The effect of Luteolin on DNA damage mediated by a copper catalyzed Fenton reaction

Copper (II) increases anti-Proliferative activity of thymoquinone in colon cancer cells by increasing genotoxic, apoptotic, and reactive oxygen species generating effects

Thymoquinone is the main active compound derived from the essential oil of the Nigella sativa plant seed. While thymoquinone is an antioxidant, it has been reported in several studies that thymoquinone has dose-dependent pro-oxidant activity with the Fenton reaction in the presence of transition elements such as iron and copper. This study aimed to investigate cytotoxic, apoptotic, genotoxic, and reactive oxygen species (ROS) generating effects of thymoquinone treated with copper in colon cancer cells. HT-29 cells were treated with pro-oxidant-acting doses of thymoquinone alone and together with the non-toxic dose of Copper (II) Sulfate for 24 h. Cytotoxic, apoptotic, genotoxic, and ROS production activities were analyzed by MTT viability test, Acridine Orange/Ethidium Bromide (AO/EB) staining, alkaline single cell gel electrophoresis and H2DCF-DA assay, respectively. Viability results showed that thymoquinone and copper synergistically affect cancer cells, and DNA damage was increased with the synergic effect. The intracellular ROS was increased when thymoquinone and copper were applied together. Applying redox-active copper (II) with thymoquinone increases DNA damage, apoptosis, and cell death by increasing the amount of intracellular ROS through pro-oxidant activity. Treatments targeting copper-related pathways may open new therapeutic avenues for cancer treatment.

Lactoperoxidase Inhibition of Celecoxib Derivatives Containing the Pyrazole Linked-Sulfonamide Moiety: Antioxidant Capacity, Antimicrobial Activity, and Molecular Docking Studies

Celecoxib derivatives that contain the pyrazole-linked sulfonamide moiety were synthesized, and the in vitro inhibitory impacts of the aforesaid compounds against the lactoperoxidase (LPO) enzyme were researched. To this end, LPO was purified using the affinity chromatography technique with a yield of 12.63% (319.23-fold). The results showed that the aromatic pyrazole compound (compound 1) containing 2,3-dimethoxyphenyl functional groups was the most effective LPO inhibitor with a Ki value of 3.2 ± 0.7 nM and noncompetitive inhibition type. The second section of the study tested the previously synthesized compounds to reveal their antioxidant and antimicrobial properties. The above-mentioned compound also displayed high activity levels compared to standard antibiotics and antifungals, while all other compounds also showed antibacterial activity. In the three antioxidant methods we used, the compound with 2,5-dimethoxy phenyl groups obtained from the reaction of the aromatic pyrazole compound with propionic anhydride in the presence of NEt3 displayed the highest activity. Furthermore, molecular docking and molecular mechanics studies were conducted to complement and validate the experimental findings. The results obtained from these computational analyses are highly consistent with the experimental data.

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

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

Metal-Flavonoid Interactions-From Simple Complexes to Advanced Systems

For many years, metal-flavonoid complexes have been widely studied as a part of drug discovery programs, but in the last decade their importance in materials science has increased significantly. A deeper understanding of the role of metal ions and flavonoids in constructing simple complexes and more advanced hybrid networks will facilitate the assembly of materials with tailored architecture and functionality. In this Review, we highlight the most essential data on metal-flavonoid systems, presenting a promising alternative in the design of hybrid inorganic-organic materials. We focus mainly on systems containing CuII/I and FeIII/II ions, which are necessary in natural and industrial catalysis. We discuss two kinds of interactions that typically ensure the formation of metal-flavonoid systems, namely coordination and redox reactions. Our intention is to cover the fundamentals of metal-flavonoid systems to show how this knowledge has been already transferred from small molecules to complex materials.

Copper Nanodrugs by Atom Transfer Radical Polymerization

In this study, some copper catalysts used for atom transfer radical polymerization (ATRP) were explored as efficient anti-tumor agents. The aqueous solution of copper-containing nanoparticles with uniform spheric morphology was in situ prepared through a copper-catalyzed activator generated by electron transfer (AGET) ATRP in water. Nanoparticles were then directly injected into tumor-bearing mice for antitumor chemotherapy. The copper nanodrugs had prolonged blood circulation time and enhanced accumulation at tumor sites, thus showing potent antitumor activity. This work provides a novel strategy for precise and large-scale preparation of copper nanodrugs with high antitumor activity.

Luteolin Alleviates Cadmium-Induced Kidney Injury by Inhibiting Oxidative DNA Damage and Repairing Autophagic Flux Blockade in Chickens

Chickens are a major source of meat and eggs in human food and have significant economic value. Cadmium (Cd) is a common environmental pollutant that can contaminate feed and drinking water, leading to kidney injury in livestock and poultry, primarily by inducing the generation of free radicals. It is necessary to develop potential medicines to prevent and treat Cd-induced nephrotoxicity in poultry. Luteolin (Lut) is a natural flavonoid compound mainly extracted from peanut shells and has a variety of biological functions to defend against oxidative damage. In this study, we aimed to demonstrate whether Lut can alleviate kidney injury under Cd exposure and elucidate the underlying molecular mechanisms. Renal histopathology and cell morphology were observed. The indicators of renal function, oxidative stress, DNA damage and repair, NAD+ content, SIRT1 activity, and autophagy were analyzed. In vitro data showed that Cd exposure increased ROS levels and induced oxidative DNA damage and repair, as indicated by increased 8-OHdG content, increased γ-H2AX protein expression, and the over-activation of the DNA repair enzyme PARP-1. Cd exposure decreased NAD+ content and SIRT1 activity and increased LC3 II, ATG5, and particularly p62 protein expression. In addition, Cd-induced oxidative DNA damage resulted in PARP-1 over-activation, reduced SIRT1 activity, and autophagic flux blockade, as evidenced by reactive oxygen species scavenger NAC application. The inhibition of PARP-1 activation with the pharmacological inhibitor PJ34 restored NAD+ content and SIRT1 activity. The activation of SIRT1 with the pharmacological activator RSV reversed Cd-induced autophagic flux blockade and cell injury. In vivo data demonstrated that Cd treatment caused the microstructural disruption of renal tissues, reduced creatinine, and urea nitrogen clearance, raised MDA content, and decreased the activities or contents of antioxidants (GSH, T-SOD, CAT, and T-AOC). Cd treatment caused oxidative DNA damage and PARP-1 activation, decreased NAD+ content, decreased SIRT1 activity, and impaired autophagic flux. Notably, the dietary Lut supplement observably alleviated these alterations in chicken kidney tissues induced by Cd. In conclusion, the dietary Lut supplement alleviated Cd-induced chicken kidney injury through its potent antioxidant properties by relieving the oxidative DNA damage-activated PARP-1-mediated reduction in SIRT1 activity and repairing autophagic flux blockade.

Luteolin, a flavone ingredient: Anticancer mechanisms, combined medication strategy, pharmacokinetics, clinical trials, and pharmaceutical researches

Current pharmaceutical research is energetically excavating the pharmacotherapeutic role of herb-derived ingredients in multiple malignancies' targeting. Luteolin is one of the major phytochemical components that exist in various traditional Chinese medicine or medical herbs. Mounting evidence reveals that this phytoconstituent endows prominent therapeutic actions on diverse malignancies, with the underlying mechanisms, combined medication strategy, and pharmacokinetics elusive. Additionally, the clinical trial and pharmaceutical investigation of luteolin remain to be systematically delineated. The present review aimed to comprehensively summarize the updated information with regard to the anticancer mechanism, combined medication strategies, pharmacokinetics, clinical trials, and pharmaceutical researches of luteolin. The survey corroborates that luteolin executes multiple anticancer effects mainly by dampening proliferation and invasion, spurring apoptosis, intercepting cell cycle, regulating autophagy and immune, inhibiting inflammatory response, inducing ferroptosis, and pyroptosis, as well as epigenetic modification, and so on. Luteolin can be applied in combination with numerous clinical anticarcinogens and natural ingredients to synergistically enhance the therapeutic efficacy of malignancies while reducing adverse reactions. For pharmacokinetics, luteolin has an unfavorable oral bioavailability, it mainly persists in plasma as glucuronides and sulfate-conjugates after being metabolized, and is regarded as potent inhibitors of OATP1B1 and OATP2B1, which may be messed with the pharmacokinetic interactions of miscellaneous bioactive substances in vivo. Besides, pharmaceutical innovation of luteolin with leading-edge drug delivery systems such as host-guest complexes, nanoparticles, liposomes, nanoemulsion, microspheres, and hydrogels are beneficial to the exploitation of luteolin-based products. Moreover, some registered clinical trials on luteolin are being carried out, yet clinical research on anticancer effects should be continuously promoted.

The Tao of Copper Metabolism: From Physiology to Pathology

As a transitional metal, copper plays a crucial role in maintaining the normal physiological activities of mammals. The intracellular copper concentration is meticulously regulated to maintain extremely low levels through homeostatic regulation. Excessive accumulation of free copper in cells can have deleterious effects, as observed in conditions such as Wilson's disease. Moreover, data accumulated over the past few decades have revealed a crucial role of copper imbalance in tumorigenesis, progression and metastasis. Recently, cuproptosis, also known as copper-induced cell death, has been proposed as a novel form of cell death. This discovery offers new prospects for treating copperrelated diseases and provides a promising avenue for developing copper-responsive therapies, particularly in cancer treatment. We present a comprehensive overview of the Yin- Yang equilibrium in copper metabolism, particularly emphasising its pathophysiological alterations and their relevance to copper-related diseases and malignancies.

A Comparative Study of the Inhibitory Effect of Some Flavonoids and a Conjugate of Taxifolin with Glyoxylic Acid on the Oxidative Burst of Neutrophils

During the storage, processing, and digestion of flavonoid-rich foods and beverages, a condensation of flavonoids with toxic carbonyl compounds occurs. The effect of the resulting products on cells remains largely unknown. The aim of the present study was to evaluate the effects of quercetin, taxifolin, catechin, eriodictyol, hesperetin, naringenin, and a condensation product of taxifolin with glyoxylic acid on the oxidative burst of neutrophils. It was found that the flavonoids and the condensation product inhibited the total production of ROS. Flavonoids decreased both the intra and extracellular ROS production. The condensation product had no effect on intracellular ROS production but effectively inhibited the extracellular production of ROS. Thus, the condensation of flavonoids with toxic carbonyl compounds may lead to the formation of compounds exhibiting potent inhibitory effects on the oxidative burst of neutrophils. The data also suggest that, during these reactions, the influence of a fraction of flavonoids and their polyphenolic derivatives on cellular functions may change. On the whole, the results of the study provide a better understanding of the effects of polyphenols on human health. In addition, these results reveal the structure-activity relationship of these polyphenols and may be useful in a search for new therapeutic agents against diseases associated with oxidative stress.

Update on new trends and progress of natural active ingredients in the intervention of Alzheimer's disease, based on understanding of traditional Chinese and Western relevant theories: A review

Alzheimer's disease (AD) is one of the major neurological disorders causing death in the elderly worldwide. As a neurodegenerative disease that is difficult to prevent and cure, the pathogenesis of AD is complex and there is no effective cure. A variety of natural products derived from plants have been reported to have promising anti-AD activities, including flavonoids, terpenes, phenolic acids and alkaloids, which can effectively relieve the symptoms of AD in a variety of ways. This paper mainly reviews the pharmacological activity and mechanisms of natural products against AD. Although the clinical efficacy of these plants still needs to be determined by further high-quality studies, it may also provide a basis for future researchers to study anti-AD in depth.

The role of redox active copper(II) on antioxidant properties of the flavonoid baicalein: DNA protection under Cu(II)-Fenton reaction and Cu(II)-ascorbate system conditions

The antioxidant properties of flavonoids are mediated by their functional hydroxyl groups, which are capable of both chelating redox active metals such as iron, copper and scavenging free radicals. In this paper, the antioxidant vs. prooxidant and DNA protecting properties of baicalein and Cu(II)-baicalein complexes were studied under the conditions of the Copper-Fenton reaction and of the Copper-Ascorbate system. From the relevant EPR spectra, the interaction of baicalein with Cu(II) ions was confirmed, while UV-vis spectroscopy demonstrated a greater stability over time of Cu(II)-baicalein complexes in DMSO than in methanol and PBS and Phosphate buffers. An ABTS study confirmed a moderate ROS scavenging efficiency, at around 37%, for both free baicalein and Cu(II)-baicalein complexes (in the ratios 1:1 and 1:2). The results from absorption titrations are in agreement with those from viscometric studies and confirmed that the binding mode between DNA and both free baicalein and Cu-baicalein complexes, involves hydrogen bonds and van der Waals interactions. The DNA protective effect of baicalein has been investigated by means of gel electrophoresis under the conditions of the Cu-catalyzed Fenton reaction and of the Cu-Ascorbate system. In both cases, it was found that, at sufficiently high concentrations, baicalein offers some protection to cells from DNA damage caused by ROS (singlet oxygen, hydroxyl radicals and superoxide radical anions). Accordingly, baicalein may be useful as a therapeutic agent in diseases with a disturbed metabolism of redox metals such as copper, for example Alzheimer's disease, Wilson's disease and various cancers. While therapeutically sufficient concentrations of baicalein may protect neuronal cells from Cu-Fenton-induced DNA damage in regard to neurological conditions, conversely, in the case of cancers, low concentrations of baicalein do not inhibit the pro-oxidant effect of copper ions and ascorbate, which can, in turn, deliver an effective damage to DNA in tumour cells.

A Physicochemical Study of the Antioxidant Activity of Corn Silk Extracts

Corn silk (CS) extracts are reported to contain flavonoids (appx. 59.65 mg quercetin/g), polysaccharides (appx. 58.75 w.%), steroids (appx. 38.3 × 10^-3 to 368.9 × 10^-3 mg/mL), polyphenols (appx. 77.89 mg/GAE/g) and other functional biological substances. This study investigated the antioxidant activity of corn silk extracts related to their functional compounds. The radical scavenging effect of corn silk extracts was evaluated by the spin-trapping electron paramagnetic resonance (EPR) technique, 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzo-thiazoline-6-sulfonate) (ABTS^•+) free radical measurement, ferric ion-reducing antioxidant power, and copper ion reductive capacity. It was found that the maturity stage of CS plant materials and the applied extraction procedure of their bioactive compounds have a profound effect on the radical scavenging capacity. Differences in the antioxidant activity of the studied corn silk samples based on their maturity were also confirmed. The strongest DPPH radical scavenging effect was observed for the corn silk mature stage (CS-M)stage (CS-MS) (65.20 ± 0.90)%, followed by the silky stage (CS-S) (59.33 ± 0.61)% and the milky stage (CS-M) (59.20 ± 0.92)%, respectively. In general, the final maturity stage (CS-MS) provided the most potent antioxidant effect, followed by the earliest maturity stage (CS-S) and the second maturity stage (CS-M).

Hesperetin-Cu(II) complex as potential α-amylase and α-glucosidase inhibitor: Inhibition mechanism and molecular docking

Inhibition of α-amylase and α-glucosidase activity is an effective way for controlling postprandial blood glucose-related diabetes. The study found that hesperetin-Cu(II) complex (Hsp-Cu(II)) exhibited a stronger inhibitory ability on α-amylase and α-glucosidase compared to hesperetin (Hsp), with smaller IC₅₀ values of Hsp-Cu(II) (60.3 ± 0.9 µM for α-amylase; 1.25 ± 0.03 µM for α-glucosidase) than Hsp (115.6 ± 1.1 µM for α-amylase; 55.2 ± 0.1 µM for α-glucosidase). Interestingly, Hsp-Cu(II) and acarbose exerted a synergistic effect on inhibition of α-glucosidase. The binding affinities of Hsp-Cu(II) to α-amylase and α-glucosidase were strong with the Ka values (binding constant) in the magnitude order of 10⁵, which was 9 times larger than Hsp. After interacting, Hsp-Cu(II) reduced α-helix contents of α-amylase and α-glucosidase, resulting in a looser conformation of these two enzymes. Molecular simulations manifested that Hsp-Cu(II) bound to the active center of enzymes driven by hydrogen bonds and interacted with the key catalytic amino acids (α-amylase: Gln63, Asp300 and His305; α-glucosidase: Tyr158, Asp215, Glu277 and Glu411), altering the conformation of enzymes, blocking the entrance of substrates, ultimately reducing the activities of α-glucosidase and α-amylase. This study has demonstrated that Hsp-Cu(II) may be a promising candidate of functional nutritional additive and medicine for the prevention of diabetes.

Why Do Dietary Flavonoids Have a Promising Effect as Enhancers of Anthracyclines? Hydroxyl Substituents, Bioavailability and Biological Activity

Anthracyclines currently play a key role in the treatment of many cancers, but the limiting factor of their use is the widespread phenomenon of drug resistance and untargeted toxicity. Flavonoids have pleiotropic, beneficial effects on human health that, apart from antioxidant activity, are currently considered small molecules-starting structures for drug development and enhancers of conventional therapeutics. This paper is a review of the current and most important data on the participation of a selected series of flavonoids: chrysin, apigenin, kaempferol, quercetin and myricetin, which differ in the presence of an additional hydroxyl group, in the formation of a synergistic effect with anthracycline antibiotics. The review includes a characterization of the mechanism of action of flavonoids, as well as insight into the physicochemical parameters determining their bioavailability in vitro. The crosstalk between flavonoids and the molecular activity of anthracyclines discussed in the article covers the most important common areas of action, such as (1) disruption of DNA integrity (genotoxic effect), (2) modulation of antioxidant response pathways, and (3) inhibition of the activity of membrane proteins responsible for the active transport of drugs and xenobiotics. The increase in knowledge about the relationship between the molecular structure of flavonoids and their biological effect makes it possible to more effectively search for derivatives with a synergistic effect with anthracyclines and to develop better therapeutic strategies in the treatment of cancer.

A Review of The Application of Spectroscopy to Flavonoids from Medicine and Food Homology Materials

Medicinal and food homology materials are a group of drugs in herbal medicine that have nutritional value and can be used as functional food, with great potential for development and application. Flavonoids are one of the major groups of components in pharmaceutical and food materials that have been found to possess a variety of biological activities and pharmacological effects. More and more analytical techniques are being used in the study of flavonoid components of medicinal and food homology materials. Compared to traditional analytical methods, spectroscopic analysis has the advantages of being rapid, economical and free of chemical waste. It is therefore widely used for the identification and analysis of herbal components. This paper reviews the application of spectroscopic techniques in the study of flavonoid components in medicinal and food homology materials, including structure determination, content determination, quality identification, interaction studies, and the corresponding chemometrics. This review may provide some reference and assistance for future studies on the flavonoid composition of other medicinal and food homology materials.

Comparative Study of Useful Compounds Extracted from Lophanthus anisatus by Green Extraction

Essential oils were obtained from different parts of Agastache foeniculum (Lophanthus anisatus) plants by means of extraction: green extraction using hydro-distillation (HD) and bio-solvent distillation, BiAD, discontinuous distillation, and supercritical fluid extraction, in two stages: (1) with CO₂, and (2) with CO₂ and ethanol co-solvent. The extraction yields were determined. The yield values varied for different parts of the plant, as well as the method of extraction. Thus, they had the values of 0.62 ± 0.020 and 0.92 ± 0.015 g/100 g for the samples from the whole aerial plant, 0.75 ± 0.008 and 1.06 ± 0.005 g/100 g for the samples of leaves, and 1.22 ± 0.011 and 1.60 ± 0.049 g/100 g for the samples of flowers for HD and BiAD, respectively. The yield values for supercritical fluid extraction were of 0.94 ± 0.010 and 0.32 ± 0.007 g/100 g for the samples of whole aerial plant, 0.9 ± 0.010 and 1.14 ± 0.008 g/100 g for the samples of leaves, and 1.94 ± 0.030 and 0.57 ± 0.003 g/100 g for the samples of flowers, in the first and second stages, respectively. The main components of Lophanthus anisatus were identified as: estragon, limonene, eugenol, chavicol, benzaldehyde, and pentanol. The essential oil from Agatache foeniculum has antimicrobial effects against Staphylococcus aureus, the Escherichia coli and Pseudomonas aeruginosa. Acclimatization of Lophantus anisatus in Romania gives it special qualities by concentrating components such as: estragole over 93%, limonene over 8%, especially in flowers; and chavicol over 14%, estragole over 30%, eugenol and derivatives (methoxy eugenol, methyl eugenol, etc.) over 30% and phenyl ether alcohol over 20% in leaves. As a result of the research carried out, it was proven that Lophanthus anisatus can be used as a medicinal plant for many diseases, it can be used as a spice and preservative for various foods, etc.

Current Use of Fenton Reaction in Drugs and Food

Iron is the most abundant mineral in the human body and plays essential roles in sustaining life, such as the transport of oxygen to systemic organs. The Fenton reaction is the reaction between iron and hydrogen peroxide, generating hydroxyl radical, which is highly reactive and highly toxic to living cells. “Ferroptosis”, a programmed cell death in which the Fenton reaction is closely involved, has recently received much attention. Furthermore, various applications of the Fenton reaction have been reported in the medical and nutritional fields, such as cancer treatment or sterilization. Here, this review summarizes the recent growing interest in the usefulness of iron and its biological relevance through basic and practical information of the Fenton reaction and recent reports.

Copper-induced tumor cell death mechanisms and antitumor theragnostic applications of copper complexes

Recent studies found that unbalanced copper homeostasis affect tumor growth, causing irreversible damage. Copper can induce multiple forms of cell death, including apoptosis and autophagy, through various mechanisms, including reactive oxygen species accumulation, proteasome inhibition, and antiangiogenesis. Hence, copper in vivo has attracted tremendous attention and is in the research spotlight in the field of tumor treatment. This review first highlights three typical forms of copper's antitumor mechanisms. Then, the development of diverse biomaterials and nanotechnology allowing copper to be fabricated into diverse structures to realize its theragnostic action is discussed. Novel copper complexes and their clinical applications are subsequently described.