Positive skeletal effects of cladrin, a naturally occurring dimethoxydaidzein, in osteopenic rats that were maintained after treatment discontinuation

LC-MS/MS method for simultaneous estimation of raloxifene, cladrin in rat plasma: application in pharmacokinetic studies

Aim: A newer LC-MS/MS method was developed and validated for the simultaneous quantification of raloxifene (RL) and cladrin (CL). Methodology: Both drugs were resolved in RP-18 (4.6 × 50 mm, 5 μ) Xbridge Shield column using acetonitrile and 0.1% aqueous solution of formic acid (FA) (70:30% v/v) as mobile phase by using biological matrices in female Sprague-Dawley rats using-MS/MS. Results: The developed method was found to be linear over the concentration ranges of 1-600 ng/ml, and lower limit of quantification was 1 ng/ml for RL and CL, respectively. Pharmacokinetic results of RL+CL showed Cmax = 4.23 ± 0.61, 26.97 ± 1.14 ng/ml, at Tmax(h) 5.5 ± 1.00 and 3.5 ± 1.00, respectively. Conclusion: Pharmacokinetic study results will be useful in the future for the combined delivery of RL and CL for osteoporosis treatment.

The potential pharmacological mechanism of prunetin against osteoporosis: transcriptome analysis, molecular docking, and experimental approaches

BACKGROUND

Prunetin is an O-methylated isoflavone, known for its beneficial properties. However, its specific pharmacological effects in the treatment of osteoporosis (OP) remain poorly understood. This study aims to elucidate the mechanisms underlying the antiosteoporotic effects of prunetin through a combination of bioinformatics analysis and cell experiments.

METHODS

We gathered predicted targets of prunetin from various online platforms. Differential expression analysis of mRNAs in patients with OP was conducted using the Limma package, based on the GSE35959 dataset. A PPI network diagram was visualized and analyzed using Cytoscape 3.7.2 software. Molecular docking was employed to assess the binding affinity between ligands and receptors, and selected key genes were further validated through cell experiments.

RESULTS

A total of 4062 differentially expressed genes (DEGs) were identified from the GSE35959 dataset. Among these, 58 genes were found to overlap with the targets of prunetin, indicating their potential as therapeutic targets. The enrichment analysis indicated these targets were mainly enriched in MAPK, FoxO, and mTOR signaling pathways. The molecular docking analysis demonstrated that prunetin exhibited strong binding activity with the core targets. Furthermore, cell experiments revealed that prunetin effectively reversed the expression levels of ALB, ESR1, PTGS2, and FGFR1 mRNA in MC3T3-E1 cells treated with dexamethasone (DEX).

CONCLUSION

Our research revealed the multi-pathway and multi-target features of prunetin in treating OP, shedding light on the potential mechanisms underlying the effectiveness of prunetin against OP. These findings serve as a theoretical foundation for future drug development in this field.

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

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

Lipoic acid (LA) dose-dependently protects bone losses in the mandible of rats during the development of osteopenia by inhibiting oxidative stress and promoting bone formation

Our study was carried out to evaluate the effect of lipoic acid (LA) on the densitometric properties, structure and mechanical strength of the mandible of Wistar rats with developing osteopenia. The study used 42 sham-operated (SHO) and ovariectomized (OVX) rats. The OVX rats were randomly divided (n = 6) onto two controls treated subcutaneously with physiological saline (OVX-PhS) and 17β-estradiol (OVX-E2), respectively, and onto four experimental OVX groups that received LA in the doses of 12.5, 25, 50 and 100 mg/kg/day for 28 days. The results demonstrated that the lack of estrogen brought about osteopenic bone changes, especially in the trabecular compartment. In addition, while the usage of LA in the doses of 12.5 and 25 LA had no effect in OVX rats, the dose of 100 effectively inhibited osteopenic changes of the mandible. This dose maintained structural, densitometric and mechanical parameters at levels like that in the SHO and OVX-E2 groups by inhibiting the destructive influence of oxidative stress. Dose 50, however, was revealed to be the most effective. It not only inhibited atrophic changes and the influence of oxidative stress, but also stimulated the formation of mandibular bone tissue. Our results suggest that the administration of LA is effective in preventing atrophic changes in the mandibular bone tissue in conditions of ovarian hormone deficiency and suggest its potential in the therapy of osteoporosis.

Diosmin, a citrus fruit-derived phlebotonic bioflavonoid protects rats from chronic kidney disease-induced loss of bone mass and strength without deteriorating renal function

Kidney Disease: Improving Global Outcomes (KDIGO) 2017 Clinical Practice Guideline recommended treatment decisions for patients with chronic kidney disease (CKD) with osteoporosis and/or high risk of fracture. Bisphosphonates, the first-line...

Phenanthrenoid Coelogin Isolated from Coelogyne cristata Exerts Osteoprotective Effect Through MAPK-Mitogen-Activated Protein Kinase Signaling Pathway

Osteoporosis is a major health problem in postmenopausal women globally. This study determined the mechanism through which coelogin stimulates osteoblastogenesis and its osteoprotective and bone regenerating potential. Coelogin effect on primary calvarial osteoblast cells was determined by measuring alkaline phosphatase activity, mineralization, osteoblast survival, and apoptosis and protein expression studies. The osteoprotective effect of coelogin was also evaluated on osteopenic adult female Swiss mice. At autopsy, bones were collected for dynamic and histomorphometry studies. Serum samples were also collected for assessment of serum parameters. Coelogin treatment led to increased osteoblast proliferation, survival, differentiation, and mineralization in osteoblast cells. Coelogin supplementation to Ovx mice promoted new bone formation, prevented Ovx-induced deterioration of bone microarchitecture, and enhanced bone regeneration. In addition, signaling studies revealed that coelogin treatment activates the ER-Erk and Akt-dependent signaling pathways which stimulate the osteoblastogenesis in osteoblast cells.

Calcium repletion to rats with calcipenic rickets fails to recover bone quality: A calcipenic "memory"

Calcipenic rickets is prevalent in underprivileged children in developing countries. Calcipenic rickets resulting from dietary calcium (Ca) deficiency decreases bone mass and deteriorates bone microstructure in humans. The effect of dietary Ca replenishment (CaR) on rachitic bones in animal models depends on the amount, critical period and duration of replenishment, however, the extent of recovery in various bone parameters including bone quality remains unclear. We investigated the effect of CaR in rat skeleton after inducing calcipenic rickets. Female SD rats (postnatal 28 days/P28) were rendered calcipenic by feeding calcium deficient (CaD) diet (0.1% Ca) till P70 while control SD rats were fed Ca sufficient diet (0.8% Ca). At P70, calcipenic rats were switched to 0.8% Ca diet till P150 for one group and P210 for another group (endpoint). The CaD groups received 0.1% Ca diet throughout the study (P210). In the CaD groups, serum Ca and phosphate, and bone mineral density (BMD) were significantly decreased whereas serum alkaline phosphatase (ALP), iPTH and CTX-1 were increased compared to age-matched controls. Moreover, at the endpoint, the CaD group had reduced bone mass, surface referent bone formation parameters, tissue mineralization and strength accompanied by the increased osteoid thickness and microarchitectural decay (measured by trabecular geometric parameters) with poor crystal packing. The CaR group showed complete recovery in serum Ca, iPTH, ALP and CTX-1, and BMD, however, the bone quality parameters including bone strength, microarchitectural decay, tissue mineralization, and crystallinity were incompletely restored. Decreased surface referent bone formation and increased unmineralized bones (osteoid) indicative of osteomalacia were also observed in the CaR group at P210 compared with control despite prolonged replenishment. We conclude that a prolonged Ca repletion following the induction of calcipenic rickets in rats although shows the recovery of biochemical measures of bone metabolism and bone mass, however, the bone quality remains compromised. This suggests that a "memory" of calcipenia occurring at the early growth stage persists in the skeleton of adult rats despite a prolonged Ca replenishment.

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.

A butanolic fraction from the standardized stem extract of Cassia occidentalis L delivered by a self-emulsifying drug delivery system protects rats from glucocorticoid-induced osteopenia and muscle atrophy

We recently reported that a butanol soluble fraction from the stem of Cassia occidentalis (CSE-Bu) consisting of osteogenic compounds mitigated methylprednisone (MP)-induced osteopenia in rats, albeit failed to afford complete protection thus leaving a substantial scope for further improvement. To this aim, we prepared an oral formulation that was a lipid-based self-nano emulsifying drug delivery system (CSE-BuF). The globule size of CSE-BuF was in the range of 100–180 nm of diluted emulsion and the zeta potential was −28 mV. CSE-BuF enhanced the circulating levels of five osteogenic compounds compared to CSE-Bu. CSE-BuF (50 mg/kg) promoted bone regeneration at the osteotomy site and completely prevented MP-induced loss of bone mass and strength by concomitant osteogenic and anti-resorptive mechanisms. The MP-induced downregulations of miR29a (the positive regulator of the osteoblast transcription factor, Runx2) and miR17 and miR20a (the negative regulators of the osteoclastogenic cytokine RANKL) in bone was prevented by CSE-BuF. In addition, CSE-BuF protected rats from the MP-induced sarcopenia and/or muscle atrophy by downregulating the skeletal muscle atrogenes, adverse changes in body weight and composition. CSE-BuF did not impact the anti-inflammatory effect of MP. Our preclinical study established CSE-BuF as a prophylactic agent against MP-induced osteopenia and muscle atrophy.

Extract and fraction of Cassia occidentalis L. (a synonym of Senna occidentalis) have osteogenic effect and prevent glucocorticoid-induced osteopenia

ETHNOPHARMACOLOGICAL RELEVANCE

Cassia occidentalis L., a synonym of Senna occidentalis (belongs to Caesalpiniaceae family) is an annual plant. Pursuing a lead from a folk practice prevalent since the late nineteenth century in Andhra Pradesh, a Southern state of India, of use of Cassia occidentalis leaf and stem for treating patients with fracture and bone diseases, we have not only confirmed its fracture healing activity but also demonstrated efficacy in preventing glucocorticoid-induced osteoporosis (GIO), the commonest form of medication-induced bone loss caused chiefly due to impairment of bone formation.

AIM OF THE STUDY

In the present work, the effects of extract and fraction of leaf and stem of Cassia occidentalis was investigated in fracture healing and GIO models of rat. The study also aimed to identify osteogenic compounds from this plant.

MATERIALS AND METHODS

Ethanolic extracts from leaf and stem of Cassia occidentalis were prepared and their efficacy tested in rat femur osteotomy (fracture healing) model. Subsequently, a butanolic fraction was prepared and osteogenic efficacy compared with the ethanolic extract, and upon finding the former to be more potent, its osteogenic effect was studied in details in GIO model. Chemical finger-printing and isolation of ten pure compounds were done to assess their osteogenic effect in rat primary osteoblast cultures.

RESULTS

Ethanolic extract of stem was more effective than the leaf extract in enhancing bone regeneration at the site of osteotomy. Further, butanolic fraction of the ethanolic extract of stem was more effective than the later in bone regeneration at the femur osteotomy site and in preventing bone loss in GIO model. The mechanism of skeletal preservation involved stimulation of new bone formation and inhibition of bone resorption. As many as six osteogenic compounds were isolated out of which apigenin-6C-glucopyranoside was most effective in vitro.

CONCLUSION

Our study found that a standardized extract of an ethanolic extract and its butanolic fraction from the stem of Cassia occidentalis has osteogenic as well as anti-resorptive effects, resulting in the protection against glucocorticoid-induced bone loss. Our results contribute towards validation of the traditional use of Cassia occidentalis in fracture healing and also suggest its beneficial use in GIO for which clinical trials are warranted.

The wakefulness promoting drug Modafinil causes adenosine receptor-mediated upregulation of receptor activator of nuclear factor κB ligand in osteoblasts: Negative impact of the drug on peak bone accrual in rats

Modafinil is primarily prescribed for treatment of narcolepsy and other sleep-associated disorders. However, its off-prescription use as a cognition enhancer increased considerably, specially among youths. Given its increasing use in young adults the effect of modafinil on peak bone accrual is an important issue but has never been investigated. Modafinil treatment to young male rats caused trabecular and cortical bone loss in tibia and femur, and reduction in biomechanical strength. Co-treatment of modafinil with alendronate (a drug that suppresses bone resorption) reversed the trabecular bone loss but failed to prevent cortical loss. Modafinil increased serum type 1 pro-collagen N-terminal protein (P1NP) and collagen type 1 cross-linked C-telopeptide (CTX-1) indicating a high turnover bone loss. The drug also increased receptor activator of nuclear factor κB ligand (RANKL) to osteoprotegerin (OPG) ratio in serum which likely resulted in increased osteoclast number per bone surface. Furthermore, conditioned medium from modafinil treated osteoblasts increased the expression of osteoclastogenic genes in bone marrow-derived macrophages and the effect was blocked by RANKL neutralizing antibody. In primary osteoblasts, modafinil stimulated cAMP production and using pharmacological approach, we showed that modafinil signalled via adenosine receptors (A_2AR and A_2BR) which resulted in increased RANKL expression. ZM-241,385 (an A_2AR inhibitor) and MRS 1754 (an A_2BR inhibitor) suppressed modafinil-induced upregulation of RANKL/OPG ratio in the calvarium of new born rat pups. Our data suggests that by activating osteoblast adenosine receptors modafinil increases the production of osteoclastogenic cytokine, RANKL that in turn results in high turnover bone loss in young rats.

Globular adiponectin reverses osteo-sarcopenia and altered body composition in ovariectomized rats

Adiponectin regulates various metabolic processes including glucose flux, lipid breakdown and insulin response. We recently reported that adiponectin receptor1 (adipoR1) activation by a small molecule reverses osteopenia in leptin receptor deficient db/db (diabetic) mice. However, the role of adiponectin in bone metabolism under the setting of post-menopausal (estrogen-deficiency) osteopenia and associated metabolic derangements has not been studied. Here, we studied the therapeutic effect of the globular form of adiponectin (gAd), which is predominantly an adipoR1 agonist, in aged ovariectomized (OVX) rats and compared it with standard-of-care anti-osteoporosis drugs. In OVX rats with established osteopenia, gAd completely restored BMD and load bearing capacity and improved bone quality. Skeletal effects of gAd were comparable to PTH (osteoanabolic) but better than alendronate (anti-catabolic). Both osteoanabolic and anti-catabolic mechanisms led to the anti-osteoporosis effect of gAd. In cultured osteoblasts and bones, gAd increased a) adipoR1 and peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α) expression to promote mitochondrial respiration, which likely fueled osteoblast differentiation, b) suppressed sclerostin (a wnt antagonist) in a sirtuin1-dependent manner and c) decreased receptor-activator of nuclear factor κB ligand (RANKL) to achieve its anti-catabolic effect. The OVX-induced sarcopenia and insulin resistance were also improved by gAd. We conclude that gAd has therapeutic efficacy in estrogen deficiency-induced osteoporosis, sarcopenia and insulin resistance and hold metabolic disease modifying potential in postmenopausal women.

Stimulation of liver IGF-1 expression promotes peak bone mass achievement in growing rats: a study with pomegranate seed oil

Peak bone mass (PBM) achieved at adulthood is a strong determinant of future onset of osteoporosis, and maximizing it is one of the strategies to combat the disease. Recently, pomegranate seed oil (PSO) has been shown to have bone-sparing effect in ovariectomized mice. However, its effect on growing skeleton and its molecular mechanism remain unclear. In the present study, we evaluated the effect of PSO on PBM in growing rats and associated mechanism of action. PSO was given at various doses to 21-day-old growing rats for 90 days by oral gavage. The changes in bone parameters were assessed by micro-computed tomography and histology. Enzyme-linked immunosorbent assay was performed to analyze the levels of serum insulin-like growth factor type 1 (IGF-1). Western blotting from bone and liver tissues was done. Chromatin immunoprecipitation assay was performed to study the histone acetylation levels at IGF-1 gene. The results of the study show that PSO treatment significantly increases bone length, bone formation rate, biomechanical parameters, bone mineral density and bone microarchitecture along with enhancing muscle and brown fat mass. This effect was due to the increased serum levels of IGF-1 and stimulation of its signaling in the bones. Studies focusing on acetylation of histones in the liver, the major site of IGF-1 synthesis, showed enrichment of acetylated H3K9 and H3K14 at IGF-1 gene promoter and body. Further, the increased acetylation at H3K9 and H3K14 was associated with a reduced HDAC1 protein level. Together, our data suggest that PSO promotes the PBM achievement via increased IGF-1 expression in liver and IGF-1 signaling in bone.

Heartwood extract from Dalbergia sissoo promotes fracture healing and its application in ovariectomy-induced osteoporotic rats

OBJECTIVES

This study was undertaken to investigate the effects of a heartwood ethanolic extract (HEE) made from the Dalbergia sissoo on facture healing and in the prevention of pathological bone loss resulting from estrogen deficiency in ovariectomized (Ovx) rats.

METHODS

Heartwood ethanolic extract (250, 500 and 1000 mg/kg per day) was administered orally immediately next day after drill-hole injury and continued for 2 weeks. Ovx rats received HEE at same doses for 12 weeks and compared with 17-β estradiol (E2; 100 μg/kg for 5 days/week subcutaneously) group. Confocal imaging for fracture healing, micro-architecture of long bones, biomechanical strength, formation of mineralized nodule by bone marrow osteoprogenitor cells, bone turnover markers and gene expression were studied. One-way ANOVA was used to test significance.

KEY FINDINGS

Heartwood ethanolic extract treatment promoted fracture healing, formation of new bone at the drill-hole site and stimulated osteogenic genes at callus region. HEE administration to the Ovx rats exhibited better micro-architectural parameters at various anatomical positions, better bone biomechanical strength and more osteoprogenitor cells in the bone marrow compared with Ovx + vehicle group. HEE exhibited no uterine estrogenicity.

CONCLUSIONS

Oral administration of HEE was found to promote fracture healing and exhibited osteoprotective effect by possibly stimulation of osteoblast function.

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.

Orally administered simvastatin partially preserves lumbar vertebral bone mass but not integrity of intervertebral discs in ovariectomized rats

The present study aimed to investigate the effect of orally administered simvastatin on lumbar vertebral bone mass and intervertebral disc (IVD) degeneration in ovariectomized (OVX) rats. A total of 30 female Sprague-Dawley (SD) rats were subjected to either bilateral ovariectomy (n=20) or sham surgery (n=10). After 12 weeks, the OVX rats were orally administered either saline vehicle (OVX + V group; n=10), or 5 mg/kg/day simvastatin (OVX + SIM group; n=10). Following 12 weeks of treatment, necropsy was conducted and bone mineral density (BMD) was determined in the L5-6 vertebrae. Furthermore, the microstructure and biomechanical properties of the L3 vertebrae were detected by micro-computed tomography and compression testing, respectively. The L5-6 vertebrae were analyzed by measurement of IVD height, observation of histological changes by van Gieson staining, and evaluation of collagen-II (col-II), aggrecan (AGG) and collagen I (col-I) expression by immunohistochemical analysis. Rats in the OVX+V group had lower BMD, bone volume/trabecular volume ratio, maximum load and elastic modulus than the sham group. Rats in the OVX + SIM group had higher BMD and biomechanical strength values than the rats in the OVX+V group. Histological analysis showed that the OVX + V and OVX + SIM groups exhibited significantly higher disc degeneration scores and significantly lower IVD height than the sham group. Immunohistochemical analysis revealed lower expression levels of col-II and AGG, but higher levels of col-I in the annulus fibrosis and endplate in OVX+V rats compared with the sham group. The OVX + SIM group exhibited levels of col-II, AGG and col-I expression comparable with those of OVX+V rats, with the exception of an upregulation of col-II expression in the annulus fibrosis. These data demonstrate that simvastatin treatment partially prevented bone loss and the deterioration of biomechanical properties of lumbar vertebrae, but not the progression of IVD degeneration in OVX rats.

Estrogenic and cytotoxic potentials of compounds isolated from Millettia macrophylla Benth (Fabaceae): towards a better understanding of its underlying mechanisms

BACKGROUND

Millettia macrophylla was previously reported to have estrogenic effects and to prevent postmenopausal osteoporosis in Wistar rats. So, the study deals with the identification of its secondary metabolites and the evaluation of their estrogenicity and cytotoxicity toward tumoural cells. Thus, 13 known compounds were obtained from successive chromatographic columns and identified by NMR data compared to those previously reported.

METHODS

In vitro estrogenicity of the isolates and the phenolic fraction (PF) of M. macrophylla were performed by E-screen and reporter gene assays, while their cytotoxicity was evaluated by Alamar Blue (resazurin) assay. A 3-days uterotrophic assay and the ability of PF to alleviate hot flushes in ovariectomized adult rats were tested in vivo.

RESULTS

Seven of the 13 secondary metabolites turned to be estrogenic. Only two exhibited cytotoxic effects on MCF-7 and MDA-MB-231 with CC50 values of 110 μM and 160 μM, respectively. PF induced a significant (p < 0.01) MCF-7 cells proliferation and transactivated both ERα and ERβ in the reported gene assay at 10-2 μg/mL. In vivo, PF acted more efficiently than the methanol crude extract, resulting to a significant (p < 0.01) increase in the uterine wet weight, uterine protein level, uterine and vaginal epithelial height at the dose of 10 mg/kg BW. In addition, PF reduced the average duration and frequency of hot flushes induced in rat.

CONCLUSION

These aforementioned results indicate that PF is a good candidate for the preparation of an improved traditional medicine able to alleviate some menopausal complaints such as vaginal dryness and hot flushes. Estrogenic and cytotoxic potentials of compounds isolated from Millettia macrophylla Benth. (Fabaceae): towards a better understanding of its underlying mechanism.

An isoflavone cladrin prevents high-fat diet-induced bone loss and inhibits the expression of adipogenic gene regulators in 3T3-L1 adipocyte

Objective

This study evaluates the effect of isoflavone cladrin on high-fat diet (HFD)-induced bone loss and adipogenesis.

Methods

Thirty-two 4-week-old male C57BL/6J mice were divided into four groups: a standard diet group, a HFD group and HFD group with cladrin (5 and 10 mg/kg per day orally) for 12 weeks. The effect of cladrin on bone micro-architecture, bone marrow cell lineages and hyperlipidaemia were assessed. For assessing anti-adipogenic activity of cladrin, 3T3-L1 cells were used.

Key findings

Cladrin attenuated HFD-induced hyperlipidaemia and bone loss by preserving bone micro-architecture and strength. Effect of cladrin was found at the level of bone marrow progenitor cells. Gene expression profile of cladrin-treated mice bone showed upregulation of osteoblast and downregulation of adipogenic transcription factors and increased OPG/RANKL ratio. Cladrin inhibited cellular lipid accumulation through downregulation of transcription factors such as PPAR-γ and C/EBP-α and modulated the expression of major adipokines involved behind obesity stimulation without eliciting cell cytotoxicity in 3T3-L1 adipocytes.

Conclusion

We conclude that cladrin may improve obesity-induced bone loss and hyperlipidaemia in mice fed HFD and adipogenesis in 3T3-L1 cells by modifying adipokines and could offer clinical benefits as a supplement to treat obesity-induced disorders.

Odanacatib Restores Trabecular Bone of Skeletally Mature Female Rabbits With Osteopenia but Induces Brittleness of Cortical Bone: A Comparative Study of the Investigational Drug With PTH, Estrogen, and Alendronate

Cathepsin K (CK), a lysosomal cysteine protease, is highly expressed in mature osteoclasts and degrades type 1 collagen. Odanacatib (ODN) is a selective and reversible CK inhibitor that inhibits bone loss in preclinical and clinical studies. Although an antiresorptive, ODN does not suppress bone formation, which led us to hypothesize that ODN may display restorative effect on the osteopenic bones. In a curative study, skeletally mature New Zealand rabbits were ovarectomized (OVX) and after induction of bone loss were given a steady-state exposure of ODN (9 mM/d) for 14 weeks. Sham-operated and OVX rabbits treated with alendronate (ALD), 17b-estradiol (E2), or parathyroid hormone (PTH) served as various controls. Efficacy was evaluated by assessing bone mineral density (BMD), bone microarchitecture (using micro-computed tomography), fluorescent labeling of bone, and biomechanical strength. Skeletal Ca/P ratio was measured by scanning electron microscopy (SEM) with X-ray microanalysis, crystallinity by X-ray diffraction, and bone mineral density distribution (tissue mineralization) by backscattered SEM. Between the sham and ODN-treated osteopenic groups, lumbar and femur metaphyseal BMD, Ca/P ratio, trabecular microstructure and geometric indices, vertebral compressive strength, trabecular lining cells, cortical parameters (femoral area and thickness and periosteal deposition), and serum P1NP were largely comparable. Skeletal improvements in ALD-treated or E2-treated groups fell significantly short of the sham/ODN/PTH group. However, the ODN group displayed reduced ductility and enhanced brittleness of central femur, which might have been contributed by higher crytallinity and tissue mineralization. Rabbit bone marrow stromal cells expressed CK and when treated with ODN displayed increased formation of mineralized nodules and decreased apoptosis in serum-deficient medium compared with control. In vivo, ODN did not suppress remodeling but inhibited osteoclast activity more than ALD. Taken together, we show that ODN reverses BMD, skeletal architecture, and compressive strength in osteopenic rabbits; however, it increases crystallinity and tissue mineralization, thus leading to increased cortical bone brittleness.

Theophylline, a methylxanthine drug induces osteopenia and alters calciotropic hormones, and prophylactic vitamin D treatment protects against these changes in rats

The drug, theophylline is frequently used as an additive to medications for people suffering from chronic obstructive pulmonary diseases (COPD). We studied the effect of theophylline in bone cells, skeleton and parameters related to systemic calcium homeostasis. Theophylline induced osteoblast apoptosis by increasing reactive oxygen species production that was caused by increased cAMP production. Bone marrow levels of theophylline were higher than its serum levels, indicating skeletal accumulation of this drug. When adult Sprague-Dawley rats were treated with theophylline, bone regeneration at fracture site was diminished compared with control. Theophylline treatment resulted in a time-dependent (at 4- and 8 weeks) bone loss. At 8 weeks, a significant loss of bone mass and deterioration of microarchitecture occurred and the severity was comparable to methylprednisone. Theophylline caused formation of hypomineralized osteoid and increased osteoclast number and surface. Serum bone resorption and formation marker were respectively higher and lower in the theophylline group compared with control. Bone strength was reduced by theophylline treatment. After 8 weeks, serum 25-D3 and liver 25-hydroxylases were decreased in theophylline group than control. Further, theophylline treatment reduced serum 1, 25-(OH)2 vitamin D3 (1,25-D3), and increased parathyroid hormone and fibroblast growth factor-23. Theophylline treated rats had normal serum calcium and phosphate but displayed calciuria and phosphaturia. Co-administration of 25-D3 with theophylline completely abrogated theophylline-induced osteopenia and alterations in calcium homeostasis. In addition, 1,25-D3 protected osteoblasts from theophylline-induced apoptosis and the attendant oxidative stress. We conclude that theophylline has detrimental effects in bone and prophylactic vitamin D supplementation to subjects taking theophylline could be osteoprotective.

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.

Positive skeletal effect of two ingredients of Psoralea corylifolia L. on estrogen deficiency-induced osteoporosis and the possible mechanisms of action

Estrogen replacement therapy (ERT) is utilized as a major regime for treatment of postmenopausal osteoporosis at present. However, long-term supplement of estrogen may cause uterine hyperplasia and hypertension leading to a high risk of endometrial cancer and breast cancer. Psoralea corylifolia L. has long been used as tonic and food additives in many countries. Previous studies had found two ingredients in P. corylifolia L.: bavachin and bakuchiol exhibited osteoblastic activity. The present study was designed to investigate the protective effect of bakuchiol and bavachin on ovariectomy-induced bone loss and explore the possible mechanism. In vivo, bakuchiol and bavachin could prevented estrogen deficiency-induced bone loss in ovariectomized rats without uterotrophic activity. In vitro studies suggested that bakuchiol and bavachin induced primary human osteoblast differentiation by up-regulating the Wnt signalling pathway. This study suggests that such a bone-protective role makes them a promising and safe estrogen supplement for the ERT.

Prunetin signals via G-protein-coupled receptor, GPR30(GPER1): Stimulation of adenylyl cyclase and cAMP-mediated activation of MAPK signaling induces Runx2 expression in osteoblasts to promote bone regeneration

Prunetin is found in red clover and fruit of Prunus avium (red cherry). The effect of prunetin on osteoblast function, its mode of action and bone regeneration in vivo were investigated. Cultures of primary osteoblasts, osteoblastic cell line and HEK293T cells were used for various in vitro studies. Adult female rats received drill-hole injury at the femur diaphysis to assess the bone regenerative effect of prunetin. Prunetin at 10nM significantly (a) increased proliferation and differentiation of primary cultures of osteoblasts harvested from rats and (b) promoted formation of mineralized nodules by bone marrow stromal/osteoprogenitor cells. At this concentration, prunetin did not activate any of the two nuclear estrogen receptors (α and β). However, prunetin triggered signaling via a G-protein-coupled receptor, GPR30/GPER1, and enhanced cAMP levels in osteoblasts. G15, a selective GPR30 antagonist, abolished prunetin-induced increases in osteoblast proliferation, differentiation and intracellular cAMP. In osteoblasts, prunetin up-regulated runt-related transcription factor 2 (Runx2) protein through cAMP-dependent Erk/MAP kinase activation that ultimately resulted in the up-regulation of GPR30. Administration of prunetin at 0.25mg/kg given to rats stimulated bone regeneration at the site of drill hole and up-regulated Runx2 expression in the fractured callus and the effect was comparable to human parathyroid hormone, the only clinically used osteogenic therapy. We conclude that prunetin promotes osteoinduction in vivo and the mechanism is defined by signaling through GPR30 resulting in the up-regulation of the key osteogenic gene Runx2 that in turn up-regulates GPR30.

Study of conformational stability, structural, electronic and charge transfer properties of cladrin using vibrational spectroscopy and DFT calculations

In the present work, a detailed conformational study of cladrin (3-(3,4-dimethoxy phenyl)-7-hydroxychromen-4-one) has been done by using spectroscopic techniques (FT-IR/FT-Raman/UV-Vis/NMR) and quantum chemical calculations. The optimized geometry, wavenumber and intensity of the vibrational bands of the cladrin in ground state were calculated by density functional theory (DFT) employing 6-311++G(d,p) basis sets. The study has been focused on the two most stable conformers that are selected after the full geometry optimization of the molecule. A detailed assignment of the FT-IR and FT-Raman spectra has been done for both the conformers along with potential energy distribution for each vibrational mode. The observed and scaled wavenumber of most of the bands has been found to be in good agreement. The UV-Vis spectrum has been recorded and compared with calculated spectrum. In addition, 1H and 13C nuclear magnetic resonance spectra have been also recorded and compared with the calculated data that shows the inter or intramolecular hydrogen bonding. The electronic properties such as HOMO-LUMO energies were calculated by using time-dependent density functional theory. Molecular electrostatic potential has been plotted to elucidate the reactive part of the molecule. Natural bond orbital analysis was performed to investigate the molecular stability. Non linear optical property of the molecule have been studied by calculating the electric dipole moment (μ) and the first hyperpolarizability (β) that results in the nonlinearity of the molecule.

The thiocarbamate disulphide drug, disulfiram induces osteopenia in rats by inhibition of osteoblast function due to suppression of acetaldehyde dehydrogenase activity

Dithiocarbamates (DTC), a sulfhydryl group containing compounds, are extensively used by humans that include metam and thiram due to their pesticide properties, and disulfiram (DSF) as an alcohol deterrent. We screened these DTC in an osteoblast viability assay. DSF exhibited the highest cytotoxicity (IC50 488nM). Loss in osteoblast viability and proliferation was due to induction of apoptosis via G1 arrest. DSF treatment to osteoblasts reduced glutathione (GSH) levels and exogenous addition of GSH prevented DSF-induced reactive oxygen species generation and osteoblast apoptosis. DSF also inhibited osteoblast differentiation in vitro and in vivo, and the effect was associated with inhibition of aldehyde dehydrogenase (ALDH) activity. Out of various ALDH isozymes, osteoblasts expressed only ALDH2 and DSF downregulated its transcript as well as activity. Alda-1, a specific activator of ALDH2, stimulated osteoblast differentiation. Subcutaneous injection of DSF over the calvarium of new born rats reduced the differentiation phenotype of calvarial osteoblasts but increased the mRNA levels of Runx-2 and osteocalcin. DSF treatment at a human-equivalent dose of 30 mg/kg p.o. to adult Sprague Dawley rats caused trabecular osteopenia and suppressed the formation of mineralized nodule by bone marrow stromal cells. Moreover, DSF diminished bone regeneration at the fracture site. In growing rats, DSF diminished growth plate height, primary and secondary spongiosa, mineralized osteoid and trabecular strength. Substantial decreased bone formation was also observed in the cortical site of these rats. We conclude that DSF has a strong osteopenia inducing effect by impairing osteoblast survival and differentiation due to the inhibition of ALDH2 function.

Total water, phosphorus relaxation and inter-atomic organic to inorganic interface are new determinants of trabecular bone integrity

Bone is the living composite biomaterial having unique structural property. Presently, there is a considerable gap in our understanding of bone structure and composition in the native state, particularly with respect to the trabecular bone, which is metabolically more active than cortical bones, and is readily lost in post-menopausal osteoporosis. We used solid-state nuclear magnetic resonance (NMR) to compare trabecular bone structure and composition in the native state between normal, bone loss and bone restoration conditions in rat. Trabecular osteopenia was induced by lactation as well as prolonged estrogen deficiency (bilateral ovariectomy, Ovx). Ovx rats with established osteopenia were administered with PTH (parathyroid hormone, trabecular restoration group), and restoration was allowed to become comparable to sham Ovx (control) group using bone mineral density (BMD) and µCT determinants. We used a technique combining (1)H NMR spectroscopy with (31)P and (13)C to measure various NMR parameters described below. Our results revealed that trabecular bones had diminished total water content, inorganic phosphorus NMR relaxation time (T1) and space between the collagen and inorganic phosphorus in the osteopenic groups compared to control, and these changes were significantly reversed in the bone restoration group. Remarkably, bound water was decreased in both osteopenic and bone restoration groups compared to control. Total water and T1 correlated strongly with trabecular bone density, volume, thickness, connectivity, spacing and resistance to compression. Bound water did not correlate with any of the microarchitectural and compression parameters. We conclude that total water, T1 and atomic space between the crystal and organic surface are altered in the trabecular bones of osteopenic rats, and PTH reverses these parameters. Furthermore, from these data, it appears that total water and T1 could serve as trabecular surrogates of micro-architecture and compression strength.

Analysis of constituents of the eastern Nigeria mistletoe, Loranthus micranthus linn revealed presence of new classes of osteogenic compounds

ETHNOPHARMACOLOGICAL RELEVANCE

Mistletoe extracts (decoctions) are used traditionally in eastern Nigeria for the management of bone pain, post menopausal syndrome and diabetes amongst several other ailments. While scientific evidence supporting its folkloric use as an antidiabetic agent has been documented, the age-long practice of its use in treatment of post menopausal syndrome has not been scientifically validated. Postmenopausal osteoporosis accounts for one of the prevalent disease conditions in aging population globally. This situation is exacerbated by the lack of osteogenic therapy. In search for plants of Nigerian origin with osteogenic potential, we evaluated eastern Nigerian mistletoe, having ethnotraditional claims of anti-diabetic, anti-hypertensive and anti-cancer activities as well as preventive effect in various post-menopausal syndromes.

MATERIALS AND METHODS

Methanolic extracts of mistletoe leaves harvested from three host tress - Kola acuminata (KM), Citrus spp (CM) and Garcinia kola (GKM) - were evaluated for osteoblast viability and osteogenic activities using primary rat calvaria culture. Lupeol (1) was isolated from the stem bark of Bombax ciba and its congener, dihydoxylupeol palmitate (2) in addition to three other compounds; 3-methoxy quercetin (3), 3,4,5-trimethoxy gallate (4), and friedelin (5) were isolated from the leaves of mistletoes species. Following their chemical characterization, the compounds were evaluated for osteogenic potential using validated models including alkaline phosphatase (ALP) assay, mineralization assay and expression of osteogenic genes - bone morphogenetic protein-2 (BMP2) and osteoblast transcription factor (RUNX2) - in primary calvarial cultures harvested from neonatal rats. Uterine estrogenicity of the extracts was tested in adult female Sprague Dawley rats.

RESULTS

Methanol extracts of mistletoe from three hosts exhibited increase in ALP activity (a marker of osteoblast differentiation) at lower concentrations (0.2-0.8 μg/ml) and either no or inhibitory effect at higher concentrations (1.6 and 3.2 μg/ml). None of the extract had cytotoxicity to osteoblasts at the concentrations tested. Five compounds viz. 1 from Bombax ciba, and 2-5 were isolated from the mistletoe leaves. Out of these, 5 exhibited significant loss of osteoblast viability and hence it was not considered further. All four compounds exhibited stimulatory effects on osteoblast differentiation as assessed by ALP assay and determination of osteogenic gene expression. Compound 2 was relatively more potent than its precursor, compound 1 in stimulating BMP2 upregulation. KM did not show uterine estrogenicity.

CONCLUSION

Methanolic extracts from the three mistletoes species possess in vitro osteogenic activity, and from these extracts three new classes of compounds have been found to promote osteoblast differentiation in vitro. In light of these findings, we propose that mistletoe species may be developed as safer alternative(s) in the management of diseases where lack of bone formation is the pathology.

Greater Skeletal Gains in Ovary Intact Rats at Maturity Are Achieved by Supplementing a Standardized Extract of Butea monosperma Stem Bark that Confers Better Bone Conserving Effect following Ovariectomy and Concurrent Treatment Withdrawal

With a longitudinally designed study, we tested whether an acetone soluble fraction (ASF) from the stem bark of Butea monosperma resulted in maximizing bone gain in rats during growth and maturation and thus protected against osteopenia following ovariectomy (OVx) with concomitant treatment withdrawal. Female rats at weaning were given ASF (100 mg/kg/d) or vehicle for 12 weeks, and baseline skeletal parameters (micro-CT) and total plasma antioxidant status (TAS) were measured. At this stage, one group was OVx and the other group was sham operated. Vehicle group (untreated) after OVx was given E2 or continued with vehicle (OVx control). ASF group after OVx was given vehicle (ASF withdrawn, ASFW). After another 12 weeks, all groups were killed and various skeletal parameters were determined. ASF resulted in substantially better skeletal parameters and higher plasma TAS over control at maturity. Rats treated with ASF before OVx had reduced rates of bone loss compared to OVx control. Twelve weeks after OVx, the ASFW group exhibited better trabecular microarchitectural preservation, bone turnover profiles, increased cortical deposition, and biomechanical strength over the OVx control, and the effects were comparable to OVx + E2 group. ASF supplementation during skeletal growth could maximize bone accrual and could confer increased resistance to post-OVx osteopenia despite treatment withdrawal.