Ilexgenin A

Ilexgenin A inhibits mitochondrial fission and promote Drp1 degradation by Nrf2-induced PSMB5 in endothelial cells.[Pubmed:30762899]

Drug Dev Res. 2019 Feb 14.

Atherosclerosis (AS) is one of important events involving in the pathological process of coronary artery disease. Many traditional Chinese medicines have been widely used for the treatment of AS. Previous studies have demonstrated that Ilexgenin A (IA) obtained from Ilex hainanensis Merr. could improve AS development. However, its underlying mechanism is still unknown. This study was conducted to explore the possible targets and mechanisms involving in the anti-atheroclerosis effect of IA. The results showed IA significantly promoted NO production, reduced reactive oxygen species (ROS) generation, and inflammatory cytokine production induced by palmitate (PA) in endothelial cells, demonstrating IA could improve endothelial dysfunction. Meanwhile, IA dramatically inhibited dynamin-related protein 1 (Drp1) expression and mitochondrial fission induced by PA whereas proteasome inhibitor epoxomicin attenuated its effect on Drp1 expression, indicating IA decreased Drp1 expression with regulation of proteasome. Furthermore, IA also could increase the expression of proteasome subunit beta type5 (PSMB5) and activate nuclear factor-like 2 (Nrf2). Nrf2 knockdown eliminated the induction effect of IA on PSMB5 expression while abrogated its inhibition on ROS generation and mitochondrial fission stimulated by PA. These results demonstrated that IA could promote PSMB5 expression in an Nrf2-dependent manner, resulting in the suppression of mitochondrial fission, and thus improve endothelial dysfunction. These findings laid a foundation to the future development of IA as an agent to the prevention and treatment of AS.

Ilexgenin A enhances the effects of simvastatin on non-alcoholic fatty liver disease without changes in simvastatin pharmacokinetics.[Pubmed:30047465]

Chin J Nat Med. 2018 Jun;16(6):436-445.

Cardiovascular disease (CVD) is the most common cause of death in patients with non-alcoholic fatty liver disease (NAFLD). New therapeutic strategies which have the potential for slowing down the evolution of NAFLD and reducing CVD-related mortality are urgently needed. Statins are well recognized in the treatment of dyslipidemia, but their use in the treatment of NAFLD is limited due to the safety concerns. Ilexgenin A (IA) is one of the main bioactive compounds in 'Shan-lv-cha', an herbal tea commonly used in China. In the present study, we investigated the possible synergistic therapeutic effects of IA and simvastatin (SV) on NAFLD. IA or SV showed beneficial effects on the rats with NAFLD by lowering the liver weight, liver index and plasma levels of alanine aminotransferase and aspartate aminotransferase, regulating abnormal metabolism of lipids and ameliorating steatosis in liver. IA significantly enhanced the hypolipidemic and anti-inflammation effects of SV. Furthermore, a sensitive, accurate, convenient and reproducible LC-MS method was developed to investigate the effects of IA on the pharmacokinetics of SV. No significant changes were observed in pharmacokinetic parameters of SV and simvastatin hydroxy acid in the IA plus SV co-treated group in comparison with those in the group treated with SV alone. The mRNA levels and activity of CYP3A1 were not altered by IA. In conclusion, the results obtained from the present study should be helpful for further clinical application of SV and IA alone or in combination.

[Determination of three pair of triterpenoid isomers in leaf of Ilex hainanensis by HPLC-ELSD].[Pubmed:29751714]

Zhongguo Zhong Yao Za Zhi. 2018 Apr;43(8):1662-1666.

The present study is to develop an HPLC-ELSD method for simultaneous determination of three pairs of triterpenoid isomers, Ilexsaponin A(1), Ilexhainanoside D, Ilexgenin A, 3beta, 19alpha-dihydroxyolean-12-ene-24, 28-dioic acid (ilexhainanin E) ursolic acid and oleanic acid in the leaf of Ilex hainanensis, which could provide evidence to the quality control of this herb. The six constituents were measured on a Waters XBridge C(1)(8) column (4.6 mmx250 mm, 5 mum), with a mobile phase consisting of methanol (A)- 0.5% formic acid in water (B) at a flow rate of 1.0 mL.min(-)(1) (0-18 min70%-85% A18-20 min85%-95% A20-35 min95% A). The carrier gas was N(2), and the pressure was 2.8 L.min(-)(1). The drift tube in this experiment were set at 70 degrees C. The injection volume was 10 muL. The contents of the six triterpenoids in 6 samples were 3.7-8.5, 10.3 -22.1, 2.8-5.9, 7.8-14.1, 2.6-3.8 and 8.8-11.9 mg.g(-)(1), respectively. The established method is proved to be accurate and sensitive for the determination of triterpenoids in Ilicis Hainanensis Folium, and may be used for the quality improvement of this herb.

Inhibition of lipolysis by ilexgenin A via AMPK activation contributes to the prevention of hepatic insulin resistance.[Pubmed:28739087]

Eur J Pharmacol. 2017 Oct 15;813:84-93.

Adipose dysfunction links tightly to hepatic insulin resistance and gluconeogenesis. Ilexgenin A is reported with the ability to regulate lipid profile and protect the liver against high fat diet (HFD) -induced impairment. Here, we propose that Ilexgenin A ameliorates hepatic insulin signaling and gluconeogenesis by regulating lipolysis in white adipose tissue (WAT). Pyruvate tolerance test and biochemical analysis coupled with the ex vivo siRNA knockdown and co-culture studies demonstrate that Ilexgenin A suppresses inflammation-associated lipolysis in epididymal fat pad via 5'-AMP-activated protein kinase (AMPK) activation, thus inhibits diacylglycerol (DAG) accumulation and protein kinase C epsilon (PKCepsilon) translocation in liver, leading to the improvement of insulin sensitivity and hepatic glucose production. These findings suggest that the relationship between adipose function and hepatic insulin action may be targeted by natural bioactive components for the potential treatment of hepatic insulin resistance related disorders.

Ilexgenin A, a novel pentacyclic triterpenoid extracted from Aquifoliaceae shows reduction of LPS-induced peritonitis in mice.[Pubmed:28104349]

Eur J Pharmacol. 2017 Feb 15;797:94-105.

Ilexgenin A (IA) is a novel pentacyclic triterpenoid, which extracted from leaves of Ilex hainanensis Merr. In the present study, we aim to explore anti-inflammatory activity of IA on LPS-induced peritonitis and its underlying molecular mechanism. The results determined that IA was capable of suppressing peritonitis in mice induced by intraperitoneal (i.p.) injection of lipopolysaccaride (LPS). Furthermore, the results showed that IA dramatically inhibited levels of inflammatory cells infiltration in peritoneal cavity and serum in LPS-induced mice peritonitis model. Besides, IA could dramatically inhibit levels of inflammatory cytokines (IL-1beta, IL-6 and TNF-alpha) in peritoneal cavity in LPS-induced mice peritonitis model. In vitro study, the results showed that IA inhibited production of IL-1beta, IL-6 and TNF-alpha at transcriptional and translational levels in RAW 264.7 cells induced by LPS. Furthermore, IA could suppress the LPS-induced activation of Akt and downstream degradation and phosphorylation of kappa B-alpha (IkappaB-alpha). Moreover, IA could significantly inhibit ERK 1/2 phosphorylation in RAW 264.7 cells induced by LPS. These results were concurrent with molecular docking which revealed ERK1/2 inhibition. These results demonstrated that IA might as an anti-inflammatory agent candidate for inflammatory disease therapy.

Ilexgenin A exerts anti-inflammation and anti-angiogenesis effects through inhibition of STAT3 and PI3K pathways and exhibits synergistic effects with Sorafenib on hepatoma growth.[Pubmed:27986624]

Toxicol Appl Pharmacol. 2017 Jan 15;315:90-101.

Recently, we reported that Ilexgenin A exhibits anti-cancer activities and induces cell arrest. Here, we investigated the effect of Ilexgenin A on the inflammation, angiogenesis and tumor growth of hepatocellular carcinoma (HCC). Our current study revealed that Ilexgenin A significantly inhibited the inflammatory cytokines TNF-alpha and IL-6 levels and downregulated pro-angiogenic factor VEGF production and transcription in HepG2 cells. The underlying mechanism for Ilexgenin A effects appears to be through inhibiting STAT3 and PI3K pathways. Furthermore, we found that not only Ilexgenin A inhibited STAT3 and PI3K pathways in HepG2 cells but also blocked these signaling pathways in HUVECs. Most importantly, by employing two HCC xenografts models - HepG2 and H22, we showed that Ilexgenin A reduced tumor growth and exhibited synergy effect with Sorafenib. ELISA assay, histological analysis and immunohistochemistry examination revealed that the expression of VEGF and MVD was significantly decreased after the treatment with Ilexgenin A and the combination. Moreover, Ilexgenin A could enhance caspase-3/7 activity in vitro and transmission electron microscope indicated that the combination induced evident apoptosis of tumor cells and caused the structural changes of mitochondria in vivo. Although no apparent adverse effects occurred during the treatment period, Sorafenib monotherapy elicited hepatotoxicity for specific expression in the increased level of AST and the ratio of AST/ALT. However, the combination could remedy this adverse effect. In conclusion, the results described in the present study identifies Ilexgenin A as a promising therapeutic candidate that modulates inflammation, angiogenesis, and HCC growth.

A novel pentacyclic triterpenoid, Ilexgenin A, shows reduction of atherosclerosis in apolipoprotein E deficient mice.[Pubmed:27588911]

Int Immunopharmacol. 2016 Nov;40:115-124.

Ilexgenin A (IA), a novel pentacyclic triterpenoid, is a compound extracted from leaves of Ilex hainanensis Merr. In this study, we explored the efficacy of IA on atherosclerosis and its underlying mechanism. We determined that treatment with IA attenuated atherosclerosis in high-fat diet-induced apolipoprotein E deficient mice via a series of effects involving regulation of lipid parameters, decrease of atherosclerosis-related indexes, inhibition of inflammatory cytokines secretion and pathological changes of main organs. Furthermore, the underlying mechanism of IA was investigated on oxidized low-density lipoprotein (Ox-LDL)-induced THP-1 cells. We showed that pre-treatment with IA decreased active inflammation cytokines involving interleukin-6 (IL-6), IL-1 and tumor necrosis factor-alpha (TNF-alpha) expression in a concentration-dependent manner. In addition, we confirmed that IA inhibited the phosphatidylinositol 3-kinase (PI3K), protein kinase B (Akt), IKKalpha phosphorylation and NF-kappaB activity induced by Ox-LDL. Overall, these findings define IA as a novel drug candidate for anti-atherosclerotic therapy.

Ilexgenin A inhibits endoplasmic reticulum stress and ameliorates endothelial dysfunction via suppression of TXNIP/NLRP3 inflammasome activation in an AMPK dependent manner.[Pubmed:26054569]

Pharmacol Res. 2015 Sep;99:101-15.

Ilexgenin A is a natural triterpenoid with beneficial effects on lipid disorders. This study aimed to investigate the effects of Ilexgenin A on endothelial homeostasis and its mechanisms. Palmitate (PA) stimulation induced endoplasmic reticulum stress (ER stress) and subsequent thioredoxin-interacting protein (TXNIP)/NLRP3 inflammasome activation in endothelial cells, leading to endothelial dysfunction. Ilexgenin A enhanced LKB1-dependent AMPK activity and improved ER stress by suppression of ROS-associated TXNIP induction. However, these effects were blocked by knockdown of AMPKalpha, indicating AMPK is essential for its action in suppression of ER stress. Meanwhile, Ilexgenin A inhibited NLRP3 inflammasome activation by down-regulation of NLRP3 and cleaved caspase-1 induction, and thereby reduced IL-1beta secretion. It also inhibited inflammation and apoptosis exposed to PA insult. Consistent with these results in endothelial cells, Ilexgenin A attenuated ER stress and restored the loss of eNOS activity in vascular endothelium, and thereby improved endothelium-dependent vasodilation in rat aorta. A further analysis in high-fat fed mice showed that oral administration of Ilexgenin A blocked ER stress/NLRP3 activation with reduced ROS generation and increased NO production in vascular endothelium, well confirming the beneficial effect of Ilexgenin A on endothelial homeostasis in vivo. Taken together, these results show ER stress-associated TXNIP/NLRP3 inflammasome activation was responsible for endothelial dysfunction and Ilexgenin A ameliorated endothelial dysfunction by suppressing ER-stress and TXNIP/NLRP3 inflammasome activation with a regulation of AMPK. This finding suggests that the application of Ilexgenin A is useful in the management of cardiovascular diseases in obesity.

Ilexgenin A induces B16-F10 melanoma cell G1/S arrest in vitro and reduces tumor growth in vivo.[Pubmed:25596038]

Int Immunopharmacol. 2015 Feb;24(2):423-431.

The present study aimed to investigate the anti-tumor activity of Ilexgenin A in B16-F10 murine melanoma and to evaluate its effect on the production of tumor-associated inflammatory cytokines. In vitro, our study showed that Ilexgenin A inhibited the proliferation of B16-F10 murine melanoma cells in a dose- and time-dependent manner, and this effect could be ascribed to the arrest of the cell cycle at G0/G1. In vivo, we evaluated the anti-tumor activity of Ilexgenin A in a tumor-bearing mouse model. The results showed that Ilexgenin A reduced the tumor weight by 51.13% (p<0.01). The Ilexgenin A treatment groups showed no apparent side effects during the treatment period. In addition, a histological analysis revealed that Ilexgenin A changed the cell morphology, and induced large areas of necrosis that correlated with a reduction in tumor size. The detection of inflammatory cytokines indicated that the IL-6 level decreased (p<0.001) and the TNF-alpha level increased (p<0.01) in mice treated with Ilexgenin A. Ilexgenin A also inhibited the IL-6 production of macrophages stimulated by melanoma conditioned medium (MCM) significantly (p<0.001). Importantly, Ilexgenin A dramatically prolonged survival time (p<0.001). In conclusion, Ilexgenin A could be regarded as a promising agent for the treatment of melanoma; it exerts anti-melanoma activity by arresting the cell cycle at G0/G1 and regulating IL-6 and TNF-alpha production.

Pharmacokinetic study of major bioactive components in rats after oral administration of extract of Ilex hainanensis by high-performance liquid chromatography/electrospray ionization mass spectrometry.[Pubmed:23384548]

J Pharm Biomed Anal. 2013 Apr 15;77:21-8.

Ilex hainanensis Merr. is commonly used as a folk remedy for treating hypertension, dyslipidemia and inflammation in Traditional Chinese Medicine (TCMs) and it also has great potential to treat non-alcoholic fatty liver disease (NAFLD). Chlorogenic acid, kaempferol-7-O-beta-d-glucoside, and Ilexgenin A are three major bioactive components in I. hainanensis extract. In this study, a rapid, sensitive and convenient LC-MS method was developed for their simultaneous determination in the plasma of normal and NAFLD rats. The method was validated in terms of selectivity, linearity and sensitivity, and shows advantages in monitoring the pharmacokinetic behaviors of these three compounds. Results revealed the pharmacokinetic behaviors of chlorogenic acid, kaempferol-7-O-beta-d-glucoside, and Ilexgenin A could be significantly changed in NAFLD rats after oral administration of I. hainanensis extract compared with normal rats. The areas under the plasma concentration-time curve (AUC) and maximum plasma concentration (Cmax) of the three analytes were greatly decreased and the plasma clearance (CL) for kaempferol-7-O-beta-d-glucoside, Ilexgenin A were greatly increased in NAFLD rats. Meanwhile, the mean residence time (MRT) of kaempferol-7-O-beta-d-glucoside and Ilexgenin A were increased in the NAFLD rats. This is the first report on the determination of the major bioactive components in rat plasma after oral administration of I. hainanensis extract. These results provided a meaningful basis for evaluating the clinical application of this medicine.