Isoorientin protects BRL-3A rat liver cell against hydrogen peroxide-induced apoptosis by inhibiting mitochondrial dysfunction, inactivating MAPKs, activating Akt and scavenging ROS and NO

Isoorientin reverses lung cancer drug resistance by promoting ferroptosis via the SIRT6/Nrf2/GPX4 signaling pathway

Cisplatin, or DDP, is a highly successful and well-known chemotherapy drug used to treat cancer. Acquired resistance to chemotherapy is a major clinical concern, yet the mechanisms of this resistance are still unknown. Ferroptosis is a type of cell death distinct from other forms, fueled by a buildup of iron-associated lipid reactive oxygen species (ROS). Gaining insight into the process of ferroptosis could lead to novel treatments for overcoming cancer resistance. In this study, the combination of isoorientin (IO) and DDP treatment resulted in a significant decrease in the viability of drug-resistant cells, a substantial increase in intracellular iron, malondialdehyde (MDA) and ROS concentrations, a notable decrease in glutathione concentration, and the occurrence of ferroptosis in cells, as revealed by in vitro and in vivo experiments. Additionally, there was a decrease in the expression of nuclear factor-erythroid factor 2-related factor 2 (Nrf2), glutathione peroxidase 4 (GPX4), and sirtuin 6 (SIRT6) proteins, and an increase in cellular ferroptosis. Isoorientin acts as a mediator to regulate cellular ferroptosis and reverse drug resistance in lung cancer cells by controlling the SIRT6/Nrf2/GPX4 signaling pathway. The findings of this study suggest that IO can promote ferroptosis and reverse drug resistance in lung cancer through the SIRT6/Nrf2/GPX4 signaling pathway, thus offering a theoretical basis for its potential clinical application.

Isoorientin attenuates doxorubicin-induced cardiac injury via the activation of MAPK, Akt, and Caspase-dependent signaling pathways

BACKGROUND

Chemotherapy drugs especially anthracyclines are widely used in the treatment of hematological malignancies and solid tumors. However, their clinical application is limited by dose-dependent and irreversible heart injury, which increases the risk of congestive heart failure and heart-related mortality.

PURPOSE

This study aims to investigate the effect and mechanism of the natural flavonoid isoorientin (ISO) combined with doxorubicin (DOX) on the proliferation of tumor cells and improve the survival rate of DOX-injured cardiomyocytes.

STUDY DESIGN/METHODS

Cardiomyocyte H9c2 and a variety of tumor cells were used to evaluate the protective effect of ISO on DOX-induced myocardial injury and enhance the anticancer effects of DOX. DOX chemotherapy-injured mice were used to evaluate the cardioprotective effect of ISO.

RESULTS

The antiproliferation of DOX on Hela, HepG2, HT-29, and A549 cells could be increased synergistically when cotreated with ISO in vitro. ISO could also improve the survival rate of DOX-injured cardiomyocytes by reducing reactive oxygen species, maintaining mitochondrial function, and inhibiting apoptosis. In mice receiving DOX, a protective effect on myocardial tissue, which was reflected by improved survival state of mice receiving chemotherapy, was observed. The ECG, myocardial zymogram data, HE staining, and TEM observation of myocardial tissue sections showed that ISO had a dose-dependent protective effect on the mouse hearts injured by DOX. Network pharmacology and cardiomyocyte proteomics were used to seek for related target proteins to reveal the protective mechanism of ISO on mouse models, and some potential targets (including caspase-3, EGFR, MAPK1, ESR1, CDC42, STAT1, JAK2, LCK, and CDK2) were generated. Western blotting was further used to verify that ISO upregulated Nrf2 and TGF-β3 by downregulating the phosphorylation levels of JNK and p38 proteins on the MAPK pathway and the Akt and Stat3 expression levels. The downregulation of cleaved caspase-3 and upregulation of Bcl-xl by ISO further confirmed its inhibition on caspase-dependent cardiomyocyte apoptosis.

CONCLUSION

ISO could be a potential synergistic anticancer agent with a favorable property of reducing the cardiotoxicity for DOX, and the effect mechanism could refer to the inhibition of ISO on MAPK and caspase-dependent apoptosis pathways.

Sasa borealis Ethanol Extract Protects PC12 Neuronal Cells against Oxidative Stress

The overproduction of reactive oxygen species (ROS) can cause oxidative stress to biomolecules such as nucleic acids, proteins, and lipids, leading to neurodegenerative disorders. Sasa borealis (SB) has antioxidant, anti-inflammatory, antidiabetic, and anti-obesity effects. We evaluated the neuroprotective activity of SB on hydrogen peroxide (H2O2)-induced oxidative stress. We investigated the antioxidant and neuroprotective effects of SB water extract (SBW) and SB ethanol extract (SBE) by measuring the radical scavenging activities and intracellular ROS production. SBE, which had a high level of isoorientin, had higher antioxidative activities than SBW in 2,2′-azino-bis-(3-ethylbenzothiazolin-6-sulfonic acid) diammonium salt (ABTS+) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays. It also reduced ROS generation in pheochromocytoma 12 (PC12) cells more significantly than SBW. It increased the translation of heme oxygenase-1 (HO-1), superoxide dismutase 2 (SOD2), catalase (CAT), and glutathione peroxidase (GPx) with a corresponding increase in the translation of NF-E2-related factor-2 (Nrf-2). In conclusion, SBE with high levels of phenolic compounds such as isoorientin shows promise for preventing neurodegenerative diseases.

Distribution of Four Bioactive Flavonoids in Maize Tissues of Five Varieties and Correlation with Expression of the Biosynthetic Genes

Flavonoids are characteristic in maize and have diverse biological functions. C-Glycosylflavones are neuroprotective against β-amyloid-induced tau hyperphosphorylation and neurotoxicity in SH-SY5Y cells, which is relevant to Alzheimer's disease prevention and treatment. The content of the flavonoids eriodictyol, luteolin, isoorientin, and maysin varied in pollens, silks, tassels, and seeds among five maize varieties. Eriodictyol content was high (51-322 ng/g dw) in pollens, while luteolin content was low (0.2-106 ng/g dw) in all four tissues. The isoorientin content was approximately 3- to 10-fold greater than eriodictyol in pollens and tassels, particularly in the hybrid M1 and sweet corn M5 varieties. Maysin content was high in most silks and tassels. The differential expression of five genes involved in the maysin biosynthesis correlated well with the profiles of the four flavonoids among tissues and varieties. The present study offers valuable data for maize breeding and the use of maize flavonoids as functional food components.

Effects of Natural Flavonoid Isoorientin on Growth Performance and Gut Microbiota of Mice

Isoorientin (ISO) is a natural flavonoid, which is a 6- C-glucoside of luteolin, and has been demonstrated to possess multiple biological properties. In this study, the effects of ISO on the growth performance and gut microbiota of BALB/c mice were investigated. The results showed that ISO could promote food intake and body weight gain, increase the digestibility of crude proteins and utilization of the gross energy, and strengthen antioxidant capacity of mice. We also demonstrated it has no side effects on hepatic and renal functions. Moreover, ISO inhibited the growth of most bacteria in gut microbiota, especially the pathogenic genera of Alistipes, Helicobacter, and Oscillibacter, which could lead to inflammation. Metabolisms of epithelial cell signaling in Helicobacter pylori infection, lipopolysaccharide (LPS) biosynthesis, and LPS biosynthesis proteins in gut microbiota of the control group were more abundant than those in the ISO group, while lipid metabolism and vitamin B₆ metabolism were enriched in the ISO group. We found the changes in enrichments of metabolic pathways of the gut microbiota along with the ISO application were positively correlated with the antioxidation, anti-inflammation, and antibiosis. This work provided a fundamental basis for the future development of ISO-functional foods used for resistance to oxidation, inflammation, and pathogens.

Tea polyphenols ameliorate hydrogen peroxide- and constant darkness-triggered oxidative stress via modulating the Keap1/Nrf2 transcriptional signaling pathway in HepG2 cells and mice liver

Tea polyphenols alleviate oxidative stressviamodulating the Keap1/Nrf2 transcriptional signaling pathway in HepG2 cells and the liver of mice kept in constant darkness.

Isoorientin Prevents Hyperlipidemia and Liver Injury by Regulating Lipid Metabolism, Antioxidant Capability, and Inflammatory Cytokine Release in High-Fructose-Fed Mice

Isoorientin (ISO), a natural flavonoid, has been found to have multiple biological properties. In the present study, obese mice with high-fructose (HF)-induced liver injury were used to investigate the hepatoprotective effects of ISO. The results showed that ISO significantly reduced the serum lipid parameters in mice fed 20% HF water. Meanwhile, ISO appeared to alleviate HF-induced lipid metabolic disorders by increasing the serum levels of apo-A1 and decreasing the serum apoB levels, apoB/apo-A1 ratio, and FAS activity in the liver. ISO also remarkably ameliorated HF-induced hepatic oxidative injury and inflammation by decreasing ALT, AST, and ALP levels; enhancing antioxidant enzyme activities; and inhibiting inflammatory cytokine (TNF-α, IL-1, IL-6) release. Histopathology of liver stained by H&E and Oil Red O showed the liver steatosis and oxidative injury after HF treatment and the protective effect of ISO. Furthermore, aortic pathology observation found that ISO had a protective effect on the vascular endothelium. This is the first report that ISO efficiently inhibited HF-induced hyperlipidemia and liver injury by ameliorating lipid metabolism, enhancing the antioxidant defensedefense system, and regulating the secretion of inflammatory cytokines.

Metabolism and plasma pharmacokinetics of isoorientin, a natural active ingredient, in Sprague-Dawley male rats after oral and intravenous administration

1. Several pharmacological effects have been revealed on isoorientin, suggesting its potential medicinal prospects. The metabolic and plasma pharmacokinetic profiles of isoorientin were investigated in rats. 2. For intra-gastric gavage, parent drug and three metabolites were detected in urine and feces by HPLC-MS/MS, but only one metabolite was found in plasma and identified as isoorientin 3'- or 4'-O-sulfate (M1) according to MS and UV absorbance spectra. 3. After a single i.v. administration of isoorientin (5, 10, or 15 mg/kg B.W.) in rats, linear pharmacokinetic property was observed with favorable terminal half-lives (1.67 ± 1.32-2.07 ± 0.50 h). After a single p.o. administration of isoorientin (150 mg/kg B.W.) in rats, plasma isoorientin concentration was low, but the concentration of M1 was comparatively high. Low systemic exposure of oral isoorientin in rats could result from its low aqueous solubility and extensive first-pass metabolism, and plasma concentration of M1 can be used as a biomarker of isoorientin intake. Isoorientin showed low oral bioavailability (8.98 ± 1.07%), and had about 6% or 45% dose recovery in urine or feces, respectively, 72 h after intra-gastric gavage. 4. These studies are the first to describe the pharmacokinetics of isoorientin via i.v. or p.o. dosing, providing important information for understanding its process in vivo.