Discovery of a Potent Antiosteoporotic Drug Molecular Scaffold Derived from Angelica sinensis and Its Bioinspired Total Synthesis.

Angelica sinensis, commonly known as Dong Quai in Europe and America and as Dang-gui in China, is a medicinal plant widely utilized for the prevention and treatment of osteoporosis. In this study, we report the discovery of a new category of phthalide from Angelica sinensis, namely falcarinphthalides A and B (1 and 2), which contains two fragments, (3R,8S)-falcarindiol (3) and (Z)-ligustilide (4). Falcarinphthalides A and B (1 and 2) represent two unprecedented carbon skeletons of phthalide in natural products, and their antiosteoporotic activities were evaluated. The structures of 1 and 2, including their absolute configurations, were established using extensive analysis of NMR spectra, chemical derivatization, and ECD/VCD calculations. Based on LC-HR-ESI-MS analysis and DFT calculations, a production mechanism for 1 and 2 involving enzyme-catalyzed Diels-Alder/retro-Diels-Alder reactions was proposed. Falcarinphthalide A (1), the most promising lead compound, exhibits potent in vitro antiosteoporotic activity by inhibiting NF-κB and c-Fos signaling-mediated osteoclastogenesis. Moreover, the bioinspired gram-scale total synthesis of 1, guided by intensive DFT study, has paved the way for further biological investigation. The discovery and gram-scale total synthesis of falcarinphthalide A (1) provide a compelling lead compound and a novel molecular scaffold for treating osteoporosis and other metabolic bone diseases.

Genistein Modified with 8-Prenyl Group Suppresses Osteoclast Activity Directly via Its Prototype but Not Metabolite by Gut Microbiota.

Postmenopausal osteoporosis is a significant threat to human health globally. Genistein, a soy-derived isoflavone, is regarded as a promising anti-osteoporosis drug with the effects of promoting osteoblastogenesis and suppressing osteoclastogenesis. However, its oral bioavailability (6.8%) is limited by water solubility, intestinal permeability, and biotransformation. Fortunately, 8-prenelylated genistein (8PG), a derivative of genistein found in Erythrina Variegate, presented excellent predicted oral bioavailability (51.64%) with an improved osteoblastogenesis effect, although its effects on osteoclastogenesis and intestinal biotransformation were still unclear. In this study, an in vitro microbial transformation platform and UPLC-QTOF/MS analysis method were developed to explore the functional metabolites of 8PG. RANKL-induced RAW264.7 cells were utilized to evaluate the effects of 8PG on osteoclastogenesis. Our results showed that genistein was transformed into dihydrogenistein and 5-hydroxy equol, while 8PG metabolites were undetectable under the same conditions. The 8PG (10-6 M) was more potent in inhibiting osteoclastogenesis than genistein (10-5 M) and it down-regulated NFATC1, cSRC, MMP-9 and Cathepsin K. It was concluded that 8-prenyl plays an important role in influencing the osteoclast activity and intestinal biotransformation of 8PG, which provides evidence supporting the further development of 8PG as a good anti-osteoporosis agent.

Eight new phenolic acids from the leaves of Illicium dunnianum and their osteoprotective activities.

Eight previously unreported phenolic acids (1-8), including three new phenylpropenoid glycosides (1-3), and five undescribed shikimic acid derivatives (4-8), together with six known analogues (9-14), were obtained from the dried leaves of Illicium dunnianum. The structures of these new compounds were elucidated by extensive spectroscopic analyses (1D, 2D-NMR, HRESIMS, IR, UV) and chemical methods. Compounds 1, 2, 4, and 5 were tested for their promotion effect on osteoblastogenesis of pre-osteoblastic MC3T3-E1 cells and inhibitory effect on osteoclastogenesis of RANKL-induced RAW264.7 cells. As a result, 1 and 4 exerted a promotion effect on osteoblastogenesis, but without activity on osteoclastogenesis. Our studies not only enrich the structural diversity of phenolic acids in nature, but also discover new lead compounds from folk plants with activities on osteoblastogenesis or osteoclastogenesis.

A new strategy for discovering effective substances and mechanisms of traditional Chinese medicine based on standardized drug containing plasma and the absorbed ingredients composition, a case study of Xian-Ling-Gu-Bao capsules.

ETHNOPHARMACOLOGICAL RELEVANCE: The overall therapeutic effect of traditional Chinese medicine formulae (TCMF) was achieved by the interactions of multiple components with multiple targets. However, current pharmacology research strategies have struggled to identify effective substance groups and encountered challenges in elucidating the underlying mechanisms of TCMF. AIM: In this study, a comprehensive strategy was proposed and applied to elucidate the interactions of the multiple components that underlie the functions of the famous TCMF: Xian-Ling-Gu-Bao (XLGB) capsule on bone metabolism in vivo and to elucidate the molecular mechanisms underlying the effects of XLGB on bone cells, especially on osteoblasts. METHODS: The efficacy of XLGB in the protection against bones loss in ovariectomized (OVX) rats was confirmed by Micro-CT analysis. The anti-osteoporosis mechanism involved in the systemic regulatory actions of XLGB was elucidated by transcriptome sequencing analysis on bone marrow mesenchymal stem cells isolated from OVX rats. Moreover, the components absorbed in XLGB-treated plasma were characterized by mass spectrometry analysis, and subsequently, a standardized preparation process of drug-containing plasma was established. The synergistic osteogenic effect of the multiple components in plasma was investigated by a combination and then knockout of components using pre-osteoblast MC3T3-E1 cells. In order to decipher the underlying mechanism of XLGB, the targets of the absorbed components on bone were predicted by target prediction and network pharmacology analysis, then several interactions were validated by biochemical and cell-based assay. RESULTS: A total of 18 genes, including HDC, CXCL1/2, TNF, IL6 and Il1b, were newly found to be the major target genes regulated by XLGB. Interestingly, we found that a combination of the three absorbed components, i.e. MSP, rather than their single form at the same concentration, stimulated the formation of calcified nodules in MC3T3-E1 cells, suggesting a synergistic effect of these components. Besides, target prediction and experimental validation confirmed the binding affinity of corylin and icaritin for estrogen receptor α and ß, the inhibitory activity of isobavachin and isobavachalcone on glycogen synthase kinase-3ß, and the inhibitory activity of isobavachalcone on cathepsin K. The cell-based assay further confirmed the result of the biochemical assay. A network that integrated absorbed components of XLGB-targets-perturbation genes-pathways against osteoporosis was established. CONCLUSION: Our current study provides a new systemic strategy for discovering active ingredient groups of TCM formulae and understanding their underlying mechanisms.

A novel strategy for exploring food originated anti-adipogenesis substances and mechanism by structural similarity evaluation, ADME prediction, network pharmacology and experimental validation.

Screening potential functional substances based on active compounds is still a challenge faced by researchers since hundreds and thousands of possible compounds exist in natural products (food, herb, etc.). In this study, an integrated strategy by a combination of structural similarity evaluation, ADME (absorption, distribution, metabolism, excretion) prediction, network pharmacology and experimental validation (SANE strategy) was proposed and applied to explore anti-adipogenesis substances. This strategy was divided into four parts: first, potential compounds were screened based on representative active compounds by similarity evaluation and ADME prediction. Second, the activity of targeted compounds was evaluated in vitro based on the molecular biology method. Third, network pharmacology was used to explore potential targets and pathways. Last, the core pharmacological mechanism was confirmed by modern pharmacology methods. As a result, 8-prenylgenistein (8PG) was screened with chemical structure similarity with genistein and improved ADME propriety. Meanwhile, 8PG was found to present significant anti-adipogenesis effects in pre-adipocyte 3T3-L1 cells and primary human bone marrow stromal cells (hBMSC). Through using methods including: chemical staining, functional assays, and Real time PCR, 8PG was found to present more potency than genistein in suppressing the adipocyte differentiation. Further, the potential pharmacological mechanism was predicted, and significant effects of 8PG on activating the Wnt/ß-catenin pathway in 3T3-L1 cells and hBMSC were confirmed by  immunoblotting in the absence/presence of signaling pathway blocker and immunofluorescence staining. A new insight for exploring more potent compounds based on accurate effect compounds is provided in our work. Moreover, a potential compound (8PG), suppressing adipogenesis, was also supplied.

Dissection of the potential pharmacological function of neohesperidin dihydrochalcone - a food additive - by in vivo substances profiling and network pharmacology.

Food additives are widely used in our daily life, and the side-effects caused by them have gained extensive attention around the world. Notably, constituent-oriented metabolites, in some sense, always contribute to pharmacological changes, inducing toxicity, therapeutic effects, etc. Characterization of the metabolites and their potential functions is of great importance to the practical applications. In this work, an integrated strategy by combining metabolite profiling and network pharmacology was applied to characterize the metabolic features and reveal pharmacological changes of neohesperidin dihydrochalcone (NHDC) in vivo to demonstrate its pharmacological mechanism and potential functions. As a result, a total of 19 metabolites (3 in plasma, 19 in urine, 8 in feces, 3 in heart, 5 in liver, 0 in spleen, 1 in lung, 2 in kidneys and 2 in brain) were screened and 18 of them were characterized for the first time. Phase I metabolic reactions of hydrolysis and phase II reactions of glucuronidation, sulfation, glutamylation, N-butyryl glycylation and lactylation were the main metabolic reactions of NHDC in vivo. Moreover, the results analyzed by network pharmacology revealed that, in addition to common pathways (steroid hormone biosynthesis) of NHDC, metabolites' targets were involved in pathways in cancer, ovarian steroidogenesis, proteoglycans in cancer, PI3K-Akt signaling pathway and progesterone-mediated oocyte maturation, indicating that these functional changes might result in potential novel functions or other side-effects, such as a disorder of steroid hormones. Our work provided the metabolic features and functional modifications of NHDC in vivo for the first time, and meaningful information for further pharmacological validations or potential functions is supplied.

8-prenylgenistein exerts osteogenic effects via ER α and Wnt-dependent signaling pathway.

8-prenylgenistein (8PG) was previously reported to exert stronger osteogenic activity than genistein, a well-known soy phytoestrogen. However, the molecular mechanism underlying the actions of 8PG on osteoblasts was far from clear. In the present study, the osteogenic effects and mechanisms of 8PG and genistein were studied using human BMSC and murine pre-osteoblast MC3T3-E1 cells. Our results indicated that the stimulatory effects of 8PG and genistein on osteoblast differentiation were abolished by co-incubation with MPP (10-6 M, an ERα antagonist), but not PHTPP (10-6 M, an ERß antagonist). Molecular docking indicated that the binding mode of 8PG toward ERα was similar to that of genistein and therefore could not account for their differential osteogenic actions. In silico target profiling identified the involvement of glycogen synthase kinase-3ß (GSK-3ß), a key mediator of Wnt/ß-catenin pathway, in the actions of 8PG. However, instead of directly inhibiting GSK-3ß enzymatic activities, 8PG and genistein were found to induce GSK-3ß phosphorylation at Serine-9 in osteoblastic MC3T3-E1 cells. 8PG exerted more potent effects than genistein in stimulating expressions of LRP5, ß-catenin, Runx2, osteocalcin, alp, opg, major protein and gene markers involved in Wnt signaling pathway in MC3T3-E1 cells. Moreover, the inhibition of Wnt signaling by DKK1 could be restored by treatment with 8PG and genistein. However, 8PG, but not genistein, stimulated ERα-dependent ß-catenin protein expression in MC3T3-E1 cells. Furthermore, the increase in ALP activity, LRP5 and phospho-Akt/Akt expression by 8PG and genistein were abolished by co-treatment with LY294002 (10-5 M, a PI3K pathway inhibitor). Collectively, our results suggested that the osteogenic activities of 8PG was mediated by GSK-3ß phosphorylation through the induction of Wnt/ß-catenin and ERα-associated PI3K/Akt signaling.

Icariin, but Not Genistein, Exerts Osteogenic and Anti-apoptotic Effects in Osteoblastic Cells by Selective Activation of Non-genomic ERα Signaling.

Genistein and icariin are flavonoid compounds that exhibit estrogen-like properties in inducing bone formation and reducing bone loss associated with estrogen deficiency in both preclinical and clinical studies. However, the mechanisms that are involved in mediating their estrogenic actions in bone cells are far from clear. The present study aimed to study the signaling pathways that mediate the estrogenic actions of genistein and icariin in osteoblastic cells. The effects of genistein and icariin on the activation of estrogen receptor (ER) and the downstream mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway in murine osteoblastic MC3T3-E1 cells and rat osteoblastic UMR-106 cells were studied. As expected, genistein displayed higher binding affinity toward ERß than ERα and significantly induced estrogen response element (ERE)-dependent transcription in UMR-106 cells in a dose-dependent manner. In contrast, icariin failed to bind to ERα or ERß and did not induce ERE-dependent transcription in UMR-106 cells at 10-10 to 10-7 M. The effects of genistein (10 nM) and icariin (0.1 µM) on cell proliferation and differentiation in osteoblastic UMR-106 cells were abolished in the presence of ER antagonist ICI 182,780 (1 µM), MAPK inhibitor U0126 (10 µM), and PI3K inhibitor LY294002 (10 µM). Genistein at 10 nM rapidly induced ERK1/2 phosphorylation at 5-10 min in UMR-106 cells and the phosphorylation of ERα at both Ser118 and Ser167 in both MC3T3-E1 and transfected UMR-106 cells whereas icariin at 0.1 µM rapidly activated both ERK1/2 and Akt phosphorylation in UMR-106 cells and subsequent ERα phosphorylation at both Ser118 and Ser167 in MC3T3-E1 and transfected UMR-106 cells. Confocal imaging studies confirmed that the phosphorylation of ERα at Ser 118 and Ser 167 by genistein and icariin in MC3T3-E1 cells was mediated via MAPK- and PI3K-dependent pathway, respectively. Furthermore, our studies showed that icariin exerted stronger anti-apoptotic effects than genistein and 17ß-estradiol (E2) and inhibited the cleavage of downstream caspase-3 in MC3T3-E1 cells induced by a potent PI3K inhibitor, PI828 (at 2 µM). These results indicated that the mechanisms that mediate the estrogenic actions of icariin in osteoblastic cells are different from those of genistein.

8-Prenylgenistein, a prenylated genistein derivative, exerted tissue selective osteoprotective effects in ovariectomized mice.

Our previous study reported that the in vitro osteogenic effects of 8-prenylgenistein (8PG) were more potent than its parent compound genistein. This study aimed to evaluate the osteoprotective effects of 8PG in ovariectomized (OVX) mice as well as to characterize its estrogenic effects in uterus. Mature OVX mice were treated with phytoestrogen-free diet containing 8PG or genistein. Trabecular bone mass and most of the micro-structural parameters were ameliorated at the distal femoral metaphysis in OVX mice upon treatment with genistein and both doses of 8PG. The beneficial effects of 8PG on trabecular bone were confirmed by safranin O and ABHO staining. 8PG markedly inhibited the ovariectomy-induced mRNA expressions of RANKL/OPG, ALP, COL, OCN, cathepsin K and ER-α in bone. In contrast, genistein further increased the ovariectomy-induced ER-α expression in bone. The uterus index was increased in genistein-treated group. Genistein up-regulated the expression of ER-α and PR, while 8PG significantly down-regulated the ER-α and C3 expression in uterus of OVX mice. Moreover, genistein, but not 8PG, increased expressions of ER-α, PCNA and C3 in Ishikawa cell. This study suggested that 8PG improved trabecular bone properties in OVX mice without exerting uterotrophic effects and its estrogenic actions were distinct from those of genistein.

New secoiridoids from the fruits of Ligustrum lucidum.

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

Discovery of a New Class of Cathepsin K Inhibitors in Rhizoma Drynariae as Potential Candidates for the Treatment of Osteoporosis.

Rhizoma Drynariae (RD), as one of the most common clinically used folk medicines, has been reported to exert potent anti-osteoporotic activity. The bioactive ingredients and mechanisms that account for its bone protective effects are under active investigation. Here we adopt a novel in silico target fishing method to reveal the target profile of RD. Cathepsin K (Ctsk) is one of the cysteine proteases that is over-expressed in osteoclasts and accounts for the increase in bone resorption in metabolic bone disorders such as postmenopausal osteoporosis. It has been the focus of target based drug discovery in recent years. We have identified two components in RD, Kushennol F and Sophoraflavanone G, that can potentially interact with Ctsk. Biological studies were performed to verify the effects of these compounds on Ctsk and its related bone resorption process, which include the use of in vitro fluorescence-based Ctsk enzyme assay, bone resorption pit formation assay, as well as Receptor Activator of Nuclear factor κB (NF-κB) ligand (RANKL)-induced osteoclastogenesis using murine RAW264.7 cells. Finally, the binding mode and stability of these two compounds that interact with Ctsk were determined by molecular docking and dynamics methods. The results showed that the in silico target fishing method could successfully identify two components from RD that show inhibitory effects on the bone resorption process related to protease Ctsk.

Isolation and identification of metabolites of bakuchiol in rats.

Bakuchiol, the main active component of Psoralea corylifolia, showed a range of significant pharmacological activities, including antimicrobial, antiinflammatory, reduction of bone loss and estrogenic activities. In this research, 12 metabolites, including 11 new compounds, were isolated from the urine and feces of rats after oral administration of bakuchiol, and their structures were elucidated by extensive spectroscopic analysis. The possible metabolic pathways of bakuchiol in rats were proposed, and a rare bile acid conjugation reaction was found. In addition, bakuchiol and its metabolites M1-M3 were studied for their alkaline phosphatase (ALP) activities on MC3T3-E1 cells and cytotoxicity on HKC-8 cells. The data showed that bakuchiol exerted significant effects on ALP activity of MC3T3-E1 cells and cytotoxicity on HKC-8 cells, while M1-M3 only showed ALP activities at 10(-5)M on MC3T3-E1 cells and no cytotoxicity on HKC-8 cells.