The biological activities, chemical stability, metabolism and delivery systems of quercetin: A review

Evaluation of antioxidant efficacy of quercetin encapsulated in micelles, mixed micelles, or liposomes in oil-in-water emulsions

Quercetin was encapsulated in polyoxyethylene laurylether (Brij 35®) micelles, 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) liposomes and Brij 35®/DMPC mixed micelles. These obtained formulations were then physically characterized for their particle size, morphology, physical stability and polydispersity index. All quercetin formulations were evaluated for their antioxidant efficiency in two oil-in-water emulsion systems and compared to the one of free quercetin. In short-term assays, results showed that among the tested formulations, quercetin liposomal form offered superior antioxidant protection, in comparison with polymer micelles or mixed micelles form or free quercetin. These results were attributed to a better synergistic effect of liposomal quercetin formulation with tocopherols present in the oil phase of the emulsion. However, in long-term assay, the loaded quercetin showed chemical degradation over the long term in the liposomal form, thus limiting its long-term antioxidant effectiveness in food emulsions.

Construction of W/O/W microcapsules based on the combination of polyglycerol polyricinoleate/protein for the co-encapsulation of crocin and quercetin: Physical properties, stability and in vitro digestion

Due to health reasons of polyglycerol polyricinoleate (PGPR), there has been a growing interest in reducing it. To address this, this study developed the PGPR/Protein (whey, pea, and chickpea protein isolates) emulsifier combinations. The effects of these combinations on the preparation, structure, physicochemical and in vitro digestive properties of W/O/W microcapsules were evaluated. The FTIR and XRD analyses revealed hydrogen bonding interactions between the protein and PGPR (or bioactive compounds), which may contribute to the enhanced encapsulation efficiency (EE) and stability of microcapsules. PGPR/pea protein isolate (PP) microcapsules exhibited more uniform size, better rehydration, and higher EE than other microcapsules. PP combinations prolonged shelf-life of microcapsules by 1.35 to 1.73-fold, as predicted by oxidation kinetic models. Furthermore, PP microcapsules improved the bioavailability of crocin (≥ 11.08 %) and quercetin (≥ 8.47 %). Overall, this study hoped to provide a promising strategy for preparing W/O/W microcapsules with low PGPR content.

Characterization and Engineering of Multifunctional Glycosyltransferase HtUGT73EW3 for the Highly Efficient Synthesis of Flavonoid Mono/di-O-glycosides

Glycosylation modification is an effective way to improve the solubility, stability, and bioavailability of flavonoids. In this study, a multifunctional flavonoid glycosyltransferase HtUGT73EW3 was identified from Helleborus thibetanus. HtUGT73EW3 exhibited multisite selectivity for 3-, 6-, 7-, 2'-, 3'-, and 4'-OH of flavonoids and showed potent 3/3'-, 3/4'-, and 7/4'-di-O-glycosylation activity. HtUGT73EW3 was able to glycosylate structurally diverse flavonoid aglycones and monoglycosides, and showed efficient glycosylation capacity toward flavonoid structures modified with functional groups at the C-3, C-7, C-8, and C-4' positions. Notably, the mutation of Gln85 to Leu greatly enhanced its catalytic activity, enabling not only the conversion of steroids and terpenoids, but also the improved utilization of UDP-sugars. Furthermore, the Q85L and I94A variants were found to catalyze specific 7,4'- and 3,4'-di-O-glycosylation, respectively. A cost-effective one-pot synthetic reaction was established by coupling AtSuSy and HtUGT73EW3, and the gram-scale synthesis of flavonoid 4'-O-glucoside and 3,4'-/7,4'-di-O-glucoside was achieved by a fed-batch strategy.

Targeted cancer therapy potential of quercetin-conjugated with folic acid-modified nanocrystalline cellulose nanoparticles: a study on AGS and A2780 cell lines

This study investigates the effects of quercetin-conjugated nanocrystalline cellulose/cetyltrimethylammonium bromide/folic acid nanoparticles (NCC/CTAB/FA NPs) on AGS and A2780 cancer cell lines, focusing on their cytotoxicity and antioxidant capacity. Dynamic light scattering (DLS) analysis revealed an average particle size of 388.70 nm, suitable for cellular uptake and release kinetics. The NCC/CTAB/FA NPs exhibited a rod and spherical morphology and uniform distribution, as confirmed by field emission scanning electron microscopy (FESEM). Fourier-transform infrared (FTIR) spectroscopy confirmed the successful synthesis and functional group integration, supporting the NPs' ability for drug delivery. The encapsulation efficiency value was 81.17%, demonstrating the effective incorporation of Quercetin. Cytotoxicity assays indicated significant reductions in cell viability for AGS and A2780 cells with IC50 values of 3.2 µg/mL and 16.04 µg/mL, respectively, while HDF cells exhibited higher viability. Flow cytometry analysis revealed a dose-dependent induction of apoptosis in AGS cells, supported by changes in gene expression related to apoptosis and inflammation. Furthermore, antioxidant capacity assays demonstrated practical free radical scavenging abilities, with IC50 values of 151.65 µg/mL for ABTS and 349.54 µg/mL for DPPH. NCC/CTAB/FA/Quercetin NPs exhibit promising characteristics for targeted cancer therapy and antioxidant applications.

Curcumin-loaded zein and shellac composite nanoparticles for ulcerative colitis treatment

This study highlights the efficacy of microfluidic technology in creating curcumin (Cur) loaded zein + shellac (Z + S) hybrid nanoparticles (NPs), presenting a promising avenue for enhancing Cur's availability in the food industry, especially in beverages, and positioning it as a potent antioxidant strategy for applications such as the treatment of enteritis. The study revealed that an increase in the proportion of shellac led to a gradual increase in the particle size of Z + S NPs, while the polydispersity index (PDI) initially decreasing and then increasing. When Cur is encapsulated, an increase in the proportion of shellac resulted in a gradual decrease in particle size and PDI, accompanied by an increase in encapsulation efficiency (EE). When the ratio of zein and shellac remained constant, elevating the Cur concentration led to a gradual decrease in EE and a gradual increase in drug loading. The consistently low Zeta potential (below -20 mV) confirmed the colloidal stability of the NPs, making them suitable for prolonged storage. The NPs exhibited excellent biocompatibility with normal cells and demonstrated effective free radical scavenging capabilities. Mixing of shellac and zein regulated the release profile of Cur from the NPs, mapping the food fate in human body, enhancing the treatment efficacy of ulcerative colitis. In vivo experiment demonstrated that the NPs are able to effectively relieve the dextran sulphate sodium induced enteritis, providing a promising approach for the treatment of ulcerative colitis.

Solid State Synthesis of Hyaluronic Acid-Quercetin Conjugate: Sustainable Protocol to Improve the Biological Activity of Quercetin

Herein, a sustainable solid-state procedure is employed for the synthesis of a water-soluble molecule obtained by linking hyaluronic acid to the hydrophobic quercetin (HA-QCT). The micellar self-aggregation of the developed conjugate suggested its employment as a drug delivery nano-system, considering the numerous biological activities of QCT. Indeed, the spectroscopic characterization (ultraviolet-visible and Fourier transform infrared) ensured that the QCT maintained its chemical integrity. In addition, a cytotoxicity test revealed that HA-QCT can be employed as a biocompatible drug vehicle for pharmacological purposes. A preliminary colorimetric test also confirmed that QCT retained its anti-oxidant activity.

Fabrication and characterization of zein/gelatin/carboxymethyl starch nanoparticles as an efficient delivery vehicle for quercetin with improved stability and bioaccessibility

Quercetin-loaded zein nanoparticles with dual coating of gelatin and carboxymethyl starch were fabricated and characterized. The composite nanoparticles demonstrated remarkable stability over a wide pH range (2.0-8.0) as well as under heat, UV irradiation, and prolonged storage conditions. Fluorescence and infrared spectroscopy analyses indicated that the primary driving forces in the formation of the composite nanoparticles were hydrogen bonding, electrostatic interactions, and hydrophobic interactions. The quercetin-loaded nanoparticles showed a substantial enhancement in the antioxidant properties and exhibited higher bioaccessibility during in vitro simulated gastrointestinal digestion. Moreover, the encapsulation efficiency of quercetin was greatly improved to 95.2 % after dual coating, in contrast to 60.5 % for the zein nanoparticle without coating. These results indicate that zein nanoparticles double-coated with gelatin and carboxymethyl starch can significantly improve the stability, antioxidant property, and bioaccessibility of the hydrophobic bioactive substance, which helps to promote its application in the field of functional foods and pharmaceuticals.

Desmodesmus Extract as a Mitochondrion-Targeted Neuroprotective Agent in Parkinson's Disease: An In Vitro Study

Parkinson's disease (PD) is the second most common neurodegenerative disease, and its prevalence is expected to double in the next 30 years. Currently, no effective treatment exists for Parkinson's disease. Thus, the research has focused on discovering new natural compounds with strong neuroprotective potential. This study aimed to investigate the effects of the methanol extract of Desmodesmus arthrodesmiformis EM13 (DaMe) on the mitochondrial damage pathway in an in vitro model of PD. The isolate of Desmodesmus arthrodesmiformis EM13 was first grown under appropriate culture conditions, and then the extract (DaMe) was prepared for use in the experiments. The total lipid and protein contents, fatty acid composition, and elemental content of DaMe were subsequently determined. Human SH-SY5Y neuroblastoma cells were pretreated with nontoxic concentrations of DaMe before 6-hydroxydopamine (6-OHDA) toxicity. Pretreatment with DaMe at concentrations of 100, 250, and 500 µg/mL showed a neuroprotective effect on 6-OHDA-induced SH-SY5Y neuroblastoma cells by decreasing the reactive oxygen species (ROS) production, decreasing the total oxidant status (TOS), increasing the total antioxidant capacity (TAC), increasing the mitochondrial membrane potential (ΔΨm), decreasing the oxidative DNA damage, and regulating gene expressions related to PD and apoptosis. Given the results of our study, we suggest that DaMe can be used as a natural source for producing drugs and dietary supplements intended to treat PD.

Inflammation-reducing thermosensitive hydrogel with photothermal conversion for skin cancer therapy

Photothermal therapy (PTT) has widely been utilized for postoperative treatment of skin cancer, while high temperature, usually >50 °C, would induce damage to healthy tissue and increased wound inflammation. Herein, we developed an "all in one" hydrogel to enhance mild PTT for postoperative skin cancer treatment while circumventing photothermo-induced inflammation by loading quercetin (Que)-coated tannin‑iron (TA-Fe) nanoparticles with poly (N-acrylylglycine) amine (PNAGA) hydrogel (Que@TA-Fe@PNAGA). Exposure to near-infrared light, Que.@TA-Fe@PNAGA occurred a mild temperature increase (∼47 °C), which induces local mild PTT and disrupts the hydrogen bonds within the hydrogel, triggering a gel-to-sol phase transition and the release of Que.@TA-Fe nanoparticles. These released nanoparticles inhibit the expression of heat shock proteins in tumor cells by producing reactive oxygen species and enter inflammatory cells to release TA and Que. via acid hydrolysis, reducing tumor necrosis factor-α expression by 66.6 % and promoting M1-to-M2 macrophage conversion. Based on this integrated functionality, Que.@TA-Fe@PNAGA hydrogel achieves over 99.4 % tumor inhibition rate, effectively avoids photothermo-induced damage in normal tissue and inflammation, and thus represents a new approach for postoperative photothermal therapy in skin cancer treatment.

Double-Layer Microneedle Patch Loaded with HA-PBA-QCT for Management of Paclitaxel-Induced Peripheral Neuropathic Pain

Chemotherapy-induced neuropathic pain (CINP) is a common adverse effect of antineoplastic drugs, often leading to dose reduction, treatment delays, or cessation of chemotherapy. Chemotherapy agents, like paclitaxel (PTX), damage the somatosensory nervous system by inducing neuroinflammation and oxidative stress, resulting in the sensitization of sensory neurons. Quercetin (QCT), known for its anti-inflammatory, antioxidant, and neuroprotective properties, is investigated for various neurological disorders. This work creates phenylboronic acid-modified hyaluronic acid (HA-PBA) gels with incorporated QCT and fabricates a double-layer microneedle (MN) patch using an HA-PBA-QCT complex in the needles and HA/polyvinyl alcohol (PVA) as the substrate. The crosslinking between PVA and HA-PBA-QCT enables a controlled, sustained release of QCT upon application. This work applies these QCT-loaded microneedle (QMN) patches to the instep skin of PTX-treated mice, which exhibits mechanical allodynia and cold hyperalgesia. Biweekly applications of the QMN patches significantly reduce pain responses. This analgesic effect is associated with the modulation of satellite glial cell activity, decreased macrophage infiltration, and reduced TNF-α and IL-6 levels in dorsal root ganglia (DRGs). Additionally, the treatment improves cellular antioxidant capacity, indicated by upregulated Nrf2 and catalase in DRGs. Overall, these findings suggest that double-layer QMN patches offer long-term anti-inflammatory and antioxidant benefits, potentially alleviating CINP in patients.

Advanced characterization of fish skin gelatin-proanthocyanidins covalent and non-covalent composite emulsions for benzyl isothiocyanate delivery

This research endeavored to engineer robust delivery matrices for bioactives, specifically benzyl isothiocyanate (BITC), by harnessing the synergistic covalent and non-covalent interactions between fish skin gelatin (FSG) and proanthocyanidins (PC) to synthesize novel composite emulsions. The objective was to delineate the influence of these molecular interactions on the emulsion's structural integrity and stability, which are pivotal for the efficacious encapsulation and controlled release of BITC. Employing a suite of analytical techniques, including Fourier transform infrared spectroscopy (FTIR), fluorescence spectroscopy, and contact angle measurements, the study delineated the predominant molecular forces at play within the FSG-PC complex, identifying electrostatic and hydrophobic interactions as the cornerstones of this interaction. An assessment of the emulsions' physicochemical properties, encompassing chromaticity, antioxidant efficacy, microstructural attributes, particle dimensions, zeta potential, and BITC retention, was undertaken to discern the optimal encapsulation strategy. The data unequivocally indicated that emulsions enriched with 0.06 wt% PC, in non-covalent synergy with FSG, afforded the most pronounced stability and retention of BITC. This work paves the way for future studies and the translational application of FSG-PC composite emulsions in the realm of bioactive substance delivery, offering a promising avenue for innovation in pharmaceutical and nutraceutical formulations.

Enhancing mechanical and blocking properties of gelatin films using zein-quercetin nanoparticle and applications for strawberry preservation

New gelatin films incorporated with zein-quercetin nanoparticles (GA/ZQNPs) were developed. The GA/ZQNP films had improved tensile strength, water vapor and oxygen barrier capabilities, hydrophobicity, UV blocking feature, antioxidant activities and antimicrobial properties, which varied with various contents of ZQNPs. Notably, the GA/ZQNP0.1-10 films exhibited enhanced tensile stress value around 3.2 MPa and strain of 142 %, a 78.4 % decrease in water vapor permeability, a 76.9 % decrease in oxygen permeability, the highest water contact angle at 112.0 ± 0.6°, an improved DPPH∙ scavenging rate of 64.9 ± 0.7 %, excellent UV blocking properties and antimicrobial properties. The GA/ZQNP films were further applied for strawberries packaging to assess their preservation capabilities under ambient conditions. The results showed that GA/ZQNP0.1-10 nanocomposite films efficiently maintained the best nutrient quality and acceptable appearance of strawberries compared with untreated strawberries, prolonging the shelflife of strawberries to approximately 8 days. These findings suggested promising applications for these new functional films in fruit packaging.

Development of barley proteins into peptides nanomicelles for encapsulation of hydrophobic bioactive ingredient

BACKGROUND

As natural polymer materials, barley proteins have been utilized to fabricate nanocarriers to encapsulate and delivery hydrophobic bioactive ingredients. However, as a result of the high proportion of hydrophobic amino acids and structural rigidity, barley protein-based nanocarriers tend to aggregate easily and have a low loading capacity, which greatly limits their application. In the present study, barley proteins were enzymolyzed to fabricate nanomicelles and then applied to encapsulate hydrophobic bioactive ingredient.

RESULTS

Self-assembled barley peptides could be obtained by controllable enzymolysis of barley proteins. The obtained barley peptides could self-assemble into nanomicelles (BPNMs) with a diameter of approximately 90 nm when the concentration was > 2.1 μg mL-1. Hydrophobic interaction, disulfide bonds and hydrogen bonds were involved in maintaining the structure of BPNMs. Six self-assembled peptides (QQPFPQ, QTPLPQ, QLPQIPE, QPFPQQPQLPH, QPFPQQPPFGL and QPFPQQPPFWQQQ) were identified and they were characterized by alternating arrangement of hydrophobic amino acids and hydrophilic amino acids. Moreover, BPNMs were utilized to encapsulate hydrophobic bioactive ingredient quercetin. When quercetin was encapsulated by BPNMs, its water solubility was significantly increased, being approximately 30-fold higher than free quercetin. Meanwhile, encapsulation of BPNMs could greatly increase quercetin stability. The interaction between BPNMs and quercetin occurred spontaneously, mainly driven by van der Waals forces and hydrogen bonds.

CONCLUSION

In the present study, BPNMs were successfully developed and could be used as a promising delivery system to improve the water solubility and stability of hydrophobic bioactive ingredients. © 2024 Society of Chemical Industry.

Phytochemicals, Organic Acid, and Vitamins in Red Rhapsody Strawberry-Content and Storage Stability

Strawberries are highly perishable fruits harvested at full ripeness, and their nutritional quality together with their phytochemical composition can be significantly affected by storage duration and temperature. This study investigated the changes in key bioactive compounds, including folate, vitamin C, anthocyanins, quercetin-3-glucoside, ellagic acid, and organic acids, in "Red Rhapsody" strawberries stored at two typical household temperatures (4 °C and 23 °C). While storage duration and temperature did not have a significant impact (p > 0.05) on folate content, significant changes in other phytochemicals were observed. The total anthocyanin content increased significantly (p < 0.05), from 30.0 mg/100 g fresh weight (FW) at Day 0 to 84.4 mg/100 g FW at Day 7 at 23 °C, a 2.8-fold increase. Conversely, the vitamin C content was significantly reduced (p < 0.05), from 54.1 mg/100 g FW at Day 0 to 28.4 mg/100 g FW at Day 7 at 23 °C, while it remained stable at 4 °C. Additionally, the concentrations of quercetin-3-glucoside, ellagic acid, and organic acids underwent significant changes during the storage period. The total folate content fluctuated between 73.2 and 81.6 μg/100 g FW at both temperatures. These results suggest that storage temperature and duration influence the individual phytochemicals and nutrients of strawberries differently, with potential implications for their nutritional value and bioactive compound content.

Preparation, characterization, and binding mechanism of quercetin-loaded composite nanoparticles based on zein-soybean protein isolate

In this study, quercetin (Que) was encapsulated for controlled release during gastrointestinal digestion using zein-soy isolate protein (SPI) composite nanoparticles that were made following an antisolvent precipitation technique. The average particle size of the composite nanoparticles ranged from 182.1 to 230.9 nm, and the polydispersity index (PDI) was small (0.105-0.323). The microstructure revealed that the composite nanoparticles were spherically distributed and that Que. was embedded on the surface of the nanoparticles. Que. has an encapsulation efficiency of up to 93.3 %. Spectrum analysis, molecular docking and zeta potential measurements revealed that the interactions between the composite nanoparticles and Que. occurred mainly through hydrophobic interactions, hydrogen bonding, and electrostatic interactions. Compared with single zein nanoparticles, the composite nanoparticles showed a significant and controlled release of Que. during the whole simulated gastrointestinal digestion process. This study provides a novel method for the development of a controlled-release drug delivery system for controlling the release of Que.

A nanodrug provokes antitumor immune responses via synchronous multicellular regulation for enhanced cancer immunotherapy

Hepatocellular carcinoma (HCC) exhibits a low response to immunotherapy due to the dense extracellular matrix (ECM) filled with immunosuppressive cells including dendritic cells (DCs) of blocked maturation. Herein, we develop a nanoprodrug self-assembled from polyethylene glycol-poly-4-borono-l-phenylalanine (mPEG-PBPA) conjugating with quercetin (QUE) via boronic ester bonds. In addition, an immune adjuvant of imiquimod (R837) is incorporated. The nanodrug (denoted as Q&R@NPs) is prepared from a simple mixing means with a high loading content of QUE reaching more than 30%. Owing to the acid and reactive oxygen species (ROS) sensitivities of boronic ester bonds, Q&R@NPs can respond to the tumor microenvironment (TME) and release QUE and R837 to synchronously exert multicellular regulation functions. Specifically, QUE inhibits the activation state of hepatic stellate cells and reduces highly expressed programmed death receptor ligand 1 (PD-L1) on tumor cells, meanwhile R837 exposes calreticulin on tumor cell surface as an "eat me" signal and leads to a large number of DCs maturing for enhanced antigen presentation. Consequently, the cooperative immune regulation results in a remodeled TME with high infiltration of cytotoxic T lymphocytes for enhanced HCC immunotherapy, which demonstrates an effective immunotherapy paradigm for dense ECM characterized solid tumors with high PD-L1 expression.

Exploring the health benefits of food bioactive compounds from a perspective of NLRP3 inflammasome activation: an insight review

The food industry has been focusing on food bioactive compounds with multiple physiological and immunological properties that benefit human health. These bioactive compounds, including polyphenols, flavonoids, and terpenoids, have great potential to limit inflammatory responses especially NLRP3 inflammasome activation, which is a key innate immune platform for inflammation. Current studies have revealed numerous food bioactive compounds with promising activities for unraveling immune metabolic disorders and excessive inflammatory responses by directly and indirectly regulating the NLRP3 inflammasome activation. This review explores the food hazards, including microbial and abiotic factors, that may trigger NLRP3-mediated illnesses and inflammation. It also highlights bioactive compounds in food that can suppress NLRP3 inflammasome activation through various mechanisms, linking its activation and inhibition to different pathways. Especially, this review provided further insight into NLRP3-related targets where food bioactive compounds can interact to block the NLRP3 inflammasome activation process, as well as mechanisms on how these compounds facilitate inactivation processes.

A comprehensive review of phytochemical approaches in treatment of acute myeloid leukemia: Associated pathways and molecular mechanisms

Acute myeloid leukemia (AML) is a type of cancer that affects the blood and bone marrow. This review conducts a thorough analysis of AML, addressing its genetic modification. The examination extends to the current therapeutic approaches employed for AML, shedding light on their efficacy and the notable side effects experienced by patients undergoing these treatments, leading to a low overall survival rate. Therefore, exploring alternative treatments, such as phytochemicals, is necessary. Furthermore, the review explores the complex landscape of phytochemicals, categorizing them based on their diverse properties, which include alkaloids, phenols, terpenoids, organo-sulfur compounds, and other compounds, including quinones, and elucidating their mechanisms of action. Special emphasis is placed on their involvement in critical signaling pathways, with a particular focus on how these phytochemicals impact AML when evaluated across a spectrum of cell lines. This in-depth exploration aims to uncover potential targets within the molecular landscape of AML where phytochemicals can exert their therapeutic effects. The review investigates the potential role of plant-derived phytochemicals as adjunctive therapies for AML. This exploration encompasses the identification of specific phytochemicals that exhibit promising anti-leukemic properties and evaluates their potential in clinical settings. Beyond conventional treatments, the review explores the integration of complementary and alternative medicine as a holistic approach to managing AML. The examination encompasses the synergy between conventional therapies and alternative interventions, exploring how these combined strategies may enhance overall therapeutic outcomes and mitigate side effects. From a forward-looking perspective, the overarching goal is to contribute to the evolving landscape of AML treatment by considering innovative approaches that harness the therapeutic potential of phytochemicals, both independently and in conjunction with established medical interventions.

Biocompatible, biodegradable, and anticancer alginate-quercetin ureteral stent via co-axial extrusion technique

Ureteral stents (US) are used as interventional medical implants in the treatment and surgery of urinary tract infections (UTIs). This study reported a new formulation of alginate-quercetin (AQ) based US through a co-axial extrusion procedure for the first time to afford a 26 cm long US with 3.2×1.7 mm external and internal diameter. The mechanical strength such as tensile strength and compression deformation was evaluated in dry and wet form. The stents were characterized through FESEM, FTIR, and XRD to check their morphology, functional groups, and amorphous or crystalline form-similarly, the hydrophilicity/hydrophilicity was observed on contact angle. All the stent formulations showed no cytotoxic effect in CCK-8 assay against human ureteral smooth muscle cells (HUSMC), and human umbilical vein endothelial cell lines (HUVECs) and are confirmed as biocompatible. Similarly, all the formulations exhibited strong anticancer activity against 786-0 and Caki-1 kidney cancer cell lines in the CCK-8 assay. Furthermore, the stent retains its shape and hollow cavity till day 12 in the artificial urine (AU) and is completely degraded on day 16. No change in the pH of the AU was observed during degradation in the AU solution. The current design shows a fast and reliable casting technique for the US, which will open a new window in the designing and manufacturing of the natural biopolymer-based US.

An in vitro investigation on the physicochemical properties of different quercetin formulations

OBJECTIVES

Quercetin is a naturally occurring plant flavonoid commonly used as a nutritional supplement due to its antioxidant and anti-inflammatory properties. Its well-known low bioavailability has led to the design of different quercetin formulations by various commercial entities seeking to market a highly bioavailable quercetin product. This study investigates four different commercially available quercetin formulations (LMQ, QUX, QUO, and QUV) for their physicochemical properties that influence bioavailability. LMQ and QUX are liquid-based formulations while QUO and QUV are solid powder-based formulations.

METHODS

Studies were conducted on particle size using a particle size analyzer; solubility (in water, simulated gastric and intestinal fluid) using Ultra High Performance Liquid Chromatography (UHPLC) to quantify the quercetin content; intestinal permeability and toxicity using Caco-2 cells and HepG2 liver cells.

RESULTS

LMQ and QUX had the narrowest particle size distribution as well as the highest solubility while QUO and QUV had the widest particle size distribution but the poorest solubility. One formulation (QUO) exhibited a significant reduction in cell viability with HepG2 and Caco-2 cells including a significant decrease in TEER value change (-39.0 %; p<0.01); its higher Caco-2 cell permeability (Papp 2.85 × 10-4 ± 4.22 × 10-5; p<0.05) likely resulted from reduced membrane integrity. The other formulations significantly increased the TEER value within the first 4 h (≥22.7 %; p<0.05).

CONCLUSIONS

The particle size distribution of each of the individual formulations reflected their solubilities in water and gastrointestinal fluids. Despite QUO having the highest permeability, its negative change in TEER value over time revealed its evident cytotoxic effects. QUV performed poorly in terms of solubility, and permeability. LMQ and QUX were the most consistent across each study with LMQ performing better than QUX overall. Findings of this study present one formulation (LMQ) with superior intestinal absorption while maintaining high cell viability, thus making it one of the safer and more effective quercetin formulations.

Studies on in vivo antithrombotic activity of quercetin, a natural flavonoid isolated from a traditional medicinal plant, African eggplant (Solanum indicum)

ETHNOPHARMACOLOGICAL RELEVANCE

Every year, cardiovascular diseases (CVDs) account for about 17.9 million deaths, making them the primary cause of both morbidity and mortality. Conventional drugs, which are often prescribed to treat cardiovascular diseases, are costly and have adverse effects. Consequently, dietary modifications and other medications are needed. Traditional use of Solanum indicum as cardiotonic to treat hypertension and anticoagulant potency has been reported but poorly evaluated scientifically.

AIM OF THE STUDY

This study investigated the in vivo anticoagulant activity and mechanism of anticoagulation of quercetin (QC), a bioactive compound isolated from S. indicum (SI) hydroethanolic fruit extract.

MATERIALS AND METHODS

Bioassay-guided fractionation (anticoagulant activity) extracted QC from hydroethanolic SI extract. QC was extensively characterized biochemically and pharmacologically. The interaction between QC and thrombin was investigated using spectrofluorometric and isothermal calorimetric methods. Cytotoxicity, antiplatelet, and thrombolytic studies were carried out in vitro. The Swiss albino mice were used to assess the in vivo, anticoagulant, and antithrombotic activities of QC.

RESULTS

QC exhibits anticoagulant activity via (i) uncompetitive inhibition of thrombin but not FXa with a Ki value of 33.11 ± 4.2 μM and (ii) a partial inhibition of thrombin-catalyzed platelet aggregation with an IC50 value of 13.2 ± 1.2 μM. The experimental validation of the in silico study's prediction of QC's binding to thrombin was confirmed by spectrofluorometric and isothermal calorimetric analyses. QC was nontoxic to mammalian, non-hemolytic cells and demonstrated thrombolytic activity by activating plasminogen. QC demonstrated in vivo anticoagulant efficacy, preventing k-carrageen-induced thrombus formation in mice's tails. In the acute circulatory stasis paradigm in mice, QC reduces thromboxane B2 (TXB2) and endothelin-1 (ET-1) while increasing nitric oxide synthase (eNOS) and 6-keto prostaglandin F1α (6-keto-PGF1 α).

CONCLUSION

Effective in vivo anticoagulant and antithrombotic properties of S. indicum's bioactive component QC point to the plant's potential use as a herbal anticoagulant medication for preventing and treating cardiovascular diseases linked to thrombosis.

Enhanced Bioactivity of Quercetin-Tetrahydroisoquinoline Derivatives: Effect on Lipophilicity, Enzymes Inhibition, Antioxidant Potential, and Cytotoxicity

Quercetin, a well-known flavonoid with significant medicinal potential, was derivatized at the C8 position with a tetrahydroisoquinoline (THIQ) moiety, and physicochemical and pharmacological properties, inhibition potential, antioxidant activity, and cytotoxicity of new compounds were evaluated. Physicochemical and pharmacological properties, including lipophilicity, membrane permeability, and P-glycoprotein substrate affinity, were assessed theoretically using the SwissADME software. The metal-chelating ability of the new compounds was evaluated on metal ions Fe2+, Zn2+, and Cu2+, whose homeostasis disruption is linked to the development of Alzheimer's disease. Inhibition potential was tested on the cholinergic enzymes acetylcholinesterase and butyrylcholinesterase, as well as Na+, K+-ATPase, an enzyme commonly overexpressed in tumours. Antioxidant potential was assessed using the DPPH assay. Cytotoxicity studies were conducted on healthy MRC-5 cells and three cancer cell lines: HeLa, MDA-231, and MDA-468. The results indicated that derivatization of quercetin with THIQ yielded compounds with lower toxicity, preserved chelating ability, improved antioxidant potential, increased selectivity toward the cholinergic enzyme butyrylcholinesterase, and enhanced inhibition potential toward Na+, K+-ATPase and butyrylcholinesterase compared to quercetin alone. Therefore, the synthesized derivatives represent compounds with an improved profile and could be promising candidates for further optimization in developing drugs for neurodegenerative and cancer diseases.

Ultrasound-assisted extraction, optimization, and purification of total flavonoids from Daphnegenkwa and analysis of their antioxidant, anti-inflammatory, and analgesic activities

Daphne genkwa (D. genkwa) is the dried flower buds of a Chinese medicinal plant with multiple biological activities. Response surface methodology (RSM) combined with artificial neural network (ANN) techniques were utilized to optimize ultrasound-assisted extraction conditions for D. genkwa. Antioxidant activity and anti-inflammatory and analgesic properties of total flavonoids from D. genkwa (TFDG) were assessed. Optimal conditions involving ultrasonic power of 225 W, 30 min extraction time, 30 mL/g liquid-solid ratio, 60 °C extraction temperature, and 70% ethanol concentration yielded a maximum total flavonoids content (TFC) of 5.41 mg/g. After microporous resin purification, four specific flavonoids in D. genkwa were identified and quantified using high-performance liquid chromatography (HPLC). The TFDG demonstrated potent antioxidant activity, with a 94% rate of scavenging the 2, 2-diphenyl-1-picrylhydrazyl (DPPH). Furthermore, TFDG exhibited pain-alleviating properties in hot plate and acetic acid-induced writhing tests and noteworthy inhibitory effects on xylene-induced ear swelling in mice. The total flavonoids extracted by ultrasound had excellent biological activity. This establishes a foundation for further investigation into the potential medical value of D. genkwa.

Preparation and Evaluation of Poloxamer/Carbopol In-Situ Gel Loaded with Quercetin: In-Vitro Drug Release and Cell Viability Study

BACKGROUND

Periodontitis is a severe chronic inflammatory disease, whose traditional systemic antimicrobial therapy faces great limitations. In-situ gels provide an effective solution as an emerging local drug delivery system.

METHODS

In this study, the novel thermosensitive poloxamer/carbopol in-situ gels loaded with 20 μmol/L quercetin for the treatment of periodontitis were prepared by cold method. Thirteen batches of in-situ gels based on two independent factors (X1: poloxamer 407 and X2: carbopol 934P) were designed and optimized by the statistical method of central composite design (CCD). The transparency, pH, injectability, viscosity, gelation temperature, gelation time, elasticity modulus, degradation rate and in-vitro drug release studies of the batches were evaluated, and the percentage of drug release in the first hour, the time required for 90% drug release, gelation temperature, and gelation time were selected as dependent variables.

RESULTS

These two independent factors significantly affected the four dependent variables (p < 0.05). The optimization result displayed that the optimized concentration of poloxamer 407 was 20.84% (w/v), and carbopol 934P was 0.5% (w/v). The optimized formulation showed a clear appearance (++), acceptable injectability (Pass), viscosity(151,798 mPa s), gelation temperature (36 °C), gelation time (213 s), preferable cell viability and cell proliferation, conformed to first-order release kinetics, and had a significant antibacterial effect.

CONCLUSIONS

The article demonstrates the great potential of the quercetin in-situ gel as an effective treatment for periodontitis.

Nose to brain strategy coupled to nano vesicular system for natural products delivery: Focus on synaptic plasticity in Alzheimer's disease

A wide number of natural molecules demonstrated neuroprotective effects on synaptic plasticity defects induced by amyloid-β (Aβ) in ex vivo and in vivo Alzheimer's disease (AD) models, suggesting a possible use in the treatment of this neurodegenerative disorder. However, several compounds, administered parenterally and orally, are unable to reach the brain due to the presence of the blood-brain barrier (BBB) which prevents the passage of external substances, such as proteins, peptides, or phytocompounds, representing a limit to the development of treatment for neurodegenerative diseases, such as AD. The combination of nano vesicular systems, as colloidal systems, and nose to brain (NtB) delivery depicts a new nanotechnological strategy to overtake this limit and to develop new treatment approaches for brain diseases, including the use of natural molecules in combination therapy for AD. Herein, we will provide an updated overview, examining the literature of the last 20 years and using specific keywords that provide evidence on natural products with the ability to restore synaptic plasticity alterations in AD models, and the possible application using safe and non-invasive strategies focusing on nano vesicular systems for NtB delivery.

Botanical drugs and their natural compounds: a neglected treasury for inhibiting the carcinogenesis of pancreatic ductal adenocarcinoma

CONTEXT

Pancreatic ductal adenocarcinoma (PDAC), which is characterized by its malignant nature, presents challenges for early detection and is associated with a poor prognosis. Any strategy that can interfere with the beginning or earlier stage of PDAC greatly delays disease progression. In response to this intractable problem, the exploration of new drugs is critical to reduce the incidence of PDAC.

OBJECTIVE

In this study, we summarize the mechanisms of pancreatitis-induced PDAC and traditional Chinese medicine (TCM) theory and review the roles and mechanisms of botanical drugs and their natural compounds that can inhibit the process of pancreatitis-induced PDAC.

METHODS

With the keywords 'chronic pancreatitis', 'TCM', 'Chinese medicinal formulae', 'natural compounds', 'PDAC' and 'pancreatic cancer', we conducted an extensive literature search of the PubMed, Web of Science, and other databases to identify studies that effectively prevent PDAC in complex inflammatory microenvironments.

RESULTS

We summarized the mechanism of pancreatitis-induced PDAC. Persistent inflammatory microenvironments cause multiple changes in the pancreas itself, including tissue damage, abnormal cell differentiation, and even gene mutation. According to TCM, pancreatitis-induced PDAC is the process of 'dampness-heat obstructing the spleen and deficiency due to stagnation' induced by a variety of pathological factors. A variety of botanical drugs and their natural compounds, such as Chaihu classical formulae, flavonoids, phenolics, terpenoids, etc., may be potential drugs to interfere with the development of PDAC via reshaping the inflammatory microenvironment by improving tissue injury and pancreatic fibrosis.

CONCLUSIONS

Botanical drugs and their natural compounds show great potential for preventing PDAC in complex inflammatory microenvironments.

Aspects of quercetin stability and its liposomal enhancement in yellow onion skin extracts

Quercetin is a flavonoid that occurs in many types of fruit and vegetables and is stable for no longer than 4.5 h in the investigated pH range (6.0-8.0), even at 4 °C in the dark. At higher temperatures, the degradation/oxidation process is much faster. Simple but effective proliposomal encapsulation was used to protect the quercetin from environmental conditions such as pH. With this approach, 65 to 90% of pure quercetin and quercetin-rich onion extract was kept after >60 days under conditions that favoured its oxidation (pH 7.4). In addition, the encapsulated quercetin decreases the lipid peroxidation induced by pulsed UV light by >50%. At a mass ratio of 1:100 quercetin to lipids (w/w), the liposomes remained intact in solutions for six months. Quercetin in lipid bilayers simultaneously protects the unsaturated lipids from peroxidation.

The bioavailability, absorption, metabolism, and regulation of glucolipid metabolism disorders by quercetin and its important glycosides: A review

Quercetin and its glycosides (QG), vitally natural flavonoid, have been popular for health benefits. However, the absorption and metabolism affect their bioavailability, and the metabolic transformation alters their biological activities. This review systematically summarizes the bioavailability and pathways for the absorption and metabolism of quercetin/QG in vivo and in vitro, the biological activities and mechanism of quercetin/QG and their metabolites in treating glucolipid metabolism are discussed. After oral administration, quercetin/QG are mainly absorbed by the intestine, undergo phase II metabolism in the small intestine and liver to form conjugates and are metabolized into small phenolic acids by intestinal microbiota. Quercetin/QG and their metabolites exert beneficial effects on regulating glucolipid metabolism disorders, including improving insulin resistance, inhibiting lipogenesis, enhancing thermogenesis, modulating intestinal microbiota, relieving oxidative stress, and attenuating inflammation. This review enhances understanding of the mechanism of quercetin/QG regulate glucolipid metabolism and provides scientific support for the development of functional foods.

Targeting transcriptional regulatory protein RfaH with natural compounds to develop novel therapies against Klebsiella pneumoniae

The growing threat of antibiotic-resistant K. pneumoniae infections demands novel treatment strategies. This study focuses on the transcriptional regulatory protein RfaH, a protein crucial for the bacteria's virulence by promoting gene expression for its capsule, cell wall, and pilus. As K. pneumoniae becomes resistant to existing antibiotics, targeting RfaH with specific inhibitors offers a promising alternative. The diverse benefits of natural compounds, including efficacy against microbial diseases, modulation of inflammatory processes, and potential in cancer therapy, have led to their increasing use in medicine. Through natural compound screening, we aimed to identify potential RfaH inhibitors and understand their interactions with the active site pocket of RfaH. Disrupting interactions of specific residues in RfaH by ligand binding could offer a means to interfere with its function selectively. We found that Naringenin and Quercetin have a strong binding affinity for RfaH β'CH binding pocket and form stable complexes, as evident from the MD simulation studies. The binding affinity of Naringenin and Quercetin was further validated experimentally by fluorescence measurements. This knowledge can be used to design potent and selective RfaH inhibitors for a new therapeutic approach to combat K. pneumoniae infections and address the urgent need for effective treatments.

A Systematic Review: Quercetin-Secondary Metabolite of the Flavonol Class, with Multiple Health Benefits and Low Bioavailability

The main goal of this systematic review on the flavonol class secondary metabolite quercetin is to evaluate and summarize the existing research on quercetin's potential health benefits, therapeutic properties, and effectiveness in disease prevention and treatment. In addition to evaluating quercetin's potential for drug development with fewer side effects and lower toxicity, this type of review attempts to collect scientific evidence addressing quercetin's roles as an antioxidant, anti-inflammatory, antibacterial, and anticancer agent. In the first part, we analyze various flavonoid compounds, focusing on their chemical structure, classification, and natural sources. We highlight their most recent biological activities as reported in the literature. Among these compounds, we pay special attention to quercetin, detailing its chemical structure, physicochemical properties, and process of biosynthesis in plants. We also present natural sources of quercetin and emphasize its health benefits, such as its antioxidant and anti-inflammatory effects. Additionally, we discuss methods to enhance its bioavailability, analyzing the latest and most effective delivery systems based on quercetin.

Quercetin: A Promising Candidate for the Management of Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD)

Metabolic dysfunction-associated steatotic liver disease (MASLD) represents a chronic liver disease. The development of MASLD is influenced by a multitude of diseases associated with modern lifestyles, including but not limited to diabetes mellitus, hypertension, hyperlipidaemia and obesity. These conditions are often consequences of the adoption of unhealthy habits, namely a sedentary lifestyle, a lack of physical activity, poor dietary choices and excessive alcohol consumption. The treatment of MASLD is primarily based on modifying the patient's lifestyle and pharmacological intervention. Despite the absence of FDA-approved pharmacological agents for the treatment of MASLD, several potential therapeutic modalities have demonstrated efficacy in reversing the histopathological features of the disease. Among the botanical ingredients belonging to the flavonoid group is quercetin (QE). QE has been demonstrated to possess a number of beneficial physiological effects, including anti-inflammatory, anticancer and antifungal properties. Additionally, it functions as a natural antioxidant. Preclinical evidence indicates that QE may play a beneficial role in reducing liver damage and improving metabolic health. Early human studies also suggest that QE may be an effective treatment for MASLD due to its antioxidant, anti-inflammatory, and lipid-regulating properties. This review aims to summarize the available information on the therapeutic effects of QE in MASLD.

Toxocara canis: Prospective activity of Quercetin and venom of Cassiopea andromeda (Cnidaria: Cassiopeidae) against third-stage larvae in vitro

Toxocariasis is a zoonotic parasitic infection with worldwide distribution and high impact on human health. It has a limited clinical resolution with the available drugs, making it challenging to treat. Quercetin, which possesses biological and pharmacological qualities including antiparasitic, antioxidant, and anticancer activities, is a possible substitute for the current medications. Marine invertebrates can produce a vast array of different molecules, many of which are biologically active substances with distinct characteristics. In this study, we assessed the in vitro nematocidal effect of both quercetin and venom of Cassiopea andromeda (jellyfish) against third larvae of Toxocara canis. In microplates with Roswell Park Memorial Institute-1640 medium, larvae were incubated with ethanolic extract of quercetin (0.01, 0.02, 0.05, 0.08, 0.1, 0.25, and 0.5 mM/mL) and water extract of C. andromeda venom (15, 20, 25, 30, 35, 40, and 60 µg/mL) to evaluate their larvicidal effect. A scanning electron microscopy has investigated the possible effect of lethal concentration (LC90) of both extracts on the body wall of cultivated larvae, in comparison with those cultivated in albendazole. Our study revealed the effects of both quercetin and C. andromeda venom exposure on the mortality rate and the ultrastructure of T. canis third larva in comparison with control and albendazole-treated groups.

Efficient glycosylation of polyphenols via dynamic complexation of cyclodextrin and synchronous coupling reaction with cyclodextrin glycosyltransferase in water

Glycosylation is an effective way to promote the total intake of polyphenols in humans by increasing the solubility of polyphenols. In this study, an efficient glycosylation system was built via the dynamic complexation of CD with polyphenols and synchronous coupling reaction with cyclodextrin glycosyltransferase (CGTase) in water. The glycosylation efficiencies of quercetin, naringenin, rutin, resveratrol and caffeic acid were 20.9, 3.6, 2.7, 3.4 and 1.5 times higher than the non-complexed system. To quantify conversion rate and determine the rate-limiting step, the mixed product was treated with amyloglucosidase to obtain α-glucosyl rutin, which was identified as rutin 4"-O-α-D-glucopyranoside with purity of 93.6 % and yield of 34.8 % from NMR, MS and HPLC analysis. The results of half-reaction kinetics showed that the catalytic efficiencies of ring-opening of γ-CD (k1) and glycosylation reaction of rutin (k2) were 621.92 and 9.43 mM-1·s-1. The rate-limiting step was clarified for the first time, showing that the ring-opening ability of CGTase to CD was much higher than its glycosylation ability to polyphenols. It is speculated that the rapid ring-opening reaction of CD affected its dynamic complexation, releasing many polyphenols which were not utilized by CGTase in time. Therefore, adjusting the ratio and concentration of CD resulted in an optimal glycosylation molar yield of 84.1 % for rutin, which was the highest yield reported so far in water. This study established a universal system and clarified the rate-limiting step in the enzymatic glycosylation, providing theoretical guidance for efficient production of polyphenol glycosylation.

Effect of tannic acid modification on antioxidant activity, antibacterial activity, environmental stability and release characteristics of quercetin loaded zein-carboxymethyl chitosan nanoparticles

The stability of quercetin remains a challenge for their application in industrial food production. In order to solve this shortcoming, zein-tannic acid covalent complex was prepared. Fourier transform infrared spectroscopy demonstrated the formation of CN bond between zein and tannic acid. Quercetin loaded nanoparticles (QZTC) were prepared by zein-tannic acid complex and carboxymethyl chitosan by anti-solvent co-precipitation and pH migration method. The structure of the nanoparticles was characterized and the effects of tannic acid modification and carboxymethyl chitosan addition on the encapsulation efficiency, oxidation resistance, antibacterial property, environmental stability and microstructure of the nanoparticles were studied. The results showed that compared with zein nanoparticles, QZTC had higher encapsulation rate, smaller and more uniform spherical microstructure. Compared with free quercetin and the other two nanoparticles, QZTC showed higher light, heat, storage stability, antioxidant and antibacterial abilities (p < 0.05). It was also found that the improvement of stability mainly depended on the formation of CN covalent bond, hydrogen bond, electrostatic interaction and hydrophobic interaction between components. This study provides new ideas for improving the environmental stability, antioxidant and antibacterial properties of quercetin and for developing nanoparticles that can be used in food processing.

Widely Targeted Metabolomics Analysis Revealed the Component Differences of Hemerocallis citrina Borani in Different Production Areas of Datong

Hemerocallis citrina Borani (H. citrina) has garnered significant attention due to its abundant nutritional quality. Datong, located in Shanxi Province, is recognized as one of the four major production regions for high-quality H. citrina. While Datong boasts multiple production areas, the nutritional composition of daylilies varies across regions due to environmental factors and planting patterns, which remain unclear. This study focuses on the total polyphenol and flavonoid contents (TPCs and TFCs) and protein content of H. citrina from three areas in Datong: Sanshilipu (DTSSLP), Dangliuzhuang (DTDLZ), and Jijiazhuang (DTJJZ). Additionally, a widely targeted metabolomics analysis was used to analyze the metabolite composition of H. citrina from these three areas. The results showed that H. citrina in DTSSLP had the highest contents of protein and amino acids, as well as TPCs and TFCs. A total of 798 differential metabolites were identified in H. citrina across the areas, with DTSSLP showing the highest levels of different classifications of metabolites, indicating its enhanced health benefits and physiological activities. Nine metabolic pathways were related with the different characteristics among DTSSLP, DTDLZ, and DTJJZ. This study provides theoretical support for distinguish H. citrina from different producing regions and elucidates the mechanisms underlying its metabolic pathways.

A near-complete assembly of the Houttuynia cordata genome provides insights into the regulatory mechanism of flavonoid biosynthesis in Yuxingcao

Houttuynia cordata, also known as Yuxingcao in Chinese, is a perennial herb in the Saururaceae family. It is highly regarded for its medicinal properties, particularly in treating respiratory infections and inflammatory conditions, as well as boosting the human immune system. However, a lack of genomic information has hindered research on the functional genomics and potential improvements of H. cordata. In this study, we present a near-complete assembly of H. cordata genome and investigate the biosynthetic pathway of flavonoids, specifically quercetin, using genomics, transcriptomics, and metabolomics analyses. The genome of H. cordata diverged from that of Saururus chinensis around 33.4 million years ago; it consists of 2.24 Gb with 76 chromosomes (4n = 76) and has undergone three whole-genome duplication (WGD) events. These WGDs played a crucial role in shaping the H. cordata genome and influencing the gene families associated with its medicinal properties. Through metabolomics and transcriptomics analyses, we identified key genes involved in the β-oxidation process for biosynthesis of houttuynin, one of the volatile oils responsible for the plant's fishy smell. In addition, using the reference genome, we identified genes involved in flavonoid biosynthesis, particularly quercetin metabolism, in H. cordata. This discovery has important implications for understanding the regulatory mechanisms that underlie production of active pharmaceutical ingredients in traditional Chinese medicine. Overall, the high-quality genome assembly of H. cordata serves as a valuable resource for future functional genomics research and provides a solid foundation for genetic improvement of H. cordata for the benefit of human health.

Microbial transformation of some phytochemicals into value-added products: A review

Phytochemicals, plant-derived compounds, are the major components of traditional medicinal plants. Some phytochemicals have restricted applications, due to low bioavailability and less efficacy. However, their medicinal properties can be enhanced by converting them into value-added products for different bioactivities like anti-oxidant, neuroprotective, anti-obesity, anti-neuroinflammatory, anti-microbial, anti-cancer and anti-inflammatory. Microbial transformation is one such process that is generally more specific and makes it possible to modify a compound without making any unwanted alterations in the molecule. This has led to the efficient production of value-added products with important pharmacological properties and the discovery of new active compounds. The present review assimilates the existing knowledge of the microbial transformation of some phytochemicals like eugenol, curcumin, ursolic acid, cinnamaldehyde, piperine, β-carotene, β-sitosterol, and quercetin to value-added products for their application in food, fragrances, and pharmaceutical industries.

Therapeutic Efficacy of Quercetin and Its Nanoformulation Both the Mono- or Combination Therapies in the Management of Cancer: An Update with Molecular Mechanisms

Quercetin, a major representative of the flavonol subclass found abundantly in almost all edible vegetables and fruits, showed remarkable therapeutic properties and was beneficial in numerous degenerative diseases by preventing lipid peroxidation. Quercetin is beneficial in different diseases, such as atherosclerosis and chronic inflammation. This study aims to find out the anticancer activities of quercetin and to determine different mechanisms and pathways which are responsible for the anticancer effect. It also revealed the biopharmaceutical, toxicological characteristics, and clinical utilization of quercetin to evaluate its suitability for further investigations as a reliable anticancer drug. All of the relevant data concerning this compound with cancer was collected using different scientific search engines, including PubMed, Springer Link, Wiley Online, Web of Science, SciFinder, ScienceDirect, and Google Scholar. This review demonstrated that quercetin showed strong anticancer properties, including apoptosis, inhibition of cell proliferation, autophagy, cell cycle arrest, inhibition of angiogenesis, and inhibition of invasion and migration against various types of cancer. Findings also revealed that quercetin could significantly moderate and regulate different pathways, including PI3K/AKT-mTORC1 pathway, JAK/STAT signaling system, MAPK signaling pathway, MMP signaling pathway, NF-κB pathway, and p-Camk2/p-DRP1 pathway. However, this study found that quercetin showed poor oral bioavailability due to reduced absorption; this limitation is overcome by applying nanotechnology (nanoformulation of quercetin). Moreover, different investigations revealed that quercetin expressed no toxic effect in the investigated subjects. Based on the view of these findings, it is demonstrated that quercetin might be considered a reliable chemotherapeutic drug candidate in the treatment of different cancers. However, more clinical studies are suggested to establish the proper therapeutic efficacy, safety, and human dose.

Co-encapsulation of quercetin and resveratrol: Comparison in different layers of zein-carboxymethyl cellulose nanoparticles

Three nanoparticles were fabricated for the co-delivery of quercetin and resveratrol. Nanoparticles consisted of a zein and carboxymethyl cellulose assembled using antisolvent precipitation/layer-by-layer deposition method. Nanoparticles contained quercetin in the core and resveratrol in the shell, resveratrol in the core and quercetin in the shell or both quercetin and resveratrol in the core. The particle sizes of nanoparticles were 280.4, 214.8, and 181.8 nm, respectively. Zeta-potential was about -50 mV and PDI was about 0.3. The different positions of polyphenol distribution nanoparticles could reduce the competition between the two polyphenols, the encapsulation rate, loading rate and storage stability reached up to 91.7 %, 5.37 % and 97.1 %, respectively. FT-IR showed that hydrophobic and electrostatic interactions were the main driving forces of nanoparticle assembly. XRD showed that two polyphenols were successfully encapsulated in nanoparticles. TGA showed that distributing the nanoparticles in different layers would enhance thermal stability. TEM and SEM showed that polysaccharides attached to the surface of nanoparticles formed a core-shell structure with uniform particle size. All three nanoparticles could release two polyphenols slowly in simulated gastrointestinal digestion, Korsmeyer-Peppas was the most suitable kinetic release model. Therefore, biopolymer-based nanocarriers can be created to enhance the loading, stability, and bioaccessibility of co-encapsulated nutraceuticals.

Development of quercetin-loaded electrospun nanofibers through shellac coating on gelatin: Characterization, colon-targeted delivery, and anticancer activity

Quercetin possesses multiple biological activities. To achieve efficient colon-specific release of quercetin, new composite nanofibers were developed by coating pH-responsive shellac on hydrophilic gelatin through coaxial electrospinning. These composite nanofibers contained bead-like structures. The encapsulation efficiency (87.6-98.5 %) and loading capacity (1.4-4.1 %) varied with increasing the initial quercetin addition amount (2.5-7.5 %). FTIR, XRD, and TGA results showed that the quercetin was successfully encapsulated in composite nanofibers in an amorphous state, with interactions occurring among quercetin, gelatin, and shellac. Composite nanofibers had pH-responsive surface wettability due to the shellac coating. In vitro digestion experiments showed that these composite nanofibers were highly stable in the upper gastrointestinal tract, with quercetin release ranging from 4.75 % to 12.54 %. In vivo organ distribution and pharmacokinetic studies demonstrated that quercetin could be sustainably released in the colon after oral administration of composite nanofibers. Besides, the enhanced anticancer activity of composite nanofibers was confirmed against HCT-116 cells by analyzing their effect on cell viability, cell cycle, and apoptosis. Overall, these novel composite nanofibers could deliver efficiently quercetin to the colon and achieve its sustained release, thus potential to regulate colon health. This system is also helpful in delivering other bioactives to the colon and exerting their functional effects.

Enhancing the antioxidant potential of ESIPT-based naringenin flavonoids based on excited state hydrogen bond dynamics: A theoretical study

Exploring antioxidant potential of flavonoid derivatives after ESIPT process provides a theoretical basis for discovering compounds with higher antioxidant capacity. In this work, employing the density functional theory (DFT) and time-dependent density functional theory (TD-DFT) methods, the antioxidant potential of two citrus-derived naringenin flavonoids after ESIPT process is explored. Based on studies of ESIPT process including IMHB intensity variations, potential energy curves, and transition state, these molecules exist only in enol and keto⁎ forms due to ultra-fast ESIPT. The HOMOs are utilized to explore electron-donating capacity, demonstrating that the molecules in keto⁎ form is stronger than that in enol form. Furthermore, the atomic dipole moment corrected Hirshfeld population (ADCH) and Fukui functions indicate that the sites attacked by the electrophilic free radical of the two molecules in the keto⁎ form are O3 and O5' respectively, and both are more active than in the enol form. Overall, a comprehensive consideration of the ESIPT process and antioxidant potential of flavonoid derivatives will facilitate the exploration and design of substances with higher antioxidant capacity.

Treatment with quercetin mitigates polystyrene nanoparticle-induced reduction in neuron capacity by inhibiting dopaminergic neurodegeneration and facilitating dopamine metabolism in Caenorhabditis elegans

In organisms, long-term nanopolystyrenes (PS-NPs) exposure can cause toxicity, including neurotoxicity. Quercetin, the flavonol with extensive distribution within plants, possesses diverse biological activities. Nevertheless, the possible effect of quercetin to suppress PS-NPs-induced neurotoxicity and its associated mechanism remains unknown. Thus, in the present work, Caenorhabditis elegans was utilized as the model animal to investigate quercetin's pharmacological effect on suppressing PS-NPs-induced neurotoxicity and the underlying mechanism. PS-NPs exposure at 1-100 μg/L remarkably reduced locomotion behavior, while only PS-NPs exposure at 100 μg/L significantly decrease sensory perception behavior. Meanwhile, the increase in the number of worms with dopaminergic neurodegeneration was detected in nematodes exposed to 100 μg/L PS-NPs and the decreased dopamine content was observed within nematodes exposed to 10-100 μg/L PS-NPs, demonstrating the function of dopaminergic neurodegeneration and disruption of dopamine metabolism in inducing PS-NPs toxicity on neuron capacity. After 100 μg/L PS-NPs exposure, the 25-100 μM quercetin treatment effectively increased the locomotion behavior and the sensory perception behavior. Developmentally, quercetin treatment (100 μM) remarkably enhanced fluorescence intensity while decreasing worm number with neurodegeneration within BZ555 transgenic strains exposed to 100 μg/L PS-NPs. Physiologically, quercetin treatment (100 μM) significantly enhanced dopamine content within nematodes exposed to 100 μg/L PS-NPs. Molecularly, quercetin treatment (100 μM) notably decreased the expressions of genes governing neurodegeneration (mec-4, deg-3, unc-68, itr-1, clp-1, and asp-3) while significantly increasing the expression of genes governing dopamine metabolism (cat-2, cat-1, dop-1, dop-2, dop-3). As revealed by molecular docking results, quercetin might bind to excitotoxic-like ion channels receptors (MEC-4 and DEG-3) and dopamine secreted protein (CAT-2). Consequently, findings in this work demonstrated that long-term PS-NPs exposure within the μg/L range (1-100 μg/L) was toxic to neuron capacity, which was associated with the enhancement in dopaminergic neurodegeneration and disruption of dopamine metabolism. Notably, PS-NPs-mediated neurotoxicity to nematodes is probably suppressed through subsequent quercetin treatment.

Advances in Cyclodextrins and Their Derivatives in Nano-Delivery Systems

The diversity of cyclodextrins and their derivatives is increasing with continuous research. In addition to monomolecular cyclodextrins with different branched chains, cyclodextrin-based polymers have emerged. The aim of this review is to summarize these innovations, with a special focus on the study of applications of cyclodextrins and their derivatives in nano-delivery systems. The areas covered include nanospheres, nano-sponges, nanogels, cyclodextrin metal-organic frameworks, liposomes, and emulsions, providing a comprehensive and in-depth understanding of the design and development of nano-delivery systems.

Synthesis of quercetin derivatives as cytotoxic against breast cancer MCF-7 cell line in vitro and in silico studies

Background: Quercetin being antioxidant and antiproliferative agent acts by inhibiting CDK2, with an increase in cancer prevalence there is a need to profile quercetin derivatives as CDK2 inhibitors.Materials & method: Schiff bases of quercetin were synthesized as cytotoxic agents against the MCF7 cell line. FTIR, 1H-NMR and 13C-NMR, CHNS/O analysis were employed along with in vivo and in silico activities.Results & conclusion: 2q, 4q, 8q and 9q derivatives have maximum cytotoxic effect with IC50 values 39.7 ± 0.7, 36.65 ± 0.25, 35.49 ± 0.21 and 36.99 ± 0.45, respectively. Molecular docking also confirmed these results 8q has the highest binding potential of -9.165 KJ/mole making it a potent inhibitor of CDK2. These derivatives can be used as lead compounds as potent CDK2 inhibitors.

Ultrasound-mediated host-guest self-assembly between different dietary fatty acids and sodium caseinate and their complexes improving the water dispersibility, stability, and bioaccessibility of quercetin

Quercetin (QUE) sufferred from poor processing adaptability and absorbability, hindering its application as a dietary supplement in the food industry. In this study, fatty acids (FAs)-sodium caseinate (NaCas) ligand complexes carriers were fabricated to improve the aqueous dispersibility, storage/thermal stability, and bioaccessibility of QUE using an ultrasound method. The results indicated that all six selected common dietary FAs formed stable hydrophilic complexes with NaCas and the FAs-NaCas complexes achieved an encapsulation efficiency greater than 90 % for QUE. Furthermore, the introduction of FAs enhanced the binding affinity between NaCas and QUE, but did not change the binding mode (static bursting) and types of intermolecular forces (mainly hydrogen bonding). In addition, a distinct improvement was discovered in the storage stability (>2.37-fold), thermal processing stability (>32.54 %), and bioaccessibility (>2.37-fold) of QUE. Therefore, the FAs-NaCas ligand complexes could effectively protect QUE to minimize degradation as fat-soluble polyphenol delivery vehicles.

Structural, physicochemical and digestive properties of non-covalent and covalent complexes of ultrasound treated soybean protein isolate with soybean isoflavone

The non-covalent and covalent complexes of ultrasound treated soybean protein isolate (SPI) and soybean isoflavone (SI) were prepared, and the structure, physicochemical properties and in vitro digestion characteristics of SPI-SI complexes were investigated. Ultrasonic treatment increased the non-covalent and covalent binding degree of SPI with SI, and the 240 W ultrasonic covalent complexes had higher binding efficiency. Appropriate ultrasonic treatment caused more uniform particle size distribution, lower average particle size and higher surface charge, which enhanced the free sulfhydryl groups and surface hydrophobicity, thus improving the stability, solubility and emulsifying properties of complexes. Ultrasonic treatment resulted in more disordered secondary structure, tighter tertiary conformation, higher thermal stability and stronger SPI-SI covalent interactions of complexes. These structural modifications of particles had important effects on the chemical stability and gastrointestinal digestion fate of SI. The ultrasonic covalent complexation had a greater resistance to heat-induced chemical degradation of SI and improved its chemical stability. Furthermore, the 240 W ultrasonic covalent complexes showed lower protein digestibility during digestion, and provided stronger protection for SI, which improved the digestion stability and antioxidant activity. Therefore, appropriate ultrasound promoted SPI-SI interactions to improve the stability and functional properties of complexes, which provided a theoretical basis for the development of new complexes and their applications in functional foods.

Biological Properties of Boletus edulis Extract on Caco-2 Cells: Antioxidant, Anticancer, and Anti-Inflammatory Effects

Boletus edulis (BE) is a mushroom well known for its taste, nutritional value, and medicinal properties. The objective of this work was to study the biological effects of BE extracts on human colon carcinoma cells (Caco-2), evaluating parameters related to oxidative stress and inflammation. In this study, a hydroethanolic extract of BE was obtained by ohmic heating green technology. The obtained BE extracts are mainly composed of sugars (mainly trehalose), phenolic compounds (taxifolin, rutin, and ellagic acid), and minerals (K, P, Mg, Na, Ca, Zn, Se, etc.). The results showed that BE extracts were able to reduce cancer cell proliferation by the induction of cell cycle arrest at the G0/G1 stage, as well as cell death by autophagy and apoptosis, the alteration of mitochondrial membrane potential, and caspase-3 activation. The extracts modified the redox balance of the cell by increasing the ROS levels associated with a decrease in the thioredoxin reductase activity. Similarly, BE extracts attenuated Caco-2 inflammation by reducing both iNOS and COX-2 mRNA expression and COX-2 protein expression. In addition, BE extracts protected the intestine from the oxidative stress induced by H2O2. Therefore, this study provides information on the potential use of BE bioactive compounds as anticancer therapeutic agents and as functional ingredients to prevent oxidative stress in the intestinal barrier.

Controlled Quercetin Release by Fluorescent Mesoporous Nanocarriers for Effective Anti-Adipogenesis

Introduction

Quercetin (QUER), a flavonoid abundant in fruits and vegetables, is emerging as a promising alternative therapeutic agent for obesity treatment due to its antioxidant and anti-adipogenic properties. However, the clinical application of QUER is limited by its poor solubility, low bioavailability, and potential toxicity at high doses. To address these challenges, this study aims to develop an advanced drug delivery system using fluorescent mesoporous silica nanoparticles (FMSNs) coated with polydopamine (PDA) for the efficient and sustained delivery of QUER to inhibit adipogenesis.

Methods

The research included the synthesis of PDA-coated FMSNs for encapsulation of QUER, characterization of their mesoporous structures, and systematic investigation of the release behavior of QUER. The DPPH assay was used to evaluate the sustained radical scavenging potential. Concentration-dependent effects on 3T3-L1 cell proliferation, cellular uptake and adipogenesis inhibition were investigated.

Results

PDA-coated FMSNs exhibited well-aligned mesoporous structures. The DPPH assay confirmed the sustained radical scavenging potential, with FMSNs-QUER@PDA showing 53.92 ± 3.48% inhibition at 72 h, which was higher than FMSNs-QUER (44.66 ± 0.57%) and free QUER (43.37 ± 5.04%). Concentration-dependent effects on 3T3-L1 cells highlighted the enhanced efficacy of PDA-coated FMSNs for cellular uptake, with a 1.5-fold increase compared to uncoated FMSNs. Adipogenesis inhibition was also improved, with relative lipid accumulation of 44.6 ± 4.6%, 37.3 ± 4.6%, and 36.5 ± 7.3% at 2.5, 5, and 10 μM QUER concentrations, respectively.

Conclusion

The study successfully developed a tailored drug delivery system, emphasizing sustained QUER release and enhanced therapeutic effects. FMSNs, especially when coated with PDA, exhibit promising properties for efficient QUER delivery, providing a comprehensive approach that integrates advanced drug delivery technology and therapeutic efficacy.

Design and Biocompatibility of Biodegradable Poly(octamethylene suberate) Nanoparticles to Treat Skin Diseases

Biodegradable aliphatic polyester formulations as carriers for topical drug delivery show the potential to encapsulate structurally different therapeutic compounds. Poly(octamethylene suberate) (POS) nanoparticles (POS-NPs) were used as a matrix to encapsulate four therapeutic molecules used to treat skin disorders: caffeine (CF), quercetin (QR), hydrocortisone (HC), and adapalene (AD). Hydrophobicity and chemical structure of bioactive compounds (BCs) influenced the physicochemical stability of drug-loaded nanoparticles. The particle size of drug-loaded nanoparticles was between 254.9 nm for the CF-POS-NP and 1291.3 for QR-POS-NP. Particles had a negative charge from -27.6 mV (QR) to -49.2 mV (HC). Drug loading content for all BC-POS-NPs varies between 36.11 ± 1.48% (CF-POS-NP) and 66.66 ± 4.87% (AD-POS-NP), and their entrapment efficiency is relatively high (28.30 ± 1.81% and 99.95 ± 0.04%, respectively). Calorimetric analysis showed the appearance of polymorphism for AD- and HC-loaded systems and the drug's complete solubilisation into all nanoparticle formulations. FTIR and NMR spectra showed apparent drug incorporation into the polymer matrix of NPs. The encapsulation of BCs enhanced the antioxidative effect. The prepared POS nanoparticles' cytotoxicity was studied using two dermal cell lines, keratinocyte (HaCaT) cells and fibroblasts (HDFn). The nanoparticle cytotoxic effect was more substantial on HaCaT cell lines. A reconstructed human epidermis (RHE) was successfully used to investigate the penetration of polymeric NPs. Based on permeation and histology studies, HC-POS-NPs and CF-POS-NPs were shown not to be suitable for dermal applications with the explored drug concentrations. AD presents a high permeation rate and no toxic impact on RHE.

The combined analysis of transcriptomics and metabolomics reveals the mechanisms by which dietary quercetin regulates growth and immunity in Penaeus vannamei

As a potent antioxidant, the flavonoid compound quercetin (QUE) has been widely used in the farming of aquatic animals. However, there are fewer reports of the beneficial effects, especially in improving immunity of Penaeus vannamei by QUE. The aim of this study was to investigate the effects of dietary QUE on growth, apoptosis, antioxidant and immunity of P. vannamei. It also explored the potential mechanisms of QUE in improving the growth and immunity of P. vannamei. P. vannamei were fed diets with QUE for 60 days. The results revealed that QUE (0.5 or 1.0 g/kg) ameliorated the growth, and the expressions of genes related to apoptosis, antioxidant, and immunity. The differentially expressed genes (DEGs) and differential metabolites (DMs) obtained through transcriptomics and metabolomics, respectively, enriched in pathways related to nutritional metabolism such as lipid metabolism, amino acid metabolism, and carbohydrate metabolism. After QUE addition, especially at 0.5 g/kg, DEGs were enriched into the functions of response to stimulus and antioxidant activity, and the pathways of HIF-1 signaling pathway, C-type lectin receptor signaling pathway, Toll-like receptor signaling pathway, and FoxO signaling pathway. In conclusion, dietary QUE can ameliorate growth, apoptosis, antioxidant and immunity of P. vannamei, the appropriate addition amount was 0.5 g/kg rather than 1.0 g/kg. Regulations of QUE on nutrient metabolism and immune-related pathways, and bioactive metabolites, were important factors for improving the aforementioned abilities in P. vannamei.