Natural Flavonoid Research Articles

Quercetin alleviates liver fibrosis via regulating glycolysis of liver sinusoidal endothelial cells and neutrophil infiltration.

Liver fibrosis, a common characteristic in various chronic liver diseases, is largely influenced by glycolysis. Quercetin (QE), a natural flavonoid known to regulate glycolysis, was studied for its effects on liver fibrosis and its underlying mechanism. In a model of liver fibrosis induced by carbon tetrachloride (CCl4), we aimed to assess pathological features, serum marker levels, and analyze the expression of glycolysis-related enzymes at both mRNA and protein levels, with a focus on changes in liver sinusoidal endothelial cells (LSECs). Our results showed that QE effectively improved liver injury and fibrosis evident by improved pathological features and lowered levels of serum markers, such as alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), γ-glutamyl transferase (GGT), total bile acid (TBA), total bilirubin (TBIL), direct bilirubin (DBIL), hyaluronic acid (HA), laminin (LN), and procollagen type III (PCIII). QE also decreased lactate production and downregulated the expression of glycolysis-related enzymes-pyruvate kinase M2 (PKM2), phosphofructokinase platelet (PFKP), and hexokinase II (HK2)-at both the mRNA and protein levels. QE reduced the expression and activity of these enzymes, resulting in reduced glucose consumption, adenosine triphosphate (ATP) production, and lactate generation. Further analysis revealed that QE inhibited the production of chemokine (C-X-C motif) ligand 1 (CXCL1) and suppressed neutrophil recruitment. Overall, QE showed promising therapeutic potential for liver fibrosis by targeting LSEC glycolysis and reducing neutrophil infiltration.

Understory growth of Paris polyphylla accumulates a reservoir of secondary metabolites of plants.

Paris polyphylla is an important traditional medicinal plant of the Himalayan region. It is extensively used for the production of natural steroidal saponins and flavonoids. Although seed dormancy of wild plants can be broken to be artificially maintained and regenerated through micropropagation in the laboratory, the success of secondary metabolite production in higher quantities and the synthesis of superior plant metabolites have been very limited. In this study, we present differential metabolic profiling of P. polyphylla plants maintained for 8 years in natural and greenhouse conditions. Untargeted profiling of the metabolites through ultra-performance liquid chromatography-mass spectrometry/mass spectrometry (UPLC-MS/MS), followed by statistical analysis, identified secondary metabolites that were enriched in the naturally occurring plant roots compared with the greenhouse plant roots. A multivariate statistical analysis revealed the differential distribution of the compounds between the two groups. Overall, we identified 1,182 secondary metabolites, with 116 metabolites being differentially upregulated and 256 metabolites being downregulated. Moreover, 810 metabolites showed no significant variation under both growing conditions. The Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that the naturally forest-grown P. polyphylla plants were significantly enriched in steroidal saponins, lipids, vitamins, flavonoids, and flavonols. An analysis of the top 10 differentially upregulated secondary metabolites indicated a significantly enriched quantity of spirost-5-en-3,12-diol and kaempferol synthesis pathways, which are known to reduce the effect of free radicals scavengers inside the cell. In addition, veratramine alkaloids were also enriched under natural conditions. Our findings indicated that naturally maintained P. polyphylla plants are suitable for the extraction of medicinally important compounds. Our study established a causal relationship between the metabolic composition of the roots and their natural growth condition. This study highlighted the importance of environmental conditions in the biosynthesis of secondary metabolites of plants.

Luteolin (LUT) Induces Apoptosis and Regulates Mitochondrial Membrane Potential to Inhibit Cell Growth in Human Cervical Epidermoid Carcinoma Cells (Ca Ski).

Background/Objectives: Luteolin (LUT) is a natural flavonoid with known anti-inflammatory, antioxidant, and anti-cancer properties. Cervical cancer, particularly prevalent in certain regions, remains a significant health challenge due to its high recurrence and poor response to treatment. This study aimed to investigate the anti-tumor effects of LUT on human cervical epidermoid carcinoma cells (Ca Ski), focusing on cell growth inhibition, apoptosis induction, and regulation of mitochondrial membrane potential. Methods: Ca Ski cells were treated with varying concentrations of LUT (0, 25, 50, 100 µM) for different time periods (24, 48, 72 hours). Cell viability was measured using the MTT assay, apoptosis was assessed by flow cytometry with annexin V-FITC/PI staining, and changes in mitochondrial membrane potential were evaluated using JC-1 staining. Caspase-3 activation was examined by flow cytometry, and expression of apoptosis-related proteins (caspase-3, -8, -9, AIF) was analyzed via Western blotting. Results: LUT significantly inhibited the growth of Ca Ski cells in a dose- and time-dependent manner, with the most pronounced effects observed at 100 µM over 72 hours. Flow cytometry confirmed that LUT induced apoptosis without causing necrosis. Mitochondrial membrane potential was reduced after LUT treatment, coinciding with increased caspase-3 activation. Western blot analysis revealed the upregulation of pro-apoptotic proteins caspase-3, -8, -9, and AIF, indicating that LUT induces apoptosis through the intrinsic mitochondrial pathway. Conclusions: Luteolin effectively inhibits cervical cancer cell proliferation and induces apoptosis by disrupting mitochondrial membrane potential and activating caspases. These findings suggest that LUT holds potential as a therapeutic agent for cervical cancer, with further studies needed to explore its in vivo efficacy and broader clinical applications.

Development of quercetin loaded biosynthesized chitosan grafted iron oxide nanoformulation and their antioxidant, antibacterial, and anti-cancer properties

In this study, we report the development and characterization of a novel nanoformulation composed of quercetin-loaded biosynthesized chitosan-grafted iron oxide nanoparticles (CH-Fe3O4 NCs). The synthesis of chitosan-grafted iron oxide nanoparticles was achieved through a green synthesis approach, utilizing chitosan derived from crustacean shells and biosynthesized iron oxide nanoparticles. Quercetin, a natural flavonoid with known antibacterial, anti-cancer, and antioxidant properties, was loaded onto the nanoparticles through physical adsorption. The optical property, crystal structure, morphology, chemical composition and surface charge were thoroughly characterized using various analytical techniques including UV–visible spectroscopy, X-ray diffractometer, scanning and transmission electron microscopy, fourier-transform infrared spectroscopy and zeta potential analyzer. The antibacterial activity of the nanoformulation was evaluated against a panel of bacterial strains using standard microbiological assays, revealing promising inhibitory effects against both Gram-positive and Gram-negative bacteria. The antibacterial activity of CH-Fe3O4 NCs was evaluated against E. coli and S. aureus bacterial species. CH-Fe3O4 NCs have a greater ability to inhibit the E.coli than S. aureus. Furthermore, the CH-Fe3O4 NCs demonstrated dose-dependent cytotoxicity and caused apoptotic cell death in the H522 cell line. Additionally, the antioxidant properties of the nanoformulation were evaluated through scavenging assays, highlighting its ability to effectively neutralize free radicals. Overall, our results suggest that the quercetin-loaded biosynthesized chitosan-grafted iron oxide nanoformulation exhibits potent antibacterial, anti-cancer, and antioxidant properties, making it a promising candidate for further development as a multifunctional therapeutic agent.

Icariin promotes skeletal muscle mitochondrial biogenesis by the AMPK-PPARδ-PGC-1α signaling pathway: A potential mechanism for beneficial muscle function homeostasis

Mitochondrial biogenesis is a key factor in regulating skeletal muscle function and homeostasis. At present, a growing number of natural polyphenols, flavonoids and other compounds have been reported to have the function of regulating skeletal muscle oxidative metabolism. Here, we aimed to explore the effect of the flavonoid compound icariin purified from Epimedium koreanum Nakai in regulating mitochondrial biogenesis in mice and C2C12 myotubes. We found that icariin elevated the inverted suspension time by 1.72-fold and the distance run on the treadmill by 1.52-fold in mice. Daytime respiratory exchange ratio was significantly lower in mice after 8 weeks of icariin treatment compared to control groups. Icariin activated the mitochondrial biogenetic signaling pathway and mitochondrial marker expression, and the mitochondrial size of gastrocnemius and soleus was increased by 2.3-fold and 2.0-fold in mice, respectively. In addition, icariin elevated mitochondrial DNA copy number by 1.41-fold and 1.54-fold in gastrocnemius and C2C12 myotube cells, respectively. In vitro studies showed that inhibition of p-AMPK and PPARδ could attenuate ICA-regulated mitochondrial biogenetic pathway. Our study suggests that icariin promotes mitochondrial biogenesis and exercise endurance through AMPK-PPARδ-PGC-1α signaling pathway in C57BL/6 J mice skeletal muscle, indicating that icariin may be able to regulate muscle mitochondria function as an exercise mimetic.

Myricetin inhibits CYP3A4, GST, and MRP1 in hepatic cancer cells

AbstractHerbal and nutritional supplements are widely used to prevent and treat many diseases, including cancer. Tumor cells modify metabolic enzyme systems like CYP3A4 and GST. They also overexpress MRP1, an ATP-binding cassette transporter subfamily G (ABCG2) member. Drug efflux may increase, reducing tumor cell drug accumulation and developing drug resistance that leads to significant obstacles in cancer care. Natural products' ability to overcome cancer's multidrug resistance is interesting. Their ability to affect several targets makes them valuable in addressing drug resistance from diverse approaches. The potential of natural flavonoid; Myricetin (MYR) to modulate CYP3A4, GST, and MRP1 activity and expression in hepatic cancer cells was evaluated to prove its targeting and preventing these pathways of multidrug resistance. The cell proliferation of MYR was determined using an MTT assay. Specific enzyme assays, efflux assay, and gene expression using RT-PCR were used to evaluate MYR effect in hepatic cell lines HepG-2 and Huh-7. MYR has a noteworthy cytotoxic effect compared to doxorubicin (DOX) with IC50 > 100 μM in HepG-2 and Huh-7 cells. MYR showed potent inhibition of CYP3A4 and GST enzyme activity and MRP1 efflux function and downregulated their gene expression in a dose-dependent manner in both cells. MYR100 dose was the most significant effective dose. MRY100 decreased CYP3A4 activity by 67.5% (P < 0.05) and 55% (P < 0.01) and downregulated the gene by 0.2-fold (P < 0.001) and 0.3-fold (P < 0.001) in HepG-2 and Hub-7 cells, respectively. After treatment with MRY100, GST activity decreased significantly in both cells, reaching 47.6% (P < 0.001) and 33.2% and GST gene downregulation was 0.12 and 0.21-fold (P < 0.001). MRY100 inhibited MRP1 efflux pump 2.3 times (P < 0.001) and 1.9 times (P < 0.001) more effectively than PC, resulting in a 0.23-fold and 0.12-fold downregulation of MRP1 genes in HepG-2 and Hub-7 cells. The result will validate the use of MYR to interact with the metabolism phases and could be used as adjuvant therapy in cancer prevention and treatment approaches.

From Life's Essential 8 to metabolic syndrome: insights from NHANES database and network pharmacology analysis of quercetin.

Metabolic syndrome (MetS), or syndrome X, is a collection of metabolic illnesses that affect the body's health, particularly insulin resistance and obesity. The prevalence of MetS is on the rise, particularly among younger individuals. Quercetin, a natural flavonoid found in many traditional Chinese medicines, can impact various pathways to disrupt the pathological advancement of MetS with few negative effects. The American Heart Association recently introduced a cardiovascular health assessment termed Life's Essential 8 (LE8), which might impact the treatment of MetS. Quercetin targets and their functions in MetS pathways were identified using a network pharmacology method and molecular docking techniques. The study examined quercetin's direct and indirect interactions with proteins linked to the pathogenic processes of MetS. Data were collected regarding the American Heart Association's LE8 cardiovascular health indicators, which include health behaviors (diet, physical activity, nicotine exposure, and sleep) and health factors (body mass index, non-high-density lipoprotein cholesterol, blood glucose, and blood pressure). The study assessed the connection between LE8 and the occurrence of MetS, taking into account dietary quercetin consumption as a variable of interest. The negative correlation between MetS and LE8 indicates that individuals with higher LE8 scores are less likely to develop MetS. Individuals in the fully adjusted highest group (LE8 ≥ 80) demonstrated a 79% lower likelihood of developing MetS than those in the lowest group (OR = 0.21; 95% CI, 0.17-0.26, p < 0.0001). Network pharmacology and molecular docking results show that quercetin may exert its therapeutic effects by modulating various biological response processes, including those related to xenobiotic stimuli, bacterial molecules, lipopolysaccharides, and oxidative stimuli. These processes involve key pathways associated with diabetic complications, such as the AGE-RAGE signaling pathway, pathways related to diabetic complications, and pathways involved in lipids and atherosclerosis. Therefore, quercetin may reduce cardiovascular risk, improve glucose-lipid metabolism, and alleviate insulin resistance and other biological processes by influencing multiple aspects of the lipid profile, blood glucose, and insulin resistance, ultimately impacting the links between LE8 score and MetS. This study discovered that an optimal LE8 score is a marker of adopting a lifestyle of wellness and is connected with a reduced likelihood of developing MetS. Quercetin acts on core targets such as IL6, BCL2, TP53, IL1B, MAPK1, and CCL2, and then plays a therapeutic role in regulating lipid metabolism, anti-inflammation, immunomodulation, autophagy, etc., through the pathways of diabetic complications, lipids, atherosclerosis, etc., and has the characteristics of multi-targets, multi-pathways, and multi-functions in regulating interventions for MetS.

Luteolin-Loaded Hyaluronidase Nanoparticles with Deep Tissue Penetration Capability for Idiopathic Pulmonary Fibrosis Treatment.

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive interstitial lung disease characterized by sustained fibrotic lesions. Orally administered drugs usually fail to efficiently penetrate the interstitial tissue and reach the lesions, resulting in low treatment efficiency. Luteolin (Lut)is a natural flavonoid, active metabolites of which possess antioxidant, anti-inflammatory, anti-fibrotic, and anti-apoptotic properties. In this study, a nano-formulation is developed by loading Lut into hyaluronidase nanoparticles (Lut@HAase). These Lut@HAase nanoparticles (NPs) exhibit small size and good stability, suitable for noninvasive inhalation and accumulation in the lungs, and hyaluronidase at the site of lesions can degrade hyaluronic acid in the interstitial tissue, enabling efficient penetration of Lut. Lut's therapeutic effect, when administered via NPs, is studied both in vitro (using MRC5 cells) and in vivo (using IPF mice models), and its anti-fibrotic properties are found to inhibit inflammation and eliminate reactive oxygen species. Conclusively, this study demonstrates that Lut@HAase can improve lung function and enhance survival rates while reducing lung damage with few abnormalities during IPF treatment.

Hyaluronic Acid-Modified Luteolin-Copper Complex Nanodelivery System for Bacterial Prostatitis.

Bacterial prostatitis is a common disease of the male genitourinary system, which seriously affects the normal life and health of male patients. Antibiotics are commonly used in the clinical treatment of bacterial prostatitis, but the efficacy of fluoroquinolones is gradually declining due to the increasing drug resistance of bacteria. Hence, it is necessary to find new antibacterial drugs to treat bacterial prostatitis. Luteolin is a natural flavonoid compound with many pharmacological activities such as antibacterial and anti-inflammatory activities, but its poor water solubility and low structural stability seriously limit its clinical application. In this study, we designed a targeting drug delivery system via a luteolin-copper complex grafted with hyaluronic acid. The results of the characterization proved the successful synthesis of the system. The results of the in vitro performance test show that the system has a good antibacterial effect and excellent blood compatibility and can be effectively released under different pH conditions. The prepared nanodrug delivery system not only provides a new idea for the treatment of bacterial prostatitis but also lays a theoretical and practical foundation for the wide application of luteolin in clinical practice.

Induction of immunogenic cell death and enhancement of the radiation-induced immunogenicity by chrysin in melanoma cancer cells

Chrysin is a natural flavonoid with anti-cancer effects. Despite its beneficial effects, little information is available regarding its immunogenic cell death (ICD) properties. In this work, we hypothesized that chrysin can potentiate radiotherapy(RT)-induced immunogenicity in melanoma cell line (B16-F10). We examined the effects of chrysin alone and in combination with radiation on ICD induction in B16-F10 cells. Cell viability was assessed using an MTT assay. Cell apoptosis and calreticulin (CRT) exposure were determined using flow cytometry. Western blotting and ELISA assay were employed to examine changes in protein expression. Combination therapy exhibited a synergistic effect, with an optimum combination index of 0.66. The synergistic anti-cancer effect correlated with increased cell apoptosis in cancer cells. Compared to the untreated control, chrysin alone and in combination with RT induced higher levels of DAMPs, such as CRT, HSP70, HMGB1, and ATP. The protein expression of p-STAT3/STAT3 and PD-L1 was reduced in B16-F10 cells exposed to chrysin alone and in combination with RT. Conditioned media from B16-F10 cells exposed to mono-and combination treatments elicited IL-12 secretion in dendritic cells (DCs), inducing a Th1 response. Our findings revealed that chrysin could induce ICD and intensify the RT-induced immunogenicity.

Dihydromyricetin ameliorate postmenopausal osteoporosis in ovariectomized mice: Integrative microbiomic and metabolomic analysis.

The gut microbiota may help mitigate bone loss linked to postmenopausal osteoporosis by affecting the immune and inflammatory responses and the gut-bone axis. Dihydromyricetin (DMY), a natural flavonoid, has some anti-inflammatory and antioxidant properties. This study aimed to investigate the mechanisms underlying the amelioration of bone loss in ovariectomized (OVX) mice treated with various doses of DMY. Eight-week-old C57/BL6 mice underwent ovariectomy and received varying DMY doses over 8 weeks. Thereafter, femoral bone microarchitecture, serum biomarker levels, and colon samples were analyzed to assess bone metabolism and inflammatory and hormonal responses. Fecal samples were subjected to 16S rDNA sequencing, and short-chain fatty acids were quantified. An untargeted metabolomics approach was applied to both serum and fecal samples to investigate alterations in the intestinal microbiota and metabolic profiles following DMY treatment in the OVX mice. The results show high-dose DMY has anti-osteoporotic effects. Compared to the OVX group, the DMY-treated group showed enhanced bone mineral density and reduced inflammation and colonic damage levels. The DMY treatment altered the gut microbiota composition, including the relative abundances at both the phylum and genus levels. In addition, DMY treatment increased the production of acetate and propionate. Metabolomic analysis revealed differential regulation of 37 and 70 metabolites in the serum and feces samples, respectively, in the DMY-treated group compared to those in the OVX group, affecting the serotonergic signaling, arachidonic acid metabolism, and unsaturated fatty acid biosynthesis pathways. In conclusion, these findings indicate that DMY can ameliorate bone loss in OVX mice via the gut-bone axis.

Investigating Sortase A inhibitory potential of herbal compounds using integrated computational and biochemical approaches

Multi-drug resistance in bacteria is emerging as a major global health challenge, causing substantial harm in terms of mortality, morbidity, and financial strain on healthcare systems. These bacteria are constantly acquiring new virulence factors and drug-resistance mechanisms, which highlights the critical need for innovative antimicrobial medicines and identification of new therapeutic targets, such as Sortase A (EfSrtAΔN59). EfSrtAΔN59, a transpeptidase significant for the adhesion and virulence of Enterococcus faecalis (E. faecalis), presents an attractive target for disrupting biofilm formation—a key factor in persistent infections. This study investigates the inhibitory effects of two natural flavonoids- Rutin Trihydrate and Quercetin, on EfSrtAΔN59 and biofilm formation in E. faecalis. With in vitro enzymatic assays and biofilm quantification techniques, we demonstrate that both compounds significantly attenuate EfSrtAΔN59 activity, thereby hindering bacterial biofilm formation. Rutin Trihydrate and Quercetin exhibited strong binding affinities to the EfSrtAΔN59 enzyme, as confirmed by molecular docking and MD simulation studies. This was further substantiated by a notable reduction in biofilm biomass in bacterial cultures treated with these compounds. These findings highlight the potential of Rutin Trihydrate and Quercetin as promising candidates for the development of novel anti-virulence therapies aimed at mitigating E. faecalis infections, thereby offering a compelling alternative to traditional antibiotics.

Dihydroquercetin nanoparticles nasal gel is a promising formulation for amelioration of Alzheimer’s disease

Dihydroquercetin is a natural flavonoid with anti-inflammatory, antioxidant, and neuroprotective activities. Dihydroquercetin exhibits a great neuroprotector promise in Alzheimer’s disorder via preventing the aggregation of amyloid-beta-peptide-Aβ(1–42). The goal of the study was to create dihydroquercetin-loaded-chitosan nanoparticles (DHQ-CS NPs) loaded to a mucoadhesive, thermosensitive in-situ gel for direct nasal administration to cure Alzheimer’s disorder. Loading drug in chitosan nanoparticles and incorporation into thermosensitive gel enhanced residence time and reduced mucociliary-clearance. Different in-vitro-physicochemical-characteristics of gels and nanoparticles-characterization were used to evaluate the formulations. The therapeutic effectiveness of DHQ-CS NPs gel was evaluated behaviorally, biochemically and histopathologically in Alzheimer’s-rat-model compared to intranasal DHQ gel. The small particles-size was obtained = 235.3 nm of DHQ-CS NPs. The DHQ-CS NPs gel demonstrated a greater release rate compared to the raw DHQ gel. Additionally, the nasal-administration of the DHQ-CS NPs gel showed better In-vivo results compared to DHQ gel, through improvement of memory and learning deficits and also the exploratory behavior and new object memory in streptozotocin induced-Alzheimer rats. Biochemically, the intranasal DHQ-CS NPs gel, showed reduced both Aβ-protein formation and tau protein hyperphosphorylation, inhibition of acetylcholine esterase activity and oxidative stress in the brain with increase of total antioxidants in the brain and serum, compared to DHQ gel. Histopathologically, the DHQ-CS NPs nasal gel produced improvement in the hippocampal and cerebral cortex structures, being comparable to the normal group. Consequently, the intranasal DHQ-CS NPs loaded in-situ gel seems to be a promising therapeutic formulation for Alzheimer’s disease medication.

Neuroprotective effects of Apigenin on prenatal Valproic acid-induced autism spectrum disorder in rats

Valproic acid (VPA) demonstrates teratogenic effects during pregnancy. Prenatal exposure to VPA may result in autism spectrum disorder (ASD) -like phenotypes. Apigenin, a natural flavonoid, has been shown to have neuroprotective impacts due to its antioxidant properties. This study aimed to investigate the protective effects of apigenin in prenatal Valproic acid-induced autism in rats. Female rats (220–240g, 2-3 months) received a single dose of VPA (600mg/kg, i.p.) on the 12.5th day of gestational. The male offspring were given oral apigenin (50mg/kg, p.o.) or the vehicle for 30 days. Behavioral tests, biochemical assessments for oxidative stress markers and pro-inflammatory cytokines were performed. VPA-treated rats exhibited increased anxiety-like behavior, and repetitive behavior. Social interaction was reduced, and detection of the novel object was impaired. Also, VPA-treated rats have shown higher levels of oxidative stress malondialdehyde (MDA) and lower GPX and superoxide dismutase (SOD) levels. Furthermore, IL-6 and TNF-α increased in the prefrotalcortex decreased. On the other hand, apigenin-treated rats restored the cognitive consequences and lowered oxidative stress and inflammation in the prefrotalcortex. ConclusionChronic apigenin treatment restored the behavioral and biochemical abnormalities caused by prenatal VPA exposure.

Natural Flavonoids as an Intervention for Hepatic Encephalopathy: Preclinical Evidence-based Review

Abstract: Hepatic encephalopathy (HE) is a serious neuropsychiatric disorder caused in patients with both; acute and chronic liver diseases, which consists of various complications ranging from cognitive impairment, disorientation, confusion, and coma. The available therapies mainly focus on decreasing ammonia levels either through increasing its elimination or decreasing its production, some medications may subside the duration and limit the consequences of HE, but there is no complete available treatment for HE-like manifestation. Thus, there is a need to explore new pharmacotherapy for the treatment and management of HE. Flavonoids are polyphenolic compounds easily found in vegetables, fruits, flowers, beverages, and plants based foods. In modern research, flavonoids have gained attention due to their broad pharmacological properties, like anti-oxidant, antiviral, anti-inflammatory, cardioprotective, cytoprotective, and neuroprotective activity. Several preclinical studies suggest that various flavonoids have a potential therapeutic role in a variety of metabolic- related neurological disorders, including HE. This review focuses on all pre-clinical reports that highlight the neuroprotective potential of natural flavonoids for the management of HE. Based on numerous pre-clinical studies and taking into account the therapeutic effects of natural flavonoids, the present study illustrates the cellular and molecular mechanisms responsible for the potential role of natural flavonoids as pharmacotherapy for the management and treatment of HE.

In vitro and in vivo evidence of the antineoplastic activity of quercetin against endothelial cells transformed by Kaposi’s sarcoma-associated herpesvirus G protein-coupled receptor

Quercetin (QUE) is a natural flavonoid with well-known anticancer capabilities, although its effect on viral-induced cancers is less studied. Kaposi’s sarcoma (KS) is a viral cancer caused by the human herpesvirus-8, which, during its lytic phase, expresses a constitutively activated viral G protein-coupled receptor (vGPCR) able to induce oncogenic modifications that lead to tumor development. The aim of this work was to investigate the potential effect of QUE on in vitro and in vivo models of Kaposi’s sarcoma, developed by transforming endothelial cells with the vGPCR of Kaposi’s sarcoma-associated herpesvirus. Initially, the antiproliferative effect of QUE was determined in endothelial cells stably expressing the vGPCR (vGPCR cells), with an IC50 of 30 μM. Additionally, QUE provoked a decrease in vGPCR cell viability, interfered with the cell cycle progression, and induced apoptosis, as revealed by annexin V/PI analysis and caspase-3 activity. The presence of apoptotic bodies and disorganized actin filaments was observed by SEM and phalloidin staining. Furthermore, tumors from vGPCR cells were induced in nude mice, which were treated with QUE (50 or 100 mg/kg/d) resulting in retarded tumor progression and reduced tumor weight. Notably, neither kidney nor liver damage was observed, as indicated by biochemical parameters in serum. In conclusion, this study suggests for the first time that QUE exhibits antineoplastic activity in both in vitro and in vivo models of KS, marking a starting point for further investigations and protocols for therapeutic purpose.

Pharmacokinetic and tissue distribution study of pectolinarigenin in rats using UPLC-MS/MS

Pectolinarigenin (PEC), a natural flavonoid isolated from Cirsium japonicum, exhibits promising therapeutic potential for multiple cancers. In present study, a simple and sensitive UPLC-MS/MS method was established for the quantification of PEC in rat plasma and tissues. The assay procedure involved a one-step protein precipitation with tadalafil as the internal standard, and separation on a Welch Xtimate UHPLC C18 column by gradient elution of acetonitrile/aqueous formic acid (0.1 %, v/v) at a flow rate of 0.2 m L·min−1. The detection was conducted using multiple-reaction monitoring via an electrospray ionization source in positive ionization mode. The established method was proved to be highly sensitive with a good linearity (R2 > 0.99) in respective concentration range (0.1–100 ng·mL−1 in plasma and 1–10000 ng·mL−1 in tissues) and acceptable extraction recovery (≥71.17 %), matrix effect and stability, which was applied to study the pharmacokinetics and tissue distribution of PEC after intravenous (100 μg·kg−1) and oral administration (10, 20 and 40 mg·kg−1). PEC was promptly absorbed (Tmax ≤ 0.222 h) and maintained at a low level with slow elimination (t1/2 z ≥ 14.47 h) in rats after oral administration, resulting in extremely low bioavailability (0.56–0.68 %). However, PEC is widely distributed in rat tissues with high exposure in GI tract, liver and kidney. The bioavailability and tissue affinity were firstly revealed, which will guide directions for further development of PEC as an anti-tumor drug candidate.

Antibiofilm mechanism of 2R,3R-dihydromyricetin by targeting sortase A and its application against Staphylococcus aureus adhesion on eggshell

Biofilm formation of Staphylococcus aureus in food processing environments raises significant safety concerns, necessitating the development of new antibiofilm approaches for controlling S. aureus contamination. This study aimed to elucidate the antibiofilm mechanism of 2R,3R-dihydromyricetin (DMY), a natural flavonoid, against S. aureus and evaluate its efficacy in reducing bacterial adhesion to eggshell. The results revealed that DMY was a potent inhibitor of S. aureus sortase A (SrtA) with an IC50 of 73.43 μM, preventing bacterial adhesion to fibrinogen and subsequent biofilm formation. Fluorescence quenching assay and surface plasmon resonance analysis confirmed that DMY could directly bind to S. aureus SrtA. Notably, circular dichroism spectra demonstrated a conformational change in SrtA from α-helical to β-sheet structure upon DMY binding. Molecular dynamics simulation suggested that DMY bound to the catalytic pocket of S. aureus SrtA via hydrophobic interactions and hydrogen bonds. Furthermore, fluorescence microscopic observations further revealed that DMY attenuated the biofilm-related phenotype of SrtA by decreasing the anchoring of S. aureus protein A (SpA) onto cell wall. Importantly, pretreatment with 125 μg/mL DMY significantly reduced 1.14–1.75 log CFU/cm2 of S. aureus adhered on eggshells. Overall, these findings highlight how specific targeting of SrtA by DMY inhibits the attachment stages of biofilm development in S. aureus, making it a promising candidate for a novel disinfectant against this pathogen in the food industry.

Kaempferol Synergistically Enhances Cisplatin-induced Apoptosis and Cell Cycle Arrest in Colon Cancer Cells.

Colon cancer remains a significant global health concern, necessitating the continuous exploration of novel therapeutic strategies. Cisplatin is a first-line chemotherapy medication that is frequently used to treat patients for a variety of malignancies, including colon cancer. However, a major obstacle to its clinical usefulness is acquired resistance. This research investigates the synergistic effects of kaempferol, a natural flavonoid with known anti-cancer properties, in combination with cisplatin, in colon cancer cells. Our study employed colon cancer cell lines to evaluate the individual and combined cytotoxic effects of kaempferol and cisplatin. The results demonstrated a notable enhancement in the cytotoxicity of colon cancer cells when treated with a combination of kaempferol and cisplatin compared to individual treatments. This synergistic effect was further characterized by an increase in apoptosis, as evidenced by morphological changes and biochemical markers of apoptosis and cell cycle. The investigations revealed that the combined treatment led to the modulation of key apoptotic pathways, including the upregulation of pro-apoptotic factors and downregulation of anti-apoptotic factors. Additionally, the synergistic effect was associated with the inhibition of cell proliferation and induction of cell cycle arrest. The findings of this study suggest that the combination of kaempferol and cisplatin holds promise as a potent therapeutic strategy for colon cancer treatment, potentially enhancing the efficacy of conventional chemotherapy while minimizing adverse effects. Further in-depth investigations, including in vivo studies, are warranted to validate these findings and explore the translational potential of this synergistic approach in clinical settings.

Development of Quercetin Solid Dispersion-Loaded Dissolving Microneedles and In Vitro Investigation of Their Anti-Melanoma Activities.

Background: Melanoma is a skin cancer that requires early treatment to prevent metastasis. In particular, the superficial spreading melanoma, excisional surgery with local administration of anti-cancer drugs via microneedles is currently considered a potential combination therapy. Quercetin is a natural flavonoid having activities against melanoma cells. Unfortunately, the therapeutic effect is limited by its poor water solubility. Objectives: This study aimed to develop formulations of solid dispersion-loaded dissolving microneedles (SD-DMNs) of quercetin and to investigate their in vitro activities against melanoma cells. Methods: Quercetin solid dispersions (Q-SDs) were prepared using polyvinylpyrrolidone K30 (PVP) via a solvent technique. The optimized Q-SD was selected for preparing Q-SD-loaded dissolving microneedles (Q-SD-DMNs) using a mold casting method. Results: Q-SDs had higher water solubility than that of quercetin by 5-10 times depending on the ratio of quercetin-to-PVP. The presence of quercetin in the Q-SD and Q-SD-DMN were in an amorphous form. The obtained Q-SD-DMNs had pyramid-shaped microneedles. Their strength depended on the compositions, i.e., ratios of hyaluronic acid-to-sodium carboxymethylcellulose and the content of Q-SD. An optimized Q-SD-DMN increased the in vitro skin permeation of quercetin compared to that of microneedles containing quercetin (without being processed). From the molecular investigations, the optimized Q-SD-DMN reduced the viability of the A375 cells (melanoma cells) through the induction of cell apoptosis. It suppressed Bcl-2 gene expression and led to a lower content of Bcl-2 in the cells. Conclusions: The optimized Q-SD-DMN has a potential for use in further in vivo studies as a synergistic method of melanoma treatment.