Galangin Attenuates Liver Injury, Oxidative Stress and Inflammation, and Upregulates Nrf2/HO-1 Signaling in Streptozotocin-Induced Diabetic Rats

Chitosan-modified dihydromyricetin liposomes promote the repair of liver injury in mice suffering from diabetes mellitus

Liver injury caused by type-II diabetes mellitus (DM) is a significant public-health concern worldwide. We used chitosan (CS) to modify dihydromyricetin (DHM)-loaded liposomes (DL) through charge interaction. The effect of CS-modified DL (CDL) on liver injury in mice suffering from DM was investigated in vivo and in vitro. CDL exhibited superior antioxidant capacity and stability. Pharmacokinetic analyses revealed a 3.23- and 1.92-fold increase in the drug concentration-time curve (953.60 ± 122.55 ng/mL/h) in the CDL-treated group as opposed to the DHM-treated group (295.15 ± 25.53 ng/mL/h) and DL-treated group (495.31 ± 65.21 ng/mL/h). The maximum drug concentration in blood (Tmax) of the CDL group saw a 2.26- and 1.21-fold increase compared with that in DHM and DL groups. We observed a 1.49- and 1.31-fold increase in the maximum drug concentration in blood (Cmax) in the CDL group compared with that in DHM and DL groups. Western blotting suggested that CDL could alleviate liver injury in mice suffering from DM by modulating inflammatory factors and the transforming growth factor-β1/Smad2/Smad3 signaling pathway. In conclusion, modification of liposomes using CS is a viable approach to address the limitations of conventional liposomes and insoluble drugs.

A narrative review on the mechanism of natural flavonoids in improving glucolipid metabolism disorders

Glucolipid metabolism disorder (GLMD) is a complex chronic disease characterized by glucose and lipid metabolism disorders with a complex and diverse etiology and rapidly increasing incidence. Many studies have identified the role of flavonoids in ameliorating GLMD, with mechanisms related to peroxisome proliferator-activated receptors, nuclear factor kappa-B, AMP-activated protein kinase, nuclear factor (erythroid-derived 2)-like 2, glucose transporter type 4, and phosphatidylinositol-3-kinase/protein kinase B pathway. However, a comprehensive summary of the flavonoid effects on GLMD is lacking. This study reviewed the roles and mechanisms of natural flavonoids with different structures in the treatment of GLMD reported globally in the past 5 years and provides a reference for developing flavonoids as drugs for treating GLMD.

Oleic Acid and Succinic Acid: A Potent Nutritional Supplement in Improving Hepatic Glycaemic Control in Type 2 Diabetic Sprague-Dawley Rats

Nutritional supplements are gaining traction for their effects in mitigating the impacts of various health conditions. In particular, many supplements are being proposed to reduce the impacts of type 2 diabetes (T2D), a metabolic condition that has reached global epidemic proportions. Recently, a supplement of oleic acid (OA) and succinic acid (SA; 1 : 1, w/w) was reported to improve glycaemic control in type 2 diabetic (T2D) Sprague-Dawley (S-D) rats through ameliorating insulin release and sensitivity. Here, we investigate the effects of the supplement (OA and SA) on hepatic and pancreatic function in T2D S-D rats. Eighteen (18) S-D rats were rendered diabetic and were divided into three equal groups: diabetic control, diabetic treatment, and diabetic glibenclamide. Another 12 S-D rats were obtained and served as the normal groups. The animals were treated daily with the vehicle, OA and SA (800 mg/kg body weight (bw); 1 : 1), or glibenclamide (10 mg/kg bw) which served as the positive control. The findings indicated that treatment with the supplement resulted in a 35.69 ± 4.22% reduction (p=0.006) in blood glucose levels (BGL). Analysis of hepatic enzymes depicted that the nutritional supplement reduced the activity of the gluconeogenesis enzyme, glucose-6-phosphatase (G6P) while improved the activity of catabolic enzymes such as glucose-6-phosphate dehydrogenase (G6PD) and pyruvate kinase (PK). Furthermore, the supplement attenuated oxidative stress through restoration of catalase (CAT) and superoxide dismutase (SOD), while reducing malondialdehyde (MDA) levels. Finally, the supplement showed no liver or kidney toxicity and improved the size and number of pancreatic islets of Langerhans, indicating its potential application in treating T2D. The study highlighted that a supplement of the two organic acids may be beneficial in reducing the rate of pathogenesis of type 2 diabetes. Therefore, it may offer therapeutic value as a dietary or nutritional supplement in the approach against diabetes and its complications.

Pharmacological activities and therapeutic potential of galangin, a promising natural flavone, in age-related diseases

BACKGROUND

The extension of average life expectancy and the aggravation of population aging have become the inevitable trend of human development. In an aging society, various problems related to medical care for the elderly have become increasingly prominent. However, most of the age-related diseases have the characteristics of multiple diseases at the same time, prone to complications, and atypical clinical manifestations, which bring great difficulties to its treatment. Galangin (3,5,7-trihydroxyflavone) is a natural active compound extracted from the root of Alpinia officinarum Hance (Zingiberaceae). Recently, many studies have shown that galangin has potential advantages in the treatment of neurodegenerative diseases and cardiovascular and cerebrovascular diseases, which are common in the elderly. In addition, it also showed that galangin had prospective activities in the treatment of tumor, diabetes, liver injury, asthma and arthritis.

PURPOSE

This review aims to systematically summarize and discuss the effects and the underlying mechanism of galangin in the treatment of age-related diseases.

METHODS

We searched PubMed, SciFinder, Web of Science and CNKI literature database resources, combined with the keywords "galangin", "neurodegenerative disease", "tumor", "diabetes", "pharmacological activity", "drug combination", "pharmacokinetics", "drug delivery system" and "safety", and comprehensively reviewed the pharmacological activities and mechanism of galangin in treating age-related diseases.

RESULTS

According to the previous studies on galangin, the anti-neurodegenerative activity, cardiovascular and cerebrovascular protective activity, anti-tumor activity, anti-diabetes activity, anti-arthritis activity, hepatoprotective activity and antiasthmatic activity of galangin were discussed, and the related mechanisms were classified and summarized in detail. In addition, the drug combination, pharmacokinetics, drug delivery system and safety of galangin were furtherly discussed.

CONCLUSIONS

This review will provide reference for galangin in the treatment of age-related diseases. Meanwhile, further experimental research and long-term clinical trials are needed to determine the therapeutic safety and efficacy of galangin.

Potential Benefits of Antioxidant Phytochemicals in Type 2 Diabetes

The clinical relationship between diabetes and inflammation is well established. Evidence clearly indicates that disrupting oxidant-antioxidant equilibrium and elevated lipid peroxidation could be a potential mechanism for chronic kidney disease associated with type 2 diabetes mellitus (T2DM). Under diabetic conditions, hyperglycemia, especially inflammation, and increased reactive oxygen species generation are bidirectionally associated. Inflammation, oxidative stress, and tissue damage are believed to play a role in the development of diabetes. Although the exact mechanism underlying oxidative stress and its impact on diabetes progression remains uncertain, the hyperglycemia-inflammation-oxidative stress interaction clearly plays a significant role in the onset and progression of vascular disease, kidney disease, hepatic injury, and pancreas damage and, therefore, holds promise as a therapeutic target. Evidence strongly indicates that the use of multiple antidiabetic medications fails to achieve the normal range for glycated hemoglobin targets, signifying treatment-resistant diabetes. Antioxidants with polyphenols are considered useful as adjuvant therapy for their potential anti-inflammatory effect and antioxidant activity. We aimed to analyze the current major points reported in preclinical, in vivo, and clinical studies of antioxidants in the prevention or treatment of inflammation in T2DM. Then, we will share our speculative vision for future diabetes clinical trials.

Meloxicam Targets COX-2/NOX1/NOX4/Nrf2 Axis to Ameliorate the Depression-like Neuropathology Induced by Chronic Restraint Stress in Rats

Meloxicam has shown significant neuroprotection in experimental models of stroke, Alzheimer's disease, and Parkinson's disease. However, the potential of meloxicam to treat depression-like neuropathology in a chronic restraint stress (CRS) model and the associated molecular changes has been insufficiently explored. The current work aimed to explore the potential neuroprotective actions of meloxicam against CRS-evoked depression in rats. In the current experiments, animals received meloxicam (10 mg/kg/day; i.p.) for 21 days, and CRS was instigated by restraining the animals for 6 h/day during the same period. The sucrose preference test and the forced swimming test were used to explore the depression-linked anhedonia/despair, whereas the open-field test examined the animals' locomotor activity. The current findings revealed that CRS elicited typical depression behavioral anomalies in the animals, including anhedonia, despair, and diminished locomotor activity; these findings were reinforced with Z-normalization scores. These observations were corroborated by brain histopathological changes and increased damage scores. In CRS-exposed animals, serum corticosterone spiked, and the hippocampi revealed decreased monoamine neurotransmitter levels (norepinephrine, serotonin, and dopamine). Mechanistically, neuroinflammation was evident in stressed animals, as shown by elevated hippocampal TNF-α and IL-1β cytokines. Moreover, the hippocampal COX-2/PGE₂ axis was activated in the rats, confirming the escalation of neuroinflammatory events. In tandem, the pro-oxidant milieu was augmented, as seen by increased hippocampal 8-hydroxy-2'-deoxyguanosine alongside increased protein expression of the pro-oxidants NOX1 and NOX4 in the hippocampi of stressed animals. In addition, the antioxidant/cytoprotective Nrf2/HO-1 cascade was dampened, as evidenced by the lowered hippocampal protein expression of Nrf2 and HO-1 signals. Interestingly, meloxicam administration mitigated depression manifestations and brain histopathological anomalies in the rats. These beneficial effects were elicited by meloxicam's ability to counteract the corticosterone spike and hippocampal neurotransmitter decrease while also inhibiting COX-2/NOX1/NOX4 axis and stimulating Nrf2/HO-1 antioxidant pathway. Together, the present findings prove the neuroprotective/antidepressant actions of meloxicam in CRS-induced depression by ameliorating hippocampal neuroinflammation and pro-oxidant changes, likely by modulating COX-2/NOX1/NOX4/Nrf2 axis.

Femtosecond laser attenuates oxidative stress, inflammation, and liver fibrosis in rats: Possible role of PPARγ and Nrf2/HO-1 signaling

Liver fibrosis is the excessive accumulation of extracellular matrix (ECM) proteins that occurs in chronic liver injury. Inflammation and oxidative stress play a key role in fibrogenesis which can develop into cirrhosis and carcinoma. Low-level laser therapy (LLLT) has promising therapeutic effects against fibrogenesis; however, the specific underlying mechanism is not fully elucidated. We investigated the potential of LLLT to attenuate carbon tetrachloride (CCl₄)-induced liver fibrosis in rats, focusing on oxidative injury, inflammatory response, and the possible role of PPARγ and Nrf2/HO-1 signaling. Rats were given CCl₄ and exposed to LLLT twice/week for 6 weeks and blood and liver samples were collected for analysis. CCl₄ caused liver injury and fibrosis manifested by hepatocyte injury, steatosis, inflammatory cell infiltration, and accumulation of collagen, elevated serum transaminases and bilirubin, and decreased albumin. ROS, MDA, NO, NF-κB p65, TNF-α, iNOS, TGF-β1, and IL-6 were increased in the liver of CCl₄-administered rats. Exposure to LLLT ameliorated histopathological alterations, collagen deposition, and liver function markers, and downregulated hepatic α-SMA, collagen 1A1, and collagen 3A1. In Addition, LLLT decreased ROS, MDA, NO, NF-κB p65, TGF-β1, and pro-inflammatory mediators, and enhanced antioxidant defenses. These effects were associated with upregulated PPARγ, Nrf2, and HO-1, both gene and protein expression. In conclusion, LLLT attenuated liver fibrosis by suppressing ECM production and deposition, oxidative injury and inflammation, and upregulating PPARγ and Nrf2/HO-1 signaling.

Renoprotective and Oxidative Stress-Modulating Effects of Taxifolin against Cadmium-Induced Nephrotoxicity in Mice

Cadmium (Cd) is an inessential trace metal that accumulates in the kidney and may lead to renal toxicity by mediating oxidative stress (OS), inflammatory reactions, and apoptosis. The main objective of this experiment was to inspect the protecting potential of taxifolin (TA) on Cd-induced renal toxicity. Adult male mice were allocated into equal five groups as follows: control, TA-treated (50 mg/kg, oral), CdCl₂-treated (4 mg/kg body weight (BW), p.o.), pretreated with TA (25 mg/kg) 1 h before CdCl₂ injection (4 mg/kg BW, p.o.), and pretreated with TA (50 mg/kg) 1 h before CdCl₂ injection (4 mg/kg BW, p.o.) for 14 days. Cd-intoxicated mice revealed higher serum urea and creatinine levels and notable histopathological alterations in the renal tissues. Malondialdehyde (MDA), nitric oxide (NO), nuclear factor-kappa B (NF-κB) p65, tumor necrosis factor-α (TNF-α), and IL-1β were increased. In contrast, glutathione levels, catalase and superoxide dismutase activities, and IL-10 levels were decreased under Cd-administered effects. Conversely, the TA pre-treatment highly protected tissues from Cd-toxicity, improved renal function, decreased MDA and NO levels, attenuated inflammation, and improved redox status in the renal tissues of Cd-intoxicated mice. The TA pre-treatment of Cd-intoxicated mice showed down-regulation of both Bax and caspase-3 protein and up-regulation of Bcl-2 protein expression in the kidney. Furthermore, TA pre-treatment induced higher upregulation of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase 1 (HO-1) expression in kidney cells of Cd-intoxicated mice. Therefore, TA can protect renal tissues against Cd-induced nephrotoxicity via improving redox status, modulating inflammation, diminishing cell apoptosis, and activating the Nrf2/HO-1 signaling pathway.

Galangin Mitigates DOX-induced Cognitive Impairment in Rats: Implication of NOX-1/Nrf-2/HMGB1/TLR4 and TNF-α/MAPKs/RIPK/MLKL/BDNF

The cognitive and behavioral decline observed in cancer survivors who underwent doxorubicin (DOX)-based treatment raises the need for therapeutic interventions to counteract these complications. Galangin (GAL) is a flavonoid-based phytochemical with pronounced protective effects in various neurological disorders. However, its impact on DOX-provoked neurotoxicity has not been clarified. Hence, the current investigation aimed to explore the ability of GAL to ameliorate DOX-provoked chemo-brain in rats. DOX (2mg/kg, once/week, i.p.) and GAL (50mg/kg, 5 times/week., via gavage) were administered for four successive weeks. The MWM and EPM tests were used to evaluate memory disruption and anxiety-like behavior, respectively. Meanwhile, targeted biochemical markers and molecular signals were examined by the aid of ELISA, Western blotting, and immune-histochemistry. In contrast to DOX-impaired rats, GAL effectively preserved hippocampal neurons, improved cognitive/behavioral functions, and enhanced the expression of the cell repair/growth index and BDNF. The antioxidant feature of GAL was confirmed by the amelioration of MDA, NO and NOX-1, along with restoring the Nrf-2/HO-1/GSH cue. In addition, GAL displayed marked anti-inflammatory properties as verified by the suppression of the HMGB1/TLR4 nexus and p-NF-κB p65 to inhibit TNF-α, IL-6, IL-1β, and iNOS. This inhibitory impact extended to entail astrocyte activation, as evidenced by the diminution of GFAP. These beneficial effects were associated with a notable reduction in p-p38^MAPK, p-JNK1/2, and p-ERK1/2, as well as the necroptosis cascade p-RIPK1/p-RIPK3/p-MLKL. Together, these pleiotropic protective impacts advocate the concurrent use of GAL as an adjuvant agent for managing DOX-driven neurodegeneration and cognitive/behavioral deficits. DATA AVAILABILITY: The authors confirm that all relevant data are included in the supplementary materials.

Upregulation of Nrf2/HO-1 Signaling and Attenuation of Oxidative Stress, Inflammation, and Cell Death Mediate the Protective Effect of Apigenin against Cyclophosphamide Hepatotoxicity

Liver injury is among the adverse effects of the chemotherapeutic agent cyclophosphamide (CP). This study investigated the protective role of the flavone apigenin (API) against CP-induced liver damage, pointing to the involvement of Nrf2/HO-1 signaling. Rats were treated with API (20 and 40 mg/kg) for 15 days and received CP (150 mg/kg) on day 16. CP caused liver damage manifested by an elevation of transaminases, alkaline phosphatase (ALP), and lactate dehydrogenase (LDH), and histological alterations, including granular vacuolation, mononuclear cell infiltration, and hydropic changes. Hepatic reactive oxygen species (ROS), malondialdehyde (MDA), and nitric oxide (NO) were increased and glutathione (GSH) and antioxidant enzymes were decreased in CP-administered rats. CP upregulated the inflammatory markers NF-κB p65, TNF-α, IL-6, and iNOS, along with the pro-apoptotic Bax and caspase-3. Pre-treatment with API ameliorated circulating transaminases, ALP, and LDH, and prevented histopathological changes in CP-intoxicated rats. API suppressed ROS, MDA, NO, NF-κB p65, iNOS, inflammatory cytokines, oxidative DNA damage, Bax, and caspase-3 in CP-intoxicated rats. In addition, API enhanced hepatic antioxidants and Bcl-2 and boosted the Nrf2 and HO-1 mRNA abundance and protein. In conclusion, API is effective in preventing CP hepatotoxicity by attenuating oxidative stress, the inflammatory response, and apoptosis. The hepatoprotective efficacy of API was associated with the upregulation of Nrf2/HO-1 signaling.

Formononetin Ameliorates Renal Dysfunction, Oxidative Stress, Inflammation, and Apoptosis and Upregulates Nrf2/HO-1 Signaling in a Rat Model of Gentamicin-Induced Nephrotoxicity

Gentamicin (GEN) is a bactericidal aminoglycoside known to cause nephrotoxicity. Formononetin (FN) is a potent flavonoid that exhibits numerous promising pharmacological activities. In this study, we have assessed the nephroprotective efficacy of FN against GEN-induced renal injury in rats. Rats were orally administered with FN (60 mg/kg/day, for 2 weeks) and were co-treated with intraperitoneal (i.p.) injection of GEN (100 mg/kg/day) during the days 8–14. GEN-treated rats demonstrated increased urea and creatinine levels in serum associated with marked histopathological changes in the kidney. Malondialdehyde (MDA) and protein carbonyl contents were elevated, whereas glutathione concentration and catalase and superoxide dismutase activities were lowered in GEN-administered rats. The FN largely prevented tissue damage, attenuated renal function, reduced MDA and protein carbonyl, and enhanced antioxidant capacity in the kidney of GEN-administrated animals. The kidney of GEN-treated rats demonstrated elevated Bax and caspase-3 protein expression, accompanied by lowered Bcl-2 protein expression, an effect that FN attenuated. Moreover, FN treatment caused upregulation of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase 1 (HO-1) expression in renal tissue of GEN-intoxicated animals. Collectively, FN protects against GEN-caused renal damage via exhibiting antioxidant, anti-inflammatory, and antiapoptotic activities and augmenting Nrf2 signaling, suggesting FN as a promising agent for preventing drug-induced organ damage.

Omarigliptin/galangin combination mitigates lipopolysaccharide-induced neuroinflammation in rats: Involvement of glucagon-like peptide-1, toll-like receptor-4, apoptosis and Akt/GSK-3β signaling

AIMS

The objectives of this work were to assess the possibility of administration of omarigliptin and/or galangin to combat lipopolysaccharide (LPS)-induced neuroinflammation in rats and to explore the possible mechanisms that might contribute to their actions.

MATERIALS AND METHODS

In a rat model of LPS-induced neuroinflammation, the changes in the behavioral tests, biochemical parameters, and the histopathological picture were assessed.

KEY FINDINGS

Administration of either omarigliptin or galangin to LPS-injected rats was able to significantly improve the behavioral changes with restoration of the oxidant/antioxidant balance, decrement of toll-like receptor-4 levels, and amelioration of the neuroinflammation associated with inhibition of apoptosis and restoration of glucagon-like peptide-1 levels in the cerebral tissues. In addition, omarigliptin and/or galangin significantly reduced the levels of phospho-Akt and glycogen synthase kinase 3 beta (GSK-3β) and significantly increased the expression of beclin-1 in the cerebral tissues compared versus the group treated with LPS alone. As a result, these changes were positively reflected on the histopathological and the electron microscopic picture of the cerebral tissues. These beneficial effects were maximally evidenced in rats treated with omarigliptin/galangin combination relative to the use of either omarigliptin or galangin alone.

SIGNIFICANCE

Omarigliptin/galangin combination might be proposed as a promising therapeutic line for mitigation of the pathophysiologic events of LPS-induced neuroinflammation.

Protective Effects of Chlorogenic Acid against Carbon Tetrachloride-Induced Hepatotoxicity in Mice

The protective effects of chlorogenic acid (CGA) against liver injury were evaluated by its reduction in carbon tetrachloride (CCl4)-induced hepatic damage in ICR mice. The animals were orally given CGA (60, 100, and 200 mg/kg, respectively) or silymairn (200 mg/kg) daily with 0.3% CCl4 administration (3 mL/kg, dissolved in olive oil) after medicament treatment on the 7th day. Compared with the normal group, CCl4 caused severe impairment in liver according to the evidence of significant reduction in the level of total albumin and expansion (p < 0.05) of the activities in aspartate aminotransferase (AST) and alanine aminotransferase (ALT), cholesterol, triglyceride (TG), and total albumin in serum, decreased the level of glutathione (GSH), and diminished the activities of catalase, superoxide dismutase (SOD), glutathione reductase (GSH-Rd), and glutathione peroxidase (GSH-Px) in liver while increasing the level of hepatic thiobarbituric acid-reactive substances (TBARS). However, oral administration of CGA or silymarin could significantly (p < 0.05) decrease the serum levels of AST, ALT, cholesterol, TG, and total albumin and elevated the serum total albumin and the activities of GSH, catalase, SOD, GSH-Rd, and GSH-Px while leading to decline the TBARS in liver compared with CCl4-intoxicated group. Moreover, histopathology displayed that CGA decreased the formation of lesions in liver resulted from CCl4. The outcomes indicate that CGA shows the efficiency hepatoprotective consequences for CCl4-incited liver injuries in mice by the elevation of the activities of antioxidant enzymes and hindrance of lipid peroxidation.