Icaritin ameliorates carbon tetrachloride-induced acute liver injury mainly because of the antioxidative function through estrogen-like effects

Estrogen receptor-mediated health benefits of phytochemicals: a review

Estrogen receptors (ERs) are transcription factors with two subtypes: estrogen receptor alpha (ERα) and estrogen receptor beta (ERβ), which are essential for the maintenance of human health and play a regulatory role in common diseases such as breast cancer, osteoporosis, neurodegenerative disorders, liver injuries and lung cancers. A number of phytochemicals extracted from various fruits and vegetables have been demonstrated to exhibit estrogenic effects and are termed phytoestrogens. As modulators of ERs, phytoestrogens can be involved in the prevention and treatment of multiple diseases as complementary or alternative therapeutic agents and have a variety of health benefits for humans. This article reviews the health benefits of phytoestrogens in clinical and epidemiologic studies for several diseases and also provides a detailed description of the molecular mechanisms of their action. A brief comparison of the advantages and disadvantages of natural phytochemicals compared to synthetic drugs is also presented. The role of phytoestrogens in the treatment of diseases and human health requires further research to fully realize their therapeutic potential.

Icaritin inhibits endometrial carcinoma cells by suppressing O-GlcNAcylation of FOXC1

BACKGROUND

Icaritin has a wide range of pharmacological activities, including significant an-titumor activity. However, the mechanism of action of icaritin in endometrial cancer (UCEC) remains unknown. FOX proteins are a highly conserved transcription factor superfamily that play important roles in epithelial cell differentiation, tumor metastasis, angiogenesis, and cell cycle regulation. FOXC1 is an important member of the FOX protein family. FOXC1 is aberrantly expressed in endometrial cancer and may play a role in the migration and invasion of endometrial cancer; however, its mechanism of action has not yet been reported. O-GlcNAc glycosylation is a common post-translational modification. In endometrial cancer, high levels of O-GlcNAcylation promote cell proliferation, migration, and invasion. Cancer development is often accompanied by O-GlcNAc modification of proteins; however, O-GlcNAc modification of the transcription factor FOXC1 has not been reported to date.

PURPOSE

To investigate the inhibitory effects of icaritin on RL95-2 and Ishikawa endometrial cancer cells in vitro and in vivo and to elucidate the possible molecular mechanisms.

METHODS/STUDY DESIGN

CCK8, colony formation, migration, and invasion assays were used to determine the inhibitory effects of icaritin on endometrial cancer cells in vitro. Cell cycle regulation was assayed by flow cytometry. Protein levels were measured based on western blotting. The level of FOXC1 expression in endometrial cancer tissues was determined by immunohistochemistry. To assess whether icaritin also has activity in vivo, its effect on tumor xenografts was evaluated.

RESULTS

Immunohistochemical analysis of clinical samples revealed that FOXC1 expression was significantly higher in endometrial cancer tissues than in normal tissues. Downregulation of FOXC1 inhibited the proliferative, colony formation, migration, and invasive abilities of RL95-2 and Ishikawa endometrial cancer cells. Icaritin inhibited the proliferation, colony formation, migration, and invasion of endometrial cancer cells and blocked the cell cycle in S phase. Icaritin affected O-GlcNAc modification of FOXC1 and thus the stability of FOXC1, which subsequently triggered the inhibition of endometrial cancer cell proliferation.

CONCLUSION

The anti-endometrial cancer effect of icaritin is related to the inhibition of abnormal O-GlcNAc modification of FOXC1, which may provide an important theoretical foundation for the use of icaritin against endometrial cancer.

Based on network pharmacology and molecular docking to explore the protective effect of Epimedii Folium extract on cisplatin-induced intestinal injury in mice

Background: Epimedii Folium, as a natural botanical medicine, has been reported to have protective effects on intestinal diseases by modulating multiple signaling pathways. This study aimed to explore the potential targets and molecular mechanisms of Epimedii Folium extract (EFE) against cisplatin-induced intestinal injury through network pharmacology, molecular docking, and animal experiments.

Methods: Network pharmacology was used to predict potential candidate targets and related signaling pathways. Molecular docking was used to simulate the interactions between significant potential candidate targets and active components. For experimental validation, mice were intraperitoneally injected with cisplatin 20 mg/kg to establish an intestinal injury model. EFE (100, 200 mg/kg) was administered to mice by gavage for 10 days. The protective effect of EFE on intestinal injury was analyzed through biochemical index detection, histopathological staining, and western blotting.

Results: Network pharmacology analysis revealed that PI3K-Akt and apoptosis signaling pathways were thought to play critical roles in EFE treatment of the intestinal injury. Molecular docking results showed that the active constituents of Epimedii Folium, including Icariin, Epimedin A, Epimedin B, and Epimedin C, stably docked with the core AKT1, p53, TNF-α, and NF-κB. In verified experiments, EFE could protect the antioxidant defense system by increasing the levels of glutathione peroxidase (GSH-Px) and catalase (CAT) while reducing the content of malondialdehyde (MDA). EFE could also inhibit the expression of NF-κB and the secretion of inflammatory factors, including TNF-α, IL-1β, and IL-6, thereby relieving the inflammatory damage. Further mechanism studies confirmed that EFE had an excellent protective effect on cisplatin-induced intestinal injury by regulating PI3K-Akt, caspase, and NF-κB signaling pathways.

Conclusion: In summary, EFE could mitigate cisplatin-induced intestinal damage by modulating oxidative stress, inflammation, and apoptosis.

Hawk Tea Flavonoids as Natural Hepatoprotective Agents Alleviate Acute Liver Damage by Reshaping the Intestinal Microbiota and Modulating the Nrf2 and NF-κB Signaling Pathways

Hawk tea (Litsea coreana Levl. var. lanuginosa) is a traditional herbal tea in southwestern China, and was found to possess hepatoprotective effects in our previous study. However, it is unclear whether hawk tea flavonoids (HTF) can alleviate alcoholic liver damage (ALD). Firstly, we extracted and identified the presence of 191 molecules categorized as HTFs, with reynoutrin, avicularin, guaijaverin, cynaroside, and kaempferol-7-O-glucoside being the most prevalent. After taking bioavailability into consideration and conducting comprehensive sorting, the contribution of guaijaverin was the highest (0.016 mg/mice). Then, by daily intragastric administration of HTF (100 mg/kg/day) to the ALD mice, we found that HTF alleviated liver lipid deposition (inhibition of TG, TC, LDL-C) by reducing liver oxidative-stress-mediated inflammation (up-regulation NRF2/HO-1 and down-regulation TLR4/MyD88/NF-κB pathway) and reshaping the gut microbiota (Lactobacillus, Bifidobacterium, Bacillus increased). Overall, we found HTF could be a potential protective natural compound for treating ALD via the gut–liver axis and guaijaverin might be the key substance involved.

Mechanism of hydroxysafflor yellow A on acute liver injury based on transcriptomics

Objective: To investigate how Hydroxysafflor yellow A (HSYA) effects acute liver injury (ALI) and what transcriptional regulatory mechanisms it may employ.

Methods: Rats were randomly divided into five groups (n = 10): Control, Model, HSYA-L, HSYA-M, and HSYA-H. In the control and model groups, rats were intraperitoneally injected with equivalent normal saline, while in the HSYA groups, they were also injected with different amounts of HSYA (10, 20, and 40 mg/kg/day) once daily for eight consecutive days. One hour following the last injection, the control group was injected into the abdominal cavity with 0.1 ml/100 g of peanut oil, and the other four groups got the same amount of a peanut oil solution containing 50% CCl4. Liver indexes were detected in rats after dissection, and hematoxylin and eosin (HE) dyeing was utilized to determine HSYA’s impact on the liver of model rats. In addition, with RNA-Sequencing (RNA-Seq) technology and quantitative real-time PCR (qRT-PCR), differentially expressed genes (DEGs) were discovered and validated. Furthermore, we detected the contents of anti-superoxide anion (anti-O2−) and hydrogen peroxide (H2O2), and verified three inflammatory genes (Icam1, Bcl2a1, and Ptgs2) in the NF-kB pathway by qRT-PCR.

Results: Relative to the control and HSYA groups, in the model group, we found 1111 DEGs that were up-/down-regulated, six of these genes were verified by qRT-PCR, including Tymp, Fabp7, Serpina3c, Gpnmb, Il1r1, and Creld2, indicated that these genes were obviously involved in the regulation of HSYA in ALI model. Membrane rafts, membrane microdomains, inflammatory response, regulation of cytokine production, monooxygenase activity, and iron ion binding were significantly enriched in GO analysis. KEGG analysis revealed that DEGs were primarily enriched for PPAR, retinol metabolism, NF-kB signaling pathways, etc. Last but not least, compared with the control group, the anti-O2− content was substantially decreased, the H2O2 content and inflammatory genes (Icam1, Bcl2a1, and Ptgs2) levels were considerably elevated in the model group. Compared with the model group, the anti-O2− content was substantially increased, the H2O2 content and inflammatory genes (Icam1, Bcl2a1, and Ptgs2) levels were substantially decreased in the HSYA group (p < 0.05).

Conclusion: HSYA could improve liver function, inhibit oxidative stress and inflammation, and improve the degree of liver tissue damage. The RNA-Seq results further verified that HSYA has the typical characteristics of numerous targets and multiple pathway. Protecting the liver from damage by regulating the expression of Tymp, Fabp7, Serpina3c, Gpnmb, Il1r1, Creld2, and the PPAR, retinol metabolism, NF-kappa B signaling pathways.

Recent advances in the synthesis of natural products containing the phloroglucinol motif

Covering: June 2009 to 2021Natural products containing a phloroglucinol motif include simple and oligomeric phloroglucinols, polycyclic polyprenylated acylphloroglucinols, phloroglucinol-terpenes, xanthones, flavonoids, and coumarins. These compounds represent a major class of secondary metabolites which exhibit a wide range of biological activities such as antimicrobial, anti-inflammatory, antioxidant and hypoglycaemic properties. A number of these compounds have been authorized for therapeutic use or are currently being studied in clinical trials. Their structural diversity and utility in both traditional and conventional medicine have made them popular synthetic targets over the years. In this review, we compile and summarise the recent synthetic approaches to the natural products bearing a phloroglucinol motif. Focus has been given on ingenious strategies to functionalize the phloroglucinol moiety at multiple positions. The isolation and bioactivities of the compounds are also provided.

Icaritin protects SH-SY5Y cells transfected with TDP-43 by alleviating mitochondrial damage and oxidative stress

Background

The aim of this study was to investigate the effect of icaritin (ICT) on TAR DNA-binding protein 43 (TDP-43)-induced neuroblastoma (SH-SY5Y) cell damage and to further explore its underlying mechanisms.

Methods

To investigate the possible mechanism, TDP-43 was used to induce SH-SY5Y cell injury. Cell viability was evaluated by the CCK-8 assay. The mitochondrial membrane potential (MMP) was determined with JC-1. The expression levels of TDP-43 and cytochrome C (CytC) were measuring by Western blotting. Changes in adenosine 5′-triphosphate (ATP) content, total antioxidative capacity (T-AOC), glutathione peroxidase (GSH-Px) activity, superoxide dismutase (SOD) activity and malondialdehyde (MDA) content were detected with specific kits.

Results

The results showed that ICT reduced the cell damage induced by TDP-43. ICT reduced the expression level of TDP-43; increased ATP content and the MMP; decreased CytC expression; increased T-AOC and GSH-Px, total SOD (T-SOD), copper/zinc SOD (CuZn-SOD), and manganese SOD (Mn-SOD) activity; and decreased MDA content.

Conclusions

The results suggest that ICT has a protective effect on TDP-43-transfected SH-SY5Y cells that is related to reductions in TDP-43 expression and mitochondrial damage and alleviation of oxidative stress.

Adverse Effects of Oxidative Stress on Bone and Vasculature in Corticosteroid-Associated Osteonecrosis: Potential Role of Nuclear Factor Erythroid 2-Related Factor 2 in Cytoprotection

Significance: Osteonecrosis (ON) is characterized by bone tissue death due to disturbance of the nutrient artery. The detailed process leading to the necrotic changes has not been fully elucidated. Clinically, high-dose corticosteroid therapy is one of the main culprits behind osteonecrosis of the femoral head (ONFH). Recent Advances: Numerous studies have proposed that such ischemia concerns various intravascular mechanisms. Of all reported risk factors, the involvement of oxidative stress in the irreversible damage suffered by bone-related and vascular endothelial cells during ischemia simply cannot be overlooked. Several articles also have sought to elucidate oxidative stress in relation to ON using animal models or in vitro cell cultures. Critical Issues: However, as far as we know, antioxidant monotherapy has still not succeeded in preventing ONFH in humans. To provide this desideratum, we herein summarize the current knowledge about the influence of oxidative stress on ON, together with data about the preventive effects of administering antioxidants in corticosteroid-induced ON animal models. Moreover, oxidative stress is counteracted by nuclear factor erythroid 2-related factor 2 (Nrf2)-dependent cytoprotective network through regulating antioxidant expressions. Therefore, we also describe Nrf2 regulation and highlight its role in the pathology of ON. Future Directions: This is a review of all available literature to date aimed at developing a deeper understanding of the pathological mechanism behind ON from the perspective of oxidative stress. It may be hoped that this synthesis will spark the development of a prophylactic strategy to benefit corticosteroid-associated ONFH patients. Antioxid. Redox Signal. 35, 357-376.

A comparative study on the in vitro and in vivo antitumor efficacy of icaritin and hydrous icaritin nanorods

Icaritin (ICT) and hydrous icaritin (HICT) are two similar flavonoids compounds isolated from Epimedium Genus. This is the first comparative study on their in vitro and in vivo antitumor effects. Nanorods (NRs) were prepared for ICT and HICT by anti-solvent precipitation method using D-alpha tocopherol acid polyethylene glycol succinate (TPGS) as a stabilizer. The prepared ICT-NRs and HICT-NRs had similar diameter (155.5 nm and 201.7 nm), high drug loading content (43.30 ± 0.22% and 41.08 ± 0.19%), excellent stability and a similar sustaining drug release manner. Nanorods improved the in vitro toxicity against 4 different cancer cells in contrast to free ICT or free HICT; however, no significant difference was observed in this regard between ICT-NRs and HICT NRs. In the in vivo study on the anticancer efficacy on MCF-7 and PLC/PRE/5 tumor-bearing mice model, HICR-NRs displayed certain advantage over ICT NRs with higher tumor inhibition rate.

Icaritin ameliorates hepatic steatosis via promoting fatty acid β-oxidation and insulin sensitivity

AIM

This study aimed to reveal the effects of icaritin (ICT) on lipotoxicity induced by palmitate (PA) in hepatic cells and steatosis in high-fat diet (HFD)-fed mice as well as exploring the potential mechanisms.

MAIN METHODS

Primary mouse hepatocytes and human hepatoma Huh7 cells were used to evaluate ICT effect in vitro. HFD-fed mice were used to evaluate the ICT effect in vivo.

RESULTS

In vitro study indicated that ICT significantly rescued PA-induced steatosis, mainly through a combination of robust increased mitochondrial respiration, fatty acid oxidation and mildly decreased synthesis of fatty acid. An HFD-fed mouse model with 8 weeks HFD-fed showed metabolic disorders, while ICT application significantly reduced the weight, serum glucose levels, insulin resistance, hepatic steatosis level and adipose contents. In consistent with the observations in cell lines, ICT rescued the HFD-impaired functions and contents of key factors related to fatty acid β-oxidation through elevated expression of peroxisome proliferator-activated receptor α (PPARα). Meanwhile, it also reversed the decreased phosphoryl levels of AKT and glucogen synthase kinase 3 (GSK3β), leading to the improvement of insulin resistance.

SIGNIFICANCE

ICT administration had a therapeutic effect on PA- or HFD-induced hepatic steatosis and metabolic disorders. It may provide a novel strategy to construct preventive and therapeutic means for hepatic steatosis.

Icaritin Alleviates Glutamate-Induced Neuronal Damage by Inactivating GluN2B-Containing NMDARs Through the ERK/DAPK1 Pathway

Excitatory toxicity due to excessive glutamate release is considered the core pathophysiological mechanism of cerebral ischemia. It is primarily mediated by N-methyl-D-aspartate receptors (NMDARs) on neuronal membranes. Our previous studies have found that icaritin (ICT) exhibits neuroprotective effects against cerebral ischemia in rats, but the underlying mechanism is unclear. This study aims to investigate the protective effect of ICT on glutamate-induced neuronal injury and uncover its possible molecular mechanism. An excitatory toxicity injury model was created using rat primary cortical neurons treated with glutamate and glycine. The results showed that ICT has neuroprotective effects on glutamate-treated primary cortical neurons by increasing cell viability while reducing the rate of lactate dehydrogenase (LDH) release and reducing apoptosis. Remarkably, ICT rescued the changes in the ERK/DAPK1 signaling pathway after glutamate treatment by increasing the expression levels of p-ERK, p-DAPK1 and t-DAPK1. In addition, ICT also regulates NMDAR function during glutamate-induced injury by decreasing the expression level of the GluN2B subunit and enhancing the expression level of the GluN2A subunit. As cotreatment with the ERK-specific inhibitor U0126 and ICT abolishes the beneficial effects of ITC on the ERK/DAPK1 pathway, NMDAR subtypes and neuronal cell survival, ERK is recognized as a crucial mediator in the protective mechanism of ICT. In conclusion, our findings demonstrate that ICT has a neuroprotective effect on neuronal damage induced by glutamate, and its mechanism may be related to inactivating GluN2B-containing NMDAR through the ERK/DAPK1 pathway. This study provides a new clue for the prevention and treatment of clinical ischemic cerebrovascular diseases.

Molecular and cellular basis of the anticancer activity of the prenylated flavonoid icaritin in hepatocellular carcinoma

The prenylated flavonoid icaritin (ICT) is currently undergoing phase 3 clinical trial for the treatment of advanced hepatocellular carcinoma (HCC), based on a solid array of preclinical and clinical data. The antitumor activity originates from the capacity of the drug to modulate several signaling effectors in cancer cells, mainly the estrogen receptor splice variant ERα36, the transcription factors STAT3 and NFκB, and the chemokine receptor CXCR4. Recent studies have implicated additional components, including different microRNAs, the generation of reactive oxygen species and the targeting of sphingosine kinase-1. ICT also engages the RAGE-HMGB1 signaling route and modulates the apoptosis/autophagy crosstalk to promote its anticancer activity. In addition, ICT exerts profound changes on the tumor microenvironment to favor an immune-response. Collectively, these multiple biochemical and cellular characteristics confer to ICT a robust activity profile which can be exploited to treat HCC, as well as other cancers, including glioblastoma and onco-hematological diseases such as chronic myeloid leukemia. This review provides an update of the pharmacological properties of ICT and its metabolic characteristics. It also addresses the design of derivatives, including both natural products and synthetic molecules, such as SNG1153 also in clinical trial. The prenylated flavonoid ICT deserves attention as a multifunctional natural product potentially useful to improve the treatment of advanced hepatocellular carcinoma.

Induction of ROS and DNA damage-dependent senescence by icaritin contributes to its antitumor activity in hepatocellular carcinoma cells

Context: Icaritin (ICT), a prenylflavonoid derivative extracted from the Epimedium (Berberidaceae) genus, has been identified to exhibit antitumor effect in hepatocellular carcinoma (HCC) cells by inducing apoptosis. However, its effect on cellular senescence has not been elucidated. Objective: To investigate the mechanism for low concentrations of ICT exerting antitumor activity through induction of cellular senescence. Materials and methods: Human HepG2 and Huh7 cells were treated with low concentrations of ICT (1 and 2 μM) once per day for a week. Cellular senescence was evaluated through cell viability and senescence-associated-β-galactosidase activity. Cell cycle distribution and ROS levels were measured with flow cytometry. Gene expression was detected using qRT-PCR and western blotting. Fluorescent punctuates formation of γH2AX was analyzed by immunofluorescence. Results: ICT (1 and 2 μM) promoted cellular senescence in HepG2 and Huh7 cells, as observed by enlarged and flattened morphology and increased senescence-associated-β-galactosidase activity (∼7-8-fold and ∼11-12-fold of vehicle controls, respectively), accompanied by significant cell cycle arrest and decrease in DNA synthesis. Mechanistically, ICT-induced senescence occurred through accumulation of ROS (∼1.3-fold and ∼1.8-fold of vehicle controls in response to 1 and 2 μM ICT, respectively), which further resulted in DNA damage response, as evidenced by strong induction of γH2AX through immunofluorescence and western blotting assays. Pharmacological inhibition of ROS production with N-acetylcysteine attenuated ICT-induced γH2AX and senescence-associated-β-galactosidase activity (∼0.28-0.30-fold decrease, p < 0.05). Discussion and conclusions: Induction of cellular senescence by ICT defines a novel anticancer mechanism of ICT and provides a rationale for generalizing the study design to a broader study population to further developing ICT as a novel therapeutic agent for treatment of HCC.

Preliminary studies on the anti-osteoporosis activity of Baohuoside I

The aim of the present study was to investigate the anti-osteoporotic activity of Baohuoside I, an active component of Herba Epimedii. Effects of Baohuoside I on the differentiation of BMSCs and the formation of adipocytes were evaluated using alkaline phosphatase staining and methylene blue staining method, respectively. Osteoporosis model was established in ovariectomized rats prior to the measurement of the serum SOD and MDA levels as well as the expression of inflammatory cytokines protein in the rats' tissues after treatment with Baohuoside I using ELISA assay kits. The estrogen-like effect of Baohuoside I was also measured on HeLa cells. The positive rates of ALP staining in Baohuoside I groups were significantly higher (p < 0.01) compared with the normal group, with no obvious adipocyte formation observed in the groups that received Baohuoside I treatments. The levels of inflammatory markers (IL-1β, TNF-α, IL-6 and IL-8) in the treated groups were significantly lower (p < 0.05) than in the model group. Likewise, the treated groups exhibited a significantly higher (p < 0.05) serum levels of MDA compared with the model group, while SOD levels were markedly lower (p < 0.05) in a dose-dependent fashion. Baohuoside I showed no estrogen-like effect on HeLa cells upon treatment with the drug. Collectively, these results indicated that the anti-osteoporotic activity of Baohuoside I could be related to the induction of BMSCs differentiation into osteoblasts coupled with the inhibition of adipocyte formation, regulation of immune functions, and antioxidant activity.

Improved Pharmacokinetics of Icariin (ICA) within Formulation of PEG-PLLA/PDLA-PNIPAM Polymeric Micelles

Icariin (ICA) is a major flavonoid that contains the active compound Epimedii Folium. However, ICA’s pharmacokinetic characteristics remain unsatisfactory due to its low bioavailability, and hence limited drugability. In order to improve its pharmacokinetics and achieve prolonged blood circulation time, a novel polymeric micelle, made of the self-assembled micelle between poly (ethylene glycol)-poly (_L-lactic acid) (PEG-PLLA) and poly (_D-lactic acid)-poly(N-isopropylacrylamide) (PDLA-PNIPAM), was designed to encapsulate ICA. Our experimental results showed that this polymeric micelle formulation of ICA exhibited uniform nano-size distribution and high stability within 48 h. The new formulation also allowed sustained ICA release in an in vitro drug release study. Furthermore, in vivo experiments revealed that ICA bioavailability in the PEG-PLLA/PDLA-PNIPAM polymeric micelle formulation was significantly higher compared to ICA alone, or ICA in the traditional Pluronic F127 micelle formulation. Finally, we show that metabolite analysis confirmed that ICA within the PEG-PLLA/PDLA-PNIPAM polymeric micelle formulation provided better drug protection, reduced drug metabolites production, and decreased undesired first-pass effects. Overall, these data show that ICA within PEG-PLLA/PDLA-PNIPAM polymeric micelle formulation exhibit advantages, in terms of improved physicochemical properties, sustained release of ICA in vitro, and improved bioavailability of ICA in vivo, which represent a feasible approach for improving the drugability of pharmaceutical small molecules with low bioavailability or poor stability.

Synthesis and Biological Evaluation of Novel Alkyl Amine Substituted Icariside II Derivatives as Potential Anticancer Agents

A series of novel alkyl amine-substituted icariside II (ICA II) derivatives were synthesized by Mannich reactions at the 6-C position (compounds 4a–d) and changing the carbon chain length at the 7-OH position (compounds 7a–h), and their in vitro antitumor activity towards human breast cancer lines (MCF-7 and MDA-MB-231) and human hepatoma cell lines (HepG2 and HCCLM3-LUC) were evaluated by the MTT assay. Compared with ICA II, most of the twelve derivatives showed good micromole level activity and a preliminary structure-activity relationship (SAR) for the anticancer activity was obtained. Compound 7g showed the most potent inhibitory activity for the four cancer cell lines (13.28 μM for HCCLM3-LUC, 3.96 μM for HepG2, 2.44 μM for MCF-7 and 4.21 μM for MDA-MB-231), which was 2.94, 5.54, 12.56 and 7.72-fold stronger than that of ICA II. The preliminary SAR showed that the introduction of a alkyl amine substituent at 6-C was not favorable for the anticancer activity, while most of the 7-O-alkylamino derivatives exhibited good antitumor activity and the anticancer activity 7-O-alkylamino derivatives were influenced by the alkyl chain length and the different terminal amine substituents. Furthermore, the effects of compound 7g on apoptosis and cell cycle of MCF-7 cells were further investigated, which showed that compound 7g triggered apoptosis and arrested the cell cycle at the G0/G1 phase in MCF-7 cells. Our findings indicate that compound 7g may be a promising anticancer drug candidate lead.

A regiospecific rhamnosyltransferase from Epimedium pseudowushanense catalyzes the 3-O-rhamnosylation of prenylflavonols

A novel rhamnosyltransferase and a UDP-rhamnose synthase were characterized and applied to the biosynthesis of bioactive prenylflavonol rhamnosides.

Icaritin induces mitochondrial apoptosis by up-regulating miR-124 in human oral squamous cell carcinoma cells

AIM OF THE STUDY

The present study is aimed to investigate the apoptosis-inducing effect of icaritin in human oral squamous cell carcinoma (OSCC) cells and the associated mechanisms.

MATERIALS AND METHODS

KB and SCC9 cell lines were used as model cell lines. Effect of icaritin on apoptosis was analyzed by flow cytometry. The effect of icaritin on mitochondrial apoptotic pathway was demonstrated by loss of mitochondrial membrane potential and release of cytocrome C from mitochondria. MiR-124 mimic and miR-124 inhibitor were used to manipulate the expression of miR-124 in OSCC cells. SiRNA targeting Sp1 and DNMT1 as well as Sp1 and DNMT1 overexpressing vector were utilized to confirm their roles in the apoptosis-inducing effect of icaritin in OSCC cells. Activation of relevant signaling pathway by icaritin and effect of icaritin on expression of targeting molecules were determined by western blots or qRT-PCR.

RESULTS

Our results showed that icaritin inhibited tumor cell viability in a dose- and time-dependent manner, and induced cell apoptosis via intrinsic mitochondrial pathway by upregulating miR-124. Moreover, our results showed that the icaritin exerted regulatory effect on miR-124 through suppressing Sp1/DNMT1 signaling.

CONCLUSION

Our data provide the first experimental evidence that icaritin induces mitochondrial apoptosis in OSCC cells by upregulating miR-124 and suggest a new mechanism to explain its anti-tumor effects.

Involvement of IGF-1 receptor signaling pathway in the neuroprotective effects of Icaritin against MPP(+)-induced toxicity in MES23.5 cells

Icaritin, a natural derivative of Icariin, is the major bioactive component of Epimedium Genus. The present study tested the hypothesis that the neuroprotective effects of Icaritin against 1-Methyl-4-phenylpyridinium ion (MPP(+))-induced toxicity involved activation of the insulin-like growth factor-1 receptor (IGF-1R) signaling pathway in MES23.5 cells. Our results revealed that Icaritin pretreatment attenuated the MPP(+)-induced decrease of cell viability in a dose-dependent fashion. Co-pretreatment with phosphatidylinositol 3-kinase (PI3-K) inhibitor LY294002, mitogen-activated protein kinase (MEK) inhibitor PD98059 or IGF-1 receptor antagonist JB-1 could completely block the protective effects of Icaritin. Moreover, Icaritin pretreatment down-regulated MPP(+)-induced increase of Bax/Bcl-2 ratio transcriptionally and post-transcriptionally. Further study revealed that Icaritin pretreatment could restore the decreased protein expression of Akt and extracellular signal-regulated kinase 1/2 (ERK1/2) induced by MPP(+) and these effects could be completely abolished by LY294002, PD98059 or JB-1. Additionally, Icaritin treatment alone time-dependently enhanced the phosphorylation of Akt and ERK1/2 in MES23.5 cells. The activation of Akt and ERK1/2 by Icaritin could be completely blocked by JB-1, LY294002 or PD98059. Taken together, our data demonstrate that IGF-1 receptor mediated activation of PI3K/Akt and MEK/ERK1/2 signaling pathways are involved in the protective effects of Icaritin against MPP(+)-induced toxicity in MES23.5 cells.

Synthesis of icariin from kaempferol through regioselective methylation and para-Claisen-Cope rearrangement

The hemisynthesis of the naturally occurring bioactive flavonoid glycoside icariin (1) has been accomplished in eleven steps with 7% overall yield from kaempferol. The 4′-OH methylation of kaempferol, the 8-prenylation of 3-O-methoxymethyl-4′-O-methyl-5-O-prenyl-7-O-benzylkaempferol (8) via para-Claisen–Cope rearrangement catalyzed by Eu(fod)₃ in the presence of NaHCO₃, and the glycosylation of icaritin (3) are the key steps.