Therapeutic effect of aqueous extract from Ecliptae herba on bone metabolism of ovariectomized rats

Chinese Ecliptae herba (Eclipta prostrata (L.) L.) extract and its component wedelolactone enhances osteoblastogenesis of bone marrow mesenchymal stem cells via targeting METTL3-mediated m6A RNA methylation

ETHNOPHARMACOLOGICAL RELEVANCE

Chinese Ecliptae herba (Eclipta prostrata (L.) L.) is an ethnomedicinal herb, which is used mainly to nourish kidney and thus strengthen bones according to traditional Chinese medicine theory. Pharmacological studies have supported the ethnomedicine use, showing that Ecliptae herba extract has an anti-osteoporotic effect in vivo and promoted osteoblast proliferation and activity in vitro. However, the molecular mechanism of Ecliptae herba on osteoblast differentiation from bone marrow mesenchymal stem cells (BMSC), the progenitors of osteoblasts, is still unclear.

AIM OF THE STUDY

N6-methyladenosine (m6A) mRNA epigenetic modification may play a key role in promoting osteoblastic differentiation, and thus treating osteoporosis. This study sought to assess the mechanism through which Eclipate herba and its component wedelolactone influence m6A modification during the process of osteoblastogenesis from BMSC.

MATERIAL AND METHODS

The alkaline phosphatase (ALP) and Alizarin red S (ARS) staining were applied to determine osteoblastogenesis from BMSC. Western blot and quantitative real-time PCR were performed. RNA sequencing analysis was used to determine the characteristics of m6A methylation. Stable knocking down of METTL3 using lentiviral-based shRNA was performed.

RESULTS

Upon 9 d treatment of BMSC with ethyl acetate extract of Ecliptae herba (MHL), ALP activity and ossification level increased in comparison with osteogenic medium (OS)-treated control. The expression of methyltransferase METTL3 and METTL14 was significantly increased, but WTAP expression had no change in response to MHL treatment. Knocking down of METTL3 resulted in a decrease in MHL-induced ALP activity, ossification level as well as mRNA expression of Osterix and Osteocalcin, two bone formation-related markers. The level of m6A increased when BMSC was treated with MHL for 9 d. RNA sequencing analysis indicated that MHL treatment altered mRNA m6A modification of genes associated with osteoblastogenesis. By kyoto encyclopedia of genes and genomes (KEGG) pathway analysis, HIF-1α, PI3K/Akt, and Hippo signaling pathways were enriched and associated with m6A modification. The expression of m6A-modified genes including HIF-1α, VEGF-A, and RASSF1, was upregulated by MHL, but the upregulation was reversed after METTL3 knockdown. Additionally, the enhanced expression of METTL3 was also observed after treatment with wedelolactone, a component from MHL.

CONCLUSIONS

These results suggested a previously uncharacterized mechanism of MHL and wedelolactone on osteoblastogenesis, by which METTL3-mediated m6A methylation is involved and thus contributes to the enhancement of osteoblastogenesis.

Role of Traditional Chinese Medicine in Bone Regeneration and Osteoporosis

According to World Health Organization (WHO), osteoporosis is a systematic bone disability marked by reduced bone mass and microarchitectural degeneration of osseous cells, which leads to increased bones feebleness and fractures vulnerability. It is a polygenetic, physiological bone deformity that frequently leads to osteoporotic fractures and raises the risk of fractures in minimal trauma. Additionally, the molecular changes that cause osteoporosis are linked to decreased fracture repair and delayed bone regeneration. Bones have the ability to regenerate as part of the healing mechanism after an accident or trauma, including musculoskeletal growth and ongoing remodeling throughout adulthood. The principal treatment approaches for bone loss illnesses, such as osteoporosis, are hormone replacement therapy (HRT) and bisphosphonates. In this review, we searched literature regarding the Traditional Chinese medicines (TCM) in osteoporosis and bone regeneration. The literature results are summarized in this review for osteoporosis and bone regeneration. Traditional Chinese medicines (TCM) have grown in popularity as a result of its success in curing ailments while causing minimal adverse effects. Natural Chinese medicine has already been utilized to cure various types of orthopedic illnesses, notably osteoporosis, bone fractures and rheumatism with great success. TCM is a discipline of conventional remedy that encompasses herbal medication, massage (tui na), acupuncture, food, and exercise (qigong) therapy. It is based on more than 2,500 years of Chinese healthcare profession. This article serves as a comprehensive review summarizing the osteoporosis, bone regeneration and the traditional Chinese medicines used since ancient times for the management of osteoporosis and bone regeneration.

Pharmacological Mechanisms Underlying the Hepatoprotective Effects of Ecliptae herba on Hepatocellular Carcinoma

BACKGROUND

The number of hepatocellular carcinoma (HCC) cases worldwide has increased significantly. As a traditional Chinese medicine (TCM) with a long history, Ecliptae herba (EH) has been widely used in HCC patients in China, but its hepatoprotective mechanism is still unclear.

METHODS

In this study, we applied a network pharmacology-based strategy and experimental verification to systematically unravel the underlying mechanisms of EH against HCC. First, six active ingredients of EH were screened from the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP) by the ADME method. Subsequently, 52 potential targets of 6 active ingredients acting on HCC were screened from various databases, including TCMSP, DGIdb, SwissTargetPrediction, CTD, and GeneCards. Then, by constructing protein-protein interaction (PPI) network from STRING, we displayed the intricate connections among these 52 targets through Cytoscape software. We also applied enrichment analysis, including Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses, to provide an outline and set of concepts for describing gene functions and the advanced functions of biological systems of these 52 targets from genomic and molecular level information. Finally, molecular docking and biological experiments were used to reconfirm these results.

RESULTS

We hypothesized that EH might exert anti-HCC activity by acting on hub genes, including RELA, MMP9, PTGS2, ESR1, EGFR, AR, AKT1, HIF1A, AHR, CYP3A4, ABCG2, and MMP2. Moreover, based on GO and KEGG analysis, we speculated that EH may exert hepatoprotective effects on HCC through the following mechanisms: regulation of the PI3K-AKT signaling pathway to promote apoptosis and inhibit the abnormal proliferation of HCC, downregulation of HIF-1A expression by activating the HIF-1 signaling pathway, prevention of HCC by regulating lipid metabolism, and inhibition of nonalcoholic fatty liver disease (NAFLD) by the cytochrome P450 subfamily. Subsequent biological experiments verified that EH inhibits the PI3K-AKT signaling pathway through its active ingredients, quercetin, and wedelolactone, thereby inhibiting the proliferation of HCC cells and promoting the apoptosis of HCC cells.

CONCLUSIONS

The network pharmacological strategy provides an efficient method to systematically explore the pharmacological mechanism of EH in HCC. Our study demonstrated that the anti-HCC proliferation activity of EH is mainly exerted by two active ingredients (quercetin and wedelolactone), which inhibit the proliferation of HCC cells (HepG2 and Huh-7) by inhibiting PI3K-AKT signaling.

Bone anti-resorptive effects of coumarins on RANKL downstream cellular signaling: a systematic review of the literature

BACKGROUND

Members of the botanical families Apiaceae/Umbelliferae, Asteraceae, Fabaceae/Leguminosae, and Thymelaeaceae are rich in coumarins and have traditionally been used as ethnomedicines in many regions including Europe, Asia, and South America. Coumarins are a class of secondary metabolites that are widely present in plants, fungi, and bacteria and exhibit several pharmacological, biochemical, and therapeutic effects. Recently, many plants rich in coumarins and their derivatives were found to affect bone metabolism.

OBJECTIVE

To review scientific literature describing the mechanisms of action of coumarins in osteoclastogenesis and bone resorption.

MATERIALS AND METHODS

For this systematic review, the PubMed, Scopus, and Periodical Capes databases and portals were searched. We included in vitro research articles published between 2010 and 2020 that evaluated coumarins using osteoclastogenic markers.

RESULTS

Coumarins have been reported to downregulate RANKL-RANK signaling and various downstream signaling pathways required for osteoclast development, such as NF-κB, MAPK, Akt, and Ca²⁺ signaling, as well as pathways downstream of the nuclear factor of activated T-cells (NFATc1), including tartrate-resistant acid phosphatase (TRAP), cathepsin K (CTSK), and matrix metalloproteinase 9 (MMP-9).

CONCLUSIONS

Coumarins primarily inhibit osteoclast differentiation and activation by modulating different intracellular signaling pathways; therefore, they could serve as potential candidates for controlled randomized clinical trials aimed at improving human bone health.

Combined Extract of Leonurus japonicus Houtt, Eclipta prostrata L., and Pueraria lobata Ohwi Improved Hot Flashes and Depression in an Ovariectomized Rat Model of Menopause

Menopause leads to ovarian hormone loss, which causes symptoms such as weight gain, hot flashes, and depression. Exploring nutraceuticals is important for treating menopausal symptoms that extensively impact women's quality of life. We hypothesized that a combination of Leonurus japonicus Houtt, Eclipta prostrata L., and Pueraria lobata Ohwi (LEPE) would alleviate menopausal symptoms in an ovariectomized menopausal rat model. Bilateral ovariectomy was performed and animals were assigned to five groups: (1) Sham, (2) Vehicle, (-) Control, (3) LEPE (100 mg/kg bw), (4) LEPE (200 mg/kg bw), and (5) Estradiol (3 μg/kg bw). LEPE was orally administered daily for 12 weeks. LEPE supplementation did not affect growth performance (body weight and feed intake) or body composition (lean mass and fat in tissue). LEPE did not cause deviations in aspartate aminotransferase, alanine aminotransferase, estradiol, and follicle-stimulating hormone levels, indicating no hepatotoxicity or endocrine disturbance. LEPE decreased type I collagen (CTX-1) but did not affect bone mineral density or osteocalcin. LEPE decreased tail temperature and increased rectal temperature, improving menopause-related vasomotor symptoms. Furthermore, LEPE ameliorated depression-related behavior, including in forced swimming and tail suspension tests. Thus, LEPE may improve menopausal symptoms by enhancing vasomotor symptoms and depression in an ovariectomized rat menopause model.

A review on traditional uses, phytochemistry and pharmacology of Eclipta prostrata (L.) L

ETHNOPHARMACOLOGICAL RELEVANCE

Eclipta prostrata, a traditional herbal medicine, has long been used in Asia and South America for the therapy of hemorrhagic diseases (e.g. hemoptysis, hematemesis, hematuria, epistaxis and uterine bleeding), skin diseases, respiratory disorders, coronary heart disease, hair loss, vitiligo, snake bite and those caused by the deficiency of liver and kidney.

AIM OF THE REVIEW

In this review, we highlight relatively comprehensive and up-to-date information of E. prostrata on traditional uses, phytochemistry, pharmacology and toxicity, along with featuring the gaps in current knowledge, aiming to provide references for future research and possible opportunities for well applications of this medicinal plant.

MATERIALS AND METHODS

Information on E. prostrata was gathered from scientific databases (Google Scholar, Web of Science, Scifinder, Baidu Scholar, PubMed and CNKI). Information was also obtained from local books, Ph.D. theses and M.Sc. dissertations and Chinese Pharmacopoeia. The plant taxonomy was validated by the database "The Plant List".

RESULTS

Various phytochemical classes has been identified and isolated from the plant covering triterpenes, flavonoids, thiopenes, coumestans, steroids and others. Among these, coumestans are reported as the most common ingredients. The isolated crude extracts and individual compounds have been reported to exhibit promising pharmacological properties, such as hepatoprotective, osteoprotective, cytotoxic, hypoglycaemic, anti-inflammatory, anti-microbial, hypolipidemic, promoting hair growth, rejuvenative and neuroprotective effects.

CONCLUSIONS

Until now, significant progress has been witnessed in phytochemistry and pharmacology of E. prostrata. Thus, some traditional uses has been well supported and clarified by modern pharmacological studies. Moreover, E. prostrata also showed therapeutic potential in some refractory diseases such as cancer, dementia and diabetes. But, present findings are still insufficient that cannot satisfactorily explain some mechanisms of action. More well-designed studies in vitro especially in vivo are required to establish links between the traditional uses and bioactivities, discover new skeletons and activity molecules, as well as ensure safety before clinical use.

The protective effect of Er-Xian decoction against myocardial injury in menopausal rat model

Background

Er-Xian decoction (EXD), a formula of Chinese medicine, is often used to treat menopausal syndrome in China. The aim of the present study was to explore the potential cardioprotective mechanism of EXD against myocardial injury in an ovariectomy-induced menopausal rat model.

Methods

We divided the female Wistar rats into ovariectomy group and sham operation group (SHAM group). The ovariectomized (OVX) rats received treatment of vehicle (OVX group), EXD (EXD group) or 17β-estradiol (E2 group). After 12-week of treatment, the level of estradiol in serum was detected using an electrochemiluminescence immunoassay, and electrophysiologic changes in myocardial action potentials (AP) were evaluated using intracellular microelectrode technique. Changes in the histopathology of the left ventricle and the ultrastructure of the cardiomyocytes were observed by hematoxylin and eosin (HE) staining and transmission electronmicroscopy to assess myocardial injury. Microarrays were applied for the evaluation of gene expression profiles in ventricular muscle of the OVX and EXD rats. Further pathway analyses of the differential expression genes were carried out using the Kyoto Encyclopedia of Genes and Genomes (KEGG). And real-time quantitative RT-PCR (qRT-PCR) was used for verification of the key findings.

Results

The results from electrophysiological and histomorphological observations demonstrated that EXD had a substantial myocardial protective effect. The EXD-treated rats, in comparison with the OVX rats, demonstrated up-regulated expression of 28 genes yet down-regulated expression of 157 genes in the ventricular muscle. The qRT-PCR assay validated all selected differential expression genes. The KEGG pathway analysis showed that the down-regulated genes were relevant to cardiomyopathy and myocardial contractility. EXD could decrease the mRNA expressions of cardiac myosin (Myh7, Myl2) and integrin (Itgb5) in the ventricular myocardium.

Conclusion

EXD had a protective effect against myocardial injury in OVX rats, and this cardioprotective effect may be associated with modulation of the expression of cardiac myosin or integrin at the mRNA level.

Electronic supplementary material

The online version of this article (10.1186/s12906-018-2311-9) contains supplementary material, which is available to authorized users.

Wedelolactone Enhances Osteoblastogenesis through ERK- and JNK-mediated BMP2 Expression and Smad/1/5/8 Phosphorylation

Our previous study showed that wedelolactone, a compound isolated from Ecliptae herba, has the potential to enhance osteoblastogenesis. However, the molecular mechanisms by which wedelolactone promoted osteoblastogenesis from bone marrow mesenchymal stem cells (BMSCs) remain largely unknown. In this study, treatment with wedelolactone (2 μg/mL) for 3, 6, and 9 days resulted in an increase in phosphorylation of extracellular signal-regulated kinases (ERKs), c-Jun N-terminal protein kinase (JNK), and p38. Phosphorylation of mitogen-activated protein kinases (MAPKs), ERK and JNK started to increase on day 3 of treatment, and p38 phosphorylation was increased by day 6 of treatment. Expression of bone morphogenetic protein (BMP2) mRNA and phosphorylation of Smad1/5/8 was enhanced after treatment of cells with wedelolactone for 6 and 9 days. The addition of the JNK inhibitor SP600125, ERK inhibitor PD98059, and p38 inhibitor SB203580 suppressed wedelolactone-induced alkaline-phosphatase activity, bone mineralization, and osteoblastogenesis-related marker genes including Runx2, Bglap, and Sp7. Increased expression of BMP2 mRNA and Smad1/5/8 phosphorylation was blocked by SP600125 and PD98059, but not by SB203580. These results suggested that wedelolactone enhanced osteoblastogenesis through induction of JNK- and ERK-mediated BMP2 expression and Smad1/5/8 phosphorylation.

New insights into the tonifying kidney-yin herbs and formulas for the treatment of osteoporosis

Osteoporosis is characterized by an increasing osseous fragility and fracture resulting from the low mass and deteriorated microarchitecture in the bone tissue. The hormone replacement therapy and alendronate were frequently used to treat osteoporosis as the primary therapeutic strategy, but their adverse effects have severely limited their extensive clinical application, therefore, it is urgent to develop alternative or complementary therapeutic agents for anti-osteoporosis. Interestingly, with more people focusing on the complementary and alternative medicine, traditional Chinese herbs and formulas are being gradually recognized as safe and effective agents in the treatment of osteoporosis. In particular, a notable trend is that increasing studies are making efforts to clarify the anti-osteoporotic effects and mechanism of the tonifying kidney-yin herbs and formulas, a category of agents identified as effective therapy. Therefore, the purpose of this study is to comprehensively review the tonifying kidney-yin herbs and formulas that have been reported in the treatment of osteoporosis as well as how the agents play their roles in detail. This current study not only will advance our understanding of the actions of tonifying kidney-yin herbs and formulas, but also provide new evidence for the clinic use of the tonifying kidney-yin herbs and formulas in the treatment of osteoporosis.

Effect of Curcumin on the Diversity of Gut Microbiota in Ovariectomized Rats

Curcumin has been proven to have a weight-loss effect in a menopausal rat model induced by ovariectomy. However, the effects of curcumin on gut microfloral communities of ovariectomized (OVX) rats remains unclear. Here, we used high-throughput 16S rDNA sequencing to explore the effects of curcumin on microbial diversity in the gut of OVX rats. Female Wistar rats were subjected to either ovariectomy or a sham operation (SHAM group). The OVX rats were treated with vehicle (OVX group) or curcumin (CUR group) by oral gavage. After 12-week treatments, the weights of the bodies and uteri of rats were recorded, the levels of estradiol in the serum were assayed by electrochemiluminescence immunoassay (ECLIA). Then, the fragments encompassing V3–V4 16S rDNA hypervariable regions were PCR amplified from fecal samples, and the PCR products of V3–V4 were sequenced on an Illumina MiSeq for characterization of the gut microbiota. Our results showed that, compared to rats in the SHAM group, rats in the OVX group had more weight gain and lower levels of estradiol in the serum, and curcumin could cause significant weight loss in OVX rats but did not increase the levels of estradiol. Sequencing results revealed the presence of 1120, 1114, and 1119 operational taxonomic units (OTUs) found in the SHAM, OVX, and CUR groups, respectively. The percentage of shared OTUs was 86.1603%. Gut microbiota of rats from the SHAM or CUR group had higher levels of biodiversity and unevenness estimations than those from the OVX group. At the phyla level, compared to rats in SHAM group, rats in the OVX group had a higher ratio of phyla Firmicutes and Bacteroidetes in the gut; at the genus level, four differential gut microbiota (Incertae_Sedis, Anaerovorax, Anaerotruncus, and Helicobacter) between SHAM and OVX groups were found, whereas seven differential gut microbiota (Serratia, Anaerotruncus, Shewanella, Pseudomonas, Papillibacter, Exiguobacterium, and Helicobacter) between OVX and CUR groups were found. In conclusion, estrogen deficiency induced by ovariectomy caused changes in the distribution and structure of intestinal microflora in rats, and curcumin could partially reverse changes in the diversity of gut microbiota.

Effects of aqueous extracts of Ecliptae herba, Polygoni multiflori radix praeparata and Rehmanniae radix praeparata on melanogenesis and the migration of human melanocytes

ETHNOPHARMACOLOGICAL RELEVANCE

Polygoni multiflori radix praeparata (PMRP), Ecliptae herba (EH) and Rehmanniae radix praeparata (RRP) are the most frequently-used herbs by Traditional Chinese Medicine practitioners for the treatment of vitiligo. Their abilities to stimulate melanogenesis, melanocyte migration and MITF (microphthalmia associated transcription factor) protein expression were evaluated in this study.

MATERIALS AND METHODS

The effects of aqueous extracts of PMRP, EH and RRP on human melanocytes in vitro were examined by MTT assay, tyrosinase activity, melanin synthesis, migration assay and Western blot.

RESULTS

Treatment with EH (at 100μg/ml and 400μg/ml) significantly increased intracellular tyrosinase activity in accordance with the elevation of melanin content at the same concentrations. Treatment with RRP (at 100μg/ml and 400μg/ml) promoted melanin production but had no stimulatory effect on tyrosinase activity. Treatment with PMRP and EH (at 100μg/ml) promoted the migration of human melanocytes in a type IV collagen-coated transwell migration assay. Western blot analysis showed MITF protein expression was elevated by PMRP, EH and RRP (at 100μg/ml).

CONCLUSION

An aqueous extract of EH has a synergistic effect on melanocytes by up-regulating tyrosinase activity, enhancing melanin synthesis and promoting melanocyte migration as well as elevating MITF protein expression. RRP exhibits a significant stimulating effect on melanogenesis and MITF protein expression. These results suggest that EH and RRP contain substances with direct enhancing effects on melanogenesis and migration, possibly via their effects on MITF protein expression.

Wedelolactone Enhances Osteoblastogenesis but Inhibits Osteoclastogenesis through Sema3A/NRP1/PlexinA1 Pathway

Bone remodeling balance is maintained by tight coupling of osteoblast-mediated bone formation and osteoclast-mediated bone resorption. Thus, agents with the capacity to regulate osteoblastogenesis and osteoclastogenesis have been investigated for therapy of bone-related diseases such as osteoporosis. In this study, we found that wedelolactone, a compound isolated from Ecliptae herba, and a 9-day incubation fraction of conditioned media obtained from wedelolactone-treated bone marrow mesenchymal stem cell (BMSC) significantly inhibited tartrate-resistant acid phosphatase (TRAP) activity in RANKL-stimulated osteoclastic RAW264.7 cells. Addition of the semaphorin 3A (Sema3A) antibody to the conditioned media partially blocked the medium’s inhibitory effects on the RAW264.7 cells. In BMSC, mRNA expression of Sema3A increased in the presence of different wedelolactone concentrations. Blocking Sema3A activity with its antibody reversed wedelolactone-induced alkaline phosphatase activity in BMSC and concurrently enhanced wedelolactone-reduced TRAP activity in osteoclastic RAW264.7 cells. Moreover, in BMSC, wedelolactone enhanced binding of Sema3A with cell-surface receptors, including neuropilin (NRP)1 and plexinA1. Furthermore, nuclear accumulation of β-catenin, a transcription factor acting downstream of wedelolactone-induced Sema3A signaling, was blocked by the Sema3A antibody. In osteoclastic RAW264.7 cells, conditioned media and wedelolactone promoted the formation of plexin A1-NRP1, but conditioned media also caused the sequestration of the plexin A1-DNAX-activating protein 12 (DAP12) complex and suppressed the phosphorylation of phospholipase C (PLC)γ2. These data suggest that wedelolactone promoted osteoblastogenesis through production of Sema3A, thus inducing the formation of a Sema3A-plexinA1-Nrp1 complex and β-catenin activation. In osteoclastic RAW264.7 cells, wedelolactone inhibited osteoclastogenesis through sequestration of the plexinA1-DAP12 complex, induced the formation of plexinA1-Nrp1 complex, and suppressed PLCγ2 activation.

Wedelolactone enhances osteoblastogenesis by regulating Wnt/β-catenin signaling pathway but suppresses osteoclastogenesis by NF-κB/c-fos/NFATc1 pathway

Bone homeostasis is maintained by formation and destruction of bone, which are two processes tightly coupled and controlled. Targeting both stimulation on bone formation and suppression on bone resorption becomes a promising strategy for treating osteoporosis. In this study, we examined the effect of wedelolactone, a natural product from Ecliptae herba, on osteoblastogenesis as well as osteoclastogenesis. In mouse bone marrow mesenchymal stem cells (BMSC), wedelolactone stimulated osteoblast differentiation and bone mineralization. At the molecular level, wedelolactone directly inhibited GSK3β activity and enhanced the phosphorylation of GSK3β, thereafter stimulated the nuclear translocation of β-catenin and runx2. The expression of osteoblastogenesis-related marker gene including osteorix, osteocalcin and runx2 increased. At the same concentration range, wedelolactone inhibited RANKL-induced preosteoclastic RAW264.7 actin-ring formation and bone resorption pits. Further, wedelolactone blocked NF-kB/p65 phosphorylation and abrogated the NFATc1 nuclear translocation. As a result, osteoclastogenesis-related marker gene expression decreased, including c-src, c-fos, and cathepsin K. In ovariectomized mice, administration of wedelolactone prevented ovariectomy-induced bone loss by enhancing osteoblast activity and inhibiting osteoclast activity. Together, these data demonstrated that wedelolactone facilitated osteoblastogenesis through Wnt/GSK3β/β-catenin signaling pathway and suppressed RANKL-induced osteoclastogenesis through NF-κB/c-fos/NFATc1 pathway. These results suggested that wedelolacone could be a novel dual functional therapeutic agent for osteoporosis.

Natural Products from Chinese Medicines with Potential Benefits to Bone Health

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

Inhibitory effect of Ecliptae herba extract and its component wedelolactone on pre-osteoclastic proliferation and differentiation

ETHNOPHARMACOLOGICAL RELEVANCE

Ecliptae herba, also known as "Mo-Han-Lian", has long been used in China to nourish Kidney and thereafter strengthen bones. Accumulating evidence indicates that extracts of Ecliptae herba have antiosteoporotic effect. However, the effective compounds and cellular mode of action are still unclear. To investigate the effect of ethyl acetate extract of Ecliptae herba (EAE) and its component wedelolactone on proliferation and differentiation of preosteoclastic RAW264.7 cells as well as proliferation of bone marrow stromal cells (BMSC).

MATERIALS AND METHODS

RAW264.7 and BMSC were examined for proliferation by a 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) method. Tartrate-resistant acid phosphatase (TRAP) activity of RAW264.7 was measured by using p-nitrophenyl sodium phosphate (pNPP) assay after the cells were treated with 30ng/ml receptor activator for nuclear factor-κ B ligand (RANKL) plus various concentrations of EAE, wedelolactone or alendronate. The formation of multinucleated TRAP-positive RAW264.7 cells was observed by using a TRAP-staining kit.

RESULTS

Treatment of RAW264.7 cells with EAE at high doses (20µg/ml and 40µg/ml) or wedelolactone at 10µg/ml resulted in a decrease in proliferation of RAW264.7 cells. Low doses of EAE (5, 10µg/ml) and wedelolactone (2.5µg/ml) inhibited RANKL-induced TRAP activity by 20.3%, 37.9%, and 48.3%. The inhibitory effect of wedelolactone is more potent than that of alendronate, an anti-resorptive drug. Morphological changes revealed that 5µg/ml EAE and 2.5µg/ml wedelolactone reduced the number of multinucleated osteoclast-like cells. At the high doses, EAE (20µg/ml) and wedelolactone (10µg/ml) inhibited the growth of BMSC.

CONCLUSIONS

EAE and its component wedelolactone inhibited osteoclast RAW264.7 proliferation and differentiation at the low doses, but at the high doses, showed cytotoxic effect on BMSC. These results indicated that EAE and wedelolatone might be potential alternative therapy for osteoporosis.