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

A review of botany, phytochemistry, pharmacology, and applications of the herb with the homology of medicine and food: Ligustrum lucidum W.T. Aiton

Ligustrum lucidum W.T. Aiton is an outstanding herb with the homology of medicine and food. Its ripe fruits are traditionally used as an important tonic for kidneys and liver in China. Ligustrum lucidum W.T. Aiton is rich in nutritional components and a variety of bioactive ingredients. A total of 206 compounds have been isolated and identified, they mainly include flavonoids, phenylpropanoids, iridoid glycosides, and triterpenoids. These compounds exert anti-osteoporosis, anti-tumor, liver protective, antioxidant, anti-inflammatory, and immunomodulatory effects. Ligustrum lucidum W.T. Aiton has been traditionally used to treat many complex diseases, including osteoporotic bone pain, rheumatic bone, cancer, related aging symptoms, and so on. In the 2020 Edition of Chinese Pharmacopoeia, there are more than 100 prescriptions containing L. lucidum W.T. Aiton. Among them, some classical preparations including Er Zhi Wan and Zhenqi fuzheng formula, are used in the treatment of various cancers with good therapeutic effects. Additionally, L. lucidum W.T. Aiton has also many excellent applications for functional food, ornamental plants, bioindicator of air pollution, algicidal agents, and feed additives. Ligustrum lucidum W.T. Aiton has rich plant resources. However, the application potential of it has not been fully exploited. We hope that this paper provides a theoretical basis for the high-value and high-connotation development of L. lucidum W.T. Aiton in the future.

Exploring the boost of steaming with wine on Ligustri Lucidi Fructus in treating postmenopausal osteoporosis based on superior "multi-component structure" and iron/bone metabolism coregulation

BACKGROUND

Clinical studies indicated that postmenopausal osteoporosis (PMOP) often accompanied by iron overload risk factor, which exacerbated bone metabolism disorders and accelerated PMOP. Previous research found that multicomponent in Ligustri Lucidi Fructus (FLL) or wine-steamed FLL (WFLL) acted on the common targets of iron overload and PMOP simultaneously, which indicated that FLL and WFLL probably regulated iron/bone metabolism dually. Additionally, WFLL had more superior effect according to the theory of Chinese medicine for thousands of years.

PURPOSE

To reveal the "superior multi-component structure (SMCS)" and its molecular mechanisms in parallelly down-regulating iron overload and rescuing bone metabolism by WFLL.

DESIGNS AND METHODS

HPLC fingerprinting was established to compare the chemical profiles of FLL and WFLL; Then, the chemical compositions and quality markers of FLL and WFLL were analyzed by UPLC-Orbitrap-MS/MS coupled with OPLS-DA; the dynamic contents of quality markers and the multi-component structure at different wine steaming times (WST) were simultaneously determined by HPLC-DAD. Meanwhile, the dynamic efficacy of FLL at different WST were hunt by systematic zebrafish model. Subsequently, potential mechanism of WFLL in treating PMOP accompanied with iron overload was obtained from network pharmacology (NP) and molecular docking (MD). Finally, zebrafish and ovariectomy rat model were carried out to validate this potential mechanism.

RESULTS

HPLC fingerprints similarity of 15 batches in FLL and WFLL were among 0.9-1.0. 126 compositions were identified, including 58 iridoids, 25 terpenes, 30 phenylethanoids, 7 flavonoids and 6 others. 20 quality markers associated with WFLL was revealed, and the ratio of phenylethanols: Iridoids: Triterpenes (P/I/T) was converted from 1: 15: 4.5 to 1: 0.8: 0.9 during steaming (0 - 24 h) calculated by the quantification of 11 quality markers; the bone mineralization and motor performance of zebrafish larvae indicated that the optimum efficacy of WFLL at 12 h (p < 0.05) in which the SMCS of P/I/T was converted to 1: 4: 1.8. NP discovered that BMP-Smad pathway is one of the potential mechanisms of FLL in anti PMOP and then regulated bone formation and iron overload simultaneously. MD revealed that 17 active ingredients and 10 core targets genes could spontaneously bind with appropriate affinity. Rats model verified that FLL and WFLL significantly reversed PMOP, based on the improvement in bone formation indexes (ALP, OPG, OGN), iron metabolism indicators (hepcidin, ferritin), bone microstructure (BMD, BV/TV, Tb. Th, Tb. N); Moreover, WFLL significant enhanced reversal effect in anti-PMOP compared to FLL (p < 0.05). FLL and WFLL increased genes and proteins expression (Hep, BMP-6, p-Smad1/5, Smad4) related to BMP-Smad pathway compared with model group, and WFLL was more superior than FLL (p< 0.05).

CONCLUSION

The SMCS of FLL was optimized by wine-steam, WFLL represented a dual effect in downregulating iron overload and promoting bone formation, and the BMP-Smad pathway is one of the potential molecular mechanisms.

Metabolomics analysis of Ligustri Lucidi Fructus at different harvest times during the whole growing period based on ultra-high-performance liquid chromatography with mass spectrometry

After medicinal market research, it was found that the harvest time of Ligustri Lucidi Fructus (LLF) was chaotic in practice. In order to determine the optimal harvest period of LLF to ensure its pharmacological activity, metabolomics analysis of LLF at different harvest times based on ultra-high-performance liquid chromatography-triple quadrupole-(linear ion trap)-tandem mass spectrometry was established. In this study, 166 differential metabolites (DMs) in 448 metabolites at different harvest times were screened out based on variable importance in projection value, and among them, 94 DMs with regular trends of change in relative content (59 increased and 35 decreased with the growth period) were chosen to further research. The result of the multivariate statistical analysis showed that November was the optimal harvest period of LLF. Additionally, 10-hydroxyligustroside, oleoside 11-methyl ester, and salidroside were screened out to be used as the evaluation indicators of immature LLF, while specnuezhenide, nuezhenoside G13, and neonuezhenide were the evaluation indicators of mature LLF. This study provides fundamental insight for metabolite identification and proposes the best harvest period of LLF to avoid confusion in the medicinal market.

Microwave-assisted synthesis of novel steroidal heterocyclic analogs as potent inhibitors of RANKL-induced osteoclastogenesis

Osteoporosis is a significant public health issue in our aging population. It is an excessive bone resorption condition brought on by osteoclastogenesis, which makes bones more brittle. In the present work, a series of novel heterosteroidal derivatives have been synthesized using the microwave technique and were evaluated as antiosteoclastogenic agents. The structures of the newly synthesized compounds have been confirmed using analytical and spectral data. The antiosteoclastogenic activity of the newly synthesized compounds was estimated in vitro against osteoclast-differentiated cells from the RAW 264.7 cell line. The pregnenolone dimer 10, the pyridinotestosterone derivative 2, and the phenylnicotinonitrile pregnenolone derivative 8a attained the most promising antiosteoclastogenic activity displaying IC50 (the half maximal inhibitory concentration) values of 5.45 ± 5.30, 11.88 ± 2.09, and 13.40 ± 3.00 µM, respectively, in comparison with dimethyl itaconate (IC50  = 17.76 ± 3.20 µM) and alendronate (IC50  = 4.48 ± 1.89 µM) as reference compounds. Finally, an in silico ADME (Absorption, Distribution, Metabolism, and Excretion) study was conducted to evaluate the synthesized compounds' pharmacokinetic and drug-likeness properties. The results manifested that almost all the investigated compounds' properties were compatible with the specified optimal range, which indicates their reassuring pharmacokinetic properties.

Mechanisms by which kidney-tonifying Chinese herbs inhibit osteoclastogenesis: Emphasis on immune cells

The immune system plays a crucial role in regulating osteoclast formation and function and has significance for the occurrence and development of immune-mediated bone diseases. Kidney-tonifying Chinese herbs, based on the theory of traditional Chinese medicine (TCM) to unify the kidney and strengthen the bone, have been widely used in the prevention and treatment of bone diseases. The common botanical drugs are tonifying kidney-yang and nourishing kidney-yin herbs, which are divided into two parts: one is the compound prescription of TCM, and the other is the single preparation of TCM and its active ingredients. These botanical drugs regulate osteoclastogenesis directly and indirectly by immune cells, however, we have limited information on the differences between the two botanical drugs in osteoimmunology. In this review, the mechanism by which kidney-tonifying Chinese herbs inhibiting osteoclastogenesis was investigated, emphasizing the immune response. The differences in the mechanism of action between tonifying kidney-yang herbs and nourishing kidney-yin herbs were analysed, and the therapeutic value for immune-mediated bone diseases was evaluated.

Ligustri Lucidi Fructus, a traditional Chinese Medicine: Comprehensive review of botany, traditional uses, chemical composition, pharmacology, and toxicity

ETHNOPHARMACOLOGICAL RELEVANCE

Ligustri Lucidi Fructus (LLF) is one of the usual Chinese herbs that has long been used with high therapeutic and condition value. LLF is used for the treatment of dizziness and tinnitus, soreness and weakness of the waist and knees, premature greying of the hair, the darkness of the eyes, internal heat and thirst, bone steam and hot flashes and other symptoms.

AIM OF THE STUDY

This review reviews botany, traditional uses, processing, phytochemistry, quality control, pharmacology, toxicity and pharmacokinetics to better understand its therapeutic potential.

MATERIALS AND METHODS

The literature on LLF was obtained from Google Scholar and Baidu Scholar, PubMed, ScienceDirect, SciFinder, Web of Science, China National Knowledge Infrastructure (CNKI), WAN FANG DATA and libraries. Some local books, official websites, PhD or MS's dissertations were also included. Phytochemical constituents' structures were drawn by ChemDraw software.

RESULTS

So far, Multiple chemical components were isolated and identified from LLF, mainly including terpenoids and flavonoids. Modern studies have shown that LLF extracts and compounds have a wide range of pharmacological effects, including antitumor, liver protection, blood glucose, lipid-lowering, immune regulation, and other aspects.

CONCLUSIONS

LLF occupies an important position in the traditional medical system. It is cost-effective and is a significant plant with therapeutic applications in modern medicine. However, further in-depth studies are needed to determine the medical use of this plant and its chemical composition, pharmacological activity, quality control, toxicity and pharmacokinetics.

Amelioration of Fructus Ligustri Lucidi and its phenol glycosides on hypercalciuria via stimulating PTH1R/PKA/TRPV5 signaling

BACKGROUND

Our early studies performed on aged rats, ovariectomized (OVX) rats and diabetic mice, indicated the calciotropic role of Fructus Ligustri Lucidi (FLL), the fruit of Ligustrum lucidum Ait., in mediating calcium homeostasis which was partially attributed to its stimulation on renal calcium reabsorption.

PURPOSE

This study aimed to explicate the underlying molecular mechanism and explore the potential bioactive ingredients in FLL.

STUDY DESIGN AND METHODS

The OVX C57BL/6 J mice were orally administered with low (FL, 75 mg/kg), middle (FM, 225 mg/kg) or high (FH, 675 mg/kg) dose of extract of Fructus Ligustri Lucidi for 10 weeks. The biological properties of trabecular bone were measured by micro-CT and H&E staining. The molecular expression was assessed by immunoblotting and immunostaining. The potential active components were identified by cell membrane chromatography (CMC) and explored in renal tubular cells with Fluo-3/AM fluorescent staining to indicate intracellular calcium level. The male mice fed with high calcium diet (1.2% Ca) and orally treated with active components for 3 weeks.

RESULTS

Treatment of OVX mice with FLL extract suppressed the elevation in urinary calcium level (FH, 0.081 ± 0.012, vs. OVX, 0.189 ± 0.038 mg/mg), and increased bone mineral density (FH, 62.41 ± 2.57, vs. OVX, 43.72 ± 8.43 mg/ccm) and percentage of trabecular bone area. It also decreased circulating PTH level (FH, 66.69 ± 10.94, vs. OVX, 303.50 ± 26.56 pg/ml) and up-regulated TRPV5 expression in renal cortex of OVX mice as well as enhanced the expression of PTH receptor (PTH1R) and the ratio of p-PKA/PKA. The PKA inhibitor H89 abolished the induction of serum, prepared from rats treated with FLL extract, on PKA/TRPV5 signaling in renal tubular cells. The CMC identified phenol glycosides, including salidroside and oleuropein, which increased intracellular calcium content, promoted expression of PTH1R and TRPV5 and ratio of p-PKA/PKA as well as decreased calcium excretion in urine of mice fed with high calcium diet.

CONCLUSION

Salidroside and oleuropein are major ingredients contributing to the anti-hypercalciuria effects of FLL via acting on PTH1R/PKA/TRPV5 signaling in kidney. Further translational research would be required.

Pharmacokinetics of ligustroflavone in rats and tissue distribution in mice by UPLC–MS/MS

An ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) method was developed and validated for quantification of ligustroflavone, which was then applied in pharmacokinetics study in rat and tissue distribution in mouse. Twelve male Sprague Dawley rats were used for pharmacokinetics after intravenous (2 or 8 mg/kg) administration of ligustroflavone, six rats for each dose. Twenty-five mice were randomly divided into 5 groups (5 mice for each group, 1 group for each time point) and received 16 mg/kg ligustroflavone via intraperitoneal administration. The linear range of the calibration curve was over 2–2000 ng/mL for ligustroflavone in rat plasma and mouse tissues. The intra-day and inter-day precision expressed in % RSD were less than 14%, and the accuracy was between 88.5% and 108.4%.

The tissue distribution results indicated that ligustroflavone diffuses rapidly and widely into major organs. The level of ligustroflavone was highest in the mouse liver, followed by the kidney, spleen, and lung. The overwhelming accumulation in the liver indicated that the liver was responsible for the extensive metabolism.

Chemical Constituents From the Fruits ofLigustrum lucidum W.T.Aitonand Their Role on the Medicinal Treatment

Fruits of Ligustrum lucidum W.T.Aiton ( FLL) is a well-known traditional Chinese medicine, which has the functions of protecting liver, anticancer, antiosteoporosis, and antioxidant, etc. Various chemical constituents including triterpenes, secoiridoids, phenylethanoid glycosides, and flavonoids have been isolated and identified from FLL. In this article, the advances in research on the chemical constituents and their pharmacological effects were summarized by reviewing the recent literatures. In addition, the relationship between the chemical constituents and pharmacological activity of FLL was also discussed.

Effects of Rambutan Peel (Nepheliumlappaceum) PhenolicExtract on RANKL-Induced Differentiation of RAW264.7 Cells into Osteoclasts and Retinoic Acid-Induced Osteoporosis in Rats

Previous studies have shown that rambutan peel phenolic (RPP) extract has excellent biological activities due to its abundant phenolic content and profile. In this study, the potential anti-osteoporosis (OP) effects of RPP were evaluated by suppressing receptor activator nuclear factor-kappa B ligand (RANKL)-induced differentiation of RAW264.7 cells into osteoclasts and amelioratingretinoic acid-induced OP in rats. Our results showed that RPP efficiently decreased the formation of tartrate-resistant acid phosphatase (TRAP)-positive cells and reduced total TRAP activity in RAW264.7 cells under RANKL stimulation. RPP treatment significantlyameliorated retinoid acid-induced calcium loss in rats (p < 0.05). The serum phosphorus level of osteoporotic rats was increased by RPP treatment, and the serum levels of total alkaline phosphatase and osteocalcin in osteoporotic rats were further reduced. RPP treatment improved the qualities of the femur and tibia, such asbone mineral density, bone length, bone maximum load, cortical bone area ratio, and trabecularelative bone density in osteoporotic rats to some extent. Furthermore, histological analysis showed that RPP effectively improved the bone microstructure of osteoporotic rats by regulating the cortical bone thickness and trabecular bone separation. These results indicate that RPP could have potential applications as a newnutraceutical and functional food in the prevention of OP.

Protective effects and network analysis of natural compounds obtained from Radix dipsaci, Eucommiae cortex, and Rhizoma drynariae against RANKL-induced osteoclastogenesis in vitro

ETHNOPHARMACOLOGICAL RELEVANCE

Osteoporosis is one of the most common bone diseases; it is characterized by bone loss and is a risk factor for hip fracture. Chinese herbal medicines (CHMs) and their related natural compounds have been used for treating many diseases, including bone diseases, since ancient times in China and are regarded as a cost-effective complementary therapy.

AIM OF THE STUDY

The goal of this study was to investigate the osteoprotective mechanisms of these three Chinese herbs and their related natural compounds. The effects of CHMs and related natural compounds on RANKL-induced osteoclastogenesis in vitro were investigated.

MATERIALS AND METHODS

A network pharmacology method was applied to study CHM-related natural compounds and their osteoporosis targets. In addition, their effect on RANKL-induced osteoclastogenesis in RAW264.7 cells was also investigated in vitro.

RESULTS

Radix dipsaci, Eucommiae cortex, and Rhizoma drynariae exhibited protective effects against mortality in hip fracture patients. Furthermore, these three herbs inhibited RANKL-induced TRAP activities and reduced the expression of bone resorption-related genes in RAW264.7 cells. Network analysis of natural compound (ingredient)-target interactions identified 11 natural compounds. Signal pathway analyses suggested that these compounds may target cytokine-cytokine receptor interactions, including RANKL-induced osteoclastogenesis. Five novel natural compounds exhibited reduced RANKL-induced TRAP activities and bone resorption-related gene expression.

CONCLUSION

The clinically used CHMs, Radix dipsaci, Eucommiae cortex, and Rhizoma drynariae, and natural compounds obtained from them may suppress RANKL-induced osteoclastogenesis in vitro.

Systems pharmacology dissection of action mechanisms of Dipsaci Radix for osteoporosis

AIMS

Osteoporosis (OP) is a systemic metabolic bone disease characterized by bone mass decrease and microstructural degradation, which may increase the risk of bone fracture and leading to high morbidity. Dipsaci Radix (DR), one typical traditional Chinese medicine (TCM), which has been applied in the treatment of OP with good therapeutic effects and few side effects. However, the underlying molecular mechanisms of DR to treat OP have not been fully elucidated. In this study, we aim to dissect the molecular mechanism of DR in the treatment of OP.

MATERIALS AND METHODS

A systems pharmacology approach was employed to comprehensively dissect the action mechanisms of DR for the treatment of OP.

KEY FINDINGS

10 compounds were screened out as the potential active ingredients with excellent biological activity based on in silico ADME (absorption, distribution, metabolism and excretion) prediction model. Then, 36 key protein targets of 6 compounds were identified by systems drug targeting model (SysDT) and they were involved in several biological processes, such as osteoclast differentiation, osteoblast differentiation and anti-inflammation. The target-pathway network indicated that targets are mainly mapped in multiple signaling pathways, i.e., MAPK, Tumor necrosis factor α (TNF-α), NF-κb and Toll-like receptor pathways. The in vitro results indicated that the compounds ursolic acid and beta-sitosterol effectively inhibited the osteoclast differentiation.

SIGNIFICANCE

These results systematically dissected that DR exhibits the therapeutic effects of OP by the regulation of immune system-related pathways, which provide novel perspective to drug development of OP.

Oleanolic acid inhibits RANKL-induced osteoclastogenesis via ER alpha/miR-503/RANK signaling pathway in RAW264.7 cells

Oleanolic acid (OA) has recently become a research hotspot in the treatment of many human diseases, especially osteoporosis and arthritis. However, the mechanisms are not elucidated completely. We aimed to elucidate the target and the mechanism via which OA inhibited osteoclast differentiation. We used TRAP staining and toluidine blue dye to test OA effect on osteoclastogenesis and bone resorption respectively. We detected the expression level of osteoclast differentiation related genes, estrogen receptor alpha (ERα) and miR-503. We blocked ERα with its specific blocker, methylpiperidino pyrazole (MPP). We antagonized the function of miR-503 with antagomir-503-5p. RT-PCR and ELISA kits were used to investigate the effects of OA on miR-503 formation and maturation-relevant enzymes Dicer and Drosha at gene and protein levels. The data suggested that OA inhibited osteoclastogenesis and bone resorption. OA upregulated ERα and miR-503 expression levels, inhibited RANK expression. MPP significantly attenuated the OA effect including inhibiting osteoclastogenesis, inhibiting bone resorption and up-regulating miR-503 expression. It showed that ERα was the target of OA and OA up-regulated miR-503 expression through ERα. Antagomir-503-5p inhibited the function of miR-503 and attenuated the inhibition of OA on osteoclastogenesis, suggesting that OA inhibited osteoclast by up-regulating miR-503 expression. In addition, OA up-regulated miR-503 by up-regulating Dicer expression. In conclusion, OA inhibits RANKL-induced osteoclastogenesis via ERα/miR-503/RANK signaling pathway in RAW264.7 cells.

Natural Products as Potential Bone Therapies

Demands for natural products, in the form of botanicals, dietary supplements, and herbal medicine, for management of chronic diseases are increasing globally. Natural products might be an alternative for the management of bone health to meet the demands of a growing aging population. Different types of natural products, including Chinese herbal medicine decoctions, herbs, and isolated phytochemicals, have been demonstrated to exert bone protective effects. The most common types of bone protective bioactives are flavonoids, stilbene, triterpenoids, coumestans, lignans, and phenolic acid. The actions of natural products can be mediated by acting systemically on the hormonal axis or locally via their direct or indirect effects on osteogenesis, osteoclastogenesis, as well as adipogenesis. Furthermore, with the use of metabolomic and microbiome approaches to understand the actions of natural products, novel mechanisms that involve gut-brain-bone axis are also revealed. These studies provide evidence to support the use of natural products as bone therapeutics as well as identify new biological targets for novel drug development.

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

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

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

Background

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

Objective

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

Methods

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

Results

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

Conclusion

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

Oleanolic Acid Exerts Osteoprotective Effects and Modulates Vitamin D Metabolism

Oleanolic acid (OA) is a triterpenoid with reported bone anti-resorption activities. The present study aimed to characterize its bone protective effects in vivo and to study its effects on vitamin D metabolism, both in vivo and in vitro. OA significantly increased bone mineral density, improved micro-architectural properties, reduced urinary Ca excretion, increased 1,25(OH)₂D₃ and renal CYP27B1 mRNA expression in mature C57BL/6 ovariectomised (OVX) mice. OA also improved bone properties, Ca balance, and exerted modulatory effects on renal CYP27B1 and CYP24A1 expressions in aged normal female Sprague–Dawley rats. In addition, OA significantly increased renal CYP27B1 mRNA and promoter activity, and suppressed CYP24A1 mRNA and protein expressions in human proximal tubule HKC-8 cells. OA exerted bone protective effects in mature OVX mice and aged female rats. This action on bone might be, at least in part, associated with its effects on Ca and vitamin D metabolism. The present findings suggest that OA is a potential drug candidate for the management of postmenopausal osteoporosis.

Vaccaria hypaphorine impairs RANKL-induced osteoclastogenesis by inhibition of ERK, p38, JNK and NF-κB pathway and prevents inflammatory bone loss in mice

Osteoclasts are sole bone-resorbing cells which exert a profound effect on skeletal metabolism. The search for medicines that affect the differentiation and function of osteoclasts is crucial in developing therapies for osteoclast-based diseases. Vaccaria hypaphorine, the main active compound of the traditionally used Chinese herb Vaccaria segetalis, has anti-inflammatory activity. The present study demonstrated for the first time that vaccaria hypaphorine could significantly inhibit the receptor activator of nuclear factor kappa B ligand (RANKL)-induced osteoclastic differentiation in vitro and alleviate lipopolysaccharide (LPS)-induced bone loss in vivo. Further study showed that vaccaria hypaphorine decreased osteoclastogenesis in a dose-dependent manner. Furthermore, vaccaria hypaphorine was confirmed to inhibit osteoclasts differentiation at early stage but not at later stage. Pit formation assay and F-actin ring staining showed that vaccaria hypaphorine inhibited the bone-resorbing activity of osteoclasts. Mechanistically, vaccaria hypaphorine impaired RANKL-induced osteoclastogenesis through reduction of extracellular signal-regulated kinases (ERK), p38, c-Jun N-terminal kinase (JNK) and NF-κB p65 phosphorylation. Taken together, our results provided evidences that vaccaria hypaphorine might be considered as potential therapeutic agent for treating osteoclast-based bone loss.

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

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

Antioxidant Effect of Fructus Ligustri Lucidi Aqueous Extract in Ovariectomized Rats Is Mediated through Nox4-ROS-NF-κB Pathway

Purpose: This study is designed to explore whether Fructus ligustri lucidi (FLL) exhibits antioxidant effect in ovariectomized (OVX) rats, and to identify the signaling pathway involved in this process.

Methods: OVX rats were treated with FLL aqueous extract (3.5 g/kg) for 12 weeks. Serum, uteri, and tibias were harvested from the rats and the levels of total antioxidant capacity (TAC), nitric oxide (NO), malondialdehyde (MDA), 8-hydroxy-desoxyguanosine (8-OHdG), and superoxide dismutase (SOD) were determined. Changes in the levels of NF-κB-p65, phosphorylation of NF-κB-p65 (NF-κB-pp65), NF-κB inhibitor alpha (IκBα), phosphorylation of IκBα (p-IκBα), and NADPH oxidase 4 (Nox4) in uteri and tibias were determined by western blot, immunofluorescent and immunohistochemical analysis, respectively. In addition, the expression of cytochrome C (Cyto-C) and B-cell lymphoma-2 (Bcl-2) were determined in the tibias of rats. Histopathological changes in the bones were evaluated by hematoxylin-eosin staining. Bone mineral density (BMD) was determined in rat femurs by dual X-ray absorptiometry.

Results: Treatment of OVX rats with FLL aqueous extract improved redox homeostasis by increasing the levels of TAC and NO as well as decreasing the levels of MDA and 8-OHdG in serum, tibias, and uteri. Further, FLL extract also downregulated the expression of Nox4, NF-κB-p65, NF-κB-pp65, and p-IκBα in the uteri and tibias. Furthermore, administration of FLL–OVX rats increased Bcl-2 expression and prevented cytoplasmic release of mitochondrial Cyto-C in the tibias. In addition, FLL treatment also improved bone microstructure and increased cortical bone thickness as well as increased BMD values in the femurs of OVX rats.

Conclusions: FLL treatment may suppress oxidative stress response in OVX rats via regulating the Nox4/ROS/NF-κB signaling pathway. These results suggest the potential of using FLL as a natural antioxidant agent in preventing the development of osteoporosis.