Taxifolin mitigates cisplatin-induced testicular damage by reducing inflammation, oxidative stress, and apoptosis in mice

Cisplatin (CIS) is effective against various cancers but causes significant side effects, including testicular damage. This study investigated the effects of taxifolin (TX), a potent flavonoid with well-known benefits, against CIS-induced testicular injury. Mice received TX (25 and 50 mg/kg) orally for 14 days, with a single injection of CIS (7 mg/kg) on day 8. CIS significantly impaired sperm parameters (motility, viability, and count) and caused notable histopathological alterations in testicular tissue. CIS-treated testicular tissue exhibited elevated MDA and protein carbonyl levels, alongside decreased antioxidant defenses, including GSH, SOD, and catalase activities. TX significantly mitigated the deterioration of sperm parameters and prevented testicular tissue damage. It also restored antioxidant levels and reduced MDA and protein carbonyl contents. Furthermore, CIS elevated pro-inflammatory markers (NF-κB p65, TNF-α, and IL-1β) and apoptosis markers (Bax and caspase-3), while reducing anti-apoptotic Bcl-2 levels. TX effectively suppressed NF-κB activation, reduced pro-inflammatory cytokine production, and inhibited apoptosis in CIS-treated mice. Overall, TX alleviated CIS-induced oxidative stress, inflammation, apoptosis, and testicular damage, thereby improving sperm quality. These findings emphasize TX's potential as a protective agent against CIS-induced testicular damage and warrant further research in human applications.

Taxifolin Protects Against 5-Fluorouracil-Induced Cardiotoxicity in Mice Through Mitigating Oxidative Stress, Inflammation, and Apoptosis: Possible Involvement of Sirt1/Nrf2/HO-1 Signaling

Although 5-fluorouracil (5-FU) is widely utilized in cancer treatment, its side effects, including cardiotoxicity, limit its use. Taxifolin (TAX) is a bioactive anti-inflammatory and antioxidant flavonoid. This study aimed to elucidate the protective effect of TAX against 5-FU-induced cardiac injury in male mice. Mice were treated with TAX (25 and 50 mg/kg, orally) for 10 days and a single dose of 150 mg/kg 5-FU at day 8. Mice intoxicated with 5-FU showed increased creatine kinase-MB and lactate dehydrogenase activities and troponin I levels, with multiple cardiac histopathological changes. They also showed a significant increase in cardiac malondialdehyde (MDA) and nitric oxide (NO) and decreases in myocardial reduced glutathione (GSH) content and superoxide dismutase (SOD) and catalase (CAT) activities (P < 0.001). Pretreatment of 5-FU-injected mice with TAX suppressed cardiac injury, decreased MDA and NO contents (P < 0.001), and boosted antioxidant defenses in the myocardium. Moreover, TAX attenuated cardiac inflammatory response, as evidenced by the decreased expression levels of cardiac NF-κB p65, inducible nitric oxide synthase (iNOS), and pro-inflammatory cytokines (P < 0.001). Largely, TAX ameliorated the decrease in Bcl-2 expression and the increase in BAX and caspase-3 in the heart. It also restored the cardiac Sirt1/Nrf2/HO-1 signaling pathway. In conclusion, TAX showed significant cardioprotective effects on 5-FU-induced cardiac injury and might represent a promising adjuvant in preventing cardiac injury associated with oxidative stress and inflammation.

Taxifolin regulates SLC31A1-mediated cuproptosis and tumor progression in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a primary malignant neoplasm exhibiting a high mortality rate. Taxifolin is a naturally occurring flavonoid compound that exhibits a range of pharmacological properties. The effects of taxifolin on HCC remain largely unexplored. Therefore, the aim of this study was to examine the potential roles of taxifolin in the development and progression of HCC. In this study, CCK-8 assay was utilized to examine the impact of taxifolin on the cell viability. The copper ions level and the activity of mitochondrial respiratory chain were determined by the correspondent kits. The biological properties of HCC cells were evaluated using colony formation, transwell, flow cytometry, and TUNEL assays, respectively. Transcriptome sequencing was carried out either with or without taxifolin treatment. The expression of cuproptosis-related proteins was determined by Western blot. We observed significant decrease of cell viability, Glutathione (GSH), and mitochondrial respiratory chain under the treatment of taxifolin, while an increase of copper ions level. Taxifolin was observed to suppress HCC progression both in vitro and in vivo. The intersection analysis was performed between upregulated genes and cuproptosis-related genes to obtain one intersection gene-SLC31A1. The knockdown of SLC31A1 reversed the tumor-suppressive effects induced by taxifolin. Taxifolin inhibited HCC progression through inducing cuproptosis in an SLC31A1-mediated manner.

Comparative Anticancer Potentials of Taxifolin and Quercetin Methylated Derivatives against HCT-116 Cell Lines: Effects of O-Methylation on Taxifolin and Quercetin as Preliminary Natural Leads

Six flavonoids present in Pulicaria jaubertii, i.e., 7,3'-di-O-methyltaxifolin (1), 3'-O-methyltaxifolin (2), 7-O-methyltaxifolin (3), taxifolin (4), 3-O-methylquercetin (5), and quercetin (6), were tested for their anticancer activities. The methylated flavonoids, compounds 1-3 and 5, were evaluated for their anticancer activities in comparison to the non-methylated parent flavonoids taxifolin (4) and quercetin (6). The structures of the known compounds were reconfirmed by spectral analyses using ¹H and ¹³C NMR data comparisons and HRMS spectrometry. The anticancer activity of these compounds was evaluated in colon cancer, HCT-116, and noncancerous, HEK-293, cell lines using the MTT antiproliferative assays. The caspase-3 and caspase-9 expressions and DAPI (4', 6-diamidino-2-phenylindole) staining assays were used to evaluate the apoptotic activity. All the compounds exhibited antiproliferative activity against the HCT-116 cell line with IC₅₀ values at 33 ± 1.25, 36 ± 2.25, 34 ± 2.15, 32 ± 2.35, 34 ± 2.65, and 36 ± 1.95 μg/mL for compounds 1 to 6, respectively. All the compounds produced a significant reduction in HCT-116 cell line proliferation, except compounds 2 and 6. The viability of the HEK-293 normal cells was found to be significantly higher than the viability of the cancerous cells at all of the tested concentrations, thus suggesting that all the compounds have better inhibitory activity on the cancer cell line. Apoptotic features such as chromatin condensation and nuclear shrinkage were also induced by the compounds. The expression of caspase-3 and caspase-9 genes increased in HCT-116 cell lines after 48 h of treatment, suggesting cell death by the apoptotic pathways. The molecular docking studies showed favorable binding affinity against different pro- and antiapoptotic proteins by these compounds. The docking scores were minimum as compared to the caspase-9, caspase-3, Bcl-xl, and JAK2.

Ethanolic extract of Lippia graveolens stem reduce biochemical markers in a murine model with metabolic syndrome

Metabolic Syndrome (MetS) is a risk to develop metabolic-chronic degenerative disease, it is important to find natural alternatives to help decrease the risk. Mexican oregano has a traditional use in Mexican food, moreover, has pharmacologic effects that can help to reduce risk the metabolic syndrome. The aim of this work was to determine the effect of Mexican oregano ethanolic extract in metabolic syndrome in murine model. Ethanolic extract of Mexican oregano (Lippia graveolens) stem (Ext) had a favorable effect on biochemical markers in a murine model of MetS, induced by injection of monosodium glutamate (MSG). From newborn female mice, two groups were formed: control and the MSG groups, which received a dosage of 2 mg/kg of MSG via subcutaneous injection at the second and fourth postnatal day (PD 2,4), and 4 mg/kg at the PD 6, 8, 10 to induce obesity. On week 13, a part of the MSG group received Ext (group MSG + Ext) at 300 mg/kg, administered orally daily from week 13 to week 18. The results indicated that ethanolic extract of Lippia graveolens stem decreases the percentage of body fat, waist circumference, and body weight gain as well as cholesterol, serum triglyceride concentrations and systolic and diastolic pressure. Insulin and leptin hormone values showed a significant effect with the Ext administration. However, hepatic lipoperoxidation levels of MSG and MSG + Ext groups did not show any statistically significant differences between them, both being higher than the control group. Taking in consideration the results obtained in this study, it is concluded that the administration of Ext had a beneficial effect in the murine model with MetS. This is the first study demonstrating the potential of the polar fraction Lippia graveolens stem in MetS.

Increasing the Efficiency of Taxifolin Encapsulation in Saccharomyces cerevisiae Yeast Cells Based on Ultrasonic Microstructuring

The aim of the present study was to investigate the possibility of encapsulating the plant antioxidant taxifolin in the living cells of the yeast Saccharomyces cerevisiae. Taxifolin is an unstable substance prone to oxidative degradation and actively enters into chemical reactions with a decrease or loss of bioactive properties. To minimize these problems, the use of encapsulation technology has been proposed. The cells of the yeast Saccharomyces cerevisiae have been chosen as a protective material for taxifolin. The encapsulation process was carried out using simple diffusion methods in living Saccharomyces cerevisiae cells in a thermostatically controlled shaker for 24 h. The aim of the study was to evaluate the effect of preliminary microstructuring of taxifolin on the efficiency of its encapsulation in yeast cells. The microstructuring process was carried out using low-frequency ultrasonic cavitation exposure for 7 min with a frequency of 22 ± 1.6 kHz and a power of 600 W/100 mL. The studies confirmed the feasibility of the proposed approach. It was found that microstructuring changes the dispersed composition of taxifolin particles and their morphology in solution and also increases the value of the antioxidant activity. Preliminary microstructuring of taxifolin increases the efficiency of its encapsulation in Saccharomyces cerevisiae yeast cells by 1.42 times compared to the initial form. A positive dependence of the growth of the encapsulation efficiency on the duration of the process was also established. Thus, the conducted studies confirmed the advantage of encapsulation of taxifolin in living cells of the yeast Saccharomyces cerevisiae in microstructured form.

Biochemical Investigation of Inhibitory Activities of Plant-Derived Bioactive Compounds Against Carbohydrate and Glucagon-Like Peptide-1 Metabolizing Enzymes

The aim of current study was to investigate the inhibitory activities of resveratrol and taxifolin against α-amylase, α-glucosidase, and DPP-IV enzymes via in vitro analysis which was further validated by in silico studies. The analysis of molecular docking was also done to determine the binding capabilities of resveratrol and taxifolin with α-amylase, α-glucosidase, and DPP-IV enzymes. Resveratrol and taxifolin having IC₅₀ values, 47.93 ± 5.21 μM and 45.86 ± 3.78 μM, respectively, showed weaker effect than acarbose (4.6 ± 1.26 μM) on α-amylase but showed significant effect to inhibit α-glucosidase (32.23 ± .556 μM and 31.26 ± .556 μM, respectively). IC₅₀ value of resveratrol and taxifolin (5.638 ± .0016 μM and 6.691 ± .004 μM) in comparison to diprotin A (IC₅₀: 7.21 ± .021 μM) showed that they have significant inhibitory effect on DPP-IV enzyme. Our results illustrated that resveratrol and taxifolin have potential to prevent the metabolism of carbohydrates via inhibition of α-amylase and α-glucosidase, and prolongs metabolic function of incretin by inhibiting the enzymatic activity of DPP-IV. The results of molecular docking have also revealed that resveratrol and taxifolin have significant affinity to bind with α-amylase, α-glucosidase, and DPP-IV in comparison with standard drugs such as acarbose, miglitol, and diprotin.

Effect of the antioxidant type phytonutrients diet supplementation on lamb quality

The aim of the study was to estimate the effect of Siberian larch dihydroquercetin and dry distilled rose petals supplementation of lambs’ diet on the quality of meat obtained from Bulgarian dairy synthetic population sheep. The experiments were performed with 30 clinically healthy male lambs aged 65 days with equal live weight. There were studied one control group (C) fed for 50 days with ground alfalfa + granulated compound feed and two experimental groups (D) and (R) fed on the same diet supplemented either with 7.5 mg dihydroquercetin/kg/day or with 545 mg DDRP/kg/day respectively. The DDRP diet supplementation increases the sensory scores, carotenoids and essential amino acids of muscles (P ≤ 0.05) but does not affect the content of tocopherols. No significant differences (P > 0.05) were found comparing the proximate composition of the group C, R and D. Compared to control group C the supplementation of lambs’ diet with dihydroquercetin and DDRP contributes to a certain increase in the sterols in muscle and adipose tissues but not in liver tissue (P ≤ 0.05). A reduction of WHC of m. Longissimus dorsi and microbial deterioration in both muscles and perirenal fatty tissue was found in experimental groups D and R.

Chemiluminescence Detection in the Study of Free-Radical Reactions. Part 2. Luminescent Additives That Increase the Chemiluminescence Quantum Yield

The present review examines the use of chemiluminescence detection to evaluate the course of free radical reactions in biological model systems. The application of the method is analyzed by using luminescent additives that enhance the luminescence thanks to a triplet-singlet transfer of the electron excitation energy from radical reaction products and its emission in the form of light with a high quantum yield; these additives are called chemiluminescence enhancers or activators. Examples of these substances are provided; differences between the so-called chemical and physical enhancers are described; coumarin derivatives, as the most promising chemiluminescence enhancers for studying lipid peroxidation, are considered in detail. The main problems related to the use of coumarin derivatives are defined, and possible ways of solving these problems are presented. Intrinsic chemiluminescence and the mechanism of luminescence accompanying biomolecule peroxidation are discussed in the first part of the review.

Exploring the Molecular Mechanism of Action of Yinchen Wuling Powder for the Treatment of Hyperlipidemia, Using Network Pharmacology, Molecular Docking, and Molecular Dynamics Simulation

Background

Yinchen Wuling powder is often used to treat clinical hyperlipidemia, although its mechanism of action remains unclear. In this study, we aimed to investigate the active ingredients found in Yinchen Wuling powder and find its mechanism of action when treating hyperlipidemia, using a combination of network pharmacology, molecular docking, and molecular dynamics simulation approaches.

Methods

The TCMSP database was used to obtain the principle active ingredients found in Yinchen Wuling powder and the NCBI and DisGeNet databases were used to obtain the main target genes involved in hyperlipidemia, and the intersectional targets were obtained by EXCEL. We also used Cytoscape 3.7.2 software to construct a “Traditional Chinese Medicine-Active Ingredient-Target” network and use STRING platform to conduct “protein-protein interactional” (PPI) analyses on the intersection targets. Bioconductor software and RX 64 4.0.0 software were then used to perform GO functional enrichment analysis and KEGG pathway enrichment analysis on the targets. Molecular docking of core protein-ligand interactions was modeled using AutoDock Vina software. A simulation of molecular dynamics was conducted for the optimal core protein-ligand obtained by molecular docking using Amber18 software.

Results

A total of 63 active ingredients were found in Yinchen Wuling powder, corresponding to 175 targets, 508 hyperlipidemia targets, and 55 intersection targets in total. Cytoscape 3.7.2 showed that the key active ingredients were quercetin, isorhamnetin, taxifolin, demethoxycapillarisin, and artepillin A. The PPI network showed that the key proteins involved were AKT1, IL6, VEGFA, and PTGS2. GO enrichment analysis found that genes were enriched primarily in response to oxygen levels and nutrient levels of the vesicular lumen and were associated with membrane rafts. These were mainly enriched in AGE-RAGE (advanced glycation end products-receptor for advanced glycation end products) signaling pathway in diabetic complications, fluid shear stress, and atherosclerosis, as well as other pathways. The molecular docking results indicated key binding activity between PTGS2-quercetin, PTGS2-isorhamnetin, and PTGS2-taxifolin. Results from molecular dynamics simulations showed that PTGS2-quercetin, PTGS2-isorhamnetin, and PTGS2-taxifolin bound more stably, and their binding free energies were PTGS2-quercetin -29.5 kcal/mol, PTGS2-isorhamnetin -32 kcal/mol, and PTGS2-taxifolin -32.9 kcal/mol.

Conclusion

This study is based on network pharmacology and reveals the potential molecular mechanisms involved in the treatment of hyperlipidemia by Yinchen Wuling powder.

Effect of taxifolin/dapagliflozin combination on colistin-induced nephrotoxicity in rats

Colistin is an antimicrobial agent that is used in resistant gram-negative infections. Its most common dose-limiting adverse effect is nephrotoxicity. The objective of our study was to explore the possible effects of each of taxifolin and dapagliflozin alone and in combination on colistin-induced nephrotoxicity in rats. Sixty male rats were randomized into six groups: Control; colistin; colistin + taxifolin; colistin + dapagliflozin; colistin + carboxymethyl cellulose (CMC) and colistin + taxifolin + dapagliflozin. Dapagliflozin, taxifolin, and CMC were given daily for 7 days, 4 hours before colistin injection. Kidney weight/body weight ratio and renal function tests were determined. Renal tissue nerve growth factor-β (NGF-β), transforming growth factor beta 1 (TGF-β1), proinflammatory cytokines, nuclear factor (erythroid-derived 2)-like 2 (Nrf2), toll-like receptor 4 (TLR4), nuclear factor kappa B (NF-κB) p65, signal transducer and activator of transcription 3 (STAT3), oxidative stress parameters, beclin-1 and c-Jun NH2-terminal kinase (JNK) activities were measured. Kidneys were examined histopathologically and immunohistochemically. Taxifolin and/or dapagliflozin induced significant improvement in the renal functions and oxidative stress parameters with significant increase in tissue Nrf2, STAT3 and NGF-β accompanied with significant decrease in kidney weight/body weight ratio, tissue proinflammatory cytokines, TGF-β1, NF-κB (p65), TLR4, beclin-1 and JNK activities and improved the histopathological picture when compared to rats treated with colistin alone. This improvement was significant with taxifolin/dapagliflozin combination compared to rats treated with each of these agents alone. So, we concluded that the combined use of taxifolin and dapagliflozin may confer a therapeutic tool for attenuation of colistin-induced nephrotoxicity.

Dietary Taxifolin Protects Against Dextran Sulfate Sodium-Induced Colitis via NF-κB Signaling, Enhancing Intestinal Barrier and Modulating Gut Microbiota

Taxifolin is a natural antioxidant polyphenol with various bioactivities and has many beneficial effects on human gut health. However, little is known of its function on colitis. In this study, the protective effects of taxifolin on colitis symptoms, inflammation, signaling pathways, and colon microbiota were investigated using dextran sulfate sodium (DSS)-induced colitis mice. Intriguingly, pre-administration of taxifolin alleviated the colitis symptoms and histological changes of the DSS-challenged mice. Supplementation of taxifolin significantly inhibited the secretions of tumor necrosis factor-α, interleukin (IL)-1β, and IL-6 and significantly increased the secretions of IL-10, secretory immunoglobulin A, superoxide dismutase, and immunoglobulins (IgA, IgG, and IgM) in DSS-induced colitis mice. In addition, the activation of nuclear factor kappa B (NF-κB; p65 and IκBα) signaling was significantly suppressed by taxifolin supplementation. The expression of tight junction proteins (claudin-1 and occludin) was significantly increased by taxifolin. Moreover, 16S rDNA sequencing revealed that the DSS-induced changes of colon microbiota composition and microbial functions (amino acid metabolism and MAPK signaling) were restored by taxifolin, including the decreases of the abundances of Bacteroides, Clostridium ramosum, Clostridium saccharogumia, Sphingobacterium multivorum, and the ratio of Bacteroidetes/Firmicutes, and the increases of the abundances of Desulfovibrio C21 c20 and Gemmiger formicilis at species level. In conclusion, these results revealed that dietary taxifolin has a great potential to prevent colitis by inhibiting the NF-κB signaling pathway, enhancing intestinal barrier, and modulating gut microbiota.

Dissecting Efficacy and Metabolic Characteristic Mechanism of Taxifolin on Renal Fibrosis by Multivariate Approach and Ultra-Performance Liquid Chromatography Coupled With Mass Spectrometry-Based Metabolomics Strategy

Taxifolin (TFN) is an important natural compound with antifibrotic activity; however, its pharmacological mechanism is not clear. In this study, our aim is to gain insight into the effects of TFN and its potential mechanisms in unilateral ureteral obstruction (UUO) animal model using metabolomics approach to identify the metabolic biomarkers and perturbed pathways. Serum metabolomics analysis by UPLC-Q-TOF/MS was carried out to discover the changes in the metabolic profile. It showed that TFN has a significant protective effect on UUO-induced renal fibrosis and a total of 32 potential biomarkers were identified and related to RF progression. Of note, 27 biomarkers were regulated by TFN treatment, which participate in eight metabolic pathways, including phenylalanine, tyrosine and tryptophan biosynthesis, and phenylalanine metabolism. It also showed that metabolomics was a promising strategy to better dissect metabolic characteristics and pharmacological mechanisms of natural compounds by multivariate approach and ultra-performance liquid chromatography coupled with mass spectrometry.

Study of Antioxidant Properties of Agents from the Perspective of Their Action Mechanisms

The creation and analysis of a large variety of existing methods for the evaluation of integrated antioxidant properties are quite relevant in connection with a range of biological mechanisms of the antioxidants (AO) action. In this work, the existing methods are correlated with mechanisms of antioxidant action. It is shown that the results obtained by various methods are mainly incomparable. This can be connected with the implementation of various mechanisms of antioxidant action in methods. The analysis of the literature data presented in this review indicates the difficulty of creating a universal method and the feasibility of using integrated approaches based on the use of several methods that implement and combine various mechanisms of the chemical conversion of antioxidants. This review describes methods for studying the chelating ability of antioxidants, except for methods based on electron and hydrogen atom transfer reactions, which are currently not widely covered in modern literature. With the description of each mechanism, special attention is paid to electrochemical methods, as the interaction of active oxygen metabolites of radical and non-radical nature with antioxidants has an electron/proton/donor-acceptor nature, which corresponds to the nature of electrochemical methods and suggests that they can be used to study the interaction.

An in silico perception for newly isolated flavonoids from peach fruit as privileged avenue for a countermeasure outbreak of COVID-19

3'-Hydroxy-4'-methoxy-chroman-7-O-β-d-glucopyranoside 4 was first isolated from a natural source, together with three known compounds, the ferulic acid heptyl ester 1, naringenin 2, and 4,2',4'-trihydroxy-6'-methoxychalcone-4'-O-β-d-glucopyranoside 3, which were isolated from peach [Prunus persica (L.) Batsch] fruits. These compounds were subjected to different virtual screening strategies in order to examine their activity to combat the COVID-19 outbreak. The study design composed of some major aspects: (a) docking with main protease (Mpro), (b) docking with spike protein, (c) 3D shape similarity study (Rapid Overlay Chemical Similarity-ROCS) to the clinically used drugs in COVID-19 patients, and finally, (d) the rule of five and the estimated pre-ADMT properties of the separated flavonoids. Docking study with Mpro of SARS-CoV-2 (PDB ID:6LU7, and 6Y2F) showed that compound 3, its aglycone part, and compound 4 have a strong binding mode to a protease receptor with key amino acids, especially Gln:166AA, and having a similar docking pose to co-crystalized ligands. Docking with the spike protein of SARS-CoV-2 illustrated that compounds 3 and 4 have a good binding affinity to PDB ID:6VSB through the formation of HBs with Asp:467A and Asn:422A. According to ROCS analysis, compounds 1, 3, and 4 displayed high similarities to drugs that prevent SARS-Co2 entry to the lung cells or block the inflammatory storm causing lung injury. Compounds 3 and 4 are good candidates for drug development especially because they showed predicted activity against SARS-CoV-2 through different mechanisms either by preventing genome replication or by blocking inflammatory storm that trigger lung injury. These compounds were isolated from peach fruit, and the study supports data and continues with the recommendation of peach fruits in controlling and managing COVID-19 cases.

Participation of Free-Radical Processes in Structural and Metabolic Disturbances in the Lung Tissues Caused by Exposure to Coal-Rock Dust and their Adaptogenic Correction

Adaptive correction of structural and metabolic disturbances in the lungs caused by longterm exposure to coal-rock dust were studied in experiments on rats. It was shown that the complex antioxidant preparation containing dihydroquercetin compensated disturbances in the redox balance in the lung tissue, prevented the formation of dust granulomas, and reduced the severity of degenerative changes in the bronchopulmonary system.

Effect of Biofermentation with Taxifolin on Physicochemical and Microbiological Properties of Cold-Smoked Pork Sausages

The aim of this work is to evaluate the effect of taxifolin on the physicochemical and microbiological properties of cold-smoked pork sausages produced using different commercial starter cultures with Leuconostoc carnosum and with a mixture of Pediococcus pentosaceus and Staphylococcus xylosus. Ultra performance liquid chromatography analysis demonstrated that after 181 days of storage total taxifolin content was the highest in samples with taxifolin and L. carnosum (60%), compared to the first day of storage. The sausages with taxifolin and the mixture of P. pentosaceus and S. xylosus (56%) followed next. Taxifolin improved the hygienic quality of sausages without significant effect on the growth of lactic acid bacteria. The accumulation of biogenic amines, including histamine and putrescine, was more effectively reduced in sausages inoculated with the taxifolin and P. pentosaceus and S. xylosus mixture. Using this mixture, the rate of lipolysis and lipid oxidation were effectively slowed down. Samples with taxifolin and L. carnosum showed the highest free radical scavenging activity on the first day of the study ((77.4±1.3) %) (p<0.05 in all samples). Mixtures containing taxifolin and starter cultures bound free radicals better than taxifolin alone. The colour parameters (L*, a* and b*) of preparations and final products were significantly influenced by taxifolin and starter cultures and storage time (p<0.05 in all samples).

Antigenotoxic Effects of Biochaga and Dihydroquercetin (Taxifolin) on H2O2-Induced DNA Damage in Human Whole Blood Cells

The health benefits of natural products have long been recognized. Consumption of dietary compounds such as supplements provides an alternative source of natural products to those obtained from the diet. There is a growing concern regarding the possible side effects of using different food supplements simultaneously, since their possible interactions are less known. For the first time, we have tested genotoxic and antigenotoxic effects of Biochaga, in combination with dihydroquercetin. No genotoxic effect on whole blood cells was observed within individual treatment of Biochaga (250 μg/mL, 500 μg/mL and 1000 μg/mL) and dihydroquercetin (100 μg/mL, 250 μg/mL and 500 μg/mL), nor in combination. Afterwards, antigenotoxic potency of both supplements against hydrogen peroxide- (H₂O₂-) induced DNA damage to whole blood cells (WBC) was assessed, using the comet assay. Biochaga and dihydroquercetin displayed a strong potential to attenuate H₂O₂-induced damage on DNA in cells at all tested concentrations, with a statistical significance (p < 0.05), whereas Biochaga at the dose of 500 μg/mL in combination with dihydroquercetin 500 μg/mL was most prominent. Biochaga in combination with dihydroquercetin is able to protect genomic material from oxidative damage induced by hydrogen peroxide in vitro.

Leishmania amazonensis ferric iron reductase (LFR1) is a bifunctional enzyme: Unveiling a NADPH oxidase activity

Leishmania amazonensis is one of leishmaniasis' causative agents, a disease that has no cure and leads to the appearance of cutaneous lesions. Recently, our group showed that heme activates a Na⁺/K⁺ ATPase in these parasites through a signaling cascade involving hydrogen peroxide (H₂O₂) generation. Heme has a pro-oxidant activity and signaling capacity, but the mechanism by which this molecule increases H₂O₂ levels in L. amazonensis has not been elucidated. Here we investigated the source of H₂O₂ stimulated by heme, ruling out the participation of mitochondria and raising the possibility of a role for a NADPH oxidase (Nox) activity. Despite the absence of a classical Nox sequence in trypanosomatid genomes, L. amazonensis expresses a surface ferric iron reductase (LFR1). Interestingly, Nox enzymes are thought to have evolved from ferric iron reductases because they share same core domain and are very similar in structure. The main difference is that Nox catalyses electron flow from NADPH to oxygen, generating reactive oxygen species (ROS), while ferric iron reductase promotes electron flow to ferric iron, generating ferrous iron. Using L. amazonensis overexpressing or knockout for LFR1 and heterologous expression of LFR1 in mammalian embryonic kidney (HEK 293) cells, we show that this enzyme is bifunctional, being able to generate both ferrous iron and H₂O₂. It was previously described that protozoans knockout for LFR1 have their differentiation to virulent forms (amastigote and metacyclic promastigote) impaired. In this work, we observed that LFR1 overexpression stimulates protozoan differentiation to amastigote forms, reinforcing the importance of this enzyme in L. amazonensis life cycle regulation. Thus, we not only identified a new source of ROS production in Leishmania, but also described, for the first time, an enzyme with both ferric iron reductase and Nox activities.

Physical and Chemical Stability of Formulations Loaded with Taxifolin Tetra-octanoate

Chemically stable ester derivatives of taxifolin have become a focus of interest for their role in the satisfactory effects on human health. Accordingly, the aim of this study was to evaluate the physical and chemical stability of different formulations containing 0.02% taxifolin tetra-octanoate, which was proved to possess higher inhibitory effect on tyrosinase activity compared with taxifolin in a cell-free system. In the studies of physical stability, a Brookfield viscometer was used to determine rheological behavior of formulations containing taxifolin tetra-octanoate, and a portable pH meter was used to determine pH change. Moreover, chemical stability was determined by HPLC with UV detection. Formulations were evaluated for 12 weeks stored at 25 and 40°C. Results showed that storage time had no significant influence on viscosity of the formulations containing taxifolin tetra-octanoate, and pH value was relatively stable, which was within the limits of normal skin pH range. In the chemical stability studies, taxifolin tetra-octanoate in the essence formulation was most unstable at 40°C with about 81% degradation in 12 weeks of storage, however, the percentage of remaining taxifolin tetra-octanoate in cream formulation stored for 12 weeks at 25°C was the highest, about 93%. The results in this study may contribute to the development of more stable formulations containing taxifolin tetra-octanoate.

Taxifolin protects neurons against ischemic injury in vitro via the activation of antioxidant systems and signal transduction pathways of GABAergic neurons

Cerebral blood flow disturbances lead to the massive death of brain cells. The death of >80% of cells is observed in hippocampal cell cultures after 40 min of oxygen and glucose deprivation (ischemia-like conditions, OGD). However, there are some populations of GABAergic neurons which are characterized by increased vulnerability to oxygen-glucose deprivation conditions. Using fluorescent microscopy, immunocytochemical assay, vitality tests and PCR-analysis, we have shown that population of GABAergic neurons are characterized by a different (faster) Ca²⁺ dynamics in response to OGD and increased basal ROS production under OGD conditions. A plant flavonoid taxifolin inhibited an excessive ROS production and an irreversible cytosolic Ca²⁺ concentration increase in GABAergic neurons, preventing the death of these neurons and further excitation of a neuronal network; neuroprotective effect of taxifolin increased after incubation of 24 h and correlated with increased expression of antiapoptocic and antioxidant genes Stat3 Nrf-2 Bcl-2, Bcl-xL, Ikk2, and genes coding for AMPA and kainate receptor subunits; in addition, taxifolin decreased expression of prooxidant enzyme NOS and proinflammatory cytokine IL-1β.

The mechanism of (+) taxifolin's protective antioxidant effect for •OH-treated bone marrow-derived mesenchymal stem cells

The natural dihydroflavonol (+) taxifolin was investigated for its protective effect on Fenton reagent-treated bone marrow-derived mesenchymal stem cells (bmMSCs). Various antioxidant assays were used to determine the possible mechanism. These included •OH-scavenging, 2-phenyl-4, 4, 5, 5-tetramethylimidazoline-1-oxyl-3-oxide radical-scavenging (PTIO•-scavenging), 1, 1-diphenyl-2-picryl-hydrazl radical-scavenging (DPPH•-scavenging), 2, 2′-azino-bis (3-ethylbenzo-thiazoline-6-sulfonic acid) radical-scavenging (ABTS⁺•-scavenging), Fe³⁺-reducing, and Cu²⁺-reducing assays. The Fe²⁺-binding reaction was also investigated using UV-Vis spectra. The results revealed that cell viability was fully restored, even increasing to 142.9 ± 9.3% after treatment with (+) taxifolin. In the antioxidant assays, (+) taxifolin was observed to efficiently scavenge •OH, DPPH• and ABTS⁺• radicals, and to increase the relative Cu²⁺- and Fe³⁺-reducing levels. In the PTIO•-scavenging assay, its IC₅₀ values varied with pH. In the Fe²⁺-binding reaction, (+) taxifolin was found to yield a green solution with two UV-Vis absorbance peaks: λ_max = 433 nm (ε =5.2 × 10² L mol⁻¹ cm ⁻¹) and λ_max = 721 nm (ε = 5.1 × 10² L mol⁻¹ cm ⁻¹). These results indicate that (+) taxifolin can act as an effective •OH-scavenger, protecting bmMSCs from •OH-induced damage. Its •OH-scavenging action consists of direct and indirect antioxidant effects. Direct antioxidation occurs via multiple pathways, including ET, PCET or HAT. Indirect antioxidation involves binding to Fe²⁺.

Taxifolin reduces the cholesterol oxidation product-induced neuronal apoptosis by suppressing the Akt and NF-κB activation-mediated cell death

The taxifolin effect on the cholesterol oxidation product-induced neuronal apoptosis was investigated using differentiated PC12 cells and human neuroblastoma SH-SY5Y cells. 7-ketocholesterol induced phosphorylation of Akt, and increase in the levels of cytosolic and nuclear NF-κB p65, cytosolic NF-κB p50 and cytosolic phosphorylated-IκB-α in PC12 cells. The cholesterol oxidation products also induced a decrease in the levels of Bid and Bcl-2, increase in the levels of p53 and Bax, loss of the mitochondrial transmembrane potential, release of cytochrome c, activation of caspases (-8, -9 and -3), production of reactive oxygen species, depletion of GSH and cell death in both cell lines. Taxifolin, N-acetylcysteine, trolox, Akt inhibitor and Bay11-7085 attenuated the cholesterol oxidation product-induced changes in the apoptosis-related protein levels, activation of the Akt and NF-κB, reactive oxygen species production, GSH depletion and cell death. These results show that taxifolin may reduce the cholesterol oxidation product-induced neuronal apoptosis by suppressing the Akt and NF-κB activation-mediated cell death. The suppressive effect appears to be attributed to the inhibition of reactive oxygen species production and GSH depletion.

Correlation between the potency of flavonoids for cytochrome c reduction and inhibition of cardiolipin-induced peroxidase activity

There are large differences between flavonoids to protect against apoptosis, a process in which cytochrome c (Cyt c) plays a key role. In this work, we show that 7 of 13 flavonoids studied have a capacity to reduce Cyt c similar or higher than ascorbate, the flavonols quercetin, kaempferol and myricetin, flavanol epigallocatechin-gallate, anthocyanidins cyanidin and malvidin, and the flavone luteolin. In contrast, the kaempferol 3(O)- and 3,4'(O)-methylated forms, the flavanone naringenin, and also apigenin and chrysin, had a negligible reducing capacity. Equilibrium dialysis and quenching of 1,6-diphenyl-1,3,5-hexatriene fluorescence experiments showed that flavonoids did not interfere with Cyt c binding to cardiolipin (CL)/phosphatidylcholine (PC) vesicles. However, the CL-induced loss of Cyt c Soret band intensity was largely attenuated by flavonoids, pointing out a stabilizing action against Cyt c unfolding in the complex. Moreover, flavonoids that behave as Cyt c reductants also inhibited the pro-apoptotic CL-induced peroxidase activity of Cyt c, indicating that modulation of Cyt c signaling are probable mechanisms behind the protective biological activities of flavonoids. © 2016 BioFactors, 43(3):451-468, 2017.

Taxifolin synergizes Andrographolide-induced cell death by attenuation of autophagy and augmentation of caspase dependent and independent cell death in HeLa cells

Andrographolide (Andro) has emerged recently as a potential and effective anticancer agent with induction of apoptosis in some cancer cell lines while induction of G2/M arrest with weak apoptosis in others. Few studies have proved that Andro is also effective in combination therapy. The flavonoid Taxifolin (Taxi) has showed anti-oxidant and antiproliferative effects against different cancer cells. Therefore, the present study investigated the cytotoxic effects of Andro alone or in combination with Taxi on HeLa cells. The combination of Andro with Taxi was synergistic at all tested concentrations and combination ratios. Andro alone induced caspase-dependent apoptosis which was enhanced by the combination with Taxi and attenuated partly by using Z-Vad-Fmk. Andro induced a protective reactive oxygen species (ROS)-dependent autophagy which was attenuated by Taxi. The activation of p53 was involved in Andro-induced autophagy where the use of Taxi or pifithrin-α (PFT-α) decreased it while the activation of JNK was involved in the cell death of HeLa cells but not in the induction of autophagy. The mitochondrial outer-membrane permeabilization (MOMP) plays an important role in Andro-induced cell death in HeLa cells. Andro alone increased the MOMP which was further increased in the case of combination. This led to the increase in AIF and cytochrome c release from mitochondria which consequently increased caspase-dependent and independent cell death. In conclusion, Andro induced a protective autophagy in HeLa cells which was reduced by Taxi and the cell death was increased by increasing the MOMP and subsequently the caspase-dependent and independent cell death.

Anthoxanthin Polyphenols Attenuate Aβ Oligomer-induced Neuronal Responses Associated with Alzheimer's Disease

AIMS

Epidemiological evidence implicates polyphenols as potential natural therapeutics for Alzheimer's disease (AD). To investigate this prospect, five anthoxanthin polyphenols were characterized for their ability to reduce amyloid-β (Aβ) oligomer-induced neuronal responses by two mechanisms of action, modulation of oligomerization and antioxidant activity, as well as the synergy between these two mechanisms.

METHODS

Anthoxanthin oligomerization modulation and antioxidant capabilities were evaluated and correlated with anthoxanthin attenuation of oligomer-induced intracellular reactive oxygen species (ROS) and caspase activation using human neuroblastoma cell treatments designed to isolate these mechanisms of action and to achieve dual-action.

RESULTS

While modulation of oligomerization resulted in only minor reductions to neuronal responses, anthoxanthin antioxidant action significantly attenuated oligomer-induced intracellular ROS and caspase activation. Kaempferol uniquely exhibited synergism when the two mechanisms functioned in concert, leading to a pronounced reduction in both ROS and caspase activation.

CONCLUSIONS

Together, these findings identify the dominant mechanism by which these anthoxanthins attenuate Aβ oligomer-induced neuronal responses, elucidate their prospective synergy, and demonstrate the potential of anthoxanthin polyphenols as natural AD therapeutics.

Enzymatic polymerization of dihydroquercetin using bilirubin oxidase

Dihydroquercetin (or taxifolin) is one of the most famous flavonoids and is abundant in Siberian larch (Larix sibirica). The oxidative polymerization of dihydroquercetin (DHQ) using bilirubin oxidase as a biocatalyst was investigated and some physicochemical properties of the products were studied. DHQ oligomers (oligoDHQ) with molecular mass of 2800 and polydispersity of 8.6 were obtained by enzymatic reaction under optimal conditions. The oligomers appeared to be soluble in dimethylsulfoxide, dimethylformamide, and methanol. UV-visible spectra of oligoDHQ in dimethylsulfoxide indicated the presence of highly conjugated bonds. The synthesized oligoDHQ was also characterized by FTIR and (1)H and (13)C NMR spectroscopy. Comparison of NMR spectra of oligoDHQ with DHQ monomer and the parent flavonoids revealed irregular structure of a polymer formed via the enzymatic oxidation of DHQ followed by nonselective radical polymerization. As compared with the monomer, oligoDHQ demonstrated higher thermal stability and high antioxidant activity.

Cranberry flavonoids prevent toxic rat liver mitochondrial damage in vivo and scavenge free radicals in vitro

The present study was undertaken for further elucidation of the mechanisms of flavonoid biological activity, focusing on the antioxidative and protective effects of cranberry flavonoids in free radical-generating systems and those on mitochondrial ultrastructure during carbon tetrachloride-induced rat intoxication. Treatment of rats with cranberry flavonoids (7 mg/kg) during chronic carbon tetrachloride-induced intoxication led to prevention of mitochondrial damage, including fragmentation, rupture and local loss of the outer mitochondrial membrane. In radical-generating systems, cranberry flavonoids effectively scavenged nitric oxide (IC50  = 4.4 ± 0.4 µg/ml), superoxide anion radicals (IC50  = 2.8 ± 0.3 µg/ml) and hydroxyl radicals (IC50  = 53 ± 4 µg/ml). The IC50 for reduction of 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH) was 2.2 ± 0.3 µg/ml. Flavonoids prevented to some extent lipid peroxidation in liposomal membranes and glutathione oxidation in erythrocytes treated with UV irradiation or organic hydroperoxides as well as decreased the rigidity of the outer leaflet of the liposomal membranes. The hepatoprotective potential of cranberry flavonoids could be due to specific prevention of rat liver mitochondrial damage. The mitochondria-addressed effects of flavonoids might be related both to radical-scavenging properties and modulation of various mitochondrial events.

Acetylcholinesterase and carbonic anhydrase isoenzymes I and II inhibition profiles of taxifolin

Taxifolin, also known as dihydroquercetin, is a flavonoid commonly found in plants. Carbonic anhydrase (CA, EC 4.2.1.1) plays an important role in many critical physiological events including carbon dioxide (CO2)/bicarbonate (HCO3(-)) respiration and pH regulation. There are 16 known CA isoforms in humans, of which human hCA isoenzymes I and II (hCA I and II) are ubiquitous cytosolic isoforms. In this study, the inhibition properties of taxifolin against the slow cytosolic isoenzyme hCA I, and the ubiquitous and dominant rapid cytosolic isoenzyme hCA II were studied. Taxifolin, as a naturally bioactive flavonoid, has a K(i) of 29.2 nM against hCA I, and 24.2 nM against hCA II. For acetylcholinesterase enzyme (AChE) inhibition, K(i) parameter of taxifolin was determined to be 16.7 nM. These results clearly show that taxifolin inhibited both CA isoenzymes and AChE at the nM levels.

Improvement of the Quality and the Shelf Life of the High Oxygen Modified Atmosphere Packaged Veal by Superficial Spraying with Dihydroquercetin Solution

The improvement of quality and the shelf life of veal by combination of 80%O₂/20%CO₂ modified atmosphere packaging and superficial spraying with 0.02% dihydroquercetin solutions was studied. The control samples C, air packaged only, D, air packaged sprayed by 0.02% dihydroquercetin solution, MAP, modified atmosphere packaging only, BMAP, modified atmosphere packaging sprayed by 0.02% butylated hydroxytoluene solution, and DMAP, modified atmosphere packaging sprayed by 0.02% dihydroquercetin solution, were measured. The best results were obtained in modified atmosphere packaging sprayed by 0.02% dihydroquercetin solution. Comparisons with control samples were expressed as reduction in acid value with 27.72%, peroxide value with 64.74%, 2-thiobarbituric acid reactive substances (TBARS) with 65.71%, and the pH with 6.18%. The acid and peroxide values, TBARS, and pH were decreased linearly in response when applying the combination of 80%O₂/20%CO₂ modified atmosphere packaging and superficial spraying with 0.02% dihydroquercetin solutions (P < 0.05). The changes of amino nitrogen content of modified atmosphere packaging veal were not influenced statistically significantly by 0.02% dihydroquercetin solution (P > 0.05). According to results obtained it was concluded that 80%O₂/20%CO₂ modified atmosphere packaged veal stored at 0 ± 0.5°C after 0.02% dihydroquercetin solution treatment can preserve its quality and shelf life to 15 d postmortem.

Taxifolin prevents diabetic cardiomyopathy in vivo and in vitro by inhibition of oxidative stress and cell apoptosis

Diabetic cardiomyopathy has been increasingly recognized as an important cause of heart failure in diabetic patients. Excessive oxidative stress has been suggested to play a critical role in the development of diabetic cardiomyopathy. The objective of this study was to investigate the potential protective effects and mechanisms of taxifolin on cardiac function of streptozotocin-induced diabetic mice and on hyperglycemia-induced apoptosis of H9c2 cardiac myoblasts. In vivo study revealed that taxifolin improved diastolic dysfunction, ameliorated myocardium structure abnormality, inhibited myocyte apoptosis and enhanced endogenous antioxidant enzymes activities. Interestingly, taxifolin reduced angiotensin II level in myocardium, inhibited NADPH oxidase activity, and increased JAK/STAT3 activation. In vitro investigation demonstrated that taxifolin inhibited 33 mM glucoseinduced H9c2 cells apoptosis by decreasing intracellular ROS level. It also inhibited caspase-3 and caspase-9 activation, restored mitochondrial membrane potential, and regulated the expression of proteins related to the intrinsic pathway of apoptosis, thus inhibiting the release of cytochrome c from mitochondria into the cytoplasm. In conclusion, taxifolin exerted cardioprotective effects against diabetic cardiomyopathy by inhibiting oxidative stress and cardiac myocyte apoptosis and might be a potential agent in the treatment of diabetic cardiomyopathy.

Cytochrome c produces pores in cardiolipin-containing planar bilayer lipid membranes in the presence of hydrogen peroxide

Interaction of cytochrome c with cardiolipin in the presence of hydrogen peroxide induces peroxidase activity in cytochrome c and the ability to oxidize membrane lipids. These cytochrome c properties play a substantial role in the cytochrome c-mediated apoptotic reactions. In the present study the electric properties (specific capacitance and integral conductance) of the cardiolipin-containing asolectin planar bilayer lipid membranes (pBLM) in the presence of cytochrome c and hydrogen peroxide were studied. Cytochrome c interaction with cardiolipin-containing pBLM in the presence of hydrogen peroxide resulted in the dramatic increase of the conductance, pore production, their growth up to 3.5 nm diameter and subsequent membrane destruction. In the absence of hydrogen peroxide cytochrome c demonstrated almost no effect on the membrane capacitance and conductance. The data obtained prove the pivotal role of cytochrome c and membrane lipids in the permeabilization of pBLM. Correlation of apoptotic reactions and cytochrome c-mediated membrane permeability is discussed.

Dihydroquercetin: More than just an impurity?

Dihydroquercetin (taxifolin) is a potent flavonoid found in onions, French maritime bark, milk thistle, tamarind seeds and commercially available semi-synthetic monoHER marketed as Venoruton. This review focuses on the therapeutic promise of dihydroquercetin in major disease states such as cancer, cardiovascular disease and liver disease by reviewing the proposed mechanism(s) of action, including the activation of the antioxidant response element (ARE) and detoxifying phase II enzymes, inhibition of cytochrome P(450) and fatty acid synthase in carcinogenesis. TNF-alpha and NF-ĸB dependent transcription in hepatitis C infections, the scavenging effect of myeloperoxidase (MPO) derived reactive nitrogen species and subsequent effects on cholesterol biosynthesis as well as the effects on apob/apoA-I, HMG-CoA reductase and apoptosis are reviewed. The stereochemistry and pro-oxidant effect of dihydroquercetin are also considered. Although the majority of research on dihydroquercetin to date has focused on the identification of molecular targets in vitro, this review will bring together evidence of the potency and mode of action of dihydroquercetin and will propose a role for the therapeutic potential of flavonoid antioxidants.