Eurycomanone stimulates bone mineralization in zebrafish larvae and promotes osteogenic differentiation of mesenchymal stem cells by upregulating AKT/GSK-3ß/ß-catenin signaling.

Background: Eurycomanone (EN) is a diterpenoid compound isolated from the roots of Eurycoma longifolia (E. longifolia). Previous studies have confirmed that E. longifolia can enhance bone regeneration and bone strength. We previously isolated and identified ten quassinoids from E. longifolia, and the result displayed that five aqueous extracts have the effects on promotion of bone formation, among whom EN showed the strongest activity. However, the molecular mechanism of EN on bone formation was unknown, and we further investigated in this study. Methods: After the verification of purity of extracted EN, following experiments were conducted. Firstly, the pharmacologic action of EN on normal bone mineralization and the therapeutic effect of EN on Dex-induced bone loss using zebrafish larvae. The mineralization area and integral optical density (IOD) were evaluated using alizarin red staining. Then the vital signaling pathways of EN relevant to OP was identified through network pharmacology analysis. Eventually in vitro, the effect of EN on cell viability, osteogenesis activities were investigated in human bone marrow mesenchymal stem cells (hMSCs) and C3H10 cells, and the molecular mechanisms by which applying AKT inhibitor A-443654 in hMSCs. Results: In zebrafish larvae, the administration in medium of EN (0.2, 1, and 5 µM) dramatically enhanced the skull mineralization area and integral optical density (IOD), and increased mRNA expressions of osteoblast formation genes (ALP, RUNX2a, SP7, OCN). Meanwhile, exposure of EN remarkably alleviated the inhibition of bone formation induced by dexamethasone (Dex), prominently improved the mineralization, up-regulated osteoblast-specific genes and down-regulated osteoclast-related genes (CTSK, RANKL, NFATc1, TRAF6) in Dex-treated bone loss zebrafish larvae. Network pharmacology outcomes showed the MAPK and PI3K-AKT signaling pathways are closely associated with 10 hub genes (especially AKT1), and AKT/GSK-3ß/ß-catenin was selected as the candidate analysis pathway. In hMSCs and C3H10 cells, results showed that EN at appropriate concentrations of 0.008-5 µM effectively increased the cell proliferation. In addition, EN (0.04, 0.2, and 1 µM) significantly stimulated osteogenic differentiation and mineralization as well as significantly increased the protein phosphorylation of AKT and GSK-3ß, and expression of ß-catenin, evidencing by the results of ALP and ARS staining, qPCR and western blotting. Whereas opposite results were presented in hMSCs when treated with AKT inhibitor A-443654, which effectively inhibited the pro-osteogenesis effect induced by EN, suggesting EN represent powerful potential in promoting osteogenesis of hMSCs, which may be closely related to the AKT/GSK-3ß/ß-catenin signaling pathway. Conclusions: Altogether, our findings indicate that EN possesses remarkable effect on bone formation via activating AKT/GSK-3ß/ß-catenin signaling pathway in most tested concentrations. The translational potential of this article: This study demonstrates EN is a new effective monomer in promoting bone formation, which may be a promising anabolic agent for osteoporosis (OP) treatment.

Cytotoxic rotenoid glycosides from the seeds of Amorpha fruticosa.

Four new rotenoid glycosides, namely amorphaside A-D (1-4), along with four known ones (5-8) were isolated from the seeds of Amorpha fruticosa. Their chemical structures and absolute configurations were elucidated by HRESIMS, NMR and CD spectra, as well as deduction from biosynthesis route. The sugar units were determined by acid hydrolysis, appropriate derivatization and HPLC analysis. The in vitro anti-proliferative activities of all compounds were evaluated against MCF-7 and HCT-116 cell lines. The results showed that compounds 1-3 had no effect on cell proliferation in the two cell lines even with the concentration of 50 µM, and compounds 4, 7 and 8 had selective cytotoxicity against MCF-7 with IC50 values of 3.90, 0.95 and 34.08 µM, respectively, while compounds 5 and 6 both showed significant cytotoxicity to the two cell lines with IC50 values less than 2.00 µM, even better than the positive control cisplatin. These preliminary results indicated that compounds 5 and 6 might be valuable to anticancer drug candidates.

Antidepressant-like effects of 3,6'-disinapoyl sucrose on hippocampal neuronal plasticity and neurotrophic signal pathway in chronically mild stressed rats.

Recent studies suggest that the behavioral effects of chronic antidepressant treatment are mediated by stimulation of hippocampal neuronal plasticity and neurogenesis. The present study was designed to examine the effects of 3,6'-disinapoyl sucrose (DISS), a bioactive component of Polygala tenuifolia Willd, on the expressions of four plasticity-associated genes: cell adhesion molecule L1 (CAM-L1), laminin, cAMP response element binding protein (CREB) and brain-derived neurotrophic factor (BDNF) in hippocampus, all of which are involved in neuronal plasticity and neurite outgrowth. We confirmed that chronic stress in rats caused a reduction in sensitivity to reward (sucrose consumption) and a decrease in mRNA levels of CAM-L1, laminin, and BDNF, together with a decrease in protein levels of phosphorylated CREB and BDNF. Repeated administration of DISS for 21 days at doses of 5, 10 and 20mg/kg reversed stress-induced alterations in sucrose consumption and these target mRNA and protein levels. In conclusion, increased expressions in the hippocampus of three noradrenergic-regulated plasticity genes and one neurotrophic factor may be one of the molecular and cellular mechanisms underlying the antidepressant action of DISS in chronic mild stress (CMS) rats.

[Effects of cembrane-type diterpenes on proliferation of PC12 cells and their antagonistic effects on neurotoxicity induced by glutamate].

OBJECTIVE: To investigate the effects of cembrane-type diterpenes extracted from Sinularia flexibilis on the proliferation of PC12 cells and their protective effects on PC12 cells exposed to glutamate. METHODS: Methyl thiazolyl tetrazolium (MTT) method was adopted to observe the effects of cembrane-type diterpenes (compound 1, compound 2 and compound 3) on the proliferation of PC12 cells. And the protective effects of the three compounds on PC12 cells exposed to glutamate were also detected by MTT. Furthermore, the influence of compound 1 on intracellular concentration of calcium in PC12 cells exposed to glutamate was detected by laser confocal microscopy. RESULTS: After 72-hour PC12 cell culture, OD values in the 2, 10 and 50 micromol/L compound 1 groups were significantly higher than that in the normal group (P<0.05, P<0.01). After 24-hour glutamate damage, OD values in the 0.4, 2 and 50 micromol/L compound 1 groups, the 0.4, 2 and 100 micromol/L compound 2 groups and the 2 micromol/L compound 3 group were obviously increased as compared with the untreated group (P<0.01, P<0.05). After 48-hour glutamate damage, OD values in the compound 1 group were approximate to those in the normal control and the positive control group while were significantly higher than that in the untreated group (P<0.01, P<0.05), but no dose-dependent effect was observed. Compound 1 of 0.4, 2, 50 micromol/L could significantly reduce the intracellular concentration of calcium in PC12 cells exposed to glutamate (P<0.05, P<0.01), which was also approximate to the effect of nimodipine (positive control drug). CONCLUSION: Cembrane-type diterpenes (compound 1, compound 2 and compound 3) extracted from Sinularia flexibilis have obvious protective effects on PC12 cells damaged by glutamate, and compound 1 has the best neuroprotective effect. The mechanism of the neuroprotective effect of compound 1 may lie in reducing the intracellular concentration of calcium in PC12 cells exposed to glutamate and relieving the calcium overload.

A bioactive compound from Polygala tenuifolia regulates efficiency of chronic stress on hypothalamic-pituitary-adrenal axis.

3,6'-Disinapoyl sucrose (DISS) is the active oligosaccharide ester component from roots of Polygala tenuifolia, and its antidepressant effects was found in the forced swimming test (FST) and tail suspension test (TST). We aimed to study the antidepressant effects of DISS in the chronic unpredictable mild stress (CMS) model in rats and explore the underlying mechanisms in the hypothalamic-pituitary-adrenal (HPA) axis. We found that when subjected to the chronic stress protocol for 28 days, animals showed reduced sensitivity to reward and abnormality in the HPA axis. DISS (10 or 20 mg/kg, i.g.) improved the reward reaction as measured by increasing sucrose consumption, remarkably reduced serum CORT, ACTH and CRH levels in the CMS-treated rats. In addition, DISS enhanced the expression of glucocorticoid receptor (GR) and mineralocorticoid receptor (MR) mRNA. These results indicated that the antidepressant effects of DISS in chronically stressed animals might relate to the modulating effects on the HPA axis, which might be an important mechanism for its antidepressant effect.

[Antidepressant effects of piperine and its neuroprotective mechanism in rats].

OBJECTIVE: To study the antidepressant effects of piperine in chronic unpredictable mild stress (CUMS) rats and to explore the underlying mechanisms in the hypothalamic-pituitary-adrenal (HPA) axis. METHODS: Fifty rats were housed alone and exposed to an unpredicted sequence of mild stressors to induce CUMS, and then were divided into untreated group, desipramine group and low-, medium- and high-dose piperine groups. Another 10 normal rats were used as normal control. The behavior of the rats was detected by body weight and sucrose preference test, and the serum levels of corticotropin-releasing hormone (CRH), adrenocorticotropic hormone (ACTH) and corticosterone (CORT) in different groups were observed by radioimmunoassay. RESULTS: The results indicated that after 21-day administration, piperine at concentrations of 10 and 20 mg/kg could significantly improve the behavioral disorder by increasing sucrose consumption. Piperione at concentrations of 5, 10 and 20 mg/kg could remarkably reduce serum ACTH and CRH levels in the CUMS rats, but had little effect on the content of CORT. CONCLUSION: Piperine can relieve depression in CUMS rats by modulating the function of HPA axis.

[Study on antidepressant components of sucrose ester from Polygala tenuifolia].

OBJECTIVE: To investigate the antidepressant components of Polygala tenuifolia. METHOD: The chromatographic method was used to isolate and purify the chemical constituents, their structures were identified by spectral analysis, MTT method was applied to investigate their cytotoxic activities. RESULT: Nine compounds were isolated from the roots of P. tenuifolia. Their structures were identified as sibiricose A, (1), sibiricose A5 (2), tenuifoliside A (3) and 3', 6-disinapoyl sucrose (4), sibiricose A6 (5), 3, 4, 5-trimethoxycinnamate (6), polygalaxanthone III (7), tenuifolioses A (8), tenuifolioses H (9) and some compounds' activities to PC12 were observed. CONCLUSION: Compound 1 was isolated from this plant for the first time. Compounds 2,3 could protect PC12 cells damage induced by P. tenuifolia.