Hepatoprotective and neuroprotective effect of taxifolin on hepatic encephalopathy in rats

Dihydroquercetin Ameliorates Neuronal Ferroptosis in Rats After Subarachnoid Hemorrhage via the PI3K/AKT/Nrf2/HO-1 Pathway

Subarachnoid hemorrhage (SAH) is a specific type of stroke. Dihydroquercetin (DHQ), a flavonoid, is known for its various pharmacological properties. This study aimed to explore the roles and mechanisms of DHQ in influencing the progression of SAH. A rat SAH model was established using the endovascular perforation technique. Following SAH induction, DHQ was administered orally 1 h later. Assessments included SAH scores, neurological function, brain swelling, blood-brain barrier (BBB) integrity, neuronal damage, apoptosis levels, inflammation, and indicators of ferroptosis using various treatments. The HT22 cells were exposed to hemin to simulate SAH-like conditions under in vitro settings. Cell counting kit-8 assays, flow cytometry, enzyme?linked immunosorbent assay, BODIPY 581/591 C11 staining, western blot analysis, and biochemical kits were employed to evaluate the potential effects of DHQ. Moreover, the mechanisms responsible for the protective effect of DHQ were examined by western blot analysis. The in vivo findings revealed that DHQ mitigated neurological impairments, brain swelling, BBB disruption, and neuronal injury at 24 h post-SAH. DHQ also reduced neuronal degeneration, inflammation, and ferroptosis following SAH. The in vitro findings revealed that DHQ enhanced cell survival and reduced ferroptosis at 24 h following hemin exposure. Mechanistically, DHQ activated phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K)/protein kinase B (AKT)/nuclear factor erythroid 2-related factor 2 (Nrf2) signaling in SAH rats and hemin-treated HT22 cells to exert neuroprotective effects. In conclusion, this study reveals that DHQ can effectively decrease BBB permeability, brain edema, neurological dysfunctions, and ferroptosis post-SAH by activating the PI3K/AKT/Nrf2/HO-1 pathway.

Absence of TNFR1 promotes a protective response in the early phase of hepatic encephalopathy induced by thioacetamide in mice

Hepatic encephalopathy (HE) is a neuropsychiatric syndrome with a wide spectrum of cognitive deficits, motor impairment, and psychiatric disturbances resulting from liver damage. The cytokine TNF has been considered the main cytokine in the development and progression of HE, with a pivotal role in the initiation and amplification of the inflammatory cascade. The aim of the present study was to evaluate the involvement of TNF type 1 receptor (TNFR1) in locomotor deficits and in the levels of TNF, IFN-γ, IL-6, IL-10, IL-12p70, CCL2, CX3CL1 and BDNF from the frontal cortex and hippocampus of TNFR1 knockout mice (TNFR1-/-) mice with HE induced by thioacetamide. Wild-type (WT) animals with HE developed locomotor deficit. The absence of TNFR1 absence of TNFR1 in HE animals attenuated the locomotor activity impairment in parallel with a balanced neuroinflammatory environment 24 h after the administration of thioacetamide. Taken together, the data suggests that the absence of TNFR1 promoted a protective response in the early phase of hepatic encephalopathy induced by thioacetamide in mice.

Taxifolin ameliorates the D-galactose-induced aging of mouse hippocampal neurons HT-22 cells through modulating SIRT1/p53 and PI3K/AKT signaling pathways

By establishing an in vitro model of D-Gal-induced brain neuronal cell (HT-22) senescence, it was found that TAX treatment significantly increased the activities of SOD and GSH, while decreasing MDA levels in aging HT-22 cells, indicating that TAX effectively restored the total antioxidant capacity and antioxidant enzyme activity of aging HT-22 cells induced by D-Gal, and attenuated cellular oxidative stress injury. In addition, taxifolin could also protect HT-22 cells from aging by up-regulating SIRT1 while reducing the expression of Ac-p53, indicating that TAX may be an active substance that can effectively delay cell aging.

Therapeutic Effect of Levetiracetam Against Thioacetamide-Induced Hepatic Encephalopathy Through Inhibition of Oxidative Stress and Downregulation of NF-κB, NLRP3, iNOS/NO, Pro-Inflammatory Cytokines and Apoptosis

Hepatic encephalopathy (HE) is a serious brain disorder which associated with neurological and psychiatric manifestations. Oxidative stress and neuroinflammation and apoptosis play main roles in the development of brain damage in HE. Levetiracetam is an antiseizure drug with established antioxidant and anti-inflammatory activities. In the present study we investigated the therapeutic effects of levetiracetam against brain injury in HE and its underlying mechanisms of action. Male C57BL/6 mice were subjected to the induction of HE by the injection of thioacetamide (200 mg/kg) for 2 days. Mice were treated with levetiracetam at two doses (50 or 100 mg/kg/day) for 3 days in the treatment groups. Animals were subjected to a behavioral test and the brain tissues were dissected for histopathological, biochemical, gene expression and immunofluorescence analysis. The results showed that levetiracetam alleviated body weight loss and improved locomotor activity of mice with HE. Levetiracetam treatment decreased the histopathological changes, lipid peroxidation and protein carbonylation while restored the antioxidants (GSH, SOD and CAT) in the brain. Levetiracetam decreased the expression and activity of NF-κB, NOD-like receptor pyrin domain-containing protein 3 (NLRP3) and pro-inflammatory cytokines (TNF-α, IL-1β, IL-6, and IFN-γ) in the brain tissue. Administration of levetiracetam inhibited iNOS/NO pathway and myeloperoxidase (MPO) activity in the brain. Moreover, caspase-3 was decreased and the ratio of Bcl2/Bax was increased in the brain of mice treated with levetiracetam. These findings suggest that levetiracetam may be a promising therapeutic agent for brain injury in HE through inhibiting the oxidative, inflammatory and apoptotic pathways.

Protective effects of arbutin against doxorubicin-induced cardiac damage

BACKGROUND

Doxorubicin is an effective antineoplastic agent but has limited clinical application because of its cumulative toxicities, including cardiotoxicity. Cardiotoxicity causes lipid peroxidation, genetic impairment, oxidative stress, inhibition of autophagy, and disruption of calcium homeostasis. Doxorubicin-induced cardiotoxicity is frequently tried to be mitigated by phytochemicals, which are derived from plants and possess antioxidant, anti-inflammatory, and anti-apoptotic properties. Arbutin, a natural antioxidant found in the leaves of the bearberry plant, has numerous pharmacological benefits, including antioxidant, anti-bacterial, anti-hyperglycemic, anti-inflammatory, and anti-tumor activity.

METHODS AND RESULTS

The study involved male Wistar rats divided into three groups: a control group, a group treated with doxorubicin (20 mg/kg) to induce cardiac toxicity, a group treated with arbutin (100 mg/kg) daily for two weeks before doxorubicin administration. After treatment, plasma and heart tissue samples were collected for analysis. The samples were evaluated for oxidative stress parameters, including superoxide dismutase, malondialdehyde, and catalase, as well as for cardiac biomarkers, including CK, CK-MB, and LDH. The heart tissues were also analyzed using molecular (TNF-α, IL-1β and Caspase 3), histopathological and immunohistochemical methods (8-OHDG, 4 Hydroxynonenal, and dityrosine). The results showed that arbutin treatment was protective against doxorubicin-induced oxidative damage by increasing SOD and CAT activity and decreasing MDA level. Arbutin treatment was similarly able to reverse the inflammatory response caused by doxorubicin by reducing TNF-α and IL-1β levels and also reverse the apoptosis by decreasing caspase-3 levels. It was able to prevent doxorubicin-induced cardiac damage by reducing cardiac biomarkers CK, CK-MB and LDH levels. In addition to all these results, histopathological analyzes also show that arbutin may be beneficial against the damage caused by doxorubicin on heart tissue.

CONCLUSION

The study suggests that arbutin has the potential to be used to mitigate doxorubicin-induced cardiotoxicity in cancer patients.

Hepatoprotective Effects of Flavonoids against Benzo[a]Pyrene-Induced Oxidative Liver Damage along Its Metabolic Pathways

Benzo[a]pyrene (B[a]P), a highly carcinogenic polycyclic aromatic hydrocarbon primarily formed during incomplete organic matter combustion, undergoes a series of hepatic metabolic reactions once absorbed into the body. B[a]P contributes to liver damage, ranging from molecular DNA damage to the onset and progression of various diseases, including cancer. Specifically, B[a]P induces oxidative stress via reactive oxygen species generation within cells. Consequently, more research has focused on exploring the underlying mechanisms of B[a]P-induced oxidative stress and potential strategies to counter its hepatic toxicity. Flavonoids, natural compounds abundant in plants and renowned for their antioxidant properties, possess the ability to neutralize the adverse effects of free radicals effectively. Although extensive research has investigated the antioxidant effects of flavonoids, limited research has delved into their potential in regulating B[a]P metabolism to alleviate oxidative stress. This review aims to consolidate current knowledge on B[a]P-induced liver oxidative stress and examines the role of flavonoids in mitigating its toxicity.

Taxifolin-mediated Nrf2 activation ameliorates oxidative stress and apoptosis for the treatment of glucocorticoid-induced osteonecrosis of the femoral head

Glucocorticoid-induced osteonecrosis of the femoral head (GIONFH) is the main complication secondary to long-term or excessive use of glucocorticoids (GCs). Taxifolin (TAX) is a natural antioxidant with various pharmacological effects, such as antioxidative stress and antiapoptotic properties. The purpose of this study was to explore whether TAX could regulate oxidative stress and apoptosis in GIONFH by activating the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway. We conducted qRT-PCR, Western blotting, TUNEL assays, flow cytometry, and other experiments in vitro. Microcomputed tomography analysis, hematoxylin-eosin staining, and immunohistochemical staining were performed to determine the therapeutic effect of TAX in vivo. TAX mitigated the overexpression of ROS and NOX gene expression induced by DEX, effectively reducing oxidative stress. Additionally, TAX could alleviate DEX-induced osteoblast apoptosis, as evidenced by qRT-PCR, Western blotting, and other experimental techniques. Our in vivo studies further demonstrated that TAX mitigates the progression of GIONFH in rats by combating oxidative stress and apoptosis. Mechanistic exploration revealed that TAX thwarts the progression of GIONFH through the activation of the Nrf2 pathway. Overall, our research herein reports that TAX-mediated Nrf2 activation ameliorates oxidative stress and apoptosis for the treatment of GIONFH.

Taxifolin Reduces Blood Pressure via Improvement of Vascular Function and Mitigating the Vascular Inflammatory Response in Spontaneously Hypertensive Rats

The effect of a 10-day-long treatment with taxifolin (TAX, 20 mg/kg/day p.o.) was investigated on spontaneously hypertensive rats (SHRs) with a focus on the vascular functions of isolated femoral arteries and thoracic aortas. TAX reduced blood pressure in SHRs. In femoral arteries, TAX increased acetylcholine-induced relaxation, reduced the maximal NA-induced contraction, and reduced acetylcholine-induced endothelium-dependent contraction (EDC); however, TAX had no effect on the vascular reactivity of isolated thoracic aortas. In addition, TAX elevated the total nitric oxide synthase (NOS) activity and iNOS protein expression but reduced cyclooxygenase-2 (COX2) protein expression in the tissue of the abdominal aorta without changes in Nos2 and Ptgs2 gene expressions. TAX also increased the gene expression of the anti-inflammatory interleukin-10 (Il10). In addition, in vitro studies showed that TAX has both electron donor and H atom donor properties. However, TAX failed to reduce superoxide production in the tissue of the abdominal aorta after oral administration. In conclusion, our results show that a decrease in the blood pressure in TAX-treated SHRs might be attributed to improved endothelium-dependent relaxation and reduced endothelium-dependent contraction. In addition, the results suggest that the effect of TAX on blood pressure regulation also involves the attenuation of COX2-mediated pro-inflammation and elevation of anti-inflammatory pathways.

Taxifolin attenuates neuroinflammation and microglial pyroptosis via the PI3K/Akt signaling pathway after spinal cord injury

Spinal cord injury (SCI) is a severe injury characterized by neuroinflammation and oxidative stress. Taxifolin is exhibits anti-inflammatory and antioxidative activities in neurologic diseases. However, the roles and mechanisms of taxifolin in neuroinflammation and microglial pyroptosis after SCI remain unclear. The present study aims to investigate the effect of taxifolin on SCI and its potential underlying mechanisms in in vivo and in vitro models. In this study, taxifolin markedly reduced microglial activation mediated oxidative stress, and inhibited the expression of pyroptosis-related proteins (NLRP3, GSDMD, ASC, and Caspase-1) and inflammatory cytokines (IL-1β and IL-18) after SCI, as shown by immunofluorescence staining and western blot assays. In addition, taxifolin promoted axonal regeneration and improved functional recovery after SCI. In vitro studies showed that taxifolin attenuated the activation of microglia and oxidative stress after lipopolysaccharide (LPS) + adenosine-triphosphate (ATP) stimulation in BV2 cells. We also observed that taxifolin inhibited the pyroptosis-related proteins and reduced the release of inflammatory cytokines. Moreover, to explore how taxifolin exerts its effects on microglial pyroptosis and axonal regeneration of neurons, we performed an in vitro study in BV-2 cells and PC12 cells co-culture. The results revealed that taxifolin facilitated axonal regeneration of PC12 cells in co-culture with LPS + ATP-induced BV-2 cells. Mechanistically, taxifolin regulated microglial pyroptosis via the PI3K/AKT signaling pathway. Taken together, these results suggest that taxifolin alleviates neuroinflammation and microglial pyroptosis through the PI3K/AKT signaling pathway after SCI, and promotes axonal regeneration and improves functional recovery, suggesting that taxifolin may represent a potential therapeutic agent for SCI.

New Perspectives of Taxifolin in Neurodegenerative Diseases

Neurodegenerative diseases, such as Alzheimer's disease (AD), Parkinson's disease (PD), cerebral amyloid angiopathy (CAA), and Huntington's disease (HD) are characterized by cognitive and motor dysfunctions and neurodegeneration. These diseases have become more severe over time and cannot be cured currently. Until now, most treatments for these diseases are only used to relieve the symptoms. Taxifolin (TAX), 3,5,7,3,4-pentahydroxy flavanone, also named dihydroquercetin, is a compound derived primarily from Douglas fir and Larix gemelini. TAX has been confirmed to exhibit various pharmacological activities, including anti-inflammation, anti-cancer, anti-virus, and regulation of oxidative stress effects. In the central nervous system, TAX has been demonstrated to inhibit Aβ fibril formation, protect neurons and improve cerebral blood flow, cognitive ability, and dyskinesia. At present, TAX is only applied as a health additive in clinical practice. This review aimed to summarize the application of TAX in neurodegenerative diseases and the underlying neuroprotective mechanisms, such as suppressing inflammation, attenuating oxidative stress, preventing Aβ protein formation, maintaining dopamine levels, and thus reducing neuronal loss.

Korean Red Pine (Pinus densiflora) Bark Extract Attenuates Aβ-Induced Cognitive Impairment by Regulating Cholinergic Dysfunction and Neuroinflammation

In this study, we investigated the anti-amnesic effect of Korean red pine (Pinus densiflora) bark extract (KRPBE) against amyloid beta_1-42 (Aβ_1-42)-induced neurotoxicity. We found that treatment with KRPBE improved the behavioral function in Aβ-induced mice, and also boosted the antioxidant system in mice by decreasing malondialdehyde (MDA) content, increasing superoxide dismutase (SOD) activities, and reducing glutathione (GSH) levels. In addition, KRPBE improved the cholinergic system by suppressing reduced acetylcholine (ACh) content while also activating acetylcholinesterase (AChE), regulating the expression of choline acetyltransferase (ChAT), postsynaptic density protein-95 (PSD-95), and synaptophysin. KRPBE also showed an ameliorating effect on cerebral mitochondrial deficit by regulating reactive oxygen species (ROS), mitochondrial membrane potential (MMP) and ATP levels. Moreover, KRPBE modulated the expression levels of neurotoxicity indicators Aβ and phosphorylated tau (p-tau) and inflammatory cytokines TNF-α, p-IκB-α, and IL-1β. Furthermore, we found that KRPBE improved the expression levels of neuronal apoptosis-related markers BAX and BCl-2 and increased the expression levels of BDNF and p-CREB. Therefore, this study suggests that KRPBE treatment has an anti-amnestic effect by modulating cholinergic system dysfunction and neuroinflammation in Aβ_1-42-induced cognitive impairment in mice.