Ethanol extract of Polyscias fruticosa leaves suppresses RANKL-mediated osteoclastogenesis in vitro and LPS-induced bone loss in vivo

Antioxidant and Anti-Inflammatory Mechanisms of Lipophilic Fractions from Polyscias fruticosa Leaves Based on Network Pharmacology, In Silico, and In Vitro Approaches

Polyscias fruticosa leaf (PFL) has been used in food and traditional medicine for the treatment of rheumatism, ischemia, and neuralgia. However, the lipophilic components of PFL and their biological properties remain unknown. This study, integrating network pharmacology analysis with in silico and in vitro approaches, aimed to elucidate the antioxidant and anti-inflammatory capacities of lipophilic extracts from PFL. A total of 71 lipophilic compounds were identified in PFL using gas chromatography-mass spectrometry. Network pharmacology and molecular docking analyses showed that key active compounds, mainly phytosterols and sesquiterpenes, were responsible for regulating core target genes, such as PTGS2, TLR4, NFE2L2, PRKCD, KEAP1, NFKB1, NR1l2, PTGS1, AR, and CYP3A4, which were mostly enriched in oxidative stress and inflammation-related pathways. Furthermore, lipophilic extracts from PFL offered powerful antioxidant capacities, as evident in our cell-free antioxidant assays. These extracts also provided a protection against oxidative stress by inducing the expression of catalase and heme oxygenase-1 in lipopolysaccharide (LPS)-treated RAW 264.7 cells. Additionally, lipophilic fractions from PFL showed anti-inflammatory potential in downregulating the level of pro-inflammatory factors in LPS-treated macrophages. Overall, these findings provide valuable insights into the antioxidant and anti-inflammatory properties of lipophilic extracts from PFL, which can be used as a fundamental basis for developing nutraceuticals and functional foods.

Neuroprotective Effects of Ethanol Extract of Polyscias fruticosa (EEPF) against Glutamate-Mediated Neuronal Toxicity in HT22 Cells

In traditional herbal medicine, the Polyscias fruticosa has been frequently used for the treatment of ischemia and inflammation. Oxidative stress mediated by elevated glutamate levels cause neuronal cell death in ischemia and various neurodegenerative diseases. However, so far, the neuroprotective effects of this plant extract against glutamate-mediated cell death have not been investigated in cell models. The current study investigates the neuroprotective effects of ethanol extracts of Polyscias fruticosa (EEPF) and elucidates the underlying molecular mechanisms of EEPFs relevant to neuroprotection against glutamate-mediated cell death. The oxidative stress-mediated cell death was induced by 5 mM glutamate treatment in HT22 cells. The cell viability was measured by a tetrazolium-based EZ-Cytox reagent and Calcein-AM fluorescent dye. Intracellular Ca²⁺ and ROS levels were measured by fluorescent dyes, fluo-3 AM and 2',7'-dichlorodihydrofluorescein diacetate (DCF-DA), respectively. Protein expressions of p-AKT, BDNF, p-CREB, Bax, Bcl-2, and apoptosis-inducing factor (AIF) were determined by western blot analysis. The apoptotic cell death was measured by flow cytometry. The in vivo efficacy of EEPF was evaluated using the Mongolian gerbil mouse by surgery-induced brain ischemia. EEPF treatment showed a neuroprotective effect against glutamate-induced cell death. The EEPF co-treatment reduced the intracellular Ca²⁺ and ROS and apoptotic cell death. Furthermore, it recovered the p-AKT, p-CREB, BDNF, and Bcl-2 levels decreased by glutamate. The EEPF co-treatment suppressed the activation of apoptotic Bax, the nuclear translocation of AIF, and mitogen-activated protein kinase (MAPK) pathway proteins (ERK1/2, p38, JNK). Further, EEPF treatment significantly rescued the degenerative neurons in the ischemia-induced Mongolian gerbil in vivo model. EEPF exhibited neuroprotective properties that suppress glutamate-mediated neurotoxicity. The underlying mechanism of EEPF is increasing the level of p-AKT, p-CREB, BDNF, and Bcl-2 associated with cell survival. It has therapeutic potential for the treatment of glutamate-mediated neuropathology.

Lipopolysaccharide-Induced Bone Loss in Rodent Models: A Systematic Review and Meta-Analysis

Osteoporosis has traditionally been characterized by underlying endocrine mechanisms, though evidence indicates a role of inflammation in its pathophysiology. Lipopolysaccharide (LPS), a component of gram-negative bacteria that reside in the intestines, can be released into circulation and stimulate the immune system, upregulating bone resorption. Exogenous LPS is used in rodent models to study the effect of systemic inflammation on bone, and to date a variety of different doses, routes, and durations of LPS administration have been used. The study objective was to determine whether systemic administration of LPS induced inflammatory bone loss in rodent models. A systematic search of Medline and four other databases resulted in a total of 110 studies that met the inclusion criteria. Pooled standardized mean differences (SMDs) and corresponding 95% confidence intervals (CI) with a random-effects meta-analyses were used for bone volume fraction (BV/TV) and volumetric bone mineral density (vBMD). Heterogeneity was quantified using the I² statistic. Shorter-term (<2 weeks) and longer-term (>2 weeks) LPS interventions were analyzed separately because of intractable study design differences. BV/TV was significantly reduced in both shorter-term (SMD = -3.79%, 95% CI [-4.20, -3.38], I² 62%; p < 0.01) and longer-term (SMD = -1.50%, 95% CI [-2.00, -1.00], I² 78%; p < 0.01) studies. vBMD was also reduced in both shorter-term (SMD = -3.11%, 95% CI [-3.78, -2.44]; I² 72%; p < 0.01) and longer-term (SMD = -3.49%, 95% CI [-4.94, -2.04], I² 82%; p < 0.01) studies. In both groups, regardless of duration, LPS negatively impacted trabecular bone structure but not cortical bone structure, and an upregulation in bone resorption demonstrated by bone cell staining and serum biomarkers was reported. This suggests systemically delivered exogenous LPS in rodents is a viable model for studying inflammatory bone loss, particularly in trabecular bone. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Acacetin inhibits RANKL-induced osteoclastogenesis and LPS-induced bone loss by modulating NFATc1 transcription

Osteolytic disorders are characterized by impaired bone volume and trabecular structure that leads to severe fragility fractures. Studies have shown that excessive osteoclast activity causes impaired bone microstructure, a sign of osteolytic diseases such as osteoporosis. Approaches of inhibiting osteoclastogenesis and bone resorption specifically could prevent osteoporosis and other osteolytic disorders. Acacetin is a potent molecule extracted from plants with anti-cancer and anti-inflammatory bioactivities. Here, we demonstrated, for the first time, that acacetin repressed osteoclastogenesis, formation of F-actin rings, bone resorption activity, and osteoclast-related gene expression in vitro through modulating ERK, P38, and NF-κB signaling pathways and preventing expression of NFATc1. Micro-CT and H & E staining results indicated that acacetin alleviated LPS-induced osteolysis in vivo. Overall, our findings suggested that acacetin could help to prevent osteoporosis and other osteoclast-related osteolytic disorders.

Identification and comparison of triterpene saponins in Aralia elata leaves and buds by the energy-resolved MSAll technique on a liquid chromatography/quadrupole time-of-flight mass spectrometry

In this study, we identify the triterpene saponins (TSs) extracted from the leaves and buds of Aralia elata (Miq.) Seems using ultra-performance liquid chromatography and positive ionization electrospray quadrupole time-of-flight mass spectrometry (UPLC-ESI⁺-QTOF). The energy-resolved MS^All (erMS^all) technique is applied in order to simultaneously collect the diverse precursors attributed to [M+H]⁺, [M + NH₄]⁺ and [M + Na]⁺ ions. A practical and effective erMS^all workflow is established to rapidly identify and compare the saponins in the analyzed samples. In total, 111 TSs of structure are estimated, including 44 new compounds that had not been identified previously in A. elata. Of the five aglycones detected in the samples, a sapogenin 3β, 16α, 23-trihydroxyoleana-11,13-dien-28-oic acid (A5) that is identified for the first time in A. elata leaves. Compared to the buds, the leaves number twice as many hederagenin-type (A2) compounds. Although the number of other aglycones does not vary significantly between the buds and the leaves, A5 compounds are exclusively detected in the latter. Moreover, the C-3 sugar chains of TSs in A. elata leaves are mainly neutral (e.g., Hex+Hex, Hex+Hex+Hex and Hex+Hex+Hex+Hex), whereas those of bud TS compounds are primarily acidic (e.g., Pen+HexA, Hex+HexA and Hex+Pen+HexA). Some of the identified TS compounds, e.g., 27, 28, 32, 46, 54, 57, 71 and 105 can be used as indices to evaluate the quality of the plant leaves and buds. Overall, this study is of great significance for the comparative study of triterpenoid saponins in the leaves and buds of Aralia elata.

Eleutherococcus sessiliflorus Inhibits Receptor Activator of Nuclear Factor Kappa-B Ligand (RANKL)-Induced Osteoclast Differentiation and Prevents Ovariectomy (OVX)-Induced Bone Loss

The aim of this study was to evaluate the effects of root bark of Eleutherococcus sessiliflorus (ES) on osteoclast differentiation and function in vitro and in vivo. In vitro, we found that ES significantly inhibited the RANKL-induced formation of TRAP-positive multinucleated osteoclasts and osteoclastic bone resorption without cytotoxic effects. ES markedly downregulated the expression of nuclear factor of activated T cells cytoplasmic 1 (NFATc1); c-Fos; and osteoclast-related marker genes, such as TRAP, osteoclast-associated receptor (OSCAR), matrix metalloproteinase-9 (MMP-9), calcitonin receptor, cathepsin K, the 38 kDa d2 subunit of the vacuolar H⁺-transporting lysosomal ATPase (Atp6v0d2), dendritic cell-specific transmembrane protein (DC-STAMP), and osteoclast-stimulatory transmembrane protein (OC-STAMP). These effects were achieved by inhibiting the RANKL-mediated activation of MAPK signaling pathway proteins, including p38, ERK, and JNK. In vivo, ES attenuated OVX-induced decrease in bone volume to tissue volume ratio (BV/TV), trabecular thickness (Tb.Th), trabecular number (Tb.N), and bone mineral density, but increased trabecular separation (Tb.Sp) in the femur. Collectively, our findings showed that ES inhibited RANKL-activated osteoclast differentiation in bone marrow macrophages and prevented OVX-mediated bone loss in rats. These findings suggest that ES has the potential to be used as a therapeutic agent for bone-related diseases, such as osteoporosis.

Arecoline suppresses RANKL-induced osteoclast differentiation in vitro and attenuates LPS-induced bone loss in vivo

BACKGROUND

Areca nut has anti-inflammatory, antiparasitic, antihypertensive, and antidepressant properties. The pathological hallmarks of inflammatory joint diseases are an increased number of osteoclasts and impaired differentiation of osteoblasts, which may disrupt the bone remodeling balance and eventually lead to bone loss.

PURPOSE

The present study assessed the effects of arecoline, the main alkaloid found in areca nut, on osteoclast and osteoblast differentiation and function.

METHOD

M-CSF/RANKL-stimulated murine bone marrow-derived macrophages (BMMs) were incubated with several concentrations of arecoline, and TRAP staining and pit formation were assessed to monitor osteoclast formation. Quantitative real-time RT-PCR and western blot analyses were used to analyze the expression of osteoclast-associated genes and signaling pathways. The effects of arecoline on bone were investigated in an in vivo mouse model of lipopolysaccharide (LPS)-induced trabecular bone loss after oral administration of arecoline. Alizarin red S staining and assays to measure ALP activity and the transcription level of osteoblast-related genes were used to evaluate the effects of arecoline on osteoblast differentiation and bone mineralization.

RESULTS

In a dose-dependent manner, arecoline at concentrations of 50-100 μM reduced both the development of TRAP-positive multinucleated osteoclasts and the formation of resorption pits in M-CSF/RANKL-stimulated BMMs. In M-CSF/RANKL-stimulated BMMs, arecoline also suppressed the expression and translocation of c-Fos and NFATcl, and osteoclast differentiated-related genes via interference with the AKT, MAPK, and NF-kB activation pathways. Femur bone loss and microcomputed tomography parameters were recovered by oral administration of arecoline in the mouse LPS-induced bone loss model. Lastly, arecoline increased ALP activity, bone mineralization, and the expression of osteoblast differentiation-related genes, such as ALP and Runx2, in MC3T3-E1 cells.

CONCLUSION

Our data suggest that arecoline may attenuate or prevent bone loss by suppressing osteoclastogenesis and promoting osteoblastogenesis. These findings provide evidence supporting arecoline's use as a potential therapeutic agent in bone-loss disorders and diseases.