Preparation of Quercetin Esters and Their Antioxidant Activity

Yigansan ameliorates maternal immune activation-induced autism-like behaviours by regulating the IL-17A/TRAF6/MMP9 pathway: Network analysis and experimental validation

BACKGROUND

Maternal immune activation (MIA) is a significant factor inducing to autism spectrum disorder (ASD) in offspring. The fundamental principle underlying MIA is that inflammation during pregnancy impedes fetal brain development and triggers behavioural alterations in offspring. The intricate pathogenesis of ASD renders drug treatment effects unsatisfactory. Traditional Chinese medicine has strong potential due to its multiple therapeutic targets. Yigansan, composed of seven herbs, is one of the few that has been proven to be effective in treating neuro-psychiatric disorders among numerous traditional Chinese medicine compounds, but its therapeutic effect on ASD remains unknown.

HYPOTHESIS

Yigansan improves MIA-induced ASD-like behaviours in offspring by regulating the IL-17 signalling pathway.

METHODS

Pregnant C57BL/6J mice were intraperitoneally injected with poly(I:C) to construct MIA models and offspring ASD models. Network analysis identified that the IL-17A/TRAF6/MMP9 pathway is a crucial pathway, and molecular docking confirmed the binding affinity between the monomer of Yigansan and target proteins. qRT-PCR and Western blot were used to detect the expression levels of inflammatory factors and pathway proteins, immunofluorescence was used to detect the distribution of IL-17A, and behavioural tests were used to evaluate the ASD-like behaviours of offspring.

RESULTS

We demonstrated that Yigansan can effectively alleviate MIA-induced neuroinflammation of adult offspring by regulating the IL-17A/TRAF6/MMP9 pathway, and the expression of IL-17A was reduced in the prefrontal cortex. Importantly, ASD-like behaviours have been significantly improved. Moreover, we identified that quercetin is the effective monomer for Yigansan to exert therapeutic effects.

CONCLUSION

Overall, this study was firstly to corroborate the positive therapeutic effect of Yigansan in the treatment of ASD. We elucidated the relevant molecular mechanism and regulatory pathway involved, determined the optimal therapeutic dose and effective monomer, providing new solutions for the challenges of drug therapy for ASD.

Development of nanoparticles incorporated with quercetin and ACE2-membrane as a novel therapy for COVID-19

INTRODUCTION

Angiotensin-converting enzyme 2 (ACE2) and AXL tyrosine kinase receptor are known to be involved in the SARS-CoV-2 entry of the host cell. Therefore, targeting ACE2 and AXL should be an effective strategy to inhibit virus entry into cells. However, developing agents that can simultaneously target ACE2 and AXL remains a formidable task. The natural compound quercetin has been shown to inhibit AXL expression.

MATERIALS AND METHODS

In this study, we employed PLGA nanoparticles to prepare nanoparticles encapsulated with quercetin, coated with ACE2-containing cell membranes, or encapsulated with quercetin and then coated with ACE-2-containing cell membranes. These nanoparticles were tested for their abilities to neutralize or inhibit viral infection.

RESULTS

Our data showed that nanoparticles encapsulated with quercetin and then coated with ACE2-containing cell membrane inhibited the expression of AXL without causing cytotoxic activity. Nanoparticles incorporated with both quercetin and ACE2-containing cell membrane were found to be able to neutralize pseudo virus infection and were more effective than free quercetin and nanoparticles encapsulated with quercetin at inhibition of pseudo virus and SARS-CoV-2 infection.

CONCLUSIONS

We have shown that the biomimetic nanoparticles incorporated with both ACE-2 membrane and quercetin showed the most antiviral activity and may be further explored for clinical application.

Overview of alkyl quercetin lipophenol synthesis and its protective effect against carbonyl stress involved in neurodegeneration

Oxidative stress and carbonyl stress resulting from the toxicity of small aldehydes are part of the detrimental mechanisms leading to neuronal cell loss involved in the progression of neurodegenerative diseases such as Alzheimer's disease. Polyunsaturated alkylated lipophenols represent a new class of hybrid molecules that combine the health benefits of anti-inflammatory omega-3 fatty acids with the anti-carbonyl and oxidative stress (anti-COS) properties of (poly)phenols in a single pharmacological entity. To investigate the therapeutic potential of quercetin-3-docosahexaenoic acid-7-isopropyl lipophenol in neurodegenerative diseases, three synthetic pathways using chemical or chemo-enzymatic strategies were developed to access milligram or gram scale quantities of this alkyl lipophenol. The protective effect of quercetin-3-DHA-7-iPr against cytotoxic concentrations of acrolein (a carbonyl stressor) was assessed in human SHSY-5Y neuroblastoma cells to underscore its ability to alleviate harmful mechanisms associated with carbonyl stress in the context of neurodegenerative diseases.

Solution blow spun bilayer chitosan/polylactic acid nanofibrous patch with antibacterial and anti-inflammatory properties for accelerating acne healing

The quercetin (QC) loaded chitosan (CS) nanofibrous patch (CSQC) was designed and fabricated successfully by solution blow spinning (SBS). And it was employed to explore a functional double-layer nanofibrous patch (CSQC/PLA) with polylactic acid (PLA) for overcoming the resistance of acne-causing bacteria to antibiotics and local cutaneous irritation. The nanofibrous patch possessed a fluffy bilayer structure with good air permeability, which may be befitted from the SBS method. The 10 % QC loaded CSQC0.10/PLA had sustained release ability of QC for 24 h. A high free radical clearance rate (91.18 ± 2.26 %) and robust antibacterial activity against P. acnes (94.4 %) were achieved for CSQC0.10/PLA with excellent biocompatibility. Meanwhile, E. coli and S. aureus were also suppressed with 99.4 % and 99.2 %, respectively. Moreover, the expression of pro-inflammatory cytokines (IL-6 and TNF-α) was significantly reduced, conducive to acne healing. Therefore, the CSQC0.10/PLA bilayer nanofibrous patch designed here may shed some light on developing multifunctional materials for treating acne infectious wounds.

Design, One-Step Highly Selective Synthesis and Enhancing Insecticidal Activity and Photo-Self-Degradation of Phenylpyrazole Esterified Derivatives as GABA and nACh Receptor Inhibitors

In the pursuit of novel insecticides with high activity and a unique mode of action on the GABA receptor, a series of phenylpyrazole esterified derivatives (PEs) were synthesized using an improved Pinner reaction with high selectivity. Lewis acid catalysis was employed in a one-step solvent-thermal method to convert the cyano group of fipronil into an ester unit. FeCl3 was found to exhibit the highest selectivity for PEs synthesis, yielding PEs at 96.4%, with the byproduct being phenylpyrazole amide (PE0) at 2.1%. Initial biological assays indicated superior insecticidal activity of the target compounds against Plutella xylostella and Mythimna separata compared to fipronil. Particularly, the smaller and shorter ester units, PE3, PE5, and PE8, demonstrated 2-2.5 times higher insecticidal activity against P. xylostella than fipronil. The higher activity of ester units compared to amide and acylhydrazone units can be attributed to the enhanced lipid solubility of PEs. Additionally, it may be due to the impact of PEs on the neurotransmitter nACh or the coordination of calcium and chloride ions with the ester's -C═O and -O- bonds, blocking the chloride ion channel. Hydrophobic parameters were confirmed by reversed-phase high-performance liquid chromatography (HPLC), indicating the enhanced lipophilicity conferred by the ester units of PEs. Molecular docking and CoMFA analysis preliminarily validated the strong interactions and structure-activity relationships between PEs and the GABA receptor and nACh receptor in P. xylostella. Furthermore, under simulated natural sunlight, PEs exhibited photodegradation capabilities, transforming back into fipronil parent fragments and enhancing their insecticidal activity. Moreover, PEs displayed excellent fluorescent properties, enabling self-detection of residues. These research findings provide new insights and directions for the development of efficient pesticides, with potential wide applications in the fields of medicine and biosensors.

Therapeutic Potential and Clinical Effectiveness of Quercetin: A Dietary Supplement

Fruits and vegetables (like apples, citrus, grapes, onions, parsley, etc.) are the primary dietary sources of quercetin. In addition, isolated quercetin is also available on the market as a dietary supplement with a daily dose of up to 1000 mg/d. The objective of the present study is to explore the therapeutic potential and clinical efficacy of quercetin as a dietary supplement. The present paper highlights the safety parameters and clinical trial studies with several targets reviewed from the data available on PubMed, Science Direct, ClinicalTrails. gov, and from many reputed foundations. The results of the studies prove the unique position of quercetin in the treatment of various disorders and the possibility of using phytochemicals such as quercetin for an efficient cure. As evidenced by the numerous published reports on human interventions, it has been concluded that quercetin intake significantly improves disease conditions with minimal adverse effects.

Controlled SPION-Exosomes Loaded with Quercetin Preserves Pancreatic Beta Cell Survival and Function in Type 2 Diabetes Mellitus

Introduction

Quercetin has an ideal therapeutic effect on islet function improvement in type 2 diabetes mellitus (T2DM). However, the therapeutic benefit of quercetin is hindered by its poor bioavailability and limited concentration in pancreatic islets. In this study, superparamagnetic iron oxide nanoparticle (SPION)-modified exosomes were prepared to load quercetin, hoping to endow quercetin with enhanced water solubility and active targeting capacity with the help of magnetic force (MF).

Methods

Transferrin-modified SPIONs (Tf-SPIONs) were synthesized by exploiting N-hydroxysuccinimidyl (NHS) conjugation chemistry, and quercetin-loaded exosomes (Qu-exosomes) were acquired by electroporation. Tf-SPION-modified quercetin-loaded exosomes (Qu-exosome-SPIONs) were generated by the self-assembly of transferrin (Tf) and the transferrin receptor (TfR). The solubility of quercetin was determined by high-performance liquid chromatography (HPLC) analysis. The pancreatic islet targeting capacity and insulin secretagogue and antiapoptotic activities of Qu-exosome-SPIONs/MF were evaluated both in vitro and in vivo.

Results

The Qu-exosome-SPIONs were well constructed and harvested by magnetic separation with a uniform size and shape in a diameter of approximately 86.2 nm. The water solubility of quercetin increased 1.97-fold when loaded into the SPION-modified exosomes. The application of SPIONs/MF endowed the Qu-exosomes with favorable targeting capacity. In vitro studies showed that Qu-exosome-SPIONs/MF more effectively inhibited or attenuated β cell apoptosis and promoted insulin secretion in response to elevated glucose (GLC) compared with quercetin or Qu-exosome-SPIONs. In vivo studies demonstrated that Qu-exosome-SPIONs/MF displayed an ideal pancreatic islet targeting capacity, thereby leading to the restoration of islet function.

Conclusion

The Qu-exosome-SPIONs/MF nano-delivery system significantly enhanced the quercetin concentration in pancreatic islets and thereby improved pancreatic islet protection.

Application of the herbal chemical marker ranking system (Herb MaRS) to the standardization of herbal raw materials: a case study

INTRODUCTION

Phytochemical standardization of herbal materials involves establishing consistent levels of one or more active ingredients or markers. It ensures the authenticity and quality of herbal materials, extracts, and their products. This research aimed to apply the herbal chemical marker ranking system (Herb MaRS) originally proposed for quality assurance of complex herbal products to establish markers for controlling the quality of herbal raw materials.

METHODS

The assessment of compounds for suitability as markers was based on the Herb MaRS, with minor modifications as follows: for more objective scoring, evidence of biological activity of the potential marker compound(s) was determined at three levels based on the number of symptoms of the disease condition a compound can treat or alleviate: (i) one symptom (1 point), two symptoms (2 points), and 3 or more symptoms (3 points). The reported concentrations of the compounds were also scored as follows: concentration not determined (0 points), concentration ≥ 5 ppm (1 point), concentration ≥ 50 ppm (2 points) and availability of analytical standards (1 point). Finally, the compounds were scored for the availability of an analytical method (1 point). The compounds were scored from 0 to 8, where 8 indicated the most suitable chemical marker.

RESULTS

The selected markers were as follows: aromadendrine, α-terpineol, globulol, and 1,8-cineol (in Eucalyptus globulus Labill. ); aloin, aloe emodin, acemannan (in Aloe barbadensis (L.) Burm.f. ), lupeol, lupenone, betulinic acid, betulin, and catechin (in Albizia coriaria Oliv.); mangiferin, catechin, quercetin, and gallic acid (in Mangifera indica L.); polygodial (in Warburgia ugandensis Sprague); azadirachtin, nimbin, nimbidin (in Azadirachta indica A. Juss. ); and 6,8,10-gingerols, and 6-shogaol (in Zingiber officinalis Roscoe).

CONCLUSIONS

Herb MaRS can be efficiently applied to select marker compounds for quality control of herbal materials. However, for herbs whose phytochemicals have not been sufficiently researched, it is difficult to establish evidence of activity, and there are no analytical standards and/or methods; this is the case for plants exclusively used in Africa. The markers identified should be incorporated into chromatographic fingerprints, their quantitative methods developed, and evaluated for applicability at the various stages of the production chain of herbal medicines; then, they can be included in future local plant monographs. There is also a need to build local capacity to isolate marker compounds, particularly those that are not sold by current vendors.

From polyphenol to o-quinone: Occurrence, significance, and intervention strategies in foods and health implications

Polyphenol oxidation is a chemical process impairing food freshness and other desirable qualities, which has become a serious problem in fruit and vegetable processing industry. It is crucial to understand the mechanisms involved in these detrimental alterations. o-Quinones are primarily generated by polyphenols with di/tri-phenolic groups through enzymatic oxidation and/or auto-oxidation. They are highly reactive species, which not only readily suffer the attack by nucleophiles but also powerfully oxidize other molecules presenting lower redox potentials via electron transfer reactions. These reactions and subsequent complicated reactions are capable of initiating quality losses in foods, such as browning, aroma loss, and nutritional decline. To attenuate these adverse influences, a variety of technologies have emerged to restrain polyphenol oxidation via governing different factors, especially polyphenol oxidases and oxygen. Despite tremendous efforts devoted, to date, the loss of food quality caused by quinones has remained a great challenge in the food processing industry. Furthermore, o-quinones are responsible for the chemopreventive effects and/or toxicity of the parent catechols on human health, the mechanisms by which are quite complex. Herein, this review focuses on the generation and reactivity of o-quinones, attempting to clarify mechanisms involved in the quality deterioration of foods and health implications for humans. Potential innovative inhibitors and technologies are also presented to intervene in o-quinone formation and subsequent reactions. In future, the feasibility of these inhibitory strategies should be evaluated, and further exploration on biological targets of o-quinones is of great necessity.

Comparison of the antioxidant capacity of sesamol esters in gelled emulsion and non-gelled emulsion

The antioxidant capacity of sesamol esters in gelled emulsion was investigated in comparison with non-gelled emulsion to assess the role of mass transfer on their antioxidant capacity. Initiation phase and propagation phase kinetic parameters of peroxidation was calculated using a sigmoidal model. Sesamol esters showed higher antioxidant activity than sesamol in gelled emulsion and non-gelled emulsion. Sesamyl acetate, sesamyl butyrate, and sesamyl hexanoate had no synergistic effect with sesamol in gelled emulsion, while in non-gelled emulsion sesamyl butyrate exhibited a slight synergistic effect with sesamol. The antioxidant activity of sesamyl acetate and sesamyl hexanoate in non-gelled emulsion samples were higher than those of gelled emulsion samples, while sesamyl butyrate exhibited higher antioxidant activity in gelled emulsion than that of non-gelled emulsion. The cut-off effect hypothesis was observed in gelled emulsion, while this hypothesis was disappeared in non-gelled emulsion. During propagation phase, sesamol esters remained active and exhibited inhibitory effect.

Atrazine Toxicity: The Possible Role of Natural Products for Effective Treatment

There are various herbicides which were used in the agriculture industry. Atrazine (ATZ) is a chlorinated triazine herbicide that consists of a ring structure, known as the triazine ring, along with a chlorine atom and five nitrogen atoms. ATZ is a water-soluble herbicide, which makes it capable of easily infiltrating into majority of the aquatic ecosystems. There are reports of toxic effects of ATZ on different systems of the body but, unfortunately, majority of these scientific reports were documented in animals. The herbicide was reported to enter the body through various routes. The toxicity of the herbicide can cause deleterious effects on the respiratory, reproductive, endocrine, central nervous system, gastrointestinal, and urinary systems of the human body. Alarmingly, few studies in industrial workers showed ATZ exposure leading to cancer. We embarked on the present review to discuss the mechanism of action of ATZ toxicity for which there is no specific antidote or drug. Evidence-based published literature on the effective use of natural products such as lycopene, curcumin, Panax ginseng, Spirulina platensis, Fucoidans, vitamin C, soyabeans, quercetin, L-carnitine, Telfairia occidentalis, vitamin E, Garcinia kola, melatonin, selenium, Isatis indigotica, polyphenols, Acacia nilotica, and Zingiber officinale were discussed in detail. In the absence of any particular allopathic drug, the present review may open the doors for future drug design involving the natural products and their active compounds.

Dietary supplements and medicinal plants in urolithiasis: diet, prevention, and cure

BACKGROUND

Urolithiasis has been a major health concern for centuries, primarily owing to the limited treatment options in the physician's armamentarium. However, various studies have underscored a lesser incidence of urolithiasis in cohorts predominantly consuming fruits and vegetables. This article aims to review various dietary plants, medicinal herbs and phytochemicals in the prevention and management of urolithiasis.

METHODS

To provide context and evidence, relevant publications were identified on Google Scholar, PubMed and Science-Direct using keywords such as urolithiasis, nephrolithiasis, urolithiasis, renal stones, phytochemicals and dietary plants.

RESULTS

Growing bodies of evidence suggest the incorporation of plant-based foods, medicinal and herbal supplements, and crude drugs containing phytochemicals into the staple diet of people. The anti-urolithiatic activity of these plant bioactives can be attributed to their antioxidant, antispasmodic, diuretic, and inhibitory effect on the crystallization, nucleation and crystal aggregation effects. These mechanisms would help alleviate the events and symptoms that aid in the development and progression of renal calculi. In addition, it will also avoid the exacerbation of secondary disorders like inflammation and injury, which can initiate a vicious circle in turn worsening the disease progression.

CONCLUSION

In conclusion, the results presented in the review demonstrate the promising role of various dietary plants, medicinal and herbal supplements, and phytochemicals in preventing and managing the precipitation of uroliths. However, more conclusive and cogent evidence from preclinical and clinical studies is required to substantiate their safety, efficacy and toxicity profiles in humans.

Quercetin as a Dietary Supplementary Flavonoid Alleviates the Oxidative Stress Induced by Lead Toxicity in Male Wistar Rats

Quercetin is a naturally existing plant pigment belonging to the flavonoid group; it is contained in a wide range of vegetables and fruits. The accumulated evidence points to the potential uses of quercetin in protection of some disease conditions. Lead is one of the highly toxicant heavy metals that are widely spread in the environment and implicated in a wide spectrum of industries. No previous study has been reported to evaluate the effect of quercetin on lead toxicity. Therefore, the present study was conducted to elucidate some aspects of quercetin bioactivities in regard to its ability to combat the oxidative stress induced by lead toxicity. For this purpose, a total of sixty male Wistar rats were randomly and equally divided into three groups of 20 animals each; untreated control animals (group 1), lead-exposed animals (group 2; exposed to lead daily by oral gavage at the dose of 80 mg/Kg b.w.), and group 3 of animals, which were exposed to lead and daily received quercetin (10 h gap time between lead exposure and the receiving of quercetin) by oral gavage at the dose of 350 mg/Kg b.w. The experiment period was 8 weeks. All the assayed hematological and biochemical parameters of animals exposed to lead were significantly altered compared with the untreated control levels. Animals exposed to lead (group 2) exhibited significant decrements of the erythrocytic and total leucocytic counts, hemoglobin concentration, packed cell volume percent, total proteins, albumin and globulin. These animals also disclosed significantly decreased levels of antioxidant markers including total thiols, catalase and glutathione. On the other hand, these animals demonstrated significant increments in the levels of bilirubin, urea, creatinine, BUN, serum enzymes, H₂O₂ and MDA. Animals exposed to lead and given quercetin (group 3) exhibited improvement of these parameters, which were brought back at varying degrees toward the untreated control levels. Basing on the improvements of the assayed hematological and biochemical parameters, it was concluded that quercetin as a dietary supplement can act efficiently as an antioxidant to counteract the oxidative stress induced by lead toxicity and to maintain the oxidant antioxidant balance.

Bioaccessibility and Bioavailability of Diet Polyphenols and Their Modulation of Gut Microbiota

It is generally accepted that diet-derived polyphenols are bioactive compounds with several potentially beneficial effects on human health. In general, polyphenols have several chemical structures, and the most representative are flavonoids, phenolic acids, and stilbenes. It should be noted that the beneficial effects of polyphenols are closely related to their bioavailability and bioaccessibility, as many of them are rapidly metabolized after administration. Polyphenols-with a protective effect on the gastrointestinal tract-promote the maintenance of the eubiosis of the intestinal microbiota with protective effects against gastric and colon cancers. Thus, the benefits obtained from dietary supplementation of polyphenols would seem to be mediated by the gut microbiota. Taken at certain concentrations, polyphenols have been shown to positively modulate the bacterial component, increasing Lactiplantibacillus spp. and Bifidobacterium spp. involved in the protection of the intestinal barrier and decreasing Clostridium and Fusobacterium, which are negatively associated with human well-being. Based on the diet-microbiota-health axis, this review aims to describe the latest knowledge on the action of dietary polyphenols on human health through the activity of the gut microbiota and discusses micro-encapsulation of polyphenols as a strategy to improve the microbiota.

Improvement of Therapeutic Value of Quercetin with Chitosan Nanoparticle Delivery Systems and Potential Applications

This paper reviews recent studies investigating chitosan nanoparticles as drug delivery systems for quercetin. The therapeutic properties of quercetin include antioxidant, antibacterial and anti-cancer potential, but its therapeutic value is limited by its hydrophobic nature, low bioavailability and fast metabolism. Quercetin may also act synergistically with other stronger drugs for specific disease states. The encapsulation of quercetin in nanoparticles may increase its therapeutic value. Chitosan nanoparticles are a popular candidate in preliminary research, but the complex nature of chitosan makes standardisation difficult. Recent studies have used in-vitro, and in-vivo experiments to study the delivery of quercetin alone or in combination with another active pharmaceutical ingredient encapsulated in chitosan nanoparticles. These studies were compared with the administration of non-encapsulated quercetin formulation. Results suggest that encapsulated nanoparticle formulations are better. In-vivo or animal models simulated the type of disease required to be treated. The types of diseases were breast, lung, liver and colon cancers, mechanical and UVB-induced skin damage, cataracts and general oxidative stress. The reviewed studies included various routes of administration: oral, intravenous and transdermal routes. Although toxicity tests were often included, it is believed that the toxicity of loaded nanoparticles needs to be further researched, especially when not orally administered.

Combined Protective Effects of Quercetin, Rutin, and Gallic Acid against Cadmium-Induced Testicular Damages in Young-Adult Rats

Cadmium (Cd) is a toxic metal that damages several tissues of animals and humans including the testis. The ameliorative effects of quercetin (QUE), rutin (RUT), and gallic acid (GAL) at 20 mg kg-1 body weight alone or in combination against testicular injury induced by Cd (24 mg kg-1 body weight) in male Wistar rats were evaluated in this study. Forty-two (42) rats were randomly grouped into six (6) groups: (1) vehicle control group, (2) Cd group, (3) RUT+Cd group, (4) GAL+Cd group, (5) QUE+Cd group, and (6) RUT+GAL+QUE+Cd group. At the end of the oral gavage of the tested chemicals, the rats were sacrificed, blood samples were collected, and testes were harvested and processed for biochemical assays. Cd exposure damaged the testis (smaller epithelium thickness and spermatogenesis index and sloughing of the epithelium); increased lipid peroxidation, glutathione S-transferase activity, and DNA fragmentation; and diminished glutathione reductase activity and serum testosterone level 40 days posttreatment. Treatment with the phenolics separately or in combination attenuated the effect of Cd on serum testosterone, glutathione reductase and glutathione S-transferase activities, lipid peroxidation, and percent fragmented DNA. The increased nitric oxide concentration in the QUE+Cd group was attenuated to control values in the combined (RUT+GAL+QUE+Cd) exposure group. Coadministration of the phenolics appears to have more substantial protective effects than their single effects against Cd-induced testicular DNA damage, glutathione S-transferase activity, and the recovery of testosterone levels and spermatogenesis index. Overall, the tested phenolics can reduce testicular damage more efficiently in their combined form than individual administration.

Wound healing properties of a new formulated flavonoid-rich fraction from Dodonaea viscosa Jacq. leaves extract

Background: Dodonaea viscosa Jacq. (D. viscosa) belongs to the family of Sapindaceae, commonly known as "Sinatha," and is used as a traditional medicine for treating wounds due to its high flavonoids content. However, to date there is no experimental evidence on its flavonoid-rich fraction of D. viscosa formulation as an agent for healing wounds. Objective: The present study aimed to evaluate the wound healing effect of ethyl acetate fraction of D. viscosa leaves on dermal wounds. Methods: The ethyl acetate fraction was produced from a water-ethanol extract of D. viscosa leaves and was quantitatively evaluated using the HPLC technique. The in-vivo wound healing ability of the ethyl acetate fraction of D. viscosa ointment (DVFO, 2.5%w/w and 5%w/w) was investigated in Sprague-Dawley rats utilizing an incision and excision paradigm with povidone-iodine ointment (5% w/w) as a control. The percentage of wound closure, hydroxyproline and hexosamine concentrations, tensile strength and epithelialization duration were measured. Subsequently, histopathology analysis of skin samples as well as western blots were performed for collagen type 3 (COL3A1), basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF). Results: The ethyl acetate fraction of D. viscosa revealed flavonoids with high concentrations of quercetin (6.46% w/w) and kaempferol (0.132% w/w). Compared to the control group, the DVFO (2.5% and 5.0% w/w) significantly accelerated wound healing in both models, as demonstrated by quicker wound contraction, epithelialization, elevated hydroxyproline levels and increased tensile strength. Histopathological investigations also revealed that DVFO treatment improved wound healing by re-epithelialization, collagen formation and vascularization of damaged skin samples. Western blot analysis further demonstrated an up-regulation of COL3A, vascular endothelial growth factor and bFGF protein in wound granulation tissue of the DVFO-treated group (p < 0.01). Conclusion: It is concluded that flavonoid-rich D. viscosa ethyl acetate fraction promotes wound healing by up-regulating the expressions of COL3A, VEGF and bFGF protein in wound granulation tissue. However, extensive clinical and pre-clinical research on the flavonoid-rich fraction of D. viscosa is needed to determine its significant impact in the healing of human wounds.

Binary Hydrogels: Induction Methods and Recent Application Progress as Food Matrices for Bioactive Compounds Delivery-A Bibliometric Review

Food hydrogels are biopolymeric materials made from food-grade biopolymers with gelling properties (proteins and polysaccharides) and a 3D network capable of incorporating large amounts of water. They have sparked considerable interest because of their potential and broad application range in the biomedical and pharmaceutical sectors. However, hydrogel research in the field of food science is still limited. This knowledge gap provides numerous opportunities for implementing their unique properties, such as high water-holding capacity, moderated texture, compatibility with other substances, cell biocompatibility, biodegradability, and high resemblance to living tissues, for the development of novel, functional food matrices. For that reason, this article includes a bibliometric analysis characterizing research trends in food protein-polysaccharide hydrogels (over the last ten years). Additionally, it characterizes the most recent developments in hydrogel induction methods and the most recent application progress of hydrogels as food matrices as carriers for the targeted delivery of bioactive compounds. Finally, this article provides a future perspective on the need to evaluate the feasibility of using plant-based proteins and polysaccharides to develop food matrices that protect nutrients, including bioactive substances, throughout processing, storage, and digestion until they reach the specific targeted area of the digestive system.

Enzymatic lipophilization of bioactive compounds with high antioxidant activity: a review

Food products contain bioactive compounds such as phenolic and polyphenolic compounds and vitamins, resulting in a myriad of biological characteristics such as antimicrobial, anticarcinogenic, and antioxidant activities. However, their application is often restricted because of their relatively low solubility and stability in emulsions and oil-based products. Therefore, chemical, enzymatic, or chemoenzymatic lipophilization of these compounds can be achieved by grafting a non-polar moiety onto their polar structures. Among different methods, enzymatic modification is considered environmentally friendly and may require only minor downstream processing and purification steps. In recent years, different systems have been suggested to design the synthetic reaction of these novel products. This review presents the new trends in this area by summarizing the essential enzymatic modifications in the last decade that led to the synthesis of bioactive compounds with attractive antioxidative properties for the food industry by emphasizing on optimization of the reaction conditions to maximize the production yields. Lastly, recent developments regarding characterization, potential applications, emerging research areas, and needs are highlighted.

Quercetin Fatty Acid Monoesters (C2:0-C18:0): Enzymatic Preparation and Antioxidant Activity

Quercetin monoesters were prepared via a one-step enzymatic transesterification. The main acylation products were eight quercetin ester derivatives, respectively, consisting of varying acyl groups ranging from 2 to 18 carbon atoms (acetate, butyrate, caproate, caprylate, caprate, laurate, myristate, and stearate). The purified quercetin esters were structurally characterized by LC-ESI-ToF and NMR HSQC. Meanwhile, several classical chemical (DPPH, ABTS, FRAP, and Fe²⁺ chelation assays), food (β-carotene bleaching assay), and biological (LDL and DNA oxidation assays) models were constructed to evaluate and systematically compare their antioxidant efficacy. O-Acylation increased the lipophilicity of quercetin derivatives, and lipophilicity increased with the increasing chain length of the acyl group. The dual effect of the acyl chain length on biasing quercetin monoesters' antioxidant efficacies has been summarized and verified. Overall, the results imply that the acylated quercetin have great potential as functional/health-beneficial ingredients for use in lipid-based matrices of cosmetics, supplements, and nutraceuticals.

Probing the synergistic effects of rutin and rutin ester on the oxidative stability of sardine oil

Multicomponent antioxidant mixture is proved to be highly effective in imparting oxidative stability to the edible oil. It is believed that the high efficacy of those mixtures is due to the synergistic effect exhibited by two or more components. The current study aims to analyse the synergistic effect of a flavonoid and its corresponding ester in improving the oxidative stability of n-3 PUFA rich sardine oil. The oxidative stability of rutin, esterified rutin and their combinations at three different concentrations was studied in sardine oil stored at 37 ºC for 12 days in contact with air under darkness. The combination of rutin and rutin ester showed maximum reduction of 54.2% in oxidation at 100 mg/kg and 150 mg/kg. Perhaps this is the first report on the synergistic effect of a flavonoid and its lipophilized ester for improving the oxidative stability of n-3 PUFA rich oil.

Modification of flavonoids: methods and influences on biological activities

Flavonoids are important active ingredients in plant-based food, which have many beneficial effects on health. But the low solubility, poor oral bioavailability, and inferior stability of many flavonoids may limit their applications in the food, cosmetics, and pharmaceutical industries. Structural modification can overcome these shortcomings to improve and extend the application of flavonoids. The study of how to modify flavonoids and the influence of various modifications on biological activity have drawn great interest in the current literature. In this review, the working principles and operating conditions of modification methods were summarized along with their potential and limitations in terms of operational safety, cost, and productivity. The influence of various modifications on biological activities and the structure-activity relationships of flavonoids derivatives were discussed and highlighted, which may give guidance for the synthesis of highly effective active agents. In addition, the safety of flavonoids derivatives is reviewed, and future research directions of flavonoid modification research are discussed.

Catalytic Routes to Produce Polyphenolic Esters (PEs) from Biomass Feedstocks

Polyphenolic esters (PEs) are valuable chemical compounds that display a wide spectrum of activities (e.g., anti-oxidative effects). As a result, their production through catalytic routes is an attractive field of research. The present review aims to discuss recent studies from the literature regarding the catalytic production of PEs from biomass feedstocks, namely, naturally occurred polyphenolic compounds. Several synthetic approaches are reported in the literature, mainly bio-catalysis and to a lesser extent acid catalysis. Immobilized lipases (e.g., Novozym 435) are the preferred enzymes thanks to their high reactivity, selectivity and reusability. Acid catalysis is principally investigated for the esterification of polyphenolic acids with fatty alcohols and/or glycerol, using both homogeneous (p-toluensulfonic acid, sulfonic acid and ionic liquids) and heterogeneous (strongly acidic cation exchange resins) catalysts. Based on the reviewed publications, we propose some suggestions to improve the synthesis of PEs with the aim of increasing the greenness of the overall production process. In fact, much more attention should be paid to the use of new and efficient acid catalysts and their reuse for multiple reaction cycles.

The Effects of Acyl Chain Length on Antioxidant Efficacy of Mono- and Multi-Acylated Resveratrol: A Comparative Assessment

Acylated derivatives of the dietary phenolic, resveratrol, were prepared via enzymatic and chemical transesterification modification with selected vinyl fatty acids to expand the potential application of resveratrol and its acylated derivatives in functional supplement, cosmetic/skincare, and pharmaceutical fields. The acylation was implemented using eight vinyl fatty acids with varying chain lengths (C2:0-C18:0). Eight monoesters enzymatically prepared, eight diesters and four triesters, chemically prepared, were isolated and purified and identified via MS (mass spectra) or/and NMR (nuclear magnetic resonance). The lipophilicity of resveratrol and its acylated derivatives was calculated using ALOGPS 2.1. Compared with related acylated products, resveratrol itself rendered higher antioxidant efficacy in all the antioxidant assays, namely DPPH, ABTS, FRAP, and ferrous chelation tests. Within various ester derivatives of resveratrol, short-chain fatty acid mono- and di-substituted resveratrols, especially the resveratrol monoacetate/diacetate, exhibited higher antioxidant efficacy in DPPH and ABTS assays than the rest of resveratrol derivatives, but the medium-chain monoesters of resveratrol, including caproate, caprylate, caprate, and laurate, showed a higher metal ion chelation ability compared to other acylated resveratrols. These results imply that resveratrol derivatives may be used in lipidic media as health-beneficial antioxidants.

Characterization, Large-Scale HSCCC Separation and Neuroprotective Effects of Polyphenols from Moringa oleifera Leaves

Moringa oleifera leaves have been widely used for the treatment of inflammation, diabetes, high blood pressure, and other diseases, due to being rich in polyphenols. The main objective of this work was to largely separate the main polyphenols from Moringa oleifera leaves using the technique of high-speed counter-current chromatography (HSCCC). The phenolic composition in Moringa oleifera leaves was first analyzed qualitatively and quantitatively by UPLC-Q-Exactive Orbitrap/MS and UPLC-QqQ/MS, respectively, indicating that quercetin and kaempferol derivatives, phenolic acid and apigenin are the main polyphenols in Moringa oleifera leaves, with quercetin and kaempferol derivatives predominating. Furthermore, the conditions of HSCCC for large-scale separation of polyphenols from Moringa oleifera leaves were optimized, which included the selection of the solvent system, flow rate and the sample load. Only by one-step HSCCC separation (within 120 min) under the optimized conditions, six quercetin and kaempferol derivatives, a phenolic acid and an apigenin could be individually isolated at a large scale (yield from 10% to 98%), each of which possessed high purity. Finally, the isolated polyphenols and phenolic extract from Moringa oleifera leaves (MLPE) were verified to have strong neuroprotective activities against H₂O₂-induced oxidative stress in PC-12 cells, suggesting that these compounds would contribute to the main beneficial effects of Moringa oleifera leaves.

A Multi-Ingredient Formula Ameliorates Exercise-Induced Fatigue by Changing Metabolic Pathways and Increasing Antioxidant Capacity in Mice

Multiple mechanisms are involved in exercise-induced fatigue, including energy depletion, metabolite accumulation, and oxidative stress, etc. The mechanistic findings provide a rationale for a multi-targeted approach to exercise-induced fatigue management. This study created a multi-ingredient formula mixed with valine, isoleucine, leucine, β-alanine, creatine, l-carnitine, quercetin, and betaine, based on the functional characteristics of these agents, and evaluated the preventive effect of this mechanism-based formula on exercise-induced fatigue. Results showed that the 7-d formula supplement significantly increased the running duration time of mice by 14% and the distance by 20% in an exhaustive treadmill test, indicating that the formula could delay fatigue appearance and improve exercise performance. Mechanistically, the formula enhanced fatty acid oxidation and spared liver glycogen by regulating the fat/glucose metabolism-related signaling pathways, including phospho-adenosine monophosphate-activated protein kinase α (p-AMPKα), phospho-acetyl CoA carboxylase (p-ACC), carnitine palmitoyl-transferase 1B (CPT1B), fatty acid translocase (CD36), and glucose transporter type 4 (GLUT4), and increased antioxidant capacity. The findings suggested that the formula tested in this study effectively ameliorated exercise-induced fatigue by targeting multi-signaling pathways, showing promise as a regimen to fight exercise-induced fatigue.

Discovery of TGFBR1 (ALK5) as a potential drug target of quercetin glycoside derivatives (QGDs) by reverse molecular docking and molecular dynamics simulation

Quercetin glycoside derivatives (QGDs) are a class of common compounds with a wide range of biological activities, such as antitumor activities. However, their molecular targets associated with biological activities have not been investigated. In this study, four common QGDs with mutual bioconversion were selected, and studied in the large-scale reverse docking experiments. Network pharmacology analysis showed that most of the four QGDs can bind several potential protein targets that were closely related to breast cancer disease. Among them, a druggable protein, transforming growth factor beta receptor I (TGFBR1/ALK5) was screened via high docking scores for the four QGDs. This protein has been proven to be an important target for the treatment of breast cancer by regulating the proliferation and migration of cancer cells in the past. Subsequently, the molecular dynamics (MD) simulation and MM/GBSA calculation demonstrated that all QGDs could thermodynamically bind with TGFBR1, indicating that TGFBR1 might be one of the potential protein targets of QGDs. Finally, the cytotoxicity test and wound-healing migration assay displayed that isoquercetin, which can perform best in MD experiment, might be a promising agent in the treatment of breast cancer metastasis.

Efficient Enzymatic Synthesis of Lipophilic Phenolic Glycoside Azelaic Acid Esters and Their Depigmenting Activity

In this paper, an enzymatic route for synthesizing phenolic glycoside azelaic acid esters was successfully set up via lipase-catalyzed esterification and transesterification. Among the lipases tested, Candida antarctica lipase B (Novozyme 435) showed the highest activity in catalyzing esterification and Thermomyces lanuginosus (Lipozyme TLIM) gave the highest substrate conversion in catalyzing transesterification for the synthesis of ester. The addition of 4A molecular sieves into the reaction system is found to be an effective method for in situ absorption of the byproduct water and methanol, with which the substrate conversions of the enzymatic esterification and transesterification were 98.7 and 95.1%, respectively. Also, the main product ratios in transesterification were above 99.0% with lipozyme TLIM as a catalyst because the hydrolysis reaction was hindered. The results of the physical and biological properties indicate that all esters had higher Clog p values than their parent compounds. Also, the esters showed higher intracellular tyrosinase inhibitory and depigmentating activities than phenolic glycosides, azelaic acid (AA), and their physical mixtures due to their higher membrane penetration and tyrosinase inhibitory effects. In particular, piceid 6″-O-azelaic acid ester (PIA) showed the strongest inhibitory effect against melanin production. Its inhibitory rate was 77.4% at a concentration of 0.25 mM, about 4.2 times higher than that of arbutin (18.5%).

Research progress on polysaccharide/protein hydrogels: Preparation method, functional property and application as delivery systems for bioactive ingredients

Some bioactive ingredients in foods are unstable and easily degraded during processing, storage, transportation and digestion. To enhance the stability and bioavailability, some food hydrogels have been developed to encapsulate these unstable compounds. In this paper, the preparation methods, formation mechanisms, physicochemical and functional properties of some protein hydrogels, polysaccharide hydrogels and protein-polysaccharide composite hydrogels were comprehensively summarized. Since the hydrogels have the ability to control the release and enhance the bioavailability of bioactive ingredients, the encapsulation and release mechanisms of polyphenols, flavonoids, carotenoids, vitamins and probiotics by hydrogels were further discussed. This review will provide a comprehensive reference for the deep application of polysaccharide/protein hydrogels in food industry.

Quercetin and its ester derivatives inhibit oxidation of food, LDL and DNA

Quercetin was esterified with fatty acids (FA) in order to expand its application in a wide range of food and biological systems. The antioxidant potential of the esters were examined using hydroxyl radical scavenging activity, antioxidation in oil-in-water emulsion and bulk oil, inhibition of low-density lipoprotein (LDL) oxidation and deoxyribonucleic acid (DNA) scission. Except for oil-in-water emulsion system, quercetin derivatives demonstrated similar and/or better antioxidant activity than quercetin itself in bulk oil (quercetin with C18:1 and C22:6), hydroxyl radical scavenging assay (quercetin with C3:0-C8:0), DNA scission (quercetin with C3:0-C8:0), and LDL oxidation (quercetin with C14:0-C22:6, except C18:0). These results suggest that esterification did not compromise the antioxidant activity of the parent compound and quercetin derivatives might be useful as possible antioxidants in food and biological systems.

Determination of soluble and insoluble-bound phenolic compounds in dehulled, whole, and hulls of green and black lentils using electrospray ionization (ESI)-MS/MS and their inhibition in DNA strand scission

The soluble and insoluble-bound phenolic fractions of hull, whole, and dehulled black and green lentil extracts were identified and quantified using electrospray ionization (ESI)-MS/MS. Several in vitro antioxidant tests and inhibition of DNA strand scission were conducted to assess different pathways of activity. The most abundant phenolics in the soluble fractions were caffeic acid (412.2 μg/g), quercetin, (486.5 μg/g) quercetin glucoside (633.6 μg/g) luteolin glucoside (239.1 μg/g) and formononetin (920 μg/g), while myricetin (534.1 μg/g) and catechin (653.4 μg/g) were the predominant phenolics in the insoluble bound fraction. Hulls of both lentil cultivars had the highest phenolic content and the strongest antioxidant activity followed by whole and dehulled samples. Thus, lentil hulls would serve as an excellent source for the production of functional foods. Moreover, ESI-MS/MS (direct infusion) analysis was the rapid and high-throughput approach for the determination of bioactives in lentils by reducing the analysis time.

Quercetin Inhibited the Formation of Lipid Oxidation Products in Thermally Treated Soybean Oil by Trapping Intermediates

In this research, we studied the inhibitory mechanism of quercetin, one popular phenolic compound, against aldehyde formation in thermally treated soybean oil. It was found that quercetin reduced unsaturated aldehyde formation significantly, with the inhibitory effect decreased with the extension of the heating time. Meanwhile, quercetin had minimum effects on the fatty acid profile compared to untreated samples. Some new phenolic derivatives were formed in thermally treated soybean oil with quercetin, further analyzed by liquid chromatography-tandem mass spectrometry, and compared to newly synthesized derivatives (characterized by mass spectrometry and nuclear magnetic resonance spectroscopy). On the basis of their chemical structures, we proposed that quercetin reacted with 13-oxo-octadecadienoic acid, 10-oxo-hexadecenoic acid, and 10-oxo-octadecenoic acid formed from peroxidation of linoleic acid, palmitoleic acid, and oleic acid, respectively, to inhibit aldehyde formation. In addition, newly formed quercetin-3-O-hexanoate, quercetin-3-O-heptanoate, and quercetin-3-O-nonanoate showed weaker 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt radical cation scavenging activity and weaker antioxidant activity in soybean oil, which explained the decreased inhibitory activity of quercetin against aldehyde formation during heat treatment. More interesting, quercetin-3-O-hexanoate showed improved cellular antioxidant activity compared to the parent quercetin. Overall, quercetin inhibited the formation of lipid oxidation products in thermally treated soybean oil by reacting with early intermediates in the lipid oxidation reaction, and quercetin derivatives formed in the process could be with enhanced cellular antioxidant activity. Our results provide novel insight into the inhibitory mechanism of quercetin against the formation of lipid oxidation products.

Antioxidative Properties and Chemical Changes of Quercetin in Fish Oil: Quercetin Reacts with Free Fatty Acids to Form Its Ester Derivatives

In this research, we studied the antioxidative properties and chemical changes of quercetin in fish oil during accelerated storage at 60 °C for 5 days. Gas chromatography (GC) analysis showed that quercetin inhibited aldehyde formation and unsaturated fatty acid oxidation in fish oil significantly; however, the inhibitory effects decreased gradually with prolonged heating time. Moreover, quercetin was consumed with increasing heating time. Some new phenolic derivatives were discovered in the fish oil with quercetin, with their structures fully elucidated by LC-MS/MS and comparison with newly synthesized ones (characterized by MS and NMR spectroscopy). Based on their chemical structures, we proposed that quercetin reacted with EPA and DHA to form the corresponding quercetin fatty acid esters in fish oil. In addition, the newly formed quercetin-3-O-eicosapentaenoate and quercetin-3-O-docosahexaenoate showed weaker DPPH and ABTS radical cation scavenging activity but much improved lipophilicity, higher cell membrane affinity, and hence enhanced cellular antioxidant activity compared with the parent quercetin. Overall, quercetin could be used as a safe dietary polyphenol to inhibit lipid oxidation. The newly formed quercetin-polyunsaturated fatty acid esters may render improved bioactivity to humans, which needs further investigation.

Quercetin: Its Main Pharmacological Activity and Potential Application in Clinical Medicine

Quercetin is a flavonoid compound widely present in plants and exhibits a variety of biological activities. Research on quercetin has shown its potential for medical application. In this research, we elucidate its antioxidant mechanism and the broad-spectrum antibacterial and antiparasite properties; summarise its potential application in antioncology and cardiovascular protection and anti-immunosuppression treatment; and demonstrate its ability to alleviate the toxicity of mycotoxins. This research is expected to offer some insights and inspirations for the further study of quercetin, its properties, and the scientific basis for its better application in clinical practice.

Synthesis and Evaluation of Antioxidant Activities of Novel Hydroxyalkyl Esters and Bis-Aryl Esters Based on Sinapic and Caffeic Acids

Novel hydroxyalkyl esters and bis-aryl esters were synthesized from sinapic and caffeic acids and aliphatic α,ω-diols of increasing chain lengths from 2 to 12 carbon atoms. Then, their antiradical reactivity (DPPH assay) and their antioxidant activity in a model oil-in-water emulsion (CAT assay) were evaluated. All the esters showed lower antiradical activities compared to their corresponding phenolic acid. This decrease was associated with the steric hindrance in hydroxyalkyl esters, and intramolecular interactions in bis-aryl esters. Regarding the two bis-aryl esters series in emulsion, the antioxidant capacity was improved with alkyl chain lengthening up to four carbons, after which it decreased for longer chains. This "cutoff" effect was not observed for both hydroxyalkyl esters series for which the alkyl chain lengthening results in a decrease of the antioxidant activity.