarkers of bone metabolism. Sexual dimorphism evidenced had a strong correlation between offspring's LC-PUFA levels and bone turnover markers in serum. A higher potential for osteoblastic differentiation in both LED offspring genders and reduced osteoclastogenesis in females was cell-autonomous effect. The human cross-sectional study also showed a positive correlation between maternal n-3 PUFA and cord blood markers of bone formation in female newborns at birth. Maternal dietary n-6/ n-3 fat quality determines offspring's bone growth and development. Our data suggest that the skeleton of female offspring is likely to be more sensitive to this early exposure.

Maternal high-cholesterol diet negatively programs offspring bone development and downregulates hedgehog signaling in osteoblasts

Cholesterol is one of the essential intrauterine factors required for fetal growth and development. Maternal high cholesterol levels are known to be detrimental for offspring health. However, its long-term effect on offspring skeletal development remains to be elucidated. We performed our studies in two strains of mice (C57BL6/J and Swiss Albino) and human subjects (65 mother-female newborn dyads) to understand the regulation of offspring skeletal growth by maternal high cholesterol. We found that mice offspring from high-cholesterol-fed dams had low birth weight, smaller body length, and delayed skeletal ossification at the E18.5 embryonic stage. Moreover, we observed that the offspring did not recover from the reduced skeletal mass and exhibited a low bone mass phenotype throughout their life. We attributed this effect to reduced osteoblast cell activity with a concomitant increase in the osteoclast cell population. Our investigation of the molecular mechanism revealed that offspring from high-cholesterol-fed dams had a decrease in the expression of ligands and proteins involved in hedgehog signaling. Further, our cross-sectional study of human subjects showed a significant inverse correlation between maternal blood cholesterol levels and cord blood bone formation markers. Moreover, the bone formation markers were significantly lower in the female newborns of hypercholesterolemic mothers compared with mothers with normal cholesterolemic levels. Together, our results suggest that maternal high cholesterol levels deleteriously program offspring bone mass and bone quality and downregulate the hedgehog signaling pathway in their osteoblasts.

Ethanolic extract from the root and leaf of Sida cordifolia promotes osteoblast activity and prevents ovariectomy-induced bone loss in mice

BACKGROUND

Sida cordifolia is traditionally found in the Indian system of medicine, well known for its medicinal and nutritional properties among local natives.

PURPOSE

The present study aims to investigate the osteo-protective effect of root and leaf ethanolic extract of S. cordifolia (RE and LE) and its underlying mechanism.

METHODS

Antioxidant activity of RE and LE was assessed. Total phenolic and flavonoid content were determined. HPLC profiling of RE and LE was performed to examine the polyphenol content. The effect of RE and LE on osteoblast cells proliferation, differentiation, mineralization, and expression of the protein associated with osteogenesis were evaluated using primary calvarial osteoblast culture. Skeletal effects of RE and LE of S. cordifolia were investigated in C57BL/6J ovariectomized mice. Micro CT was employed to evaluate the alteration in trabecular and cortical bone microarchitecture. Histology studies were performed on the isolated vertebra. qPCR analysis and western blotting was done to check the key bone markers.

RESULTS

RE and LE showed a potent antioxidant activity, owing to a notable polyphenol content. Both RE and LE did not alter the cell viability but significantly increased the osteoblast cell proliferation, differentiation, and mineralization. Moreover, they enhanced the mRNA expression of osteogenic genes. Both RE and LE stimulated the activation of ERK, AKT, and CREB. Both RE and LE had no direct effect on osteoclastogenesis, but both increased Opg/Rankl ratio expression in osteoblast cells. Both RE and LE at 750 mg/kg/day significantly improved the trabecular and cortical microarchitecture of femur and tibia by increasing bone mineral density, bone volume fraction, trabecular number, and trabecular thickness, and decreasing trabecular separation and structural model index in ovariectomized mice. Furthermore, vertebral histology of lumbar vertebrae revealed that RE and LE significantly enhance the vertebral bone mass and exert osteo-protective effects by stimulating osteoblast function and inhibiting osteoclast function.

CONCLUSION

In conclusion, both RE and LE stimulate osteoblast differentiation through activating ERK, AKT, and CREB signalling pathways and indirectly inhibits osteoclast differentiation. RE and LE also improve the trabecular and cortical microarchitecture of ovariectomized mice, making it a promising agent to prevent postmenopausal bone loss.

Adiponectin receptors by increasing mitochondrial biogenesis and respiration promote osteoblast differentiation: Discovery of isovitexin as a new class of small molecule adiponectin receptor modulator with potential osteoanabolic function

Previously, we established adiponectin receptors (AdipoRs) as osteoanabolic target. To discover small molecule agonists of AdipoRs, we studied apigenin and apigenin-6C-glucopyranose (isovitexin) that induced osteoblast differentiation. In-silico, in vitro and omics-based studies were performed. Molecular docking using the crystal structures of AdipoRs showed different interaction profiles of isovitexin and apigenin. In osteoblasts, isovitexin but not apigenin rapidly phosphorylated AMP-activated protein kinase (pAMPK) which is downstream of AdipoRs and a master regulator of cellular energy metabolism, and upregulated expression of AdipoRs. Blocking AMPK abolished the osteogenic effect of isovitexin and its effect on AdipoR expression. Isovitexin upregulated the expression of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), the mitochondrial biogenesis factor in osteoblasts, and the effect was blocked by AMPK inhibition. Upregulation of PGC-1α by isovitexin was accompanied by increased mitochondrial membrane proteins and mitochondrial DNA (mtDNA). Isovitexin via AdipoRs and PGC-1α induced oxidative phosphorylation (OxPhos) and ATP synthesis that resulted in osteoblast differentiation. Isovitexin had no agonistic/antagonistic activity and stimulatory/inhibitory effect in screening platforms for G protein-coupled receptors and kinases, respectively. In vivo, isovitexin upregulated AdipoRs and osteogenic genes, and increased mtDNA in rat calvarium. We conclude that isovitexin selectively via AdipoRs induced osteoblast differentiation that was fuelled by mitochondrial respiration.

Monocrotophos, an organophosphorus insecticide, induces cortical and trabecular bone loss in Swiss albino mice

Till now monocrotophos (MCP) has been addressed as a neurotoxic stressor. Limited studies investigate its aftermath on bone pathologies. Given the fact that MCP is a propensely used insecticide in developing countries, this study investigates its potential to mirror osteoporotic features and bone loss incurred in a rodent model. Briefly, Swiss albino mice were orally gavaged daily with varying doses of MCP for 8 weeks. Musculoskeletal changes were analyzed through micro-computed tomography and histology. A series of in vitro and ex vivo cell culture experiments were performed on MC3T3E-1 and primary osteoclast cultures. Results highlight that oral gavaging with MCP causes bone loss from the cortico-trabecular interface by decreasing the osteoblast and increasing the osteoclast number. Results from in vitro studies establish that MCP treatment increases the TRAP-positive multinucleated cell number during osteoclast differentiation. Ex-vivo experiments with MCP-treated animal sera further substantiate the in vivo claims with significant decreases seen in cell viability, proliferation, mineralization and differentiation studies. In conclusion MCP induces osteoclastogenesis (bone loss) on direct stimulation and alters the circulating factors in MCP-treated serum. Holistically, this work would be of potential significance to patients suffering from pesticide induced osteoporosis.

Orthobiologics with phytobioactive cues: A paradigm in bone regeneration

Bone injuries occur due to various traumatic and disease conditions. Healing of bone injury occurs via a multi-stage intricate process. Body has the potential to rectify most of the bone injuries but some severe traumatic cases with critical size defects may require interventions. Autografts are still considered the "gold standard" for fracture healing but due to limitations associated with it, new alternatives are warranted. The field of orthobiologics has provided novel approaches using scaffolds, bioactive molecules, stem cells for the treatment of bone defects. Phyto-bioactives have been widely used in alternative medicine and folklore practices for curing bone ailments. It is believed that different bioactive constituents in plants work synergistically to give the therapeutic efficacy. Bioactives in plants extracts act upon different signal transduction pathways aiding in bone healing. The present review focuses on the use, chemical composition, mode of delivery, mechanism of action, and possible future strategies of three medicinal plants popularly used in traditional medicine for bone healing: Cissus quadrangularis, Withania somnifera and Tinospora cordifolia. Plants extracts seem to be a natural and non-toxic therapeutic alternative in treating bone injuries. Most of the studies on bone healing for these plants have reported oral administration of the extracts and presented them as a safe alternative without any side effects despite giving higher doses. Forthcoming studies could be directed towards the local delivery of extracts at the defect site. Unification of herbal extracts and orthobiologics could be an interesting direction in the field of bone healing in future. The present review intends to provide a bird's eye view of different strategies used in bone healing, mechanisms involved and future direction of advancements using phytobioactives and orthobiologics.

Chlorpyrifos Exposure Induces Parkinsonian Symptoms and Associated Bone Loss in Adult Swiss Albino Mice

Prenatal and early life exposure of chlorpyrifos (CPF), a widely used pesticide, is known to cause neuronal deficits and Parkinson's disease (PD). However, data about the effect of its exposure at adult stages on PD-like symptoms and associated bone loss is scanty. In the present study, we investigated the impact of CPF on the behavioral alterations seen in PD using adult Swiss albino mice. PD is often associated with bone loss. Hence, skeletal changes were also evaluated using micro-computed tomography and histology. MPTP was used as a positive control. Cell culture studies using MC3T3E-1, SHSY5Y, and primary osteoclast cultures were done to understand the cellular mechanism for the behavioral and skeletal changes. Our results showed that CPF treatment leads to PD-like symptoms due to the loss of dopaminergic neurons. Moreover, CPF has a deleterious effect on the trabecular bone through both indirect changes in circulating factors and direct stimulation of multinucleate osteoclast cell formation. The impact on the bone mass was even stronger than MPTP. In conclusion, this is the first report demonstrating that CPF induces parkinsonian features in adult Swiss albino mice and it is accompanied by loss of trabecular bone.

An extract from Myracrodruon urundeuva inhibits matrix mineralization in human osteoblasts

ETHNOPHARMACOLOGICAL RELEVANCE

Phytotherapy based on plant-derived compounds is an alternative medicinal strategy for the relief of symptoms and the curing of diseases. The leaves of Myracrodruon urundeuva a medicinal plant also known as "aroeira", has been used in traditional medicine as healing, antiulcer and anti-inflammatory to treat skeletal diseases in Brazil, but its role in bone cell toxicity, as well as in bone formation, remains to be established.

AIM OF THE STUDY

We sought to determine the in vitro osteogenic effects of a hydroalcoholic M. urundeuva leaves extract in primary human osteoblasts.

MATERIALS AND METHODS

Cell viability, reactive oxygen species (ROS) production, alkaline phosphatase (ALP) activity and matrix mineralization were evaluated by MTT assay, DCFH-DA probe, colorimetric-based enzymatic assay and Alizarin Red-staining, respectively. Besides, the matrix metalloproteinase (MMP)-2 and progressive ankylosis protein homolog (ANKH) gene expression were determined by real-time RT-qPCR and MMP-2 activity by zymography.

RESULTS

Exposure of osteoblasts to M. urundeuva extract significantly decreased viability and increased reactive oxygen species (ROS) production, regardless of the extract concentration. The M. urundeuva extract at 10 μg/mL also downregulated matrix metalloproteinase (MMP)-2, while upregulating progressive ankylosis protein homolog (ANKH) gene expression. By contrast, the MMP-2 activity was unchanged. The M. urundeuva extract at 10 μg/mL also reduced alkaline phosphatase (ALP) activity and mineralization.

CONCLUSIONS

Overall, our findings suggest that the inhibition of osteogenic differentiation and matrix mineralization promoted by M. urundeuva may be due more to an increase in oxidative stress than to the modulation of MMP-2 and ANKH expression.

Ulmosides A: Flavonoid 6-C-glycosides from Ulmus wallichiana attenuates lipopolysacchride induced oxidative stress, apoptosis and neuronal death

Extract of Ulmus wallichiana is being used as traditional medicine used for the treatment of fractured bones however the effect of its individual flavonols is not known. The present study was conducted to investigate the effect of its novel flavonol, (2S, 3S)-(+)-30, 40, 5, 7-tetrahydroxydihydroflavonol-6-C-b-d-glucopyranoside named as Ulmoside A (UA), on lipopolysaccharides (LPS) treated neurons. LPS treatment to neuronal cells caused significant cytotoxicity, reactive oxygen species generation, depletion in glutathione and mitochondrial impairment which were significantly inhibited with UA treatment. LPS treatment also caused significant translocation of cytochrome-c, decreased level of Bcl2, increased level of Bax and cleaved caspase-3 in neuronal cells reflecting the involvement of intrinsic apoptotic pathway in neuronal death which was attenuated with UA treatment. Since LPS is a well known pro-inflammatory agent it also offered the significant increase in proinflammatory cytokines (tumor necrosis factors-α & interleukin 1-beta) however, UA treatment did not exhibit significant inhibition against LPS induced inflammatory response. LPS also caused the augmented level of inducible nitric oxide synthase (iNOS) which was also not inhibited with co treatment of UA. We have also observed the significant DNA fragmentation and augmented level of cleaved Poly (ADP-Ribose) polymerase 1 after LPS treatment which was significantly reverted with UA treatment. Findings suggested that UA acts through mitochondria and exhibited its anti-oxidative and anti-apoptotic activities in neuronal cells while no significant anti-inflammatory activity and effect on iNOS were observed.

Bone loss in MPTP mouse model of Parkinson's disease is triggered by decreased osteoblastogenesis and increased osteoclastogenesis

Bone loss is a non-motor symptom of Parkinson's disease (PD). It is unclear whether a patient's immobility or the endocrine changes in the body causes bone deterioration. To address this issue, we used an animal model of the disease where Swiss albino mice were injected with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) on day 1 and were left untreated for eight weeks. Behavioral phenotypes of PD, and striatal acetylcholinesterase and dopamine levels were measured. Cortical and trabecular bones were assessed by μ-CT and histology. Gene expression studies were done through quantitative real-time PCR. Effect of MPP+ and MPTP-treated mice serum on MC3T3E-1, SH-SY5Y, and primary osteoclast cells were also studied. Our results demonstrated that MPTP treatment leads to PD like symptoms. It shows a loss of trabecular bone mass and quality by decreasing osteoblast and increased osteoclast number and activity. This effect was accompanied by reduced osteogenic and elevated osteoclastogenic genes expression. While MPP+ had a cytotoxic effect on dopaminergic neurons, it did not affect bone cells. However, ex-vivo treatment of the serum from MPTP-treated mice decreased osteoblastogenesis and increased osteoclastogenesis in cell culture. In conclusion, our study suggests that MPTP-induced parkinsonian features in mice leads to trabecular bone loss by decreased bone formation and increased bone resorption due to changes in the serum circulating factors. This study characterizes the microarchitectural and cellular changes in the skeleton of a mouse model of PD that can be further utilized to investigate therapeutic avenues to treat bone loss in PD patients.

Bioinformatics analysis of novel transcription factors and related differentially regulated modules in non-union skeletal fractures

OBJECTIVE

This study aimed to further clarify the underlying pathomechanism of non-union skeletal fractures.

METHODS

Gene expression profile dataset GSE494 obtained from six non-union skeletal fracture and six normal samples was downloaded from the Gene Expression Omnibus database. Overlapping genes in at least two platforms were analyzed, and differentially expressed genes (DEGs) between normal and disease groups were screened. Transcriptional regulatory relationships and differentially regulated modules of various transcription factors (TFs) were determined. Differentially regulated modules with unknown functions were subjected to functional enrichment analysis.

RESULTS

Overall, 4,252 overlapping genes in at least two platforms and 77 DEGs, including 31 up and 46 downregulated genes, were obtained. Overall, 64,623 transcriptional regulatory relationships, including 49 TFs and 3,900 target genes, and 9 significant modules for differential regulation were identified. Three modules with unknown functions regulated by TFs, including zinc finger, ZZ-type containing 3 (ZZZ3), nuclear TF Y, alpha (NFYA), and POU class 2 homeobox 2 (POU2F2), were identified. Enriched GO-BP terms of NFYA and POU2F2 modules included cell adhesion and related terms and those of ZZ3 included cell cycle, cell proliferation, and associated terms.

CONCLUSION

Three TFs, including ZZZ3, POU2F2, and NFYA, and their regulated modules may have important effects on non-union skeletal fractures. Cell proliferation may be related with ZZZ3; cell adhesion and its similar process may be related with POU2F2 and NFYA.

Evaluation of antimicrobial potential of successive extracts of Ulmus wallichiana Planch

BACKGROUND

The plant Ulmus wallichiana Planch. is found in hills of Uttarakhand, India. Bark of U. wallichiana is commonly used as traditional healer for bone fracture of animals as well as human beings and also used as wound healer remedy.

OBJECTIVE

The present study was designed to evaluate antimicrobial potential of various extracts of U. wallichiana bark.

MATERIALS AND METHODS

Soxhlet extraction method was used for preparation of different extracts viz. petroleum ether, chloroform, ethyl acetate, ethanol and aqueous. Antioxidant activity was determined by DPPH and FRAP assay method. In vitro antimicrobial activity was evaluated using agar well diffusion method.

RESULTS

Ethyl acetate extract exhibited the highest significant antioxidant activity. Antibacterial activity was performed against Escherichia coli, Bacillus subtilis, Staphylococcusaureus and Pseudomonas aeruginosa. Amongst the various extracts tested, only ethyl acetate exhibited highest zone of inhibition as compared to other extracts and greater than standard drug. Chloroform extract also showed moderate zone of inhibition. Antifungal activity was evaluated against Aspergillus fumigates and Aspergillus flavus. The ethyl acetate extract showed maximum zone of inhibition as compared to other extracts. Chloroform extract showed mild antifungal activity. Chloramphenicol and nystatin were used as a positive control as antibacterial and antifungal agent respectively. Furthermore, the highest percentage of phenolic and flavonoid compounds was estimated in ethyl acetate extract.

CONCLUSION

The ethyl acetate extract of U. wallichiana showed the highest antimicrobial activity, and should be further investigated for isolating active compound(s) responsible for antimicrobial activity.

Dual Effect of Cyanidin on RANKL-Induced Differentiation and Fusion of Osteoclasts

Bone homeostasis is maintained by the balance between osteoblastic bone formation and osteoclastic bone resorption. Osteoclasts are multinucleated cells derived from hematopoietic stem cells (HSCs) or monocyte/macrophage progenitor cells and formed by osteoclasts precursors (OCPs) fusion. Cyanidin is an anthocyanin widely distributed in food diet with novel antioxidant activity. However, the effect of cyanidin on osteoclasts is still unknown. We investigated the effect of cyanidin on RANKL-induced osteoclasts differentiation and cell fusion. The results showed that cyanidin had a dual effect on RANKL-induced osteoclastogenesis. Lower dosage of cyanidin (< 1 µg/ml) has a promoting effect on osteoclastogenesis while higher dosage of cyanidin (> 10 µg/ml) has an inhibitory effect. Fusogenic genes like CD9, ATP6v0d2, DC-STAMP, OC-STAMP, and osteoclasts related genes like NFATc1, mitf, and c-fos were all regulated by cyanidin consistent to its dual effect. Further exploration showed that low concentration of cyanidin could increase osteoclasts fusion whereas higher dosage of cyanidin lead to the increase of LXR-β expression and activation which is suppressive to osteoclasts differentiaton. All these results showed that cyanidin exhibits therapeutic potential in prevention of osteoclasts related bone disorders.

Ovariectomized Rats with Established Osteopenia have Diminished Mesenchymal Stem Cells in the Bone Marrow and Impaired Homing, Osteoinduction and Bone Regeneration at the Fracture Site

We investigated deleterious changes that take place in mesenchymal stem cells (MSC) and its fracture healing competence in ovariectomy (Ovx)-induced osteopenia. MSC from bone marrow (BM) of ovary intact (control) and Ovx rats was isolated. (99m)Tc-HMPAO (Technitium hexamethylpropylene amine oxime) labeled MSC was systemically transplanted to rats and fracture tropism assessed by SPECT/CT. PKH26 labeled MSC (PKH26-MSC) was bound in scaffold and applied to fracture site (drill-hole in femur metaphysis). Osteoinduction was quantified by calcein binding and microcomputed tomography. Estrogen receptor (ER) antagonist, fulvestrant was used to determine ER dependence of osteo-induction by MSC. BM-MSC number was strikingly reduced and doubling time increased in Ovx rats compared to control. SPECT/CT showed reduced localization of (99m)Tc-HMPAO labeled MSC to the fracture site, 3 h post-transplantation in Ovx rats as compared with controls. Post-transplantation, Ovx MSC labeled with PKH26 (Ovx PKH26-MSC) localized less to fracture site than control PKH26-MSC. Transplantation of either control or Ovx MSC enhanced calcein binding and bone volume at the callus of control rats over placebo group however Ovx MSC had lower efficacy than control MSC. Fulvestrant blocked osteoinduction by control MSC. When scaffold bound MSC was applied to fracture, osteoinduction by Ovx PKH26-MSC was less than control PKH26-MSC. In Ovx rats, control MSC/E2 treatment but not Ovx MSC showed osteoinduction. Regenerated bone was irregularly deposited in Ovx MSC group. In conclusion, Ovx is associated with diminished BM-MSC number and its growth, and Ovx MSC displays impaired engraftment to fracture and osteoinduction besides disordered bone regeneration.

Potential osteogenic activity of ethanolic extract and oxoflavidin isolated from Pholidota articulata Lindley

ETHNOPHARMACOLOGICAL RELEVANCE

Pholidota articulata Lindley (PA) locally known as Hadjojen (bone jointer) belongs to family Orchidaceae is used for healing fractures in folklore tradition of Kumaon region of Uttarakhand, Himalaya, India. Bone is a dynamic organ and is constantly being remodeled in order to facilitate growth and repair. This process requires the involvement of bone forming osteoblast and bone resorbing osteoclast cells, which function in generating and mineralizing bone, giving strength and rigidity to the skeletal system. Present study was aimed to determine the therapeutic potential of ethanolic extract of PA and its isolated compound oxoflavidin, by characterizing their fracture healing properties.

MATERIALS AND METHODS

Ovariectomized (Ovx) estrogen deficient adult female Balb/c mice were used for in vivo evaluation of osteogenic or bone healing potential of ethanolic extract of PA. Further, its isolated compounds were tested for their osteogenic efficacy using alkaline phosphatase assay and mineralization assay in vitro in mice calvarial osteoblasts.

RESULTS

The ethanolic extract of PA exhibited significant restoration of trabecular micro-architecture in both femoral and tibial bones. Additionally, treatment with PA extract led to better bone quality and devoid of any uterine estrogenicity in ovariectomized estrogen deficient mice. One of the isolated compound, oxoflavidin enhanced ALP activity (a marker of osteoblast differentiation), mineral nodule formation and mRNA levels of osteogenic markers like BMP-2, Type 1 Collagen, RUNX-2 and osteocalcin.

CONCLUSION

These results warrant that ethanolic extract of PA and it's pure compound oxoflavidin have fracture healing properties. The extract and oxoflavidin exhibit a strong threapeutical potential for the treatment and management of postmenopausal osteoporosis.

Methanol Extract of Euchelus asper Prevents Bone Resorption in Ovariectomised Mice Model

Marine molluscs are widely distributed throughout the world and many bioactive compounds exhibiting antiviral, antitumor, antileukemic, and antibacterial activity have been reported worldwide. The present study was designed to investigate the beneficial effect of methanol extract of Euchelus asper (EAME) on estrogen deficiency induced osteoporosis in ovariectomised mice model. Forty-two female Swiss albino mice were randomly assigned into Sham operated (Sham) group and six ovariectomised (OVX) subgroups such as OVX with vehicle (OVX); OVX with estradiol (2 mg/kg/day); OVX with EAME of graded doses (25, 50, 100, and 200 mg/kg/day). Bone turnover markers like serum alkaline phosphatase (ALP), serum acid phosphatase (ACP), serum calcium, and histological investigations of tibia and uterus were analysed. Metaphyseal DNA content of the femur bone was also studied. Antiosteoclastogenic activity of EAME was examined. Administration of EAME was able to reduce the increased bone turnover markers in the ovariectomised mice. Histomorphometric analysis revealed an increase in bone trabeculation and restoration of trabecular separation by EAME treatment. Metaphyseal DNA content of the femur of the OVX mice was increased by EAME administration. EAME also showed a potent antiosteoclastogenic behaviour. Thus, the present study reveals that EAME was able to successfully reduce the estrogen deficiency induced bone loss.

Aromadendrin Inhibits Lipopolysaccharide-Induced Nuclear Translocation of NF-κB and Phosphorylation of JNK in RAW 264.7 Macrophage Cells

Aromadendrin, a flavonol, has been reported to possess a variety of pharmacological activities such as anti-inflammatory, antioxidant, and anti-diabetic properties. However, the underlying mechanism by which aromadendrin exerts its biological activity has not been extensively demonstrated. The objective of this study is to elucidate the anti-inflammatory mechanism of aromadedrin in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophage cells. Aromadendrin significantly suppressed LPS-induced excessive production of pro-inflammatory mediators such as nitric oxide (NO) and PGE2. In accordance, aromadendrin attenuated LPSinduced overexpression iNOS and COX-2. In addition, aromadendrin significantly suppressed LPS-induced degradation of IκB, which sequesters NF-κB in cytoplasm, consequently inhibiting the nuclear translocation of pro-inflammatory transcription factor NF- κB. To elucidate the underlying signaling mechanism of anti-inflammatory activity of aromadendrin, MAPK signaling pathway was examined. Aromadendrin significantly attenuated LPS-induced activation of JNK, but not ERK and p38, in a concentration-dependent manner. Taken together, the present study clearly demonstrates that aromadendrin exhibits anti-inflammatory activity through the suppression of nuclear translocation of NF-κB and phosphorylation of JNK in LPS-stimulated RAW 264.7 macrophage cells.

The beneficial effect of icaritin on osteoporotic bone is dependent on the treatment initiation timing in adult ovariectomized rats

BACKGROUND

Epimedium-derived flavonoids (EFs) have a potential to treat established osteoporosis in postmenopausal women. However, one of the main disadvantages of the compound is the high volume and dosage during long-term administration period. Meanwhile, the beneficial effect of EFs on osteoporotic bone depends greatly on the intervention timing. Whether icaritin (ICT), an active molecular compound from EFs, can exert beneficial effect on osteoporotic bone and whether the beneficial effect is also dependent on the intervention timing remain unknown.

OBJECTIVE

The objective of this study was to evaluate the effect of the early and late ICT treatment on bone turnover markers, trabecular architecture, bone remodeling, biomechanics, colony formation of bone marrow stromal cells and osteoblast, adipocyte and osteoclast-related gene expression in adult ovariectomized rats.

METHODS

Eighty 9-month-old female rats (n=8/group) were sham-operated (Sham) or ovariectomized (OVX). The OVX rats were subjected to ICT treatment initiation at 1 month (early treatment) and 3 months (late treatment) post-operation, respectively. The vehicle-treated Sham and OVX rats starting at month 1 and month 3 post-operation served as the corresponding controls (Sham and OVX controls) for early and late ICT treatment, respectively. Those Sham and OVX rats sacrificed immediately before early and late ICT treatment served as the pretreatment baseline controls. Both ICT and vehicle treatments lasted for 2 months. The bone turnover markers, trabecular architecture, bone remodeling and bone biomechanical properties were analyzed with biochemistry, microCT, histomorphometry and mechanical testing, respectively. The population of bone marrow stromal cells (BMSCs) and osteoblasts were evaluated with colony formation assays, respectively. The expression levels of osteoblast, adipocyte and osteoclast-related genes in bone marrow were assessed by real-time polymerase chain reaction (PCR), respectively.

RESULTS

At the tissue level, early ICT treatment remarkably restored the trabecular bone mass, trabecular architecture and bone biomechanical properties towards pretreatment Sham levels, and significantly increased bone formation from pretreatment OVX level and markedly inhibited bone resorption towards pretreatment Sham level, whereas late ICT treatment failed to have any effect. At the cellular and molecular level, early ICT treatment significantly increased the number of osteoblastic colonies and the level of osteoblast-related gene expression compared to pretreatment OVX levels and remarkably decreased adipocyte and osteoclast-related gene expression towards pretreatment Sham levels. Late ICT treatment failed to have beneficial effect on any of these parameters.

CONCLUSION

ICT can exert anabolic and anti-resorptive effect on osteoporotic bone. The beneficial effect of ICT treatment is dependent on the intervention timing in established osteoporosis induced by estrogen depletion.

Ethanol extract of Peperomia pellucida (Piperaceae) promotes fracture healing by an anabolic effect on osteoblasts

ETHNOPHARMACOLOGICAL RELEVANCE

The whole plant or some part of Peperomia pellucida (L.) HBK is used in some parts of Cameroon as a treatment for fracture healing.

AIM OF THE STUDY

To evaluate the effect of ethanolic extracts of Peperomia pellucida (L.), a Cameroonian medicinal plant on bone regeneration following bone and marrow injury, and determine the mode of action.

MATERIALS AND METHODS

Ethanol extract of Peperomia pellucida was administered at 100 and 200mg/kg doses orally to adult female Sprague-Dawley rats having a drill hole injury (0.8mm) in the femur diaphysis. Vehicle (gum-acacia in distilled water) was given to the control group. After 12 days of treatment, animals were euthanized and femur bones collected. Confocal microscopy of calcein labeling at the drill hole site was performed to evaluate bone regeneration. 3-D microarchitecture of drill hole site was analyzed by micorocomputed tomography. Osteogenic effects of the extract were evaluated by assessing mineralized nodule formation of bone marrow stromal cells and expression of osteogenic genes (mRNA level of type-1 collagen, bone morphogenetic protein-2 and osteocalcin genes) in the femur.

RESULTS

Ethanol extract from Peperomia Pellucida (L.) dose-dependently induced bone regeneration at the fracture site. At 200mg/kg dose, the extract significantly increased mineral deposition compared to controls. The extract also improved microarchitecture of the regenerating bone evident from increased bone volume fraction, trabecular thickness, trabecular number, and decreased trabecular separation and structure model index. In addition, the extract increased the formation of mineralized nodules from the bone marrow stromal cells. Furthermore, the extract induced the expression of osteogenic genes in the femur including type 1 collagen, osteocalcin and BMP-2, compared to control.

CONCLUSION

Ethanolic extract of P. pellucid (L.) accelerates fracture repair in rats via stimulatory effects on osteoblast differentiation and mineralization, thereby justifying its traditional use.

Lipid lowering and antioxidant effect of miglitol in triton treated hyperlipidemic and high fat diet induced obese rats

Miglitol, an anti-diabetic drug, has been shown to reduce plasma lipids and inhibit free radical generation. The anti-hyperlipidemic and antioxidant effects of miglitol were studied in triton-induced hyperlipidemic rats and high fat diet-fed obese rats. Plasma cholesterol and triglycerides levels were significantly lowered by miglitol at 100 mg/kg body weight doses. Miglitol inhibited generation of superoxide anion and hydroxyl free radicals by 14 and 31 % in enzymatic systems and 19 and 25 % in non-enzymatic systems, respectively. The in-vitro effect of the drug on adipogenesis using 3T3-L₁ preadipocytes at 2-, 5- and 10-μM concentrations showed significant inhibition of adipogenesis (34.2 %) at 10-μM concentration. High fat diet-fed rat model was used to investigate anti-hyperlipidemic, anti-obesity and antioxidant effect of miglitol. Miglitol increased the activities of lecithin-cholesterol-acyltransferase (19 %), post heparin lipolytic activity (26 %), lipoprotein lipase (26 %) and triglyceride lipase (31 %) which result in a decrease in plasma lipid levels. The antioxidant enzymes viz., catalase, superoxide dismutase, glutathione peroxidase, glutathione reductase and thioredoxin reductase were increased by the drug in the treated animals. The antihyperlipidemic and antioxidant effect of miglitol can be correlated to its effect on different enzymes and it can be used for inhibiting the development of cardiovascular diseases.

Potential antiosteoporotic agents from plants: a comprehensive review

Osteoporosis is a major health hazard and is a disease of old age; it is a silent epidemic affecting more than 200 million people worldwide in recent years. Based on a large number of chemical and pharmacological research many plants and their compounds have been shown to possess antiosteoporosis activity. This paper reviews the medicinal plants displaying antiosteoporosis properties including their origin, active constituents, and pharmacological data. The plants reported here are the ones which are commonly used in traditional medical systems and have demonstrated clinical effectiveness against osteoporosis. Although many plants have the potential to prevent and treat osteoporosis, so far, only a fraction of these plants have been thoroughly investigated for their physiological and pharmacological properties including their mechanism of action. An attempt should be made to highlight plant species with possible antiosteoporosis properties and they should be investigated further to help with future drug development for treating this disease.

EGb 761 promotes osteoblastogenesis, lowers bone marrow adipogenesis and atherosclerotic plaque formation

AIM OF THE STUDY

Our earlier study has demonstrated that EGb 761 (standardized extract of Ginkgo) has the bone sparing effect on the estrogen deficiency induced bone loss model. In the present study, we have addressed the question whether treatment of osteoporosis benefits arterial calcification or vice versa, because both adipocyte and osteoblast originate from the same mesenchymal cell of the bone marrow cell (BMC) population.

MATERIALS AND METHODS

Bone marrow cells were isolated to study the effect of EGb 761 on osteoblast and adipocytes. For in vivo effect hamsters were fed high fat diet and the effect of EGb 761 studied on atherosclerotic plaque formation and endothelial function.

RESULTS

BMC's undergoing induced osteogenic or adipogenic differentiations in the presence of EGb 761 show increase and decrease in mineralization and adipogenesis respectively. Osteogenic and adipogenic mRNAs, reveal lineage dependent expression patterns. Runx-2 (osteoblast transcription factor) showed a progressive increase, whereas PPAR-γ (adipogenic regulator) was attenuated, with same pattern of expression being for late osteogenic and adipogenic genes. EGb 761 led to increase in apoptotic cells and ROS, an important upstream signal. In vivo experiments in hamsters after induction with high cholesterol diet (HCD) show improvement in endothelial function by EGb 761 with lowering in total plasma cholesterol levels. EGb 761 led to vascular preservation of the aortic lumen with impairment of the endothelium dependent relaxation which was corroborated by micro-CT and histological sections of the thoracic region of the aorta.

CONCLUSION

From this data, it can be implied that EGb 761 controls bone loss, adiposity and lowers atherogenic risk factor after HCD induction.

A naturally occurring naringenin derivative exerts potent bone anabolic effects by mimicking oestrogen action on osteoblasts

BACKGROUND AND PURPOSE

Naringenin and its derivatives have been assessed in bone health for their oestrogen-'like' effects but low bioavailability impedes clinical potential. This study was aimed at finding a potent form of naringenin with osteogenic action.

EXPERIMENTAL APPROACH

Osteoblast cultures were harvested from mouse calvaria to study differentiation by naringenin, isosakuranetin, poncirin, phloretin and naringenin-6-C-glucoside (NCG). Balb/cByJ ovariectomized (OVx) mice without or with osteopenia were given naringenin, NCG, 17β-oestradiol (E2) or parathyroid hormone (PTH). Efficacy was evaluated by bone microarchitecture using microcomputed tomography and determination of new bone formation by fluorescent labelling of bone. Plasma levels of NCG and naringenin were determined by HPLC.

KEY RESULTS

NCG stimulated osteoblast differentiation more potently than naringenin, while isosakuranetin, poncirin or phloretin had no effect. NCG had better oral bioavailability than naringenin. NCG increased the mRNA levels of oestrogen receptors (ERs) and bone morphogenetic protein (an ER responsive gene) in vivo, more than naringenin. In OVx mice, NCG treatment in a preventive protocol increased bone formation rate (BFR) and improved trabecular microarchitecture more than naringenin or E2. In osteopenic mice, NCG but not naringenin, in a therapeutic protocol, increased BFR and improved trabecular microarchitecture, comparable with effects of PTH treatment. Stimulatory effects of NCG on osteoblasts were abolished by an ER antagonist. NCG transactivated ERβ but not ERα. NCG exhibited no uterine oestrogenicity unlike naringenin.

CONCLUSIONS AND IMPLICATIONS

NCG is a potent derivative of naringenin that has bone anabolic action through the activation of osteoblast ERs and exhibited substantial oral bioavailability.

Evaluation of Cameroonian plants towards experimental bone regeneration

ETHNOPHARMACOLOGICAL RELEVANCE

Elephantopus mollis, Spilanthes africana, Urena lobata, Momordica multiflora, Asystasia gangetica and Brillantaisia ovariensis are used in Cameroonian traditional medicine for the treatment of bone diseases and fracture repair. The aim of this study was to evaluate the effect of ethanolic extracts of six Cameroonian medicinal plants on bone regeneration following bone and marrow injury.

MATERIALS AND METHODS

Ethanol extract of Cameroonian medicinal plants were administered (each extract at 250, 500 and 750mg/kg doses) orally to adult female Sprague-Dawley rats having a drill hole injury (0.8mm) in the femur diaphysis. Vehicle (gum-acacia in distilled water) was given to the control group. After 12 days of treatment, animals were euthanized and femur bones collected. Confocal microscopy of fractured bone was performed to evaluate bone regeneration (calcein labeling). Only active plant extracts were used for further experiments. Thus, callus was analyzed by microcomputed tomography. Osteogenic effects of the extracts were evaluated by assessing mineralized nodules formation of bone marrow stromal cells and osteoblast recruitment at drill hole site by immunohistochemistry.

RESULTS

Ethanolic extract of the leaves and twigs of Elephantopus mollis (EM) and whole plant of Spilanthes africana (SA) dose-dependently stimulated bone regeneration at the drill hole site. EM at 250 and 750mg/kg doses and SA at 750mg/kg dose significantly increased mineral deposition compared to controls. Both extracts at 500 and 750mg/kg doses improved microarchitecture of the regenerating bone evident from increased bone volume fraction, trabecular thickness, trabecular number, and decreased trabecular separation and structure model index. EM and SA extracts increased the formation of mineralized nodules from the bone marrow stromal cells. In addition, EM and SA extracts increased osteoblast recruitment at the drill hole site evident from increased Runx-2 positive cells following their treatments compared to control.

CONCLUSION

Ethanolic extracts of EM and SA accelerate fracture repair in rats via stimulatory effects on osteoblast differentiation and mineralization, thereby justifying their traditional use.

Targeting adipocyte apoptosis: a novel strategy for obesity therapy

Obesity is an increasing world problem that may cause several metabolic complications including insulin resistance, hyperlipidemia, hypertension, and atherosclerosis. Development of therapeutic drugs for obesity has been proven difficult. Current strategies for weight reduction are inhibition of food intake through the central nervous system or blocking the absorption of lipids in the gut. These therapies have many side effects, so new treatments are urgently needed. Fat loss could also be achieved through a decrease in the size and number of adipocytes through apoptosis. Apoptosis is a normal phenomenon of cell death for the purpose of maintaining homeostasis. Induction of apoptosis is a reasonable way to remove adipocytes in obese patients. It is reported that several adipokines and natural products play roles in induction of adipocyte apoptosis. Here we review the recent progress of the roles and mechanisms of adipocyte apoptosis induced by leptin, tumor necrosis factor-α (TNF-α), and natural compounds.

A novel quercetin analogue from a medicinal plant promotes peak bone mass achievement and bone healing after injury and exerts an anabolic effect on osteoporotic bone: the role of aryl hydrocarbon receptor as a mediator of osteogenic action

We recently reported that extracts made from the stem bark of Ulmus wallichiana promoted peak bone mass achievement in growing rats and preserved trabecular bone mass and cortical bone strength in ovariectomized (OVX) rats. Further, 6-C-β-D-glucopyranosyl-(2S,3S)-(+)-3',4',5,7-tetrahydroxyflavanol (GTDF), a novel flavonol-C-glucoside isolated from the extracts, had a nonestrogenic bone-sparing effect on OVX rats. Here we studied the effects of GTDF on osteoblast function and its mode of action and in vivo osteogenic effect. GTDF stimulated osteoblast proliferation, survival, and differentiation but had no effect on osteoclastic or adipocytic differentiation. In cultured osteoblasts, GTDF transactivated the aryl hydrocarbon receptor (AhR). Activation of AhR mediated the stimulatory effect of GTDF on osteoblast proliferation and differentiation. Furthermore, GTDF stimulated cAMP production, which mediated osteogenic gene expression. GTDF treatments given to 1- to 2-day-old rats or adult rats increased the mRNA levels of AhR target genes in calvaria or bone marrow stromal cells. In growing female rats, GTDF promoted parameters of peak bone accrual in the appendicular skeleton, including increased longitudinal growth, bone mineral density, bone-formation rate (BFR), cortical deposition, and bone strength. GTDF promoted the process of providing newly generated bone to fill drill holes in the femurs of both estrogen-sufficient and -deficient rats. In osteopenic OVX rats, GTDF increased BFR and significantly restored trabecular bone compared with the ovaries-intact group. Together our data suggest that GTDF stimulates osteoblast growth and differentiation via the AhR and promotes modeling-directed bone accrual, accelerates bone healing after injury, and exerts anabolic effects on osteopenic rats likely by a direct stimulatory effect on osteoprogenitors. Based on these preclinical data, clinical evaluation of GTDF as a potential bone anabolic agent is warranted.