Antagonizing effect of icaritin on apoptosis and injury of hippocampal neurocytes induced by amyloid beta via GR/BDNF signaling pathway

Icariin improves oxidative stress injury during ischemic stroke via inhibiting mPTP opening

BACKGROUND

Ischemic stroke presents a significant threat to human health due to its high disability rate and mortality. Currently, the clinical treatment drug, rt-PA, has a narrow therapeutic window and carries a high risk of bleeding. There is an urgent need to find new effective therapeutic drugs for ischemic stroke. Icariin (ICA), a key ingredient in the traditional Chinese medicine Epimedium, undergoes metabolism in vivo to produce Icaritin (ICT). While ICA has been reported to inhibit neuronal apoptosis after cerebral ischemia-reperfusion (I/R), yet its underlying mechanism remains unclear.

METHODS

PC-12 cells were treated with 200 µM H2O2 for 8 h to establish a vitro model of oxidative damage. After administration of ICT, cell viability was detected by Thiazolyl blue tetrazolium Bromide (MTT) assay, reactive oxygen species (ROS) and apoptosis level, mPTP status and mitochondrial membrane potential (MMP) were detected by flow cytometry and immunofluorescence. Apoptosis and mitochondrial permeability transition pore (mPTP) related proteins were assessed by Western blotting. Middle cerebral artery occlusion (MCAO) model was used to establish I/R injury in vivo. After the treatment of ICA, the neurological function was scored by ZeaLonga socres; the infarct volume was observed by 2,3,5-Triphenyltetrazolium chloride (TTC) staining; HE and Nissl staining were used to detect the pathological state of the ischemic cortex; the expression changes of mPTP and apoptosis related proteins were detected by Western blotting.

RESULTS

In vitro: ICT effectively improved H2O2-induced oxidative injury through decreasing the ROS level, inhibiting mPTP opening and apoptosis. In addition, the protective effects of ICT were not enhanced when it was co-treated with mPTP inhibitor Cyclosporin A (CsA), but reversed when combined with mPTP activator Lonidamine (LND). In vivo: Rats after MCAO shown cortical infarct volume of 32-40%, severe neurological impairment, while mPTP opening and apoptosis were obviously increased. Those damage caused was improved by the administration of ICA and CsA.

CONCLUSIONS

ICA improves cerebral ischemia-reperfusion injury by inhibiting mPTP opening, making it a potential candidate drug for the treatment of ischemic stroke.

Icaritin alleviates cerebral ischemia‒reperfusion injury by regulating NMDA receptors through ERK signaling

N-methyl-D-aspartate (NMDA) receptors are key signaling molecules that mediate excitotoxicity during cerebral ischemia. GluN2A-containing NMDA receptors, which are mostly located in the intrasynaptic region, mediate normal physiological processes and promote neuronal survival. GluN2B-containing NMDA receptors, which are mostly located in the extrasynaptic region, mediate excitotoxicity injury and promote neuronal death during ischemia. This study investigated the ability of icaritin (ICT) to protect against cerebral ischemia‒reperfusion injury (CI/RI) by regulating GluN2B-containing NMDA receptors through extracellular signaling regulatory kinases/death associated protein kinase 1 (ERK/DAPK1) signaling. A rat CI/RI model was established by transient middle cerebral artery occlusion (tMCAO). Following treatment with ICT and the ERK-specific inhibitor U0126, cerebral infarction, neurological function, and excitotoxicity-related molecule expression were assessed 24 h after reperfusion. ICT treatment significantly decreased cerebral infarct volume, improved neurological function, and regulated NMDA receptor subtype expression and ERK/DAPK1 signaling activation. The ability of ICT to increase GluN2A and postsynaptic density protein 95 (PSD95) mRNA and protein expression, inhibit GluN2B expression, and regulate DAPK1 activation was reversed after administration of the ERK-specific inhibitor U0126. These data indicated that ICT inhibited excitotoxicity injury and exerted a protective effect against CI/RI that was likely mediated by increased ERK signaling pathway activation and regulation of extrasynaptic and intrasynaptic NMDA receptor function, providing a new therapeutic target for ischemic encephalopathy.

Impact of Icariin and its derivatives on inflammatory diseases and relevant signaling pathways

Herba Epimedii is a famous herb collected from China and Korea. It has been used for impotency, osteoporosis, and amnestic treatment for thousands of years. Icariin, a typical flavonoid compound isolated from Herba Epimedii, was reported as a potential anti-inflammatory drug. Icariside and icaritin are the two metabolites of icariin. Icariin and its metabolites have been used to treat a wide range of inflammatory diseases, such as atherosclerosis, Alzheimer's disease, depression, osteoarthritis, and asthma. They exert powerful suppression of proinflammatory signaling, such as NF-κB and MAPKs. More importantly, they can upregulate anti-inflammatory signaling, such as GR and Nrf2. In this study, we review the therapeutic effects and mechanisms of icariin and its metabolites in inflammatory diseases and provide novel insights into these potential anti-inflammatory drugs.

Chinese Herbal Medicine for Primary Liver Cancer Therapy: Perspectives and Challenges

Primary liver cancer (PLC) is one of the most common solid malignancies. However, PLC drug development has been slow, and first-line treatments are still needed; thus, studies exploring and developing alternative strategies for effective PLC treatment are urgently needed. Chinese herbal medicine (CHM) has long been applied in the clinic due to its advantages of low toxicity and targeting of multiple factors and pathways, and it has great potential for the development of novel natural drugs against PLC.

Purpose: This review aims to provide an update on the pharmacological mechanisms of Chinese patent medicines (CPMs) and the latest CHM-derived compounds for the treatment of PLC and relevant clinical evaluations.

Materials and Methods: A systematic search of English literature databases, Chinese literature, the Clinical Trials Registry Platform, and the Chinese Clinical Trial Registry for studies of CHMs for PLC treatment was performed.

Results: In this review, we summarize the clinical trials and mechanisms of CPMs for PLC treatment that have entered the clinic with the approval of the Chinese medicine regulatory authority. These CPMs included Huaier granules, Ganfule granules, Fufang Banmao capsules, Jinlong capsules, Brucea javanica oil emulsions, and compound kushen injections. We also summarize the latest in vivo, in vitro, and clinical studies of CHM-derived compounds against PLC: icaritin and ginsenoside Rg3. Dilemmas facing the development of CHMs, such as drug toxicity and low oral availability, and future developments are also discussed.

Conclusion: This review provides a deeper the understanding of CHMs as PLC treatments and provides ideas for the development of new natural drugs against PLC.

Roles of traditional chinese medicine regulating neuroendocrinology on AD treatment

The incidence of sporadic Alzheimer's disease (AD) is increasing in recent years. Studies have shown that in addition to some genetic abnormalities, the majority of AD patients has a history of long-term exposure to risk factors. Neuroendocrine related risk factors have been proved to be strongly associated with AD. Long-term hormone disorder can have a direct detrimental effect on the brain by producing an AD-like pathology and result in cognitive decline by impairing neuronal metabolism, plasticity and survival. Traditional Chinese Medicine(TCM) may regulate the complex process of endocrine disorders, and improve metabolic abnormalities, as well as the resulting neuroinflammation and oxidative damage through a variety of pathways. TCM has unique therapeutic advantages in treating early intervention of AD-related neuroendocrine disorders and preventing cognitive decline. This paper reviewed the relationship between neuroendocrine and AD as well as the related TCM treatment and its mechanism. The advantages of TCM intervention on endocrine disorders and some pending problems was also discussed, and new insights for TCM treatment of dementia in the future was provided.