Ginkgetin

Ginkgetin derived from Ginkgo biloba leaves enhances the therapeutic effect of cisplatin via ferroptosis-mediated disruption of the Nrf2/HO-1 axis in EGFR wild-type non-small-cell lung cancer

Background: Cisplatin (DDP) is the first-in-class drug for advanced and non-targetable non-small-cell lung cancer (NSCLC). A recent study indicated that DDP could slightly induce non-apoptotic cell death ferroptosis, and the cytotoxicity was promoted by ferroptosis inducer. The agents enhancing the ferroptosis may therefore increase the anticancer effect of DDP. Several lines of evidence supporting the use of phytochemicals in NSCLC therapy. Ginkgetin, a bioflavonoid derived from Ginkgo biloba leaves, showed anticancer effects on NSCLC by triggering autophagy. Ferroptosis can be triggered by autophagy, which regulates redox homeostasis. Thus, we aimed to elucidate the possible role of ferroptosis involved in the synergistic effect of ginkgetin and DDP in cancer therapy. Methods: The promotion of DDP-induced anticancer effects by ginkgetin was examined via a cytotoxicity assay and western blot. Ferroptosis triggered by ginkgetin in DDP-treated NSCLC was observed via a lipid peroxidation assay, a labile iron pool assay, western blot, and qPCR. With ferroptosis blocking, the contribution of ferroptosis to ginkgetin + DDP-induced cytotoxicity, the Nrf2/HO-1 axis, and apoptosis were determined via a luciferase assay, immunostaining, chromatin immunoprecipitation (CHIP), and flow cytometry. The role of ferroptosis in ginkgetin + DDP-treated NSCLC cells was illustrated by the application of ferroptosis inhibitors, which was further demonstrated in a xenograft nude mouse model. Results: Ginkgetin synergized with DDP to increase cytotoxicity in NSCLC cells, which was concomitant with increased labile iron pool and lipid peroxidation. Both these processes were key characteristics of ferroptosis. The induction of ferroptosis mediated by ginkgetin was further confirmed by the decreased expression of SLC7A11 and GPX4, and a decreased GSH/GSSG ratio. Simultaneously, ginkgetin disrupted redox hemostasis in DDP-treated cells, as demonstrated by the enhanced ROS formation and inactivation of the Nrf2/HO-1 axis. Ginkgetin also enhanced DDP-induced mitochondrial membrane potential (MMP) loss and apoptosis in cultured NSCLC cells. Furthermore, blocking ferroptosis reversed the ginkgetin-induced inactivation of Nrf2/HO-1 as well as the elevation of ROS formation, MMP loss, and apoptosis in DDP-treated NSCLC cells. Conclusion: This study is the first to report that ginkgetin derived from Ginkgo biloba leaves promotes DDP-induced anticancer effects, which can be due to the induction of ferroptosis.

Ginkgetin: A natural biflavone with versatile pharmacological activities

Natural products, being richly endowed with curative powers, have become spotlight for biomedical and pharmaceutical research to develop novel therapeutics during recent years. Ginkgetin (GK), a natural non-toxic biflavone, has been shown to exhibit anti-cancer, anti-inflammatory, anti-microbial, anti-adipogenic, and neuroprotective activities. GK combats cancer progression by arresting cell cycle, inducing apoptosis, stimulating autophagy, and targeting many deregulated signaling pathways such as JAK/STAT and MAPKs. GKhalts inflammation mediators like interleukins, iNOS, COX-2, PGE2, NF-κB, and acts as an inhibitor of PLA2. GK shows strong neuroprotection against oxidative stress-promoted cell death, inhibits cerebral micro-hemorrhage, decreases neurologic deficits, and halts apoptosis of neurons. GK also acts as anti-fungal, anti-viral, anti-bacterial, leishmanicidal and anti-plasmodial agent. GK shows substantial preventive or therapeutic effects in in vivo models of many diseases including atherosclerosis, cancer, neurodegenerative, hepatic, influenza, and inflammatory diseases. Based on various computational, in vitro and in vivo evidences, this article demonstrates the potential of ginkgetin for development of therapeutics against various diseases. Although GK has been systematically studied from pharmacological point of view, a vast field of pharmacokinetics, pre-clinical and clinical studies is still open for the researchers to fully validate its potential for the treatment of various diseases.

Ginkgetin promotes proliferation and migration of Schwann cells via PIGF/p38 MAPK signaling pathway

The proliferation and migration of Schwann cells is pivotal to peripheral nerve injury (PNI) repair. Recent studies have revealed that Ginkgetin has neuroprotective effects. Hence, we focused on identifying whether Ginkgetin could regulate the proliferation and migration of Schwann cells, thereby contributing to the repair of PNI. Rat Schwann cells RSC96 were treated with different concentrations of Ginkgetin. Short hairpin RNA targeting phosphatidylinositol glycan anchor biosynthesis class F (shPIGF) was employed to investigate the effects of PIGF on Ginkgetin-induced RSC96 cells. Viability of RSC96 cells was estimated via cell counting kit-8 (CCK-8) assay and proliferation of the cells was assessed by 5-ethynyl-2'-deoxyuridine (EdU) assay. Migration was estimated via wound healing assay and invasion was evaluated through transwell assay. Western blot was employed to test the expressions of PIGF, protein-38 (p38), and phosphorylated p-38 (p-p38). Ginkgetin (50 or 100 μg/ml) increased the viability, proliferation, migration, and invasion of RSC96 cells, up-regulated PIGF expression and raised the ratio of p-p38/p38, which were all reversed by PIGF silencing. Ginkgetin promotes proliferation, migration, and invasion of Schwann cells via PIGF/p38 MAPK signaling pathway.

Ginkgetin alleviates high glucose-evoked mesangial cell oxidative stress injury, inflammation, and extracellular matrix (ECM) deposition in an AMPK/mTOR-mediated autophagy axis

Diabetic nephropathy constitutes the leading cause for end-stage kidney disease. Ginkgetin is a common natural non-toxic biflavone and fulfills pleiotropic pharmacological characterizations, such as anti-inflammation and kidney injury. Nevertheless, its efficacy in diabetic nephropathy remains elusive. Here, ginkgetin exhibited little cytotoxicity in glomerular mesangial cells. Of note, ginkgetin restrained high glucose (HG)-induced mesangial cell proliferation and oxidative stress by inhibiting ROS and malonaldehyde levels, but enhancing antioxidant SOD activity. Additionally, ginkgetin suppressed HG-evoked transcript and release of inflammatory cytokine TNF-α, IL-1β, and IL-6. Concomitantly, the increased extracellular matrix (ECM) deposition in HG-treated glomerular mesangial cells was attenuated by ginkgetin via decreasing expression of collagen IV, fibronectin, and laminin. Intriguingly, ginkgetin-restored HG-impaired autophagy; whereas blocking autophagy by its inhibitor 3-MA overturned ginkgetin function against HG-evoked mesangial cell dysfunction. Mechanistically, ginkgetin-mediated AMPK/mTOR axis accounted for HG-impaired autophagy. Importantly, blockage of AMPK signaling reversed ginkgetin-restored autophagy and its protective efficacy against HG-induced dysfunction in mesangial cells. Thus, these findings highlight that ginkgetin may attenuate HG-evoked mesangial cell hyperplasia, oxidative stress, inflammation, and ECM accumulation by activating AMPk/mTOR-mediated autophagy pathway. Therefore, ginkgetin may alleviate the progression of diabetic nephropathy by regulating glomerular mesangial cell dysfunction, supporting a promising therapeutic agent against diabetic nephropathy.

Ginkgetin Promotes M2 Polarization of Microglia and Exert Neuroprotection in Ischemic Stroke via Modulation of PPARγ Pathway

Neuroinflammation plays an important role in the pathophysiological process of acute cerebral infarction, which may aggravate brain injury and hinder neuro-repair. Microglia are innate immune cells in the brain. Ginkgetin has anti-inflammatory and neuroprotective effects, but the mechanism remains unclear. This study aims to explore the regulatory effects of ginkgetin on microglia polarization in brain ischemia. Oxygen glucose deprivation (OGD) cellular model and middle cerebral artery occlusion (MCAO) animal model was used in this study. We first observed the dynamic process of microglia polarization in ischemic stroke, and then investigated the effect of ginkgetin treatment on microglia polarization. Finally, we studied the role of PPARγ signaling pathway and the blocking effect of PPARγ antagonist GW9662 in this process. OGD and cerebral ischemia polarized microglia mainly to M1 type. However, ginkgetin treatment converted microglia from M1 type to M2 type, inhibited neuroinflammation, and exerted neuronal protective effects. PPARγ signaling pathway was activated during this process. The above effects could be blocked by GW9662. Ginkgetin can promote M2 polarization of microglia through PPARγ signaling pathway, thereby inhibiting neuroinflammation and promoting recovery of neurological functions in ischemic stroke.