Inhibitory effect of taxifolin on mast cell activation and mast cell-mediated allergic inflammatory response

Quercetin and Kaempferol inhibit HMC-1 activation via SOCE/NFATc2 signaling and suppress hippocampal mast cell activation in lipopolysaccharide-induced depressive mice

OBJECTIVE AND DESIGN

Mast cells (MCs), as the fastest immune responders, play a critical role in the progression of neuroinflammation-related diseases, especially in depression. Quercetin (Que) and kaempferol (Kae), as two major diet-derived flavonoids, inhibit MC activation and exhibit significant antidepressant effect due to their anti-inflammatory capacity. The study aimed to explore the mechanisms of inhibitory effect of Que and Kae on MC activation, and whether Que and Kae suppress hippocampal mast cell activation in LPS-induced depressive mice.

SUBJECTS AND TREATMENT

In vitro assays, human mast cells (HMC-1) were pretreated with Que or Kae for 1 h, then stimulated by phorbol 12-myristate 13-acetate (PMA) and 2,5-di-t-butyl-1,4-benzohydroquinone (tBHQ) for 3 h or 12 h. In vivo assays, Que or Kae was administered by oral gavage once daily for 14 days and then lipopolysaccharide (LPS) intraperitoneally injection to induce depressive behaviors.

METHODS

The secretion and expression of TNF-α were determined by ELISA and Western blotting. The nuclear factor of activated T cells (NFAT) transcriptional activity was measured in HMC-1 stably expressing NFAT luciferase reporter gene. Nuclear translocation of NFATc2 was detected by nuclear protein extraction and also was fluorescently detected in HMC-1 stably expressing eGFP-NFATc2. We used Ca2+ imaging to evaluate changes of store-operated calcium entry (SOCE) in HMC-1 stably expressing fluorescent Ca2+ indicator jGCamP7s. Molecular docking was used to assess interaction between the Que or Kae and calcium release-activated calcium modulator (ORAI). The  hippocampal mast cell accumulation and activation  were detected by toluidine blue staining and immunohistochemistry with β-tryptase.

RESULTS

In vitro assays of HMC-1 activated by PtBHQ (PMA and tBHQ), Que and Kae significantly decreased expression and secretion of TNF-α. Moreover, NFAT transcriptional activity and nuclear translocation of NFATc2 were remarkably inhibited by Que and Kae. In addition, the Ca2+ influx mediated by SOCE was suppressed by Que, Kae and the YM58483 (ORAI inhibitor), respectively. Importantly, the combination of YM58483 with Que or Kae had no additive effect on the inhibition of SOCE. The molecular docking also showed that Que and Kae both exhibit high binding affinities with ORAI at the same binding site as YM58483. In vivo assays, Que and Kae significantly reversed LPS-induced depression-like behaviors in mice, and inhibited hippocampal mast cell activation  in LPS-induced depressive mice.

CONCLUSIONS

Our results indicated that suppression of SOCE/NFATc2 pathway-mediated by ORAI channels may be the mechanism of inhibitory effect of Que and Kae on MC activation, and also suggested Que and Kae may exert the antidepressant effect through suppressing hippocampal mast cell activation.

Synthesis of Taxifolin-Loaded Polydopamine for Chemo-Photothermal-Synergistic Therapy of Ovarian Cancer

Chemotherapy is a well-established method for treating cancer, but it has limited effectiveness due to its high dosage and harmful side effects. To address this issue, researchers have explored the use of photothermal agent nanoparticles as carriers for precise drug release in vivo. In this study, three different sizes of polydopamine nanoparticles (PDA-1, PDA-2, and PDA-3) were synthesized and evaluated. PDA-2 was selected for its optimal size, encapsulation rate, and drug loading rate. The release of the drug from PDA-2@TAX was tested at different pH and NIR laser irradiation levels. The results showed that PDA-2@TAX released more readily in an acidic environment and exhibited a high photothermal conversion efficiency when exposed to an 808 nm laser. In vitro experiments on ovarian cancer cells demonstrated that PDA-2@TAX effectively inhibited cell proliferation, highlighting its potential for synergistic chemotherapy-photothermal treatment.

Inflammatory mediators, oxidative stress and genetic disturbance in rheumatoid arthritis rats supported by alfalfa seeds metabolomic constituents via blocking interleukin-1receptor

Rheumatoid arthritis (RA) is an autoimmune disease characterized by aggressive cartilage and bone erosion. This work aimed to evaluate the metabolomic profile of Medicago sativa L. (MS) (alfalfa) seeds and explore its therapeutic impact against RA in rats. Arthritis was induced by complete Freund's adjuvant (CFA) and its severity was assessed by the arthritis index. Treatment with MS seeds butanol fraction and interlukin-1 receptor antagonist (IL-1RA) were evaluated through measuring interlukin-1 receptor (IL-1R) type 1 gene expression, interlukin-1 beta (IL-1β), oxidative stress markers, C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-α), prostaglandin E2 (PGE2), caspase-3 (Cas-3), intracellular adhesion molecule-1 (ICAM-1), DNA fragmentation, and chromosomal damage. Total phenolics/ flavonoids content in the ethyl acetate, butanol fraction and crude extract of MS seeds were estimated. The major identified compounds were Quercetin, Trans-taxifolin, Gallic acid, 7,4'-Dihydroxyflavone, Cinnamic acid, Kudzusaponin SA4, Isorhamnetin 3-O-beta-D-2'',3'',4''-triacetylglucopyranoside, Apigenin, 5,7,4'-Trihydroxy-3'-methoxyflavone, Desmethylxanthohumol, Pantothenic acid, Soyasapogenol E, Malvidin, Helilandin B, Stigmasterol, and Wairol. Treatment with MS seeds butanol fraction and IL-1RA enhanced all the biochemical parameters and the histopathological features of the ankle joint. In conclusion, Trans-taxifolin was isolated for the first time from the genus Medicago. MS butanol fraction seeds extract and IL-1 RA were considered as anti-rheumatic agents.

Genista tridentata Phytochemical Characterization and Biological Activities: A Systematic Review

Genista tridentata (L.) Willk., known as "prickled broom", is a Leguminosae (Fabaceae) species native to the Iberian Peninsula, Morocco, Algeria, and Tunisia. It is used in folk medicine as an anti-inflammatory, for gastrointestinal and respiratory disorders, rheumatism, and headaches, to lower blood pressure, against hypercholesterolemia and hyperglycemia. This study aimed to systematically review the literature on the bioactivities and phytochemical profile of Genista tridentata to understand its pharmacological potential. For this, four electronic databases (PubMed, GoogleScholar, Repositórios Cientificos de Acesso Aberto de Portugal (RCCAP), and ScienceDirect) were searched from inception up to 31 December 2022. From a total of 264 potentially eligible studies considered for screening, 34 papers were considered eligible for this systematic review. The sampling included 71 extracts, collected mainly in Portugal. Genista tridentata extracts present a high level of flavonoids and phenolic compounds. The flowers and aerial parts of the plant were the most studied, and aqueous extracts were the most used. The results predict a high potential for the application of Genista tridentata as a new source of natural antioxidants and preservatives for the food industry with subsequent health benefits, such as the production of nutraceuticals. Moreover, the results indicate that the plant can be collected at all seasons of the year, which represents a benefit for the industry.

Pharmacological activation of the Nrf2 pathway by Taxifolin remodels articular cartilage microenvironment for the therapy of Osteoarthritis

BACKGROUND

Osteoarthritis (OA) is a widely prevalent degenerative disease marked by extracellular matrix (ECM) degradation, inflammation, and apoptosis. Taxifolin (TAX) is a natural antioxidant possessing various pharmacological benefits, such as combating inflammation, oxidative stress, apoptosis, and serves as a potential chemopreventive agent by regulating genes through an antioxidant response element (ARE)-dependent mechanism. Currently, no studies have investigated the therapeutic impact and precise mechanism of TAX on OA.

PURPOSE

The aim of this study is to examine the potential role and mechanism of TAX in reshaping the cartilage microenvironment, thereby offering a stronger theoretical foundation for pharmacologically activating the Nrf2 pathway to manage OA.

STUDY DESIGN AND METHODS

The pharmacological effects of TAX were examined in chondrocytes through in vitro studies and in a destabilization of the medial meniscus (DMM) rat model for in vivo analysis.

RESULTS

TAX suppresses IL-1β triggered secretion of inflammatory agents, chondrocyte apoptosis, and ECM degradation, contributing to the remodeling of the cartilage microenvironment. In vivo experiment results demonstrated that TAX counteracted cartilage degeneration induced by DMM in rats. Mechanistic investigations revealed that TAX hinders OA development by reducing NF-κB activation and ROS production through the activation of the Nrf2/HO-1 axis.

CONCLUSION

TAX reshapes the articular cartilage microenvironment by suppressing inflammation, mitigating apoptosis, and decreasing ECM degradation through the activation of the Nrf2 pathway. As a result, pharmacological activation of the Nrf2 pathway by TAX holds potential clinical significance in remodeling the joint microenvironment for OA treatment.

Hovenia dulcis Thunb. Fruit Extract Attenuates Psoriatic Skin Inflammation in Tumor Necrosis Factor-α-Stimulated Human Keratinocyte HaCaT Cells In Vitro

Hovenia dulcis Thunb. fruit (HDF) is traditionally used for treating liver diseases and alcohol poisoning. The purpose of this study was to explore the effects of HDF on hyperproliferation, levels of inflammatory cytokines, and signaling mechanisms in human psoriatic keratinocyte HaCaT cells. HDF showed a preventive effect on tumor necrosis factor-α (TNF-α)-induced abnormal proliferation of psoriatic keratinocytes. Furthermore, real-time reverse transcription-PCR analysis showed that HDF suppressed the expressions of inflammatory cytokines; interleukin (IL)-1α and IL-1β and chemokines; CCL-20 and CXCL-8 in TNF-α-induced HaCaT cells. Western blotting revealed that HDF suppressed the levels of phosphorylated IκB and STAT3 together with a decline in the levels of phosphorylated mitogen-activated protein kinases (MAPKs). These outcomes indicate that HDF prevents the abnormal proliferation of keratinocytes and modulates inflammatory responses by suppressing nuclear factor-κB (NF-κB) and STAT3 activation through downregulation of the MAPK signaling pathway in TNF-α-induced psoriatic keratinocytes. Our study demonstrates that HDF is prospective and beneficial for psoriatic skin inflammation.

An insight into novel therapeutic potentials of taxifolin

Taxifolin is a flavonoid compound, originally isolated from the bark of Douglas fir trees, which is often found in foods such as onions and olive oil, and is also used in commercial preparations, and has attracted the interest of nutritionists and medicinal chemists due to its broad range of health-promoting effects. It is a powerful antioxidant with excellent antioxidant, anti-inflammatory, anti-microbial and other pharmacological activities. This review focuses on the breakthroughs in taxifolin for the treatment of diseases from 2019 to 2022 according to various systems of the human body, such as the nervous system, immune system, and digestive system, and on the basis of this review, we summarize the problems of current research and try to suggest solutions and future research directions.

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.

Secondary Metabolites with Biomedical Applications from Plants of the Sarraceniaceae Family

Carnivorous plants have fascinated researchers and hobbyists for centuries because of their mode of nutrition which is unlike that of other plants. They are able to produce bioactive compounds used to attract, capture and digest prey but also as a defense mechanism against microorganisms and free radicals. The main purpose of this review is to provide an overview of the secondary metabolites with significant biological activity found in the Sarraceniaceae family. The review also underlines the necessity of future studies for the biochemical characterization of the less investigated species. Darlingtonia, Heliamphora and Sarracenia plants are rich in compounds with potential pharmaceutical and medical uses. These belong to several classes such as flavonoids, with flavonol glycosides being the most abundant, monoterpenes, triterpenes, sesquiterpenes, fatty acids, alkaloids and others. Some of them are well characterized in terms of chemical properties and biological activity and have widespread commercial applications. The review also discusses biological activity of whole extracts and commercially available products derived from Sarraceniaceae plants. In conclusion, this review underscores that Sarraceniaceae species contain numerous substances with the potential to advance health. Future perspectives should focus on the discovery of new molecules and increasing the production of known compounds using biotechnological methods.

Modification of taxifolin particles with an enteric coating material promotes repair of acute liver injury in mice through modulation of inflammation and autophagy signaling pathway

PURPOSE

Taxifolin (TAX) is a flavanol compound with hepatoprotective effect, but its application is severely limited by its poor water solubility and low oral bioavailability. Therefore, it is important to urgently find a method to improve the oral bioavailability of TAX.

METHODS

In this study, hydroxypropyl methylcellulose acetate succinate modified taxifolin liposomes (HPMCAS-TAX-Lips) were prepared by a thin-film dispersion method, and a series of physicochemical properties of the liposomes were studied. The cumulative in vitro release rates of free TAX, taxifolin liposomes (TAX-Lips), and HPMCAS-TAX-Lips in the simulated gastrointestinal fluid were measured by in vitro release experiments, and the effect of HPMCAS-TAX-Lips on the human hepatoellular carcinomas (HepG2) cells was detected by MTT assay. Finally, the hepatoprotective mechanism of HPMCAS-TAX-Lips was explored through in vivo experiments.

RESULTS

The results showed that the particle size of HPMCAS-TAX-Lips was 100.44 ± 2.85 nm, the zeta potential was - 51.13 ± 0.57 mV, the PDI was 0.170 ± 0.088, and the EE was 87.9 ± 3.73%. The in vitro release results showed that the cumulative release rates of TAX-Lips and HPMCAS-TAX-Lips in simulated gastric fluid for 24 h were 92.60 ± 5.31% and 66.91 ± 1.20%, respectively. The cumulative release rates in simulated intestinal fluid for 24 h were 72.61 ± 4.38% and 53.94 ± 3.2%, respectively. The results of cytotoxicity experiments proved that HPMCAS-TAX-Lips had a significant inhibitory effect on HepG2 cells. In vivo experiments further showed that HPMCAS-TAX-Lips significantly improved the survival rate of lipopolysaccharide (LPS)/D-galactosamine (D-GalN)-induced acute liver injury mice and exerted hepatoprotective effects by regulating the expression of autophagy proteins and inhibiting the activation of toll-like receptor 4 (TLR4)/nuclear factor kappa B (NF-κB) signaling pathway.

CONCLUSION

This study proved the significant hepatoprotective effect of HMPCAS-TAX-Lips and provided a new idea for the application of TAX.

Dihydroquercetin Attenuates Silica-Induced Pulmonary Fibrosis by Inhibiting Ferroptosis Signaling Pathway

Silicosis is a fatal occupational lung disease which currently has no effective treatment. Dihydroquercetin (DHQ) is a flavonoid compound known for its anti-inflammatory, anti-oxidant and anti-cancer bioactivity. However, whether DHQ protects against silica-induced lung fibrosis remains unknown. Therefore, we aimed to investigate the effect of DHQ on silica-induced lung fibrosis and the underlying molecular mechanism in vivo and in vitro. Our results demonstrated that DHQ treatment markedly attenuated SiO₂-induced inflammation and fibrosis degree of lung tissues in the C57BL/6 mice. Additionally, experiments in vitro also confirmed that conditioned medium from DHQ-treated human bronchial epithelial (HBE) cells significantly decreased expression of fibrosis markers of human fetal lung fibroblast cells (MRC-5), such as α-SMA, collagen1 and fibronectin. Interestingly, HBE cells treated by DHQ showed few morphological features of ferroptosis compared with SiO₂-treated cells. Furthermore, DHQ treatment remarkably inhibited ferroptosis in activated HBE cells by decreasing the accumulation of iron and lipid peroxidation products, and increasing levels of glutathione (GSH) and glutathione peroxidase 4 (GPX4), whereas stimulation of ferroptosis by specific inducer erastin deeply impaired anti-fibrosis effect of DHQ in vitro. More importantly, our results showed that DHQ also evidently suppressed ferritinophagy by down-regulation of microtubule-associated protein 1A/1B-light chain 3 (LC3), and up-regulation of ferritin heavy chain 1 (FTH1), nuclear receptor co-activator 4 (NCOA4) in activated HBE cells. Nevertheless, activation of ferritinophagy by specific inducer rapamycin (Rapa) evidently blocked DHQ-inhibited HBE cells ferritinophagy and anti-fibrosis effect of DHQ. Overall, our research revealed that inhibition of ferritinophagy-mediated HBE cells ferroptosis was responsible for DHQ to ameliorate SiO₂-induced lung fibrosis, which provided a preliminary theoretical basis for the clinical application of DHQ in the treatment of silicosis.

Conditioned Medium of Human Amniotic Epithelial Cells Alleviates Experimental Allergic Conjunctivitis Mainly by IL-1ra and IL-10

Allergic conjunctivitis (AC) is the most prevalent form of mucosal allergy, and the conditioned medium (CM) from mesenchymal stem cells has been reported to attenuate some allergic diseases. However, the therapeutic effects of CM from different tissue stem cells (TSC-CM) on allergic diseases have not been tested. Here, we studied the effects of topical administration of different human TSC-CM on experimental AC (EAC) mice. Only human amniotic epithelial cell-CM (AECM) significantly attenuated allergic eye symptoms and reduced the infiltration of immune cells and the levels of local inflammatory factors in the conjunctiva compared to EAC mice. In addition, AECM treatment decreased immunoglobulin E (IgE) release, histamine production, and the hyperpermeability of conjunctival vessels. Protein chip assays revealed that the levels of anti-inflammatory factors, interleukin-1 receptor antagonist (IL-1ra) and IL-10, were higher in AECM compared to other TSC-CM. Furthermore, the anti-allergic effects of AECM on EAC mice were abrogated when neutralized with IL-1ra or IL-10 antibody, and the similar phenomenon was for the activation and function of B cells and mast cells. Together, the present study demonstrated that AECM alleviates EAC symptoms by multiple anti-allergic mechanisms mainly via IL-1ra and IL-10. Such topical AECM therapy may represent a novel and feasible strategy for treating AC.

Pharmacological basis and new insights of taxifolin: A comprehensive review

The pharmacological characteristics of phytochemicals have prompted a lot of interest in their application in disease management. Due to the high incidence of cancer related mortality and morbidity throughout the world; experiments have concentrated on identifying the anticancer potential of natural substances. Many phytochemicals such as flavonoids and their derivatives produced from food offer a variety of new anti-cancer agents which prevent the cancer progression. Taxifolin, a unique bioactive flavonoid, is a dietary component that has grabbed the interest of dietitians and medicinal chemists due to its wide range of health benefits. It is a powerful antioxidant with a well-documented effect in the prevention of several malignancies in humans. Taxifolin has shown promising inhibitory activity against inflammation, malignancies, microbial infection, oxidative stress, cardiovascular disease, and liver disease. Anti-cancer activity has been shown to be relatively significant than other activities investigated in vitro and in vivo with a little or no side effects to the normal healthy cells. In summary this review offers the synopsis of recent breakthroughs in the use of taxifolin as a cancer treatment, as well as mechanisms of action. However, to develop a medicine for human usage, more study on pharmacokinetic profile, profound molecular mechanisms, and drug safety criteria should be conducted utilizing well-designed randomized clinical trials.

STIM1 promotes angiogenesis by reducing exosomal miR-145 in breast cancer MDA-MB-231 cells

Cancer cells secrete abundant exosomes, and the secretion can be promoted by an increase of intracellular Ca2+. Stromal interaction molecule 1 (STIM1) plays a key role in shaping Ca2+ signals. MicroRNAs (miRNAs) have been reported to be potential therapeutic targets for many diseases, including breast cancer. Recently, we investigated the effect of exosomes from STIM1-knockout breast cancer MDA-MB-231 cells (Exo-STIM1-KO), and from SKF96365-treated MDA-MB-231 cells (Exo-SKF) on angiogenesis in human umbilical vein endothelial cells (HUVECs) and nude mice. The exosomes Exo-STIM1-KO and Exo-SKF inhibited tube formation by HUVECs remarkably. The miR-145 was increased in SKF96365 treated or STIM1-knockout MDA-MB-231 cells, Exo-SKF and Exo-STIM1-KO, and HUVECs treated with Exo-SKF or Exo-STIM1-KO. Moreover, the expressions of insulin receptor substrate 1 (IRS1), which is the target of miR-145, and the downstream proteins such as Akt/mammalian target of rapamycin (mTOR), Raf/extracellular signal regulated-protein kinase (ERK), and p38 were markedly inhibited in HUVECs treated with Exo-SKF or Exo-STIM1-KO. Matrigel plug assay in vivo showed that tumor angiogenesis was suppressed in Exo-STIM1-KO, but promoted when miR-145 antagomir was added. Taken together, our findings suggest that STIM1 promotes angiogenesis by reducing exosomal miR-145 in breast cancer MDA-MB-231 cells.

Chinese Medicine Huzhen Tongfeng Formula Effectively Attenuates Gouty Arthritis by Inhibiting Arachidonic Acid Metabolism and Inflammatory Mediators

The Chinese herbal medicine, Huzhen Tongfeng Formula (HZTF), derived from traditional Chinese medicine (TCM) practice, has recognized therapeutic benefits for gouty arthritis (GA). HZTF is currently in the late stage of approval process as a new anti-GA drug application. However, the underlying mechanism of HZTF as an antigout medication is unclear. In this study, we combined network pharmacology and experimental validation approaches to elucidate the mechanism of action of HZTF. First, the relative drug-disease target networks were constructed and analyzed for pathway enrichment. Potential pathways were then validated by in vitro and in vivo experiments. We found that 34 compounds from HZTF matched 181 potential drug targets. Topology analysis revealed 77 core targets of HZTF, which were highly related to gout, following screening of KEGG pathway enrichment. Further analysis demonstrated that the arachidonic acid metabolic pathway was the most relevant pathway involved in the mechanism of HZTF. Validation experiments showed that HZTF significantly inhibited the inflammatory cell infiltration into gouty joints, improved the swelling of affected joints, and increased the pain threshold. HZTF significantly reduced the transcription and production of various cytokines and inflammatory mediators in vitro. In particular, cyclooxygenase (COX)-1, COX-2, and 5-lipoxygenase were simultaneously downregulated. In conclusion, our study suggests that the antigout mechanism of HZTF is associated with the inhibition of the arachidonic acid pathway, resulting in the suppression of inflammatory cytokines and mediators. These findings extend our understanding of the pharmacological action of HZTF, rationalizing the application HZTF as an effective herbal therapy for GA.

Genista tridentata L.: A Rich Source of Flavonoids with Anti-inflammatory Activity

Background:Genista tridentata L. is an endemic species from the Iberian Peninsula used in Portuguese traditional medicine to treat inflammation-related diseases; this and other health-promoting effects are usually associated with the flavonoids produced by this species. In fact, anti-inflammatory properties were established for several of these flavonoid derivatives. Methods: A careful survey of the reported data, using mainly the Scopus database and Genista tridentata and Pterospartum tridentatum as keywords, was done. We have examined the papers involving the plant and those about the most relevant flavonoids anti-inflammatory activity. Results: The literature survey demonstrates that species are used to treat several health problems such as antihyperglycemia, hypertension, and inflammatory episodes. It was also possible to establish its richness in flavonoid derivatives, from which several are potential anti-inflammatory agents. Conclusions: From our described and discussed analysis, it can be concluded that Genista tridentata is an excellent source of bioactive flavonoids. Moreover, its traditional use to treat inflammation episodes may be due to its flavonoid content, from which genistein, biochanin A, rutin, and daidzein can be emphasized.

Ultrasound-Assisted Extraction of Taxifolin, Diosmin, and Quercetin from Abies nephrolepis (Trautv.) Maxim: Kinetic and Thermodynamic Characteristics

Extraction behaviors of the 3 flavonoids taxifolin, diosmin, and quercetin have been investigated in Abies nephrolepis leaves and bark. The following operation parameters—ethanol volume fraction, liquid–solid ratio, temperature, ultrasound irradiation power and time, and ultrasound frequency—were varied to study their effect on the yield of the 3 flavonoids during extraction. The results showed that a low extraction efficiency occurred at 293.15 K due to slow kinetics, while the situation was significantly improved at 333.15 K. The kinetic data for the extraction yields of the 3 flavonoids achieved good fits by the first-order kinetic model. From the thermodynamic analysis results, we realized that the ultrasound-assisted extraction of taxifolin, diosmin, and quercetin from the leaves and bark of A. nephrolepis was a spontaneous and endothermic process in which the disorder increased (ΔG⁰ < 0, ΔH⁰ > 0, and ΔS⁰ > 0). According to the response surface methodology (RSM) analysis, under the optimal operation conditions (ethanol concentration of 50%, liquid–solid ratio of 20 mL/g, frequency of 45 kHz, extraction time of 39.25 min, ultrasound irradiation power of 160 W and temperature of 332.19 K), the total yield of the 3 flavonoids were 100.93 ± 4.01 mg/g from the leaves of A. nephrolepis (with 31.03 ± 1.51 mg/g, 0.31 ± 0.01 mg/g, 69.59 ± 2.57 mg/g for taxifolin, diosmin, and quercetin, respectively), and under the optimal operation conditions (ethanol concentration of 50%, liquid–solid ratio of 20 mL/g, frequency of 45 kHz, extraction time of 36.80 min, ultrasound irradiation power of 150 W and temperature of 328.78 K), 16.05 mg/g ± 0.38 mg/g were obtained from the bark of A. nephrolepis (with 1.44 ± 0.05 mg/g, 0.47 ± 0.01 mg/g, 14.14 ± 0.38 mg/g for taxifolin, diosmin, and quercetin, respectively), which were close to the prediction values.

A study on the protective effects of taxifolin on human umbilical vein endothelial cells and THP-1 cells damaged by hexavalent chromium: a probable mechanism for preventing cardiovascular disease induced by heavy metals

Taxifolin suppressed the toxicity and THP-1 cell adhesion to HUVECs induced by Cr(vi) via regulating the p38 MAPK and JNK pathways.