Curculigoside attenuates human umbilical vein endothelial cell injury induced by H2O2

Curculigoside Attenuates Endoplasmic Reticulum Stress-Induced Epithelial Cell and Fibroblast Senescence by Regulating the SIRT1-P300 Signaling Pathway

The senescence of alveolar epithelial cells (AECs) and fibroblasts plays a pivotal role in the pathogenesis of idiopathic pulmonary fibrosis (IPF), a condition lacking specific therapeutic interventions. Curculigoside (CCG), a prominent bioactive constituent of Curculigo, exhibits anti-osteoporotic and antioxidant activities. Our investigation aimed to elucidate the anti-senescence and anti-fibrotic effects of CCG in experimental pulmonary fibrosis and delineate its underlying molecular mechanisms. Our findings demonstrate that CCG attenuates bleomycin-induced pulmonary fibrosis and lung senescence in murine models, concomitantly ameliorating lung function impairment. Immunofluorescence staining for senescence marker p21, alongside SPC or α-SMA, suggested that CCG's mitigation of lung senescence correlates closely with the deceleration of senescence in AECs and fibroblasts. In vitro, CCG mitigated H2O2-induced senescence in AECs and the natural senescence of primary mouse fibroblasts. Mechanistically, CCG can upregulate SIRT1 expression, downregulating P300 expression, enhancing Trim72 expression to facilitate P300 ubiquitination and degradation, reducing the acetylation levels of antioxidant enzymes, and upregulating their expression levels. These actions collectively inhibited endoplasmic reticulum stress (ERS) and alleviated senescence. Furthermore, the anti-senescence effects and mechanisms of CCG were validated in a D-galactose (D-gal)-induced progeroid model. This study provides novel insights into the mechanisms underlying the action of CCG in cellular senescence and chronic diseases, offering potential avenues for the development of innovative drugs or therapeutic strategies.

Curculigoside attenuates osteoporosis through regulating DNMT1 mediated osteoblast activity

This work aims to study the function of curculigoside in osteoporosis and explore whether DNMT1 is closely involved in osteoblast activity. After OB-6 osteoblasts were treated with hydrogen peroxide (H2O2), a curculigoside treatment group was set up and a series of biological tests including MTT, flow cytometry, western blotting, ROS fluorescence intensity, mitochondrial membrane potential, and ELISA experiments were performed to verify the effect of curculigoside on the activity of osteoblasts. Then, alkaline phosphatase (ALP) activity, alizarin red staining, PCR, and western blotting assays were performed to detect the effects of curculigoside on osteoblast function. By constructing DNMT1 knockdown and overexpression OB-6 cell lines, the effect of DNMT1 on osteoblast function was verified. In addition, the expression level of Nrf2 in each group was detected to speculate the mechanism of DNMT1 in osteoporosis. The cell activity and level of bcl-2 and SOD were significantly increased; the cell apoptosis, ROS fluorescence intensity, mitochondrial membrane potential, MDA and level of caspase-3, Bax, and CAT was reduced in curculigoside treatment group compared with H2O2-induced OB-6 osteoblasts. Meanwhile, the ALP activity, number and area of bone mineralized nodules, and gene and protein expression of OSX and OPG were significantly elevated in curculigoside group. Moreover, DNMT1 knockdown had a similar promotion effect on osteoblast function as curculigoside, and DNMT1 overexpression could reverse the promotion effect of curculigoside on osteoblast function. Further mechanistic studies speculated that DNMT1 might play a role in osteoporosis by affecting Nrf2 methylation. Curculigoside enhances osteoblast activity through DNMT1 controls of Nrf2 methylation.

ATP purinergic receptor signalling promotes Sca-1+ cell proliferation and migration for vascular remodelling

AIMS

Vascular resident stem cells expressing stem cell antigen-1 (Sca-1⁺ cells) promote vascular regeneration and remodelling following injury through migration, proliferation and differentiation. The aim of this study was to examine the contributions of ATP signalling through purinergic receptor type 2 (P2R) isoforms in promoting Sca-1⁺ cell migration and proliferation after vascular injury and to elucidate the main downstream signalling pathways.

METHODS AND RESULTS

ATP-evoked changes in isolated Sca-1⁺ cell migration were examined by transwell assays, proliferation by viable cell counting assays and intracellular Ca²⁺ signalling by fluorometry, while receptor subtype contributions and downstream signals were examined by pharmacological or genetic inhibition, immunofluorescence, Western blotting and quantitative RT-PCR. These mechanisms were further examined in mice harbouring TdTomato-labelled Sca-1⁺ cells with and without Sca-1⁺-targeted P2R knockout following femoral artery guidewire injury. Stimulation with ATP promoted cultured Sca-1⁺ cell migration, induced intracellular free calcium elevations primarily via P2Y₂R stimulation and accelerated proliferation mainly via P2Y₆R stimulation. Enhanced migration was inhibited by the ERK blocker PD98059 or P2Y₂R-shRNA, while enhanced proliferation was inhibited by the P38 inhibitor SB203580. Femoral artery guidewire injury of the neointima increased the number of TdTomato-labelled Sca-1⁺ cells, neointimal area and the ratio of neointimal area to media area at 3 weeks post-injury, and all of these responses were reduced by P2Y₂R knockdown.

CONCLUSIONS

ATP induces Sca-1⁺ cell migration through the P2Y₂R-Ca²⁺-ERK signalling pathway, and enhances proliferation through the P2Y₆R-P38-MAPK signalling pathway. Both pathways are essential for vascular remodelling following injury. Video Abstract.

Curculigoside mitigates hepatic ischemia/reperfusion-induced oxidative stress, inflammation, and apoptosis via activation of the Nrf-2/HO-1 pathway

Curculigoside has been shown to decrease oxidative stress and inflammatory reactions in many disorders, but its effects during hepatic ischemia-reperfusion injury (IRI) remain unknown. This research aims to determine the protective role and the potential mechanism of action of curculigoside in hepatic IRI. Here, a well-established rat model of partial warm IRI was constructed; serum ALT/AST and H&E staining were employed to assay the extent of liver injury; the superoxide dismutase, malondialdehyde, IL-6, and TNF-α contents were determined using the corresponding kits; the apoptosis index was evaluated by TUNEL staining; and the expression of Nrf-2, HO-1, and apoptosis-associated proteins was detected by qRT-PCR and Western blotting. The results showed that curculigoside pretreatment effectively mitigated hepatic IRI, as demonstrated by decreases in the levels of serum aminotransferases, hepatocellular necrosis and apoptosis, oxidative stress markers, infiltration of inflammatory cells, and secretion of proinflammatory cytokines. Mechanistically, the expression of Nrf-2 and HO-1 was greatly suppressed by hepatic IRI and reactivated by curculigoside. Furthermore, cotreatment with ML-385, an inhibitor of Nrf-2, counteracted the protective effect of curculigoside against hepatic IRI. The results of our study show that curculigoside plays a protective role in hepatic IRI by inhibiting oxidative stress, inflammation, and apoptosis and that its effects may be associated with activation of the Nrf-2/HO-1 pathway.

Curculigoside inhibits ferroptosis in ulcerative colitis through the induction of GPX4

Curculigoside (CUR) is natural ingredient from Curculigo orchioides Gaertn with multiple biological activities. However, whether CUR protects from ulcerative colitis (UC) and underlying mechanisms are unclear. Herein, mice challenged with dextran sulfate sodium (DSS) were established and administrated with CUR for 7 days. Then histological pathologies and ferroptosis regulators were determined in vivo. The ferroptotic IEC-6 cells were prepared to investigate the underlying mechanism of CUR. Results showed that CUR inhibited the disease activity index, histological damage and cell death in mice with colitis. We also found that ferroptosis was induced in mice with colitis, as evidenced by iron overload, GSH depletion, ROS and MDA production, accompanied by decreased expression of SOD and GPX4. CUR treatment significantly reversed these alterations of ferroptotic features in DSS-induced mice. Furthermore, similar effects of CUR on ferroptosis were observed in IEC-6 cells under the combined treatment of H₂O₂ and iron chloride hexahydrate. Interestingly, we found that CUR could increase the selenium sensitivity and promote GPX4 transcription level in IEC-6 cells. Knockdown of GPX4 significantly blocked the protective effects of CUR on cell death, GSH and MDA contents as well as LDH activity in ferroptotic IEC-6 cells. Taken together, these findings suggest that CUR protects against ferroptosis in UC by the induction of GPX4, which presents a potential agent for UC treatment.

Cytoprotective Effects Evaluation of a Novel Danshensu Derivative DEX-018 against Oxidative Stress Injury in HUVECs

Ischemic heart disease (IHD) is one of the most common cardiovascular diseases with high morbidity and mortality. Danshensu (DSS) is widely used in the treatment of coronary heart disease. In this study, the carboxy group of DSS was esterified with edaravone to synthesize the novel DSS derivative DEX-018 to achieve a synergistic protective effect and overcome the structural deficiency of DSS. The pharmacological effect of DEX-018 against tert-butyl hydrogen peroxide (t-BHP) induced oxidative damage in human umbilical vein endothelial cells (HUVECs) was evaluated. The results demonstrated that pretreatment with DEX-018 significantly increased cell viability and superoxide dismutase (SOD) activity and decreased the lactate dehydrogenase (LDH) leakage rate, malondialdehyde (MDA) level and intracellular reactive oxygen species (ROS) level. In addition, DEX-018 inhibited cell apoptosis and reversed the expression of apoptosis-related proteins (Bcl-2, Bax, and caspase-3) in HUVECs stimulated by t-BHP. Further study on the mechanism of DEX-018 revealed that the expression of p-Akt and p-extracellular signal-regulated kinase 1/2 (ERK1/2) was increased, which suggested that DEX-018 may protect HUVECs against t-BHP induced oxidative injury via the Akt and ERK1/2 signaling pathways. To further validate the correlation, CCK8 was used to detect cell viability after treatment with DEX-018 plus Akt inhibitor (MK2206) and phosphadylinositol 3-kinase (PI3K) inhibitor (LY294002). Compared with DEX-018 alone, MK2206 or LY294002 significantly decreased cell viability of HUVECs, indicating that the protective effect of DEX-018 against t-BHP induced oxidative injury was significantly weakened. It was further verified that the antioxidant and anti-apoptotic effects of DEX-018 were partly related to the PI3K-Akt signaling pathway.

Curculigoside attenuates myocardial ischemia‑reperfusion injury by inhibiting the opening of the mitochondrial permeability transition pore

The aim of the present study was to determine whether curculigoside protects against myocardial ischemia-reperfusion injury (MIRI) and to investigate the underlying mechanisms. An in vitro model of hypoxia/reoxygenation (H/R) was established by culturing H9c2 cells under hypoxic conditions for 12 h, followed by reoxygenation for 1 h. Cell Counting kit-8 and lactate dehydrogenase (LDH) assays were subsequently used to examine cell viability and the degree of cell injury. In addition, isolated rat hearts were subjected to 30 min of ischemia followed by 1 h of reperfusion to establish a MIRI model. Triphenyltetrazolium chloride (TTC) staining was performed to measure the infarct size. Furthermore, TUNEL staining and flow cytometry were employed to evaluate cell apoptosis. The opening of the mitochondrial permeability transition pore (MPTP) and changes in the mitochondrial membrane potential (ΔΨm) were assessed. Reverse transcription-quantitative PCR and western blot analysis were performed to investigate the expression levels of mitochondrial apoptosis-related proteins. Curculigoside pre-treatment significantly improved cell viability, decreased cell apoptosis and LDH activity, and reduced the infarct size and myocardial apoptosis in vitro and ex vivo, respectively. Moreover, curculigoside markedly inhibited MPTP opening and preserved the ΔΨm. In addition, curculigoside significantly decreased the expression of cytochrome c, apoptotic protease activating factor-1, cleaved caspase-9 and cleaved caspase-3. Notably, atractyloside, a known MPTP opener, abrogated the protective effects of curculigoside. On the whole, the present study demonstrated that curculigoside protected against MIRI, potentially by decreasing the levels of mitochondria-mediated apoptosis via the inhibition of MPTP opening. Therefore, the results obtained in the present study may provide the theoretical basis for the future clinical application of curculigoside.

Erxian Decoction Attenuates TNF-α Induced Osteoblast Apoptosis by Modulating the Akt/Nrf2/HO-1 Signaling Pathway

Erxian decoction (EXD), a traditional Chinese medicine formula, has been used for treatment of osteoporosis for many years. The purpose of this study was to investigate the pharmacological effect of EXD in preventing osteoblast apoptosis and the underlying mechanism of prevention. Putative targets of EXD were predicted by network pharmacology, and functional and pathway enrichment analyses were also performed. Evaluations of bone mineral density, serum estradiol level, trabecular area fraction, serum calcium levels, and tumor necrosis factor (TNF)-α levels in ovariectomized rats, as well as cell proliferation assays, apoptosis assays, and western blotting in MC3T3-E1 osteoblasts were performed for further experimental validation. Ninety-three active ingredients in the EXD formula and 259 potential targets were identified. Functional and pathway enrichment analyses indicated that EXD significantly influenced the PI3K-Akt signaling pathway. In vivo experiments indicated that EXD treatment attenuated bone loss and decreased TNF-α levels in rats with osteoporosis. In vitro experiments showed that EXD treatment increased cell viability markedly and decreased levels of caspase-3 and the rate of apoptosis. It also promoted phosphorylation of Akt, nuclear translocation of transcription factor NF-erythroid 2-related factor (Nrf2), and hemeoxygenase-1 (HO-1) expression in TNF-α-induced MC3T3-E1 cells. Our results suggest that EXD exerted profound anti-osteoporosis effects, at least partially by reducing production of TNF-α and attenuating osteoblast apoptosis via Akt/Nrf2/HO-1 signaling pathway.

Aspirin Eugenol Ester Reduces H2O2-Induced Oxidative Stress of HUVECs via Mitochondria-Lysosome Axis

The oxidative stress of vessel endothelium is a major risk factor of cardiovascular disorders. Antioxidative stress drugs are widely used in cardiovascular therapy. Aspirin eugenol ester (AEE) is a new pharmaceutical compound synthesized by esterification reaction of aspirin with eugenols and possesses antioxidative activity. The present study was designed to investigate the mechanism how AEE protects human umbilical vein endothelial cells (HUVECs) from H₂O₂-induced oxidative stress. H₂O₂ was given to the HUVECs with or without AEE pretreatment. Changes in the oxidative stress-related factors, including those related to the mitochondria-lysosome axis, were determined with Western blotting, cellular immunofluorescence, and enzyme activity test. The results showed that, in the HUVECs, 300 μM H₂O₂ treatment significantly increased the apoptosis rate, MDA concentration, reactive oxygen species (ROS) production, mitochondrial membrane potential, expression of Bax and mature cathepsin D (CTSD), and activity of CTSD and Caspase3 (Cas3) but decreased the expression of Bcl2 and lysosomal membrane stability, while in the HUVECs pretreated with AEE, the above changes caused by either the stimulatory or the inhibitory effect of H₂O₂ on the relevant factors were significantly reduced. AEE pretreatment significantly enhanced the activity of cellular superoxide dismutase and glutathione peroxidase in the HUVECs. Our findings suggest that AEE effectively reduced H₂O₂-induced oxidative stress in the HUVECs via mitochondria-lysosome axis.

A novel mechanism of Gamma-aminobutyric acid (GABA) protecting human umbilical vein endothelial cells (HUVECs) against H2O2-induced oxidative injury

Vascular endothelial cell damage is related to many vascular diseases, including cardiovascular disease (CVD). Reactive oxygen species (ROS) play a vital role in the pathogenesis of many cardiovascular diseases. Herein, H₂O₂-induced human umbilical vein endothelial cell (HUVEC) injury model was used to explore the mechanisms involved in the pathogenesis of ROS-induced oxidative stress and cell dysfunction. Gamma-aminobutyric acid (GABA), a naturally occurring four-carbon non-protein amino acid, has antioxidant activity and anti-inflammatory action. In the present study, we demonstrated that GABA could scavenge free radicals including DPPH and ABTS, reverse H₂O₂-induced suppression on HUVEC proliferation, HUVEC apoptosis and ROS formation via p65 signaling. Interestingly, GABA treatment alone did not cause significant changes in p65 phosphorylation, suggesting that GABA will not cause imbalance in NF-κB signaling and ROS formation without oxidative stress. Moreover, GABA also modulated Keap1-Nrf2 and Notch signaling pathways upon H₂O₂ stimulation, suggesting that GABA may exert its effect via multi mechanisms. In conclusion, the present study demonstrated that GABA inhibits H₂O₂-induced oxidative stress in HUVECs via inhibiting ROS-induced NF-κB and Caspase 3 pathway activation. GABA may, therefore, have potential as a pharmacological agent in the prevention or treatment of oxidative injury-related cardiovascular disease.

Renin-angiotensin system inhibitor attenuates oxidative stress induced human coronary artery endothelial cell dysfunction via the PI3K/AKT/mTOR pathway

INTRODUCTION

The renin-angiotensin system is associated with blood pressure regulation, inflammation, oxidative stress and insulin resistance. It can decrease intracellular oxidative stress. Stimulation with H₂O₂ leads to increased oxidative stress and activation of the AKT/mTOR pathway. However, the role of renin-angiotensin system inhibitors in oxidative stress-induced endothelial cell dysfunction and H₂O₂-induced AKT activation remains unclear.

MATERIAL AND METHODS

Human coronary artery endothelial cells (HCAECs) were used. The cells were treated with H₂O₂, captopril, the AKT inhibitor MK-2206, and the AKT activator SC79, either separately, or in combination. p53 and ICAM-1 expression, and p-eNOS, p-Akt and mTOR activation were measured by Western blot. Cell viability was assessed by MTT assay. Levels of reactive oxygen species (ROS) were assayed by flow cytometry. Proliferation was monitored by BrdU labeling, while cell migration and invasion were determined by wound healing and Transwell assays, respectively.

RESULTS

The renin-angiotensin system inhibitor captopril reversed H₂O₂-induced oxidative stress and apoptosis in HCAECs. Co-treatment with captopril and the AKT inhibitor MK-2206 reduced the H₂O₂-induced P53 and ICAM-1 protein expression (p < 0.05). The proliferation, migration and invasion of HCAECs were significantly enhanced by co-treatment with captopril and MK-2206 (p < 0.05).

CONCLUSIONS

The study revealed the protective effect of captopril against H₂O₂-induced endothelial cell dysfunction through the AKT/mTOR pathway, and its enhancement of cell survival. These findings provide new insights into the protective effects of captopril and novel therapeutic approaches to treatment of cardiovascular disease.

Sphingomyelin synthase 2 promotes H2O2-induced endothelial dysfunction by activating the Wnt/β-catenin signaling pathway

Atherosclerosis (AS) is the primary cause of various cardiovascular and cerebrovascular diseases and has high morbidity and mortality rates. Oxidative stress-induced endothelial cells (ECs) dysfunction is the pathological basis of AS. In addition, sphingomyelin (SM) and the Wnt/β-catenin signaling pathway are considered to be closely associated with AS; however, the specific mechanism is not clear. Therefore, the present study investigated whether SM may induce ECs dysfunction through the Wnt/β-catenin signaling pathway. Firstly, a sphingomyelin synthase 2 (SMS2) overexpression cell model was constructed. It was identified that the expression of SMS2 was increased when ECs were treated with H₂O₂. In addition, these results demonstrated that SMS2 overexpression promoted apoptosis and macrophage adhesion of H₂O₂-induced ECs, thereby increasing the expression of β-catenin. Furthermore, SMS activity was inhibited with Dy105, combined with simultaneous treatment with LiCl or H₂O₂. This additionally confirmed that Dy105 significantly inhibited SMS activity and decreased the level of ECs dysfunction and β-catenin content; however, LiCl served a key role in activating the Wnt/β-catenin signaling pathway to promote ECs dysfunction. Collectively, these results suggested that SMS2 overexpression may promote ECs dysfunction by activating the Wnt/β-catenin signaling pathway, while Dy105 may inhibit the evolution of oxidative stress-induced dysfunction.

Curculigoside and polyphenol-rich ethyl acetate fraction of Molineria latifolia rhizome improved glucose uptake via potential mTOR/AKT activated GLUT4 translocation

Adipose tissue is one of the major organs responsible for rapid restoration of postprandial glucose fluxes. Being the major isoform of glucose transporter in adipose tissue, regulations of insulin-dependent GLUT4 trafficking have always been of research interest. The present study aimed to examine the molecular mechanisms underlying the efficacy of curculigoside and polyphenol-rich ethyl acetate fraction (EAF) of Molineria latifolia rhizome in triggering glucose uptake. We assessed the adipogenic potential and glucose uptake stimulatory activity of curculigoside and EAF by employing a murine 3T3-L1 adipocyte model. The transcriptional and translational expressions of selected intermediates in the insulin signalling pathway were evaluated. While curculigoside neither promoted adipogenesis nor activated peroxisome proliferator activated receptor gamma, treatment with polyphenol-rich EAF resulted otherwise. However, both treatments enhanced insulin-stimulated uptake of glucose. This was coupled with increased availability of GLUT4 at the plasma membrane of the differentiated adipocytes although the total GLUT4 protein level was unaffected. In addition, the treatment increased the phosphorylation of both AKT and mTOR, which have been reported to be associated with GLUT4 translocation. The present findings proposed that curculigoside and EAF increased glucose transport activity of 3T3-L1 adipocytes via GLUT4 translocation as a result of potential mTOR/AKT activation. The more potent efficacy observed with EAF suggested potential synergistic and multi-targeted action.

Rice Bioactive Peptide Binding with TLR4 To Overcome H2O2-Induced Injury in Human Umbilical Vein Endothelial Cells through NF-κB Signaling

Reactive oxygen species-induced vessel endothelium injury is crucial in cardiovascular diseases progression. Rice-derived bran bioactive peptides (RBAP) might exert antioxidant effect through unknown mechanisms. Herein, we validated the antioxidant effect and mechanism of RBAP on H₂O₂-induced oxidative injury in human umbilical vein endothelial cells (HUVECs). Here, HUVECs were treated with RBAP under H₂O₂ stimulation; the effects of RBAP on HUVECs oxidative injury were evaluated. H₂O₂ injury-induced cell morphology changes were ameliorated by RBAP. The effect of H₂O₂- on HUVEC apoptosis (percentage of apoptotic cell: 38.00 ± 2.00 in H₂O₂ group vs 21.07 ± 2.06 in RBAP + H₂O₂ group, P = 0.0013 compared to H₂O₂ group), the protein levels of cleaved caspase-3 (relative protein expression: 2.90 ± 0.10 in H₂O₂ group vs 1.82 ± 0.09 in RBAP + H₂O₂ group, P < 0.0001 compared to H₂O₂ group) and p-p65 (relative protein expression: 1.86 ± 0.09 in H₂O₂ group vs 1.35 ± 0.08 in RBAP + H₂O₂ group, P < 0.0001 compared to H₂O₂ group) could be attenuated by RBAP. RBAP exerts its protective function through binding with Toll-like receptor 4 (TLR4). Taken together, RBAP protects HUVECs against H₂O₂-induced oxidant injury, which provided the theoretical basis for the molecular mechanism of rice deep processing and exploitation of functional peptides.

Astragalus polysaccharide ameliorates H2O2-induced human umbilical vein endothelial cell injury

Endothelial dysfunction caused by reactive oxygen species (ROS) has been implicated in numerous cardiovascular diseases. Astragalus polysaccharide (APS), an important bioactive component extracted from the Chinese herb Astragalus membranaceus, has been widely used for the treatment of cardiovascular disease. The present study aimed to investigate the effects of APS on hydrogen peroxide (H₂O₂)-induced human umbilical vein endothelial cell (HUVEC) injury. Following treatment with 400 µM H₂O₂ for 24 h, cell viability was decreased and apoptosis was increased. However, pretreatment with APS for 1 h significantly attenuated H₂O₂-induced injury in HUVECs. In addition, APS decreased intracellular ROS levels, increased the protein expression of endothelial nitric oxide synthase and copper-zinc superoxide dismutase, elevated intracellular cyclic guanosine monophosphate (an activity marker for nitric oxide) levels and restored the mitochondrial membrane potential, compared with cells treated with H₂O₂ only. In conclusion, the results of the present study suggested that APS may protect HUVECs from injury induced by H₂O₂ via increasing the cell antioxidant capacity and nitric oxide (NO) bioavailability, which may contribute to the improvement of the imbalance between ROS and NO levels.

The effects of verapamil on the pharmacokinetics of curculigoside in rats

CONTEXT

Clarifying the potential mechanism of the poor oral bioavailability of curculigoside would be helpful for for investigating pharmacological effects and clinical applications.

OBJECTIVE

To clarify the main mechanism for poor oral bioavailability.

MATERIALS AND METHODS

First, the pharmacokinetics of curculigoside (20 mg/kg) in rats with and without pretreatment with verapamil (10 mg/kg) was determined using a sensitive and reliable LC-MS method. Then the effects of verapamil on the transport and metabolic stability of curculigoside were investigated using Caco-2 cell transwell model and rat liver microsome incubation systems.

RESULTS

The results showed that verapamil could significantly increase the peak plasma concentration (from 60.17 ng/mL to 93.66 ng/mL) and AUC_0-t (from 289.57 to 764.02 ng·h/mL) of curculigoside. The Caco-2 cell experiments indicated that the efflux ratio of curculigoside was 3.92 (P_appAB 6.43 ± 0.57 × 10 ^-7cm/s; P_appBA 2.52 ± 0.37 × 10 ^-36cm/s), P-gp might be involved in the transport of curculigoside, and verapamil could inhibit the efflux of curculigoside and increase the absorption of curculigoside significantly in the Caco-2 cell monolayer. Additionally, the rat liver microsome incubation experiments indicated that verapamil could significantly decrease the intrinsic clearance rate of curculigoside (from 38.8 to 23.6 μL/min/mg protein).

DISCUSSION AND CONCLUSION

These results indicated that verapamil could significantly change the pharmacokinetic profiles of curculigoside in rats, the poor absorption due to P-gp mediated efflux in intestine and high intrinsic clearance rate in rat liver may be the main reason for the poor oral absolute bioavailability of curculigoside.

Mechanisms underlying the antiapoptotic and anti-inflammatory effects of monotropein in hydrogen peroxide-treated osteoblasts

Monotropein, the primary iridoid glycoside isolated from Morindacitrifolia, has been previously reported to possess potent antioxidant and antiosteoporotic properties. However, there is no direct evidence correlating the antiosteoporotic effect of monotropein with its observed antioxidant capacity, and the molecular mechanisms involved in mediating these processes remain unclear. Therefore, the aim of the present study was to investigate the protective effects of monotropein against oxidative stress in osteoblasts and the mechanisms involved in mediating this process. Osteoblast viability was evaluated using the MTT assay. The mitochondrial membrane potential and reactive oxygen species were detected by flow cytometry analyses. Western blotting and enzyme‑linked immunosorbent assays were performed to detect protein expression levels. A significant reduction in osteoblast viability was observed at 24 h following exposure to various concentrations (100‑1,000 µM) of H2O2 compared with untreated osteoblasts. The cytotoxic effect of H2O2 was notably reversed when osteoblasts were pretreated with 1‑10 µg/ml monotropein. Pretreatment with 1-10 µg/ml monotropein increased the mitochondrial membrane potential and reduced the generation of reactive oxygen species in osteoblasts following exposure to H2O2. In addition, the H2O2‑induced increase in apoptotic markers (caspase-3 and caspase-9) and H2O2-induced reduction in sirtuin 1 levels were significantly reversed following pretreatment of cells with monotropein. Furthermore, monotropein significantly reduced H2O2‑induced stimulation of NF‑κB expression, in addition to the expression of a number of proinflammatory mediators. These results indicate that monotropein suppresses apoptosis and the inflammatory response in H2O2‑induced osteoblasts through the activation of the mitochondrial apoptotic signaling pathway and inhibition of the NF‑κB signaling pathway.

Bioprospecting the Curculigoside-Cinnamic Acid-Rich Fraction from Molineria latifolia Rhizome as a Potential Antioxidant Therapeutic Agent

Increasing evidence from both experimental and clinical studies depicts the involvement of oxidative stress in the pathogenesis of various diseases. Specifically, disruption of homeostatic redox balance in accumulated body fat mass leads to obesity-associated metabolic syndrome. Strategies for the restoration of redox balance, potentially by exploring potent plant bioactives, have thus become the focus of therapeutic intervention. The present study aimed to bioprospect the potential use of the curculigoside-cinnamic acid-rich fraction from Molineria latifolia rhizome as an antioxidant therapeutic agent. The ethyl acetate fraction (EAF) isolated from M. latifolia rhizome methanolic extract (RME) contained the highest amount of phenolic compounds, particularly curculigoside and cinnamic acid. EAF demonstrated glycation inhibitory activities in both glucose- and fructose-mediated glycation models. In addition, in vitro chemical-based and cellular-based antioxidant assays showed that EAF exhibited high antioxidant activities and a protective effect against oxidative damage in 3T3-L1 preadipocytes. Although the efficacies of individual phenolics differed depending on the structure and concentration, a correlational study revealed strong correlations between total phenolic contents and antioxidant capacities. The results concluded that enriched phenolic contents in EAF (curculigoside-cinnamic acid-rich fraction) contributed to the overall better reactivity. Our data suggest that this bioactive-rich fraction warrants therapeutic potential against oxidative stress-related disorders.

Pretreatment with Astragaloside IV protects human umbilical vein endothelial cells from hydrogen peroxide induced oxidative stress and cell dysfunction via inhibiting eNOS uncoupling and NADPH oxidase - ROS - NF-κB pathway

Endothelial cell injury caused by reactive oxygen species (ROS) plays a critical role in the pathogenesis of cardiovascular disorders. Astragaloside IV (AsIV) possesses potent antioxidant properties against oxidative stress through undefined mechanism(s). We sought to investigate whether AsIV protects human umbilical vein endothelial cells (HUVECs) from hydrogen peroxide (H₂O₂) induced oxidative stress focusing on eNOS uncoupling and the NADPH oxidase - ROS - NF-κB pathway. Compared with HUVECs incubated with H₂O₂ alone, pretreatment with AsIV significantly increased the viability of HUVECs, which was accompanied with apparent increase in nitric oxide (NO) production and decrease in intracellular superoxide anion production. Furthermore, pretreatment with AsIV increased endothelial nitric oxide synthase (eNOS) dimer/monomer ratio and its critical cofactor tetrahydrobiopterin (BH₄) content, decreased Nox4 protein expression (the most abundant Nox isoform in HUVECs), inhibited translocation of NF-κB p65 subunit into nuclear fraction while enhanced the protein expression of IκB-α (the inhibitor of NF-κB p65), reduced the levels of IL-1β, IL-6, and TNF-α in HUVECs medium, and decreased iNOS protein expression. These results suggest that AsIV may protect HUVECs from H₂O₂-induced oxidative stress via inhibiting NADPH oxidase - ROS - NF-κB pathway and eNOS uncoupling.

The protective effects of curculigoside A on adjuvant-induced arthritis by inhibiting NF-кB/NLRP3 activation in rats

The purpose of this study was to investigate the protective effects of curculigoside A (CA) on adjuvant arthritis (AA) rats and explore its possible mechanisms. AA was induced by intradermal injection of Freund's complete adjuvant (FCA). Male SD rats were treated with CA(10 and 20mg/kg) from days 18 to 24 after immunization. The levels of interleukin (IL)-6, IL-1β, tumor necrosis factor-α (TNF-α) and prostaglandin E2 (PGE2) in serum were determined by ELISA. Moreover, the levels of super oxide dismutase (SOD) and malondialdehyde (MDA) were determined using commercial kits. In particular, NLRP3 inflammasome and NF-кB pathway were detected by Western blot. As expected, CA at 10 and 20mg/kg significantly relieved the hind paw swelling and arthritis index, reduced the levels of IL-6 IL-1β, PGE2, TNF-α, MDA and increased SOD activity in serum. In addition, CA effectively down-regulated the expression of NF-кB/NLRP3 pathway. These findings showed that CA exerted beneficial effects on rheumatoid arthritis in rats.

Mechanisms of angiogenesis in a Curculigoside A-treated rat model of cerebral ischemia and reperfusion injury

Curculigoside A has shown protective effects against rat cortical neuron damage in vivo. However, the molecular mechanisms through which Curculigoside A affords this protection are unclear. In the present study, we sought to elucidate the mechanisms of angiogenesis in rat aortic endothelial cells (RAEC), rat aortic smooth muscle cells (RASMC) as well as a rat model of cerebral ischemia and reperfusion injury following treatment with Curculigoside A. We examined the role of Curculigoside A on RAEC and RASMC proliferation, migration, and tube formation in vitro and in a cerebral ischemia and reperfusion injury rat model. We used the recombinant Dickkopf (DKK)-1 protein, a Wnt/β-catenin inhibitor, and the recombinant WIF-1 protein, a Wnt5a antagonist to determine mechanisms. In addition, we measured leakage of the blood-brain barrier (BBB) and tested for angiogenesis associated proteins. Our data suggest that Curculigoside A induces angiogenesis in vitro by increasing proliferation, migration and tube formation in RAEC and RASMC. The increase in Curculigoside A-induced proliferation and tube formation was counteracted by DKK-1 and WIF-1. Curculigoside A increased expression of VEGF, p-VEGFR, p-CREB, Egr-3, VCAM-1, Ang1 and Tie2 while prohibiting BBB leakage in cerebral ischemia and reperfusion injured rats. However, Cyclosporine A, a CREB inhibitor, reduced the expression of p-CREB, Egr-3, VCAM-1, Ang1 and Tie2. These data suggest that Curculigoside A induces cell proliferation and angiogenesis through the Wnt5a/β-catenin and VEGF/CREB/Egr-3/VCAM-1 signaling axis and promotes maturation and stability of new blood vessels via increasing Ang1 and Tie-2 expression.

Effects of Curculigoside on Memory Impairment and Bone Loss via Anti-Oxidative Character in APP/PS1 Mutated Transgenic Mice

Alzheimer's disease (AD) and osteoporosis are two closely related multifactorial progressively degenerative diseases that predominantly affect aged people. These two diseases share many common risk factors, including old age, being female, smoking, excessive drinking, low estrogen, and vitamin D3 levels. Additionally, oxidative damage and the dysfunction of the antioxidant system play important roles in the pathogenesis of osteoporosis and AD. Aβ not only leads to impaired memory but also plays a crucial role in the demineralization process of bone tissues of older people and women with menopause. Curculigoside can promote calcium deposition and increase the levels of ALP and Runx2 in osteoblasts under oxidative stress via anti-oxidative character. Therefore, we investigated the effects of CUR on the spatial learning and memory by the Morris water maze and brain immunohistochemistry, and bone microstructure and material properties of femurs by micro-computed tomography and mechanical testing in APP/PS1 mutated transgenic mice. Oral administration of CUR can significantly enhance learning performance and ameliorate bone loss in APP/PS1 mutated transgenic mice, and the mechanism may be related to its antioxidant effect. Based on these results, CUR has real potential as a new natural resource for developing medicines or dietary supplements for the prevention and treatment of the two closely linked multifactorial progressive degenerative disorders, AD and osteoporosis.

Ethnomedicinal plants used to treat skin diseases by Tharu community of district Udham Singh Nagar, Uttarakhand, India

ETHNOPHARMACOLOGICAL RELEVANCE

Tharu community is the largest primitive indigenous community of the Uttarakhand, India. In this article we have scientifically enumerated medicinal plants and herbal preparations used by the Tharu community to treat various skin diseases, and discussed dermatological properties of these plants in the light of previous ethnomedicinal, microbiological, pharmacological, toxicological, phytochemical and clinical studies.

MATERIALS AND METHODS

Ethnomedicinal survey was conducted in different villages of Tharu community located in district Udham Singh Nagar, Uttarakhand, India. Ethnomedicinal information on plants used to treat various skin diseases was collected from 122 individuals (93 males and 29 females), including 35 experienced herbal practitioners and 87 local villagers. For each of the recorded plant species the use value (UV) and fidelity level (FL) was calculated. The informant consensus factor (Fic) was also calculated to find out the homogeneity in the information given by the informants.

RESULTS

A total of 90 plant species belonging to 86 genera and 48 families were used by the Tharu community to treat various skin diseases viz., wounds (38 spp.), boils (32 spp.), cuts (18 spp.), leprosy (11 spp.), eczema (10 spp.), itching (7 spp.), ringworm (5 spp.), burns (4 spp.), leucoderma (4 spp.), cracked heels (2 spp.), dandruff (3 spp.), body infection (2 spp.), chilblains (2 spp.), hair fall (2 spp.) and toes infection (2 spp.). Information on botanical name, family, vernacular name, ailments treated, mode and dose of herbal preparations, UV and FL values are provided for each of the recorded species. According to UV value most preferred plant species used to treat skin diseases by Tharu community was Ricinus communis L. followed by Tridax procumbens (L.) L., Azadirachta indica A. Juss., Ageratum conyzoides and Allium cepa L.

CONCLUSIONS

The present study has revealed significant information on various medicinal plants used to treat skin diseases by Tharu community. Literature review has confirmed most of the claims made by the Tharu community regarding treatment of various skin diseases by the reported plants. The literature review has also revealed that products from very few of the reported plants are available in market, while most of the reported plants are still under preclinical or clinical trials. There are various known phytochemicals, and antibiotic, antibacterial, antiviral and antifungal agents present in these plants which may be synthesized or transformed to make pharmaceuticals. Some of the reported plants have shown promising results in preclinical trails and there is a need of clinical trials to see their safety and efficacy in treating various skin diseases. These plants may be targeted for development of new medicines, ointments or drugs for the treatment of skin diseases. However further toxicological, preclinical and clinical studies are needed to validate claims about little worked out plant species reported in the present study viz., Sida cordata (Burm. F.) Borss. Waalk., Millettia extensa (Benth.) Baker, Caesulia axillaris Roxb., Ehretia laevis Roxb., Vanda tessellate (Roxb.) Hook. Ex G.Don. and Eualaliopsis binata (Retz.) C.E. Hubb. Further studies on these plants are recommended to assess their potential in development of new skin care products.

Tanshinol protects human umbilical vein endothelial cells against hydrogen peroxide‑induced apoptosis

The present study was designed to investigate the effect of tanshinol on hydrogen peroxide (H2O2)‑induced apoptosis in human umbilical vein endothelial cells (HUVECs), and to determine the underlying mechanisms. HUVECs were pre‑incubated with tanshinol (25‑200 µM) for 24 h, followed by an incubation with 600 µM H2O2 for 6 h. The cell viability was assessed using MTT reagent and the level of cell death was determined by measuring lactate dehydrogenase (LDH) activity. Superoxide dismutase (SOD) activity, levels of malondialdehyde (MDA), reactive oxygen species (ROS) production and NADPH oxidase activity were measured spectrophotometrically using commercially available kits. The apoptotic rate of the HUVECs was detected using Annexin‑V/propidium iodide (PI) staining, followed by flow cytometry analysis using a fluorescence microscope. The protein expression of SOD‑1, SOD‑2, B‑cell lymphoma‑2 (Bcl‑2), cytochrome c and caspase‑3 was determined by western blot analysis. Pretreatment with tanshinol resulted in a significant increase in the cellular viability of HUVECs and SOD activity, and a decrease of cell apoptosis, MDA levels and ROS production, induced by H2O2. These findings were accompanied by the upregulation of Bcl‑2 protein expression, reduction in the release of cytochrome c from the mitochondria to the cytosol and a downregulation of caspase‑3 protein expression. This study showed that tanshinol protects against atherosclerosis by preventing H2O2‑induced apoptosis of HUVECs. These effects appear to be mediated by enhancing the antioxidant defenses and preserving the mitochondrial function of the cells.

Allicin prevents H₂O₂-induced apoptosis of HUVECs by inhibiting an oxidative stress pathway

Background

Allicin, a primary ingredient of garlic, has been proposed to possess cardioprotective properties, which are commonly mediated by improved endothelial function.

Methods

To investigate the effect and mechanism of allicin on the apoptosis of human umbilical vein endothelial cells (HUVECs), we used Propidium iodide (PI) staining and Annexin V/ PI staining assays to establish a model of oxidative stress apoptosis induced by H₂O₂. MTT, RT-PCR and western-blot assays were used to detect the effects and mechanism of allicin on the model.

Results

PI staining, Annexin V/ PI staining assays and morphological assessment suggest that the cell death induced by 0.5 mM H₂O₂ is primarily apoptotic. Conversely, allicin reverses the effect of H₂O₂ on cell death, suggesting a role in protecting HUVECs from apoptosis. We demonstrated that H₂O₂ activates PARP cleavage, reduces pro-Caspase-3 levels and activates Bax expression; however, allicin inhibits each of these apoptotic signaling indicators. Allicin also reduces the levels of malondialdehyde and increases the levels of superoxide dismutase, nitric oxide release and endothelial nitric oxide synthase mRNA, but has no significant effect on inducible nitric oxide synthase mRNA levels.

Conclusion

These results demonstrate that allicin has powerful effects in protecting HUVECs from apoptosis and suggest that protection occurs via a mechanism involving the protection from H₂O₂-mediated oxidative stress.

Esterification enhanced intestinal absorption of ginsenoside Rh2 in Caco-2 cells without impacts on its protective effects against H₂O₂-induced cell injury in human umbilical vein endothelial cells (HUVECs)

Ginsenoside Rh2 and its octyl ester derivative (Rh2-O) were investigated for their transcellular transport in the Caco-2 cell system and their protective effect against oxidative stress in human umbilical vein endothelial cells (HUVECs). Results showed that the transport rates for apical-to-basolateral (AP-BL) flux of Rh2 (0.21 × 10⁻⁶ cm/s) was enhanced by the synthesis of its esterified derivative Rh2-O (1.93 × 10⁻⁶ cm/s) over the concentrations of 10-50 μM. In addition, both Rh2 and its esterified derivative Rh2-O exhibited similar protective effects against oxidative damage induced by H₂O₂. Pretreatment of Rh2 and Rh2-O significantly decreased the activation of caspase-3 known to play a key role in H₂O₂-induced cell apoptosis. These results were consistent with that of a flow cytometry assay analyzing HUVECs apoptosis. The present study demonstrated that the absorption of ginsenoside Rh2 in vitro can be significantly enhanced by synthesis of its ester derivative. Meanwhile, no significant discrepancy between Rh2 and Rh2-O on their bioactivities against the oxidative damage induced by H₂O₂ was observed, which means that esterification of Rh2 might have a higher bioavailability than Rh2 in vitro without impacts on pharmaceutical actions.

Protective effects of timosaponin B-II on high glucose-induced apoptosis in human umbilical vein endothelial cells

This study was designed to investigate the action of timosaponin B-II, a main bioactive compound in Anemarrhena asphodeloides Bunge, on the prevention from high glucose-induced cytotoxicity and apoptosis in human umbilical vein endothelial cells (HUVECs) and the potential mechanisms involved. The results showed that compared with the normal control group, exposure of HUVECs to high glucose media for 72 h resulted in a significant increase in lactates dehydrogenise release, reactive oxygen species production, Caspase-3 activity and the percentage of apoptotic cells (p<0.01). However, pretreatment with timosaponin B-II significantly increased the viability of HUVECs and decreased lactates dehydrogenise release, Caspase-3 activity and the apoptosis rate in a concentration-dependent manner (p<0.05). In addition, timosaponin B-II notably decreased the amount of reactive oxygen species and malondialdehyde, as well as promoted glutathione peroxidase activity, endothelial nitric oxide synthase activity and nitric oxide release (p<0.05). These results suggest that timosaponin B-II has the antiapoptotic effect in endothelial cells through inhibition of high glucose-induced oxidative stress and has the potential for preventing diabetic cardiovascular complications.

Curculigo orchioides protects cisplatin-induced cell damage

Cisplatin is commonly used as a chemotherapeutic agent against many human cancers. However, it generates reactive oxygen species (ROS) and has serious dose-limiting side effects, including ototoxicity. The roots of Curculigo orchioides (C. orchioides) have been used to treat auditory diseases such as tinnitus and hearing loss in Chinese traditional medicine. In the present study, we investigated the protective effects of an ethanol extract obtained from C. orchioides rhizome (COR) on cisplatin-induced cell damage in auditory cells (HEI-OC1). COR (2.5-25 μg/ml) inhibited cisplatin-induced HEI-OC1 cell damage in a dose-dependent manner. To investigate the protective mechanism of COR on cisplatin cytotoxicity in HEI-OC1 cells, we measured the effects of COR on ROS generation and lipid peroxidation in cisplatin-treated cells as well as its scavenging activities against superoxide radicals, hydroxyl radicals, hydrogen peroxide, and DPPH radicals. COR (1-25 μg/ml) had scavenging activities against superoxide radicals, hydroxyl radicals, hydrogen peroxide, and DPPH radicals, as well as reduced lipid peroxidation. In in vivo experiments, COR was shown to reduce cochlear and peripheral auditory function impairments through cisplatin-induced auditory damage in mice. These results indicate that COR protects from cisplatin-induced auditory damage by inhibiting lipid peroxidation and scavenging activities against free radicals.

Medicinal plants of genus Curculigo: traditional uses and a phytochemical and ethnopharmacological review

ETHNOPHARMACOLOGICAL RELEVANCE

In the genus Curculigo, Curculigo orchioides Gaertn, Curculigo capitulata (Lour) O. Ktze and Curculigo pilosa (Schumach. & Thonn.) Engl are often used in traditional medicine. Curculigo orchioides is used for the treatment of impotence, limb limpness, arthritis of the lumbar and knee joints, and watery diarrhea in traditional Chinese medicine, and also used as a potent immunomodulator and aphrodisiac in the Ayurvedic medical system. Curculigo capitulata is used for the treatment of consumptive cough, kidney asthenia, impotence and spermatorrhea, hemorrhoids, asthma, jaundice, diarrhea, colic and gonorrhea in traditional Chinese and India medicine, and to treat urinary tract infection, acute renal pelvis and nephritis, nephritis-edema, cystitis, nephrolithiasis, hypertension and rheumatic arthritis in traditional Dai medicine. Curculigo pilosa are applied to treat gastrointestinal and heart diseases in Africa.

AIM OF THE REVIEW

This review aims to exhibit up-to-date and comprehensive information about traditional uses, phytochemistry, pharmacology and toxicology of medicinal plants in the genus Curculigo, and has an insight into the opportunities for the future research and development of Curculigo plant.

METHODS

A bibliographic investigation was performed by analyzing the information available on Curculigo plant from worldwide accepted scientific databases (Pubmed, Scopus and Web of Science, SciFinder, Google Scholar, Yahoo). Furthermore, information also was obtained from some local and foreign books on ethnobotany and ethnomedicines.

RESULTS

Curculigo orchioides, Curculigo capitulata and Curculigo pilosa have been used as traditional medicine to treat kinds of diseases such as impotence, limb limpness, gastrointestinal and heart diseases, etc. Phytochemical investigation of eight species of the genus Curculigo has resulted in identification of more than 110 compounds. The content of curculigoside is used as an indicator to evaluate the quality of rhizome of Curculigo orchioides. The medicinal plants have showed a wide spectrum pharmacological activities, including adaptive, immunostimulatory, taste-modifying and sweet-tasting, antioxidant, mast cell stabilization, antihistaminic and antiasthmatic, hepatoprotective and neuroprotective activity. Toxicological test indicated that Curculigo orchioides at the dose of 120 g/kg after administrating rats for 180 days may cause injury of liver and kidney.

CONCLUSION

The medicinal plants of genus Curculigo have emerged as a good source of the traditional medicines. Some uses of these plants in the traditional medicines have been validated by pharmacological investigation. However, the mechanism of their actions should be further elucidated; the particular constituent responsible for toxicity should be isolated and identified, and the target tissue and mechanism of toxic ingredients also deserve to be further investigated; more reference substances should be prepared, and sophisticated analytical technologies should be developed to comprehensively assess the quality of Curculigo herbs. These investigations will be helpful for further utilization of the plants of genus Curculigo.

Effect of Curculigo orchioides on reflux esophagitis by suppressing proinflammatory cytokines

This study was performed to investigate effects of Curculigo orchioides rhizome (curculiginis rhizome) on acute reflux esophigitis (RE) in rats that are induced by pylorus and forestomach ligation operation. Proinflammatory cytokine, as well as tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6 were all assayed and the expression of TNF-α and COX2 analyzed by RT-PCR. The esophagic tissue damage of reflux esophagitis rat was increased compared to that of normal intact group. However, the esophagic damage percentage from the extract of curculiginis rhizoma (ECR) 600 mg/kg and ECR 300 mg/kg were significantly lower than that of the RE control group. Administration of α-tocopherol (30 mg/kg) and ECR (600 mg/kg, 300 mg/kg, and 150 mg/kg) had a significant effect on the gastric acid pH in rats with induced reflux esophagitis (p < 0.05). The treatment with ECR significantly reduced the production of cytokines TNF-α, IL-1β and IL-6 levels compared to the model group (p < 0.05). The expression of TNF-α and COX2 in the intact esophageal mucosa was low while those of the RE control group were significantly higher due to an inflammatory reaction in the esophagus. Compare to the model group, treatment with α-tocopherol or ECR significantly inhibited the expression levels of COX2 and TNF-α in a dose-dependent manner. These results suggest that anti-inflammatory and protective effects of ECR could attenuate the severity of reflux esophagitis and prevent esophageal mucosal damage.

6-Shogaol Protects against Oxidized LDL-Induced Endothelial Injruries by Inhibiting Oxidized LDL-Evoked LOX-1 Signaling

Endothelial dysfunction and oxLDL are believed to be early and critical events in atherogenesis. 6-Shogaol is the major bioactive compound present in Zingiber officinale and possesses the anti-atherosclerotic effect. However, the mechanisms remain poorly understood. The goal of this study was to investigate the effects of 6-shogaol on oxLDL-induced Human umbilical vein endothelial cells (HUVECs) injuries and its possible molecular mechanisms. Hence, we studied the effects of 6-shogaol on cell apoptosis, cellular reactive oxygen species (ROS), NF-κB activation, Bcl-2 expression, and caspase -3, -8, -9 activities. In addition, E-selectin, MCP-1, and ICAM-1 were determined by ELISA. Our study show that oxLDL increased LOX-1 expression, ROS levels, NF-κB, caspases-9 and -3 activation and decreased Bcl-2 expression in HUVECs. These alterations were attenuated by 6-shogaol. Cotreatment with 6-shogaol and siRNA of LOX-1 synergistically reduced oxLDL-induced caspases -9, -3 activities and cell apoptosis. Overexpression of LOX-1 attenuated the protection by 6-shogaol and suppressed the effects of 6-shogaol on oxLDL-induced oxidative stress. In addition, oxLDL enhanced the activation of NF-κB and expression of adhesion molecules. Pretreatment with 6-shogaol, however, exerted significant cytoprotective effects in all events. Our data indicate that 6-shogaol might be a potential natural antiapoptotic agent for the treatment of atherosclerosis.

Ameliorative effects of curculigoside from Curculigo orchioides Gaertn on learning and memory in aged rats

This study was designed to evaluate the ameliorating effects of curculigoside from Curculigo orchioides Gaertn on learning and memory in aged rats. In the present study, the ameliorating effects of curculigoside were determined through animal behaviour studies (including step-down test and Y-maze test), and the possible mechanisms were explored by evaluation of the activity of acetylcholinesterase (AchE) and determination of the expression of BACE1. Oral adminstration of the curculigoside (20, 40 mg/kg/day) for 14 days can significantly improve the latency and number of errors in aged rats based on the behaviour study results. In addition, the activity of AchE can be decreased by treatment of the curculigoside (10, 20, 40 mg/kg/day). Moreover, the expression of BACE1 can be down-regulated in the hippocampus of aged rats treated with curculigoside. The results of our present work have indicated that curculigoside can improve cognitive function in aged animals, possibly by decreasing the activity of AchE in the cerebra and inhibiting the expression of BACE1 in the hippocampus. In conclusion, our results suggested that curculigoside can be possible developed as a new drug for the treatment of Alzheimer's disease in the future.

Effects of Low-Dose versus High-Dose γ-Tocotrienol on the Bone Cells Exposed to the Hydrogen Peroxide-Induced Oxidative Stress and Apoptosis

Oxidative stress and apoptosis can disrupt the bone formation activity of osteoblasts which can lead to osteoporosis. This study was conducted to investigate the effects of γ-tocotrienol on lipid peroxidation, antioxidant enzymes activities, and apoptosis of osteoblast exposed to hydrogen peroxide (H₂O₂). Osteoblasts were treated with 1, 10, and 100 μM of γ-tocotrienol for 24 hours before being exposed to 490 μM (IC₅₀) H₂O₂ for 2 hours. Results showed that γ-tocotrienol prevented the malondialdehyde (MDA) elevation induced by H₂O₂ in a dose-dependent manner. As for the antioxidant enzymes assays, all doses of γ-tocotrienol were able to prevent the reduction in SOD and CAT activities, but only the dose of 1 μM of GTT was able to prevent the reduction in GPx. As for the apoptosis assays, γ-tocotrienol was able to reduce apoptosis at the dose of 1 and 10 μM. However, the dose of 100 μM of γ-tocotrienol induced an even higher apoptosis than H₂O₂. In conclusion, low doses of γ-tocotrienol offered protection for osteoblasts against H₂O₂ toxicity, but itself caused toxicity at the high doses.

Water Caltrop Pericarps Extracts Attenuate H2O2-Induced Human Umbilical Vein Endothelial Cell Injury

Natural antioxidants could inhibit ROS production and attenuate injury, which is important event of cardiovascular diseases. Water caltrop pericarps from three different Chinese water caltrop cultivars were collected and extracted using 70% methanol and hot water (WCPE). WCPE exhibited strong in vitro antioxidant activities tested by DPPH assay. Incubation with 100μM H2O2 for 1 h would reduce viability of HUVECs to 76.46±0.05%, decrease SOD, CAT and GSH-Px activities to 12.50±0.06, 10.08±0.57 and 107.98±2.68 U/mg protein compared with 20.57±0.02, 22.56±0.41 and 215.28±23.13 U/mg protein of normal cells, increase MDA content from 3.31±0.38 to 9.52±1.87 nmol/mg protein. Pre-treatment, post-treatment and simultaneous with WCPE could attenuate HUVECs injury and recover the viability to 107.77±0.06%, SOD, CAT and GSH-Px activities to 19.11±0.02, 26.14±0.89 and 192.62±7.75 U/mg protein and MDA content to 4.31±0.71 nmol/mg protein. These results suggested that WCPE attenuates H2O2-induced HUVECs injury through promoting proliferation, enhance antioxidant enzymes activities and reduce lipid peroxidation.

Curculigoside isolated from Curculigo orchioides prevents hydrogen peroxide-induced dysfunction and oxidative damage in calvarial osteoblasts

Reactive oxygen species (ROS), including H(2)O(2), play a critical role in the pathophysiology of osteoporosis. Therefore, agents or antioxidants that can inhibit ROS production have a high clinical value in the treatment of osteoporosis. Curculigoside (CUR), one of the main bioactive phenolic compounds isolated from the rhizome of Curculigo orchioides Gaertn., is reported to have potent antioxidant and anti-osteoporotic properties. However, there is no direct evidence to link the antioxidant capacity of CUR with the observed anti-osteoporotic effect, and relevant molecular mechanisms remain unclear. Therefore, we investigated the protective effects of CUR against oxidative stress in calvarial osteoblasts and discussed the related mechanisms. It was found that osteoblast viability decreased significantly after 48-h exposure to 400 μM of H(2)O(2), compared with vehicle-treated cells, and the cytotoxic effect of H(2)O(2) was reversed significantly when pretreated with 0.1-10 μM of CUR (P< 0.05). Pretreatment with 0.1-10 μM of CUR decreased ROS production and lipid peroxidation, and increased the activities of antioxidant enzymes, such as superoxide dismutase and glutathione peroxidase in osteoblasts induced by H(2)O(2). In addition, H(2)O(2)-induced reduction of differentiation markers such as alkaline phosphatase, calcium deposition, and Runx2 level was significantly recovered in the presence of CUR. CUR also reversed H(2)O(2)-induced stimulation of extracellular signal-regulated kinase 1/2, and nuclear factor-κB signaling and the inhibition of p38 mitogen-activated protein kinase activation. These results provide new insights into the osteoblast-protective mechanisms of CUR through reducing the production of ROS, suggesting that CUR may be developed as a bio-safe agent for the prevention and treatment of osteoporosis and other bone-related human diseases.