Prooxidant property of green tea polyphenols epicatechin and epigallocatechin-3-gallate: implications for anticancer properties

Synthesis and evaluation of water-soluble antioxidants derived from l-carnosine and syringaldehyde (or vanillin)

Polyphenols are well known for their health-related benefits, including antioxidant activities, but most of them are hydrophobic, decreasing their bioavailability. This study reports water-soluble trimeric antioxidants synthesized with l-carnosine and the hydrophobic ortho-methoxy-substituted phenolic unit, syringaldehyde or vanillin. In the DPPH assay, carnosine-syringaldehyde (7.5 μM) and carnosine-vanillin (19 μM) derivatives showed much lower IC50 values than ascorbic acid (27.5 μM) and sodium ascorbate (30.5 μM) standards. According to the AAPH assay, carnosine-syringaldehyde and carnosine-vanillin protect DNA at concentrations as low as 6.5 μM and 26 μM, respectively, while both sodium ascorbate and ascorbic acid protected until 52 μM. Another notable property of these antioxidants is that they can protect DNA well against hydroxyl radicals, produced via the Fenton reaction: carnosine-syringaldehyde showed DNA protection at all tested concentrations (833-1.6 μM), but the protection was slightly weaker between 26 and 1.6 μM. Carnosine-vanillin showed strong protection in the 833-104 μM range and some protection between 52 and 3.2 μM. Conversely, both sodium ascorbate and ascorbic acid did not protect DNA at any tested concentrations. In the pro-oxidant potential assessments, the synthesized antioxidants did not show any pro-oxidant effects at all tested concentrations. In comparison, sodium ascorbate at 833-13 μM and ascorbic acid at 833-52 μM both exhibited severe pro-oxidant effects. Our study highlights the significance of ortho-methoxy groups in antioxidants. Their electron-donating properties enhance antioxidant activities, while their steric bulk hinders the binding of transition metal ions to the phenolic hydroxyl group, thereby preventing pro-oxidant effects. The hydrophobicity of ortho-methoxy substituted phenols can be mitigated by attaching them to a highly water-soluble scaffold containing functional groups that can facilitate charge formation in the end products, such as carnosine.

Phytochemical Characterization, Prooxidant, Antiproliferative and Anti-Inflammatory Potential of Meyna spinosa Roxb. Ex Link Ripe Fruit

This study highlights the prooxidant, antiproliferative and anti-inflammatory potential of ripe Meyna spinosa Roxb. Ex Link fruit extracts. Chemical analysis by high-resolution mass spectrometry and AAS identified compounds like ursolic acid, oleanolic acid, lupeol, betulin, scopoletin, phloroglucinol and secoxyloganin and micro-elements like iron, copper, zinc and manganese. Antioxidant assays (DPPH, FRAP, metal chelation, reaction oxygen species) revealed that the M. spinosa ethyl acetate extract (MSEA) had higher phenolic (37.83 mg GAE/g DW) and flavonoid (60.22 mg QE/g DW) content, showing strong antioxidant activity (IC50 of 7.5 µg/mL), while the M. spinosa methanolic extract (MSM) exhibited higher FRAP activity (39.666 µg AAE/g DW). Prooxidant activity was demonstrated through Trolox and NADH oxidation. Both extracts exhibited antiproliferative effects in A549 and MCF7 cancer cells with an increase in concentration and time. Anti-inflammatory effects were observed by reductions in nitric oxide, COX-2, IL-6 and TNF-α levels in lipopolysaccharides-stimulated RAW 264.7 and THP-1 cells. Nitrite levels reduced from 23.778 to 5.222 µM, COX-2 levels from 51.136 to 9.581 µg/mL, IL-6 levels from 62.728 ng/mL to 13.463 pg/mL and TNF-α level from 474.890 to 143.115 pg/mL. In vivo, MSEA reduced carrageenan-induced paw oedema by 23.45%.

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.

Fine-Scale Dietary Polyphenol Intake Is Associated with Systemic and Gastrointestinal Inflammation in Healthy Adults

BACKGROUND

Polyphenols are dietary bioactive compounds, many of which have anti-inflammatory properties. However, information on the intake of dietary polyphenols at the class and compound levels and their associations with gastrointestinal (GI) and systemic inflammation is lacking.

OBJECTIVES

Estimate dietary polyphenol intake in healthy adults and examine its relationship with GI and systemic inflammation markers.

METHODS

Healthy adults (n = 350) completed the United States Department of Agriculture Nutritional Phenotyping Study, an observational, cross-sectional study balanced for age, sex, and body mass index. Dietary intake, assessed via multiple 24-h recalls, was ingredientized and mapped to FooDB, a comprehensive food composition database. Dietary polyphenol intake (total, class, compound) was estimated and examined for its relationship to GI and systemic inflammation markers using linear models and random forest regressions.

RESULTS

Mean total polyphenol intake was ∼914 mg/1000 kcal/d with flavonoids as the greatest class contributor (495 mg/1000 kcal/d). Tea, coffee, and fruits were among the largest food contributors to polyphenol intake. Total polyphenol intake was negatively associated with the GI inflammation marker, fecal calprotectin (β = -0.004, P = 0.04). At the class level, polyphenols categorized as prenol lipids (β = -0.94, P < 0.01) and phenylpropanoic acids (β = -0.92, P < 0.01) were negatively associated with plasma lipopolysaccharide-binding protein, a proxy for GI permeability. Food sources of these two classes included mainly olive products. We further detected a positive association between C-reactive protein and polyphenols in the "cinnamic acids and derivatives" class using hierarchical feature engineering and random forest modeling.

CONCLUSIONS

Even in healthy adults, dietary polyphenol intake was negatively associated with GI inflammation and intake of prenol lipids and phenylpropanoic acids was negatively associated with GI permeability. Relationships between polyphenol intake and inflammatory outcomes varied with the resolution-total, class, compound-of polyphenol intake, suggesting a nuanced impact of polyphenols on GI and systemic inflammation. This trial was registered at clinicaltrials.gov as NCT02367287.

Arsenic Induced Oxidative Neural-Damages in Rat are Mitigated by Tea-Leave Extract via MMPs and AChE Inactivation, Shown by Molecular Docking and in Vitro Studies with Pure Theaflavin and AChE

BACKGROUND

Chronic arsenic-exposure causes neuromuscular disorders and other health anomalies. Damage to DNA and cytoskeletal/extracellular matrix is brought on by reactive-oxygen-species (ROS)-induced intrinsic antioxidant depletion (thiols/urate). Therapeutic chelating-agents have multiple side-effects.

OBJECTIVES

The protection of (Camellia sinensis) tea-extract and role of uric-acid (UA) or allopurinol (urate-depletor) on arsenic-toxicity were verified in rat model.

METHODS

Camellia sinensis (CS dry-leaves), UA or allopurinol was supplemented to arsenic-intoxicated rats for 4-weeks. Purified theaflavins and their galloyl-ester were tested in-vitro on pure AChE (acetylcholinesterase) and their PDB/PubChem 3-D structures were utilized for in-silico binding studies. The primary chemical components were evaluated from CS-extracts. Biochemical analysis, PAGE-zymogram, DNA-stability comet analysis, HE-staining was performed in arsenic-exposed rat brain tissues.

RESULTS

Animals exposed to arsenic showed symptoms of erratic locomotion, decreased intrinsic antioxidants (catalase/SOD1/uric acid), increased AChE, and malondialdehyde. Cerebellar and cerebrum tissue damages were shown with increased levels of matrix-metalloprotease (MMP2/9) and DNA damage (comets). Allopurinol- supplemented group demonstrated somewhat similar biochemical responses. In the CS-group brain tissues especially cerebellum is considerably protected which is evident from endogenous antioxidant and DNA and cytoskeleton protection with concomitant inactivation of MMPs and AChE. Present study indicates theaflavin-digallate (TFDG) demonstrated the highest inhibition of purified AChE (IC50 = 2.19 µg/ml with the lowest binding free-energy; -369.87 kcal/mol) followed by TFMG (IC50 = 3.86 µg/ml, -347.06 kcal/mol) suggesting their possible restoring effects of cholinergic response.

CONCLUSIONS

Favorable responses in UA-group and adverse outcome in allo-group justify the neuro-protective effects of UA as an endogenous antioxidant. Role of flavon-gallate in neuro protection mechanism may be further studied.

(-)-Epicatechin metabolites as a GPER ligands: a theoretical perspective

Diet habits and nutrition quality significantly impact health and disease. Here is delve into the intricate relationship between diet habits, nutrition quality, and their direct impact on health and homeostasis. Focusing on (-)-Epicatechin, a natural flavanol found in various foods like green tea and cocoa, known for its positive effects on cardiovascular health and diabetes prevention. The investigation encompasses the absorption, metabolism, and distribution of (-)-Epicatechin in the human body, revealing a diverse array of metabolites in the circulatory system. Notably, (-)-Epicatechin demonstrates an ability to activate nitric oxide synthase (eNOS) through the G protein-coupled estrogen receptor (GPER). While the precise role of GPER and its interaction with classical estrogen receptors (ERs) remains under scrutiny, the study employs computational methods, including density functional theory, molecular docking, and molecular dynamics simulations, to assess the physicochemical properties and binding affinities of key (-)-Epicatechin metabolites with GPER. DFT analysis revealed distinct physicochemical properties among metabolites, influencing their reactivity and stability. Rigid and flexible molecular docking demonstrated varying binding affinities, with some metabolites surpassing (-)-Epicatechin. Molecular dynamics simulations highlighted potential binding pose variations, while MMGBSA analysis provided insights into the energetics of GPER-metabolite interactions. The outcomes elucidate distinct interactions, providing insights into potential molecular mechanisms underlying the effects of (-)-Epicatechin across varied biological contexts.

The Role of Polyphenolic Antioxidants from Tea and Rosemary in the Hydroxyl Radical Oxidation of N-Acetyl Alanine

In dead biological tissues such as human hair, the ability of antioxidants to minimise autoxidation is determined by their chemical reactions with reactive oxygen species. In order to improve our understanding of factors determining such antioxidant properties, the mechanistic chemistry of four phenolic antioxidants found in tea and rosemary extracts (epicatechin, epigallocatechin gallate, rosmarinic and carnosic acids) has been investigated. The degradation of N-acetyl alanine by photochemically generated hydroxyl radicals was used as a model system. A relatively high concentration of the antioxidants (0.1 equivalent with respect to the substrate) tested the ability of the antioxidants to intercept both initiating hydroxyl radicals (preventive action) and propagating peroxyl radicals (chain-breaking action). LC-MS data showed the formation of hydroxylated derivatives, quinones and hydroperoxides of the antioxidants. The structure of the assignment was aided by deuterium exchange experiments. Tea polyphenolics (epicatechin and epigallocatechin gallate) outperformed the rosemary compounds in preventing substrate degradation and were particularly effective in capturing the initiating radicals. Carnosic acid was suggested to act mostly as a chain-breaking antioxidant. All of the antioxidants except for rosmarinic acid generated hydroperoxides which was tentatively ascribed to the insufficient lability of the benzylic C-H bond of rosmarinic acid.

Rowanberry-A Source of Bioactive Compounds and Their Biopharmaceutical Properties

After a period of intense development in the synthesis pharmaceutical industry, plants are making a comeback in the public focus as remedies or therapeutic adjuvants and in disease prevention and ensuring the wellbeing and equilibrium of the human body. Plants are being recommended more and more in alimentation, in their natural form, or as extracts, supplements or functional aliments. People, in general, are in search of new sources of nutrients and phytochemicals. As a result, scientific research turns to lesser known and used plants, among them being rowanberries, a species of fruit very rich in nutrients and underused due to their bitter astringent taste and a lack of knowledge regarding the beneficial effects of these fruit. Rowan fruits (rowanberries) are a rich source of vitamins, polysaccharides, organic acids and minerals. They are also a source of natural polyphenols, which are often correlated with the prevention and treatment of modern world diseases. This article presents the existing data regarding the chemical composition, active principles and biopharmaceutical properties of rowan fruits and the different opportunities for their usage.

Oxidative Stress, Inflammation, Gut Dysbiosis: What Can Polyphenols Do in Inflammatory Bowel Disease?

Inflammatory bowel disease (IBD) is a long-term, progressive, and recurrent intestinal inflammatory disorder. The pathogenic mechanisms of IBD are multifaceted and associated with oxidative stress, unbalanced gut microbiota, and aberrant immune response. Indeed, oxidative stress can affect the progression and development of IBD by regulating the homeostasis of the gut microbiota and immune response. Therefore, redox-targeted therapy is a promising treatment option for IBD. Recent evidence has verified that Chinese herbal medicine (CHM)-derived polyphenols, natural antioxidants, are able to maintain redox equilibrium in the intestinal tract to prevent abnormal gut microbiota and radical inflammatory responses. Here, we provide a comprehensive perspective for implementing natural antioxidants as potential IBD candidate medications. In addition, we demonstrate novel technologies and stratagems for promoting the antioxidative properties of CHM-derived polyphenols, including novel delivery systems, chemical modifications, and combination strategies.

Pathophysiological basis and promise of experimental therapies for Gulf War Illness, a chronic neuropsychiatric syndrome in veterans

This article describes the pathophysiology and potential treatments for Gulf War Illness (GWI), which is a chronic neuropsychiatric illness linked to a combination of chemical exposures experienced by service personnel during the first Gulf War in 1991. However, there is currently no effective treatment for veterans with GWI. The article focuses on the current status and efficacy of existing therapeutic interventions in preclinical models of GWI, as well as potential perspectives of promising therapies. GWI stems from changes in brain and peripheral systems in veterans, leading to neurocognitive deficits, as well as physiological and psychological effects resulting from multifaceted changes such as neuroinflammation, oxidative stress, and neuronal damage. Aging not only renders veterans more susceptible to GWI symptoms, but also attenuates their immune capabilities and response to therapies. A variety of experimental models are being used to investigate the pathophysiology and develop therapies that have the ability to alleviate devastating symptoms. Over two dozen therapeutic interventions targeting neuroinflammation, mitochondrial dysfunction, neuronal injury, and neurogenesis are being tested, including agents such as curcumin, curcumin nanoparticles, monosodium luminol, melatonin, resveratrol, fluoxetine, rolipram, oleoylethanolamide, ketamine, levetiracetam, nicotinamide riboside, minocycline, pyridazine derivatives, and neurosteroids. Preclinical outcomes show that some agents have promise, including curcumin, resveratrol, and ketamine, which are being tested in clinical trials in GWI veterans. Neuroprotectants and other compounds such as monosodium luminol, melatonin, levetiracetam, oleoylethanolamide, and nicotinamide riboside appear promising for future clinical trials. Neurosteroids have been shown to have neuroprotective and disease-modifying properties, which makes them a promising medicine for GWI. Therefore, accelerated clinical studies are urgently needed to evaluate and launch an effective therapy for veterans displaying GWI.

Soy Isoflavones Induce Cell Death by Copper-Mediated Mechanism: Understanding Its Anticancer Properties

Cancer incidence varies around the globe, implying a relationship between food and cancer risk. Plant polyphenols are a class of secondary metabolites that have recently attracted attention as possible anticancer agents. The subclass of polyphenols, known as isoflavones, includes genistein and daidzein, which are present in soybeans and are regarded as potent chemopreventive agents. According to epidemiological studies, those who eat soy have a lower risk of developing certain cancers. Several mechanisms for the anticancer effects of isoflavones have been proposed, but none are conclusive. We show that isoflavones suppress prostate cancer cell growth by mobilizing endogenous copper. The copper-specific chelator neocuproine decreases the apoptotic potential of isoflavones, whereas the iron and zinc chelators desferroxamine mesylate and histidine do not, confirming the role of copper. Reactive oxygen species (ROS) scavengers reduce isoflavone-induced apoptosis in these cells, implying that ROS are cell death effectors. Our research also clearly shows that isoflavones interfere with the expression of the two copper transporter genes, CTR1 and ATP7A, in cancerous cells. Copper levels are widely known to be significantly raised in all malignancies, and we confirm that isoflavones can target endogenous copper, causing prooxidant signaling and, eventually, cell death. These results highlight the importance of copper dynamics within cancer cells and provide new insight into the potential of isoflavones as cancer-fighting nutraceuticals.

Chlorophyll Pigments of Olive Leaves and Green Tea Extracts Differentially Affect Their Antioxidant and Anticancer Properties

Plant-based extracts possess biological potential due to their high content of phytochemicals. Nevertheless, photosynthetic pigments (e.g., chlorophylls) that are also present in plant extracts could produce undesirable pro-oxidant activity that might cause a negative impact on their eventual application. Herein, the phenolic content of olive leaf (OLE) and green tea (GTE) extracts was assayed, and their antioxidant and anticancer activities were evaluated before and after the removal of chlorophylls. Regarding phenolic content, OLE was rich in hydroxytyrosol, tyrosol as well as oleuropein, whereas the main compounds present in GTE were gallocatechin, epigallocatechin (EGC), epigallocatechin gallate (EGCG), gallocatechin gallate, and caffeine. Interestingly, fresh extracts’ antioxidant ability was dependent on phenolic compounds; however, the elimination of chlorophyll compounds did not modify the antioxidant activity of extracts. In addition, both OLE and GTE had high cytotoxicity against HL-60 leukemic cell line. Of note, the removal of chlorophyll pigments remarkably reduced the cytotoxic effect in both cases. Therefore, our findings emphasize the remarkable antioxidant and anticancer potential of OLE and GTE and suggest that chlorophylls are of paramount importance for the tumor-killing ability of such plant-derived extracts.

Effects of some medicinal plant extracts on dermal papilla cells

INTRODUCTION

Miniaturization of the hair follicles is evident on the balding scalp. Approved medications, topical minoxidil, and oral finasteride for the treatment of alopecia sometimes come with undesirable adverse effects. The study was to examine the bioactivity of medicinal plants for finding the promising source of anti-hair loss application.

METHODS

Ten ethanolic extracts were prepared from Acacia concina (Willd.) DC., Acanthus ebracteatus Vahl, Bridelia ovata Decne, Cleome viscosa L., Cocos nucifera L., Hibiscus subdariffla L., Oryza sativa L., Terminalia chebula Retz., Tinospora crispa (L.) Hook. f. & Thomson and cytotoxic tested on dermal papilla cells using MTT assay. The effect of the extracts on cell cycle was also determined using flow cytometry technique. Anti-inflammatory activity was examined by determining IL-1β inhibition in RAW 257.4 cells. In vitro study of androgenic and 5α-reductase inhibitory activities were also determined using MTT assay and enzymatic reaction couple with liquid chromatography-mass spectrometry (LC-MS), respectively.

RESULTS

Our results revealed that only A. ebracteatus promoted dermal papilla cell proliferation and the S and G2/M phases in cell cycle. A. ebracteatus also showed inhibitory activity against 5α-reductase and testosterone in reducing cell viability of the dermal papilla. Moreover, A. ebracteatus extract strongly inhibited LPS-stimulating IL-1β production in RAW 264.7 cells in a dose-dependent manner.

CONCLUSION

Our finding indicated that the ethanolic extract of A. ebracteatus is a promising candidate for anti-hair loss treatment.

Curcumin and Its Derivatives Induce Apoptosis in Human Cancer Cells by Mobilizing and Redox Cycling Genomic Copper Ions

Turmeric spice contains curcuminoids, which are polyphenolic compounds found in the Curcuma longa plant’s rhizome. This class of molecules includes curcumin, demethoxycurcumin, and bisdemethoxycurcumin. Using prostate cancer cell lines PC3, LNCaP, DU145, and C42B, we show that curcuminoids inhibit cell proliferation (measured by MTT assay) and induce apoptosis-like cell death (measured by DNA/histone ELISA). A copper chelator (neocuproine) and reactive oxygen species scavengers (thiourea for hydroxyl radical, superoxide dismutase for superoxide anion, and catalase for hydrogen peroxide) significantly inhibit this reaction, thus demonstrating that intracellular copper reacts with curcuminoids in cancer cells to cause DNA damage via ROS generation. We further show that copper-supplemented media sensitize normal breast epithelial cells (MCF-10A) to curcumin-mediated growth inhibition, as determined by decreased cell proliferation. Copper supplementation results in increased expression of copper transporters CTR1 and ATP7A in MCF-10A cells, which is attenuated by the addition of curcumin in the medium. We propose that the copper-mediated, ROS-induced mechanism of selective cell death of cancer cells may in part explain the anticancer effects of curcuminoids.

Structure-activity assessment of flavonoids as modulators of copper transport

Flavonoids are polyphenolic small molecules that are abundant in plant products and are largely recognized for their beneficial health effects. Possessing both antioxidant and prooxidant properties, flavonoids have complex behavior in biological systems. The presented work investigates the intersection between the biological activity of flavonoids and their interactions with copper ions. Copper is required for the proper functioning of biological systems. As such, dysregulation of copper is associated with metabolic disease states such as diabetes and Wilson's disease. There is evidence that flavonoids bind copper ions, but the biological implications of their interactions remain unclear. Better understanding these interactions will provide insight into the mechanisms of flavonoids' biological behavior and can inform potential therapeutic targets. We employed a variety of spectroscopic techniques to study flavonoid-Cu(II) binding and radical scavenging activities. We identified structural moieties important in flavonoid-copper interactions which relate to ring substitution but not the traditional structural subclassifications. The biological effects of the investigated flavonoids specifically on copper trafficking were assessed in knockout yeast models as well as in human hepatocytes. The copper modulating abilities of strong copper-binding flavonoids were largely influenced by the relative hydrophobicities. Combined, these spectroscopic and biological data help elucidate the intricate nature of flavonoids in affecting copper transport and open avenues to inform dietary recommendations and therapeutic development.

Understanding the Prooxidant Action of Plant Polyphenols in the Cellular Microenvironment of Malignant Cells: Role of Copper and Therapeutic Implications

Plant derived polyphenolic compounds are considered critical components of human nutrition and have shown chemotherapeutic effects against a number of malignancies. Several studies have confirmed the ability of polyphenols to induce apoptosis and regression of tumours in animal models. However, the mechanism through which polyphenols modulate their malignant cell selective anticancer effects has not been clearly established. While it is believed that the antioxidant properties of these molecules may contribute to lowering the risk of cancer induction by causing oxidative damage to DNA, it could not be held responsible for chemotherapeutic properties and apoptosis induction. It is a well known fact that cellular copper increases within the malignant cell and in serum of patients harboring malignancies. This phenomenon is independent of the cellular origin of malignancies. Based on our own observations and those of others; over the last 30 years our laboratory has shown that cellular copper reacts with plant derived polyphenolic compounds, by a Fenton like reaction, which generates reactive oxygen species and leads to genomic DNA damage. This damage then causes an apoptosis like cell death of malignant cells, while sparing normal cells. This communication reviews our work in this area and lays the basis for understanding how plant derived polyphenols can behave as prooxidants (and not antioxidants) within the microenvironment of a malignancy (elevated copper levels) and gives rationale for their preferential cytotoxicity towards malignant cells.

The Effect of Gambier Catechin Isolate on Cervical Cancer Cell Death (HeLa Cell Lines)

BACKGROUND: Cervical cancer is the second most common type of cancer in women worldwide. Human Papilloma Virus infection on the surface of the cervix is the most common cause which can cause abnormal growth of cervical cells. AIM: This research was conducted in vitro which aims to determine whether catechin compounds can inhibit the growth and regulation of cervical cancer cells (HeLa cell line). METHODS: This is experimental research using the colourimetric assay method and qualitative observation of cervical cancer cell morphology (HeLa cell line) under a fluorescence microscope. The administration of catechin compounds was tested at different concentrations to HeLa cells, namely 1000 g/ml, 500 g/ml, 250 g/ml, 125 g/ml, 62.5 g/ml, 31.25 g/ml. RESULTS: The smallest cell viability was obtained from a concentration of 1000 g/ml which was 5.98% while the largest cell viability was found at a concentration of 31.25 g/ml, which was 40.01%. The resulting IC50 value was 22.91 g/ml. Gambier catechin compounds have very high antioxidants because they contain an IC50 value < 50 g/ml. The effect of gambier catechin compounds on HeLa cell death can be found by increasing the percentage of dead cells. The difference in the fluorescence images of HeLa cells in the experimental group was assessed based on the percentage of the number of cells that died or underwent apoptosis, which was marked by a red or orange fluorescent image. At the concentration of IC25, 31.87% of dead cells were found, the concentration of IC50 was 51.09% of dead cells, and the concentration of IC75 was 82.51% of dead cells. The test results showed that there was a significant difference in the average percentage of cells undergoing apoptosis in all study groups with p <0.05. CONCLUSION: Based on research, it can be concluded that catechin compounds could inhibit the growth and regulation of cervical cancer cells (HeLa cell line). Later, it has the potential to be developed as an anticancer candidate for cervical cancer. Keyword: Cervical cancer, Catechin, Apoptosis, HeLa cell line, Cell death.

Cryptochlorogenic acid and its metabolites ameliorate myocardial hypertrophy through a HIF1α-related pathway

Cryptochlorogenic acid (4-CQA) is a phenolic acid that has antioxidant and anti-inflammatory activities. Our preliminary study found that 4-CQA has a good effect on isoproterenol (ISO)-induced myocardial hypertrophy, while the mechanism remains largely unknown. This study aimed at delineating the metabolites and metabolic pathways of 4-CQA using liquid mass spectrometry and molecular biotechnology, exploring possible active metabolites and the mechanism of myocardial hypertrophy amelioration in H9c2 cells, and finally, investigating the pharmacokinetics of 4-CQA and its active metabolites in vivo. In summary, 56 potential effective metabolites were distinguished in rat urine, feces, plasma samples and heart tissue after intragastric administration of 4-CQA, and the main metabolic reaction types of 4-CQA included hydrogenation, methylation, glucuronidation, sulfation, hydration and their composite reactions in in vivo biotransformation. Besides, 4-CQA and its main active metabolites, caffeic acid and 4-O-feruloylquinic acid, significantly ameliorated pathological cardiac hypertrophy of H9c2 cells treated with ISO based on the Akt/mTOR/HIF-1α pathway. In addition, this study demonstrated that the prototype drugs 4-CQA and 4-O-ferulylquinic acid generally exhibit similar pharmacokinetic characteristics and caffeic acid presents relatively late peak time and low peak concentration in rats, which make them suitable candidate drugs.

The interplay between reactive oxygen species and antioxidants in cancer progression and therapy: a narrative review

Objective

To unveil the role of reactive oxygen species (ROS) and antioxidants in signaling and involvement in cancer progression and therapy.

Background

Cancer is considered one of the main causes of mortality in developed countries and expected to be more in developing countries as well. Although some cancers may develop at young age, yet almost all types of cancers are an accumulation of genetic and epigenetic cell damages. Cancer is considered a diverse collection of diseases on a cellular level rather than a single disease; and each disease has a different cause as well. ROS have been seen as harmful toxic molecules; however, they are recognized for cellular signaling capabilities. Elevated levels of ROS have protumorigenic activities; they induce cancer cell proliferation, and adaptation to hypoxia in addition to other effects like DNA damage and genetic instability. They are produced excessively by cancer cells to hyperactivate cellular transformation meanwhile increasing antioxidant capacity to avoid cell death.

Methods

We discussed peer reviewed published research work from 1987 to 2021. In this paper, we review the role of antioxidants as defensive barrier against excessive ROS levels for maintaining oxidation-reduction (redox) balance; however, antioxidant can also strive in tumor cells with their scavenging capacities and maintain protumorigenic signaling and resist the cancer cell oxidative stress and apoptosis. High doses of antioxidant compounds could be toxic to cells as they are capable of reacting with the physiological concentrations of ROS present for normal cellular processes and signaling.

Conclusions

Maintaining cellular redox homeostasis is vital for healthy biological system. Therefore, therapeutic modalities for cancer including antioxidants and ROS management should be used at certain doses to target specific redox pathways involved in cancer progression without disrupting the overall redox balance in normal cells.

Effects of phenolic acids and quercetin-3-O-rutinoside on the bitterness and astringency of green tea infusion

Phenolic acids are important taste components in green tea. The aim of this study was to analyze the taste characteristics of phenolic acids and their influence on the bitterness and astringency of green tea by sensory evaluation and chemical determination. The major tea phenolic acids and quercetin-3-O-rutinoside (Que-rut) were significantly positively correlated with the bitterness (r = 0.757, p < 0.01; r = 0.605, p < 0.05) and astringency (r = 0.870, p < 0.01; r = 0.576, p < 0.05) of green tea infusion. The phenolic acids have a sour and astringent taste, whereas Que-rut has a mild astringent taste. Phenolic acids and Que-rut can increase the bitterness of epigallocatechin gallate (EGCG). However, these components behaved differently for astringency on EGCG. Gallic acid (GA) enhances the astringency throughout all the concentrations in this study. While it seemed to be double effects of caffeic acid (CA), chlorogenic acid (CGA), and Que-rut on that, i.e., the inhibition at lower concentrations (CA: 0–0.2 mM; CGA: 0–0.2 mM; Que-rut: 0–0.05 mM) but enhancement at higher ones. The phenolic acids and Que-rut interacted synergistically with tea infusion and as their concentration increased, the synergistic enhancement of the bitterness and astringency of tea infusion increased. These findings help provide a theoretical basis for improving the taste of middle and green tea.

Natural Products as Sources of Multitarget Compounds: Advances in the Development of Ferulic Acid as Multitarget Therapeutic

Nature has provided therapeutic substances for millennia, with many valuable medications derived from plant sources. Multitarget drugs become essential in the management of various disorders including hepatic disorders, neurological disorders, diabetes, and carcinomas. Ferulic acid is a significant potential therapeutic agent, which is easily available at low cost, possesses a low toxicity profile, and has minimum side effects. Ferulic acid exhibits various therapeutic actions by modulation of various signal transduction pathways such as Nrf2, p38, and mTOR. The actions exhibited by ferulic acid include anti-apoptosis, antioxidant, anti-inflammatory, antidiabetic, anticarcinogenic, hepatoprotection, cardioprotection, activation of transcriptional factors, expression of genes, regulation of enzyme activity, and neuroprotection, which further help in treating various pathophysiological conditions such as cancer, skin diseases, brain disorders, diabetes, Parkinson's disease, Alzheimer's disease, hypoxia, hepatic disorders, H1N1 flu, and viral infections. The current review focuses on the significance of natural products as sources of multitarget compounds and a primary focus has been made on ferulic acid and its mechanism, role, and protective action in various ailments.

Alcohol and Head and Neck Cancer: Updates on the Role of Oxidative Stress, Genetic, Epigenetics, Oral Microbiota, Antioxidants, and Alkylating Agents

Head and neck cancer (HNC) concerns more than 890,000 patients worldwide annually and is associated with the advanced stage at presentation and heavy outcomes. Alcohol drinking, together with tobacco smoking, and human papillomavirus infection are the main recognized risk factors. The tumorigenesis of HNC represents an intricate sequential process that implicates a gradual acquisition of genetic and epigenetics alterations targeting crucial pathways regulating cell growth, motility, and stromal interactions. Tumor microenvironment and growth factors also play a major role in HNC. Alcohol toxicity is caused both directly by ethanol and indirectly by its metabolic products, with the involvement of the oral microbiota and oxidative stress; alcohol might enhance the exposure of epithelial cells to carcinogens, causing epigenetic modifications, DNA damage, and inaccurate DNA repair with the formation of DNA adducts. Long-term markers of alcohol consumption, especially those detected in the hair, may provide crucial information on the real alcohol drinking of HNC patients. Strategies for prevention could include food supplements as polyphenols, and alkylating drugs as therapy that play a key role in HNC management. Indeed, polyphenols throughout their antioxidant and anti-inflammatory actions may counteract or limit the toxic effect of alcohol whereas alkylating agents inhibiting cancer cells' growth could reduce the carcinogenic damage induced by alcohol. Despite the established association between alcohol and HNC, a concerning pattern of alcohol consumption in survivors of HNC has been shown. It is of primary importance to increase the awareness of cancer risks associated with alcohol consumption, both in oncologic patients and the general population, to provide advice for reducing HNC prevalence and complications.

Genoprotective Effect of Some Flavonoids against Genotoxic Damage Induced by X-rays In Vivo: Relationship between Structure and Activity

Flavonoids constitute a group of polyphenolic compounds characterized by a common gamma-benzo- pyrone structure considered in numerous biological systems to possess antioxidant capacity. Among the different applications of flavonoids, its genoprotective capacity against damage induced by ionizing radiation stands out, which has been related to antioxidant activity and its chemical structure. In this study, we determined the frequency of appearance of micronucleus in vivo by means of the micronucleus assay. This was conducted in mice treated with different flavonoids before and after exposure to 470 mGy X-rays; thereafter, their bone marrow polychromatophilic erythrocytes were evaluated to establish the structural factors enhancing the observed genoprotective effect. Our results in vivo show that the presence of a monomeric flavan-3-ol type structure, with absence of carbonyl group in position C4 of ring C, absence of conjugation between the carbons bearing the C2 = C3 double bond and the said ring, presence of a catechol group in ring B and characteristic hydroxylation in positions 5 and 7 of ring A are the structural characteristics that determine the highest degree of genoprotection. Additionally, a certain degree of polymerization of this flavonoid monomer, but maintaining significant levels of monomers and dimers, contributes to increasing the degree of genoprotection in the animals studied at both times of their administration (before and after exposure to X-rays).

Aqueous Extract of Cocoa Phenolic Compounds Protects Differentiated Neuroblastoma SH-SY5Y Cells from Oxidative Stress

Cocoa is a rich source of polyphenols, especially flavanols and procyanidin oligomers, with antioxidant properties, providing protection against oxidation and nitration. Cocoa phenolic compounds are usually extracted with methanol/ethanol solvents in order to obtain most of their bioactive compounds; however, aqueous extraction seems more representative of the physiological conditions. In this study, an aqueous extract of cocoa powder has been prepared and chemically characterized, and its potential protective effect against chemically-induced oxidative stress has been tested in differentiated human neuroblastoma SH-SY5Y cells. Neuronal-like cultured cells were pretreated with realistic concentrations of cocoa extract and its major monomeric flavanol component, epicatechin, and then submitted to oxidative stress induced by a potent pro-oxidant. After one hour, production of reactive oxygen species was evaluated by two different methods, flow cytometry and in situ fluorescence by a microplate reader. Simultaneously, reduced glutathione and antioxidant defense enzymes glutathione peroxidase and glutathione reductase were determined and the results used for a comparative analysis of both ROS (reactive oxygen species) methods and to test the chemo-protective effect of the bioactive products on neuronal-like cells. The results of this approach, never tested before, validate both analysis of ROS and indicate that concentrations of an aqueous extract of cocoa phenolics and epicatechin within a physiological range confer a significant protection against oxidative insult to neuronal-like cells in culture.

Biological Actions and Molecular Mechanisms of Sambucus nigra L. in Neurodegeneration: A Cell Culture Approach

Sambucus nigra flowers (elderflower) have been widely used in traditional medicine for the relief of early symptoms of common cold. Its chemical composition mainly consists of polyphenolic compounds such as flavonoids, hydroxycinnamic acids, and triterpenes. Although the antioxidant properties of polyphenols are well known, the aim of this study is to assess the antioxidant and protective potentials of Sambucus nigra flowers in the human neuroblastoma (SH-SY5Y) cell line using different in vitro approaches. The antioxidant capacity is first evaluated by the oxygen radical absorbance capacity (ORAC) and the free radical scavenging activity (DPPH) methods. Cell viability is assessed by the crystal violet method; furthermore, the intracellular ROS formation (DCFH-DA method) is determined, together with the effect on the cell antioxidant defenses: reduced glutathione (GSH) and antioxidant enzyme activities (GPx, GR). On the other hand, mTORC1 hyperactivation and autophagy blockage have been associated with an increase in the formation of protein aggregates, this promoting the transference and expansion of neurodegenerative diseases. Then, the ability of Sambucus nigra flowers in the regulation of mTORC1 signaling activity and the reduction in oxidative stress through the activation of autophagy/mitophagy flux is also examined. In this regard, search for different molecules with a potential inhibitory effect on mTORC1 activation could have multiple positive effects either in the molecular pathogenic events and/or in the progression of several diseases including neurodegenerative ones.

Goji berry (Lycium barbarum L.) juice reduces lifespan and premature aging of Caenorhabditis elegans: Is it safe to consume it?

Goji berry fruit is considered a healthy food. However, studies on its effects on aging and safety are rare. This study is the first to evaluate the effects of goji berry juice (GBJ) on oxidative stress, metabolic markers, and lifespan of Caenorhabditis elegans. GBJ caused toxicity, reduced the lifespan of C. elegans by 50%, and increased the reactive oxygen species (ROS) production by 45-50% at all tested concentrations (1-20 mg/µL) of GBJ. Moreover, the highest concentration of GBJ increased lipid peroxidation by 80% and altered the antioxidant enzymes. These effects could be attributed to a pro-oxidant effect induced by GBJ polyphenols and carotenoids. Moreover, GBJ increased lipofuscin, glucose levels, number of apoptotic bodies, and lipase activity. The use of mutant strains demonstrated that these effects observed in the worms treated with GBJ were not associated with the Daf-16/FOXO or SKN-1 pathways. Our findings revealed that GBJ (mainly the highest concentration) exerted toxic effects and promoted premature aging in C. elegans. Therefore, its consumption should be carefully considered until further studies in mammals are conducted.

Available technologies on improving the stability of polyphenols in food processing

Polyphenols are the most important phytochemicals in our diets and have received great attention due to their broad benefits for human health by suppressing oxidative stress and playing a protective role in preventing different pathologies such as cardiovascular disease, cancer, diabetes, and obesity. The stability of polyphenols depends on their environments of processing and storage, such as pH and temperature. A wide range of technologies has been developed to stabilize polyphenols during processing. This review will provide an overview of the stability of polyphenols in relation to their structure, the factors impacting the stability of polyphenols, the new products deriving from unstable polyphenols, and the effect of a series of technologies for the stabilization of polyphenols, such as chemical modification, nanotechnology, lyophilization, encapsulation, cold plasma treatment, polyphenol–protein interaction, and emulsion as a means of improving stability. Finally, the effects of cooking and storage on the stability of polyphenols were discussed.

Maclurin exerts anti-cancer effects in human osteosarcoma cells via prooxidative activity and modulations of PARP, p38, and ERK signaling

Maclurin [(3,4-dihydroxyphenyl)-(2,4,6-trihydroxyphenyl) methanone] is a natural compound that can be extracted from white mulberry(Morus alba) and purple mangosteen(Garcinia mangostana). Maclurin is known for its dual-sided effect on reactive oxygen species (ROS). Osteosarcoma is a primary malignant tumor of the bone and is one of the most aggressive cancers. It is common especially in children and young adults and can progress into highly metastatic cancer. In this study, we investigated the anti-cancer effects of maclurin on U2OS human osteosarcoma cells. The results indicated that maclurin exerts prooxidative effects and induces apoptosis via capase-3-independent PARP regulation in U2OS human osteosarcoma cells. Maclurin also inhibits the migration of U2OS human osteosarcoma cells. Maclurin modulates two of the three major mitogen-activated protein kinases that are closely linked with cancer metastasis; that is, it activates p38 and inactivates Extracellular signal-regulated kinase. The apoptosis-inducing effects of maclurin on U2OS osteosarcoma cells were diminished by additional treatment with antioxidant N-acetyl cysteine (NAC), but the migration-inhibiting effect was not affected by NAC treatment. This further suggested the only apoptosis-inducing effect of maclurin may be strongly related to its prooxidative activity. Taken together, these results suggested that maclurin may be a strong candidate molecule as an anti-osteosarcoma agent.

Ingredient-Dependent Extent of Lipid Oxidation in Margarine

This study reports the impact of margarine-representative ingredients on its oxidative stability and green tea extract as a promising antioxidant in margarine. Oil-in-water emulsions received much attention regarding factors that influence their oxidative stability, however, water-in-oil emulsions have only been scarcely investigated. Margarine, a widely consumed water-in-oil emulsion, consists of 80-90% fat and is thermally treated when used for baking. As different types of margarine contain varying additives, their impact on the oxidative stability of margarine during processing is of pressing importance. Thus, the influence of different ingredients, such as emulsifiers, antioxidants, citric acid, β-carotene and NaCl on the oxidative stability of margarine, heated at 80 °C for 1 h to accelerate lipid oxidation, was analyzed by the peroxide value and oxidation induction time. We found that monoglycerides influenced lipid oxidation depending on their fatty acyl chain. α-Tocopheryl acetate promoted lipid oxidation, while rosemary and green tea extract led to the opposite. Whereas green tea extract alone showed the most prominent antioxidant effect, combinations of green tea extract with citric acid, β-carotene or NaCl increased lipid oxidation in margarine. Complementary, NMR data suggested that polyphenols in green tea extracts might decrease lipid mobility at the surface of the water droplets, which might lead to chelating of transition metals at the interface and decreasing lipid oxidation.

Pomegranate juice rescues developmental, neurobehavioral and biochemical disorders in aluminum chloride-treated male mice

PURPOSE

Aluminum (Al) is a harmful metal to organisms and is capable of entering the human body in multiple ways, such as through drinking, breathing, deodorant use, and vaccination. This study examined the prospective toxicity of Al and the protective attributes of pomegranate juice (PJ) on neurobehavioral and biochemical parameters of male mice.

METHODS

Six groups of male mice were treated for 35 days with 20 % PJ (group II), 40 % PJ (group III), 400 mg/kg Al (group IV), Al + 20 % PJ (group V), Al + 40 % PJ (group VI) or tap water (control, group I). Behavioral assessments were conducted for learning and memory evaluations at the end of experiment. In addition, the forebrain was isolated for biochemical analysis.

RESULTS

The exposure of male mice to Al decreased learning and memory retention in the shuttle box, Morris water-maze and T-Maze tests. Biochemical analysis revealed significant depletions in neurotransmitters including DA, 5-HT and AChE and oxidative proteins including GSH, GST, CAT and SOD and increased TBARES levels in Al-treated mice compared to untreated mice. Pomegranate juice provided protection against these effects after Al exposure by ameliorating learning and memory retention and oxidative state in a dose-independent manner.

CONCLUSION

Our data demonstrated that Al exposure caused behavioral and biochemical disorders. Pomegranate juice in lower dose has beneficial properties for health and can be used as a source of antioxidants to reduce the toxicity of Al and other substances.

Arsenal of Phytochemicals to Combat Against Arsenic-Induced Mitochondrial Stress and Cancer

Significance: Phytochemicals are important dietary constituents with antioxidant properties. They affect various signaling pathways involved in the overall maintenance of interior milieu of the cell. Arsenic, an environmental toxicant, is well known for its deleterious consequences, such as various diseases, including cancers in humans. Mitochondria are the cell's powerhouse that fuel all metabolic energy requirements. Dysfunctional mitochondria due to stressors may lead to abnormal functioning of the organelle, hampering the crucial cellular cross talks and ultimately leading to cancer. Application of phytochemicals against arsenic-induced mitochondrial disorders may be a preventive measure to counteract the ruinous impacts of the metalloid. Recent Advances: In recent years, extensive research on the role of mitochondria in cancer gives a better understanding of the areas the organelle covers in maintaining a healthy cell or in inducing carcinogenicity. Detailed knowledge of the mitochondrial governances would enable researchers to administer numerous phytochemicals to ameliorate altered oxidative phosphorylation, mitochondrial membrane potential (MMP), mitochondrial oxidative stress, unfolded protein response, glycolysis, or even apoptosis. Critical Issues: In this review, we have addressed how various phytochemicals belonging to diverse classes combat against arsenic-induced mitochondrial oxidative stress, depletion of MMP, cell cycle abrogation, apoptosis, glycolytic damages, oncogenic regulations, chaperones, mitochondrial complexes, and mitochondrial membrane pore formation in both in vitro and in vivo models. Future Directions: Insightful application of mitoprotective phytochemicals against arsenic-induced mitochondrial oxidative stress and carcinogenesis may guide researchers to develop preclinical chemopreventive agents to fight arsenic toxicity in humans.

Redox Potential of Antioxidants in Cancer Progression and Prevention

The benevolent and detrimental effects of antioxidants are much debated in clinical trials and cancer research. Several antioxidant enzymes and molecules are overexpressed in oxidative stress conditions that can damage cellular proteins, lipids, and DNA. Natural antioxidants remove excess free radical intermediates by reducing hydrogen donors or quenching singlet oxygen and delaying oxidative reactions in actively growing cancer cells. These reducing agents have the potential to hinder cancer progression only when administered at the right proportions along with chemo-/radiotherapies. Antioxidants and enzymes affect signal transduction and energy metabolism pathways for the maintenance of cellular redox status. A decline in antioxidant capacity arising from genetic mutations may increase the mitochondrial flux of free radicals resulting in misfiring of cellular signalling pathways. Often, a metabolic reprogramming arising from these mutations in metabolic enzymes leads to the overproduction of so called ’oncometabolites’ in a state of ‘pseudohypoxia’. This can inactivate several of the intracellular molecules involved in epigenetic and redox regulations, thereby increasing oxidative stress giving rise to growth advantages for cancerous cells. Undeniably, these are cell-type and Reactive Oxygen Species (ROS) specific, which is manifested as changes in the enzyme activation, differences in gene expression, cellular functions as well as cell death mechanisms. Photodynamic therapy (PDT) using light-activated photosensitizing molecules that can regulate cellular redox balance in accordance with the changes in endogenous ROS production is a solution for many of these challenges in cancer therapy.

Comparative study on the bioactive components and in vitro biological activities of three green seedlings

To explore functional food ingredients from green seedlings, the bioactive components (phenolic compounds and γ-aminobutyric acid) and antioxidant activities (DPPH radical scavenging ability, ABTS radical scavenging ability and reducing power) of three green seedlings, including coix seed seedling (CSS), highland barely seedling (HBS) and naked oats seedling (NOS) cultivars were respectively measured and deeply compared. Results indicated that CSS showed the highest contents of the total polyphenol (183.35 mg/100 g), total flavonoid (348.68 mg/100 g), and γ-aminobutyric acid (54.17 mg/100 g). As expected, CSS also exerted the highest level of antioxidant activity, followed by HBS and NOS. Moreover, CSS possessed the potential of stimulating immune responses, including promoting proliferation and strengthening phagocytosis function of RAW264.7 cells. Taken together, all results suggested that the three green seedlings, especially CSS could be used as natural ingredients for functional food.

Modifying effects of leaf litter extracts from invasive versus native tree species on copper-induced responses in Lemna minor

Invasive plant species tend to migrate from their native habitats under favourable climatic conditions; therefore, trophic and other relationships in ecosystems are changing. To investigate the effect of natural organic matter derived from native Alnus glutinosa tree species and from invasive in Lithuania Acer negundo tree species on copper toxicity in Lemna minor, we analysed the dynamics of Cu binding in aqueous leaf litter extracts (LLE) and plant accumulation, morphophysiological parameters, and antioxidative response. The results revealed that A. glutinosa LLE contained polyphenols (49 mg pyrogallol acid equivalent (PAE)/g DM) and tannins (7.5 mg PAE/g DM), while A. negundo LLE contained only polyphenols (23 mg PAE/g DM). The ability of LLE to bind Cu increased rapidly over 1.5-3 h to 61% and 49% of the total Cu concentration (6.0 ± 0.9 mg/L), respectively for A. glutinosa (AG) and A. negundo (AN), then remained relatively stable until 48 h. At the same time, L. minor accumulated 384, 241 or 188 µg Cu/g FW when plants were exposed to Cu (100 µM CuSO4), Cu with 100 mg/L dissolved organic carbon (DOC) from either AG LLE or AN LLE, accordingly. Catalase (CAT) and guaiacol peroxidase (POD) played a dominant role in hydrogen peroxide scavenging when plants were exposed to Cu and 10 or 100 mg/L DOCAG mixtures in both the first (up to 6h) and the second (6-48 h) response phases. Due to functioning of oxidative stress enzymes, the levels of the lipid peroxidation product malondialdehyde (MDA) reduced in concentration-dependent manner, compared to Cu treatment. When combining Cu and DOCAN treatments, the most sensitive enzymes were POD, ascorbate peroxidase and glutathione reductase. Their activities collectively with CAT were sufficient to reduce MDA levels to Cu-induced in the initial, but not the second response phase. These data suggest that leaf litter extracts of different phenolic compositions elicited different antioxidant response profiles resulting in different reductions of Cu stress, thus effecting L. minor frond and root development observed after seven days. The complex data from this study may be useful in modelling the response of the aquatic ecosystem to a changing environment.

Epigallocatechin gallate reverses gastric cancer by regulating the long noncoding RNA LINC00511/miR-29b/KDM2A axis

Epigallocatechin gallate (EGCG), as one of the main ingredients of green tea, has been reported to have potential prevention on a variety of solid tumors. However, the system-wide molecular mechanisms targeted to EGCG's anti-tumor effect have not been illustrated. Here, AGS and SGC7901 GC cells were used to investigate the EGCG-mediated change of gene expression. Our data showed that EGCG retarded cell growth and promoted cell death of GC in dose-dependent manner. Analyses based on transcription, translation as well as function were performed to explore the elusive anticancer role of EGCG. Of them, cell cycle was probably implicated key pathway of EGCG. Besides, our data revealed numerous LncRNAs activated after EGCG treatment. In this study, LINC00511 was discovered to be suppressed by EGCG and highly expressed in GC cells and tissues. Knockdown of LINC00511 inhibited cell growth and promoted cell death ratio in GC. Additionally, our data suggested LINC00511 could decrease the expression of miR-29b, followed by inducing GC development. Knockdown of miR-29b recovered the effects of LINC00511 silencing. In addition, we found overexpression of KDM2A, a target of miR-29b, would rescue the level of LINC00511. All the data showed that the LINC00511/miR-29b/KDM2A axis can be used as a diagnostic and therapeutic target for GC.

Black tea polyphenol theaflavin as promising antioxidant and potential copper chelator

BACKGROUND

In this work, we investigated the antioxidant and copper chelating abilities of theaflavin, a polyphenol responsible for astringency, color, and sensation in black tea. Using voltammetric techniques, the analyses were conducted with disposable electrochemical printed carbon chips in conjunction with a portable hand-held potentiostat.

RESULTS

Voltammograms of theaflavin showed five separate oxidation peaks, corresponding to the oxidation of five individual functional groups. Electroanalytical data indicated that, after interaction with copper, theaflavin had higher antioxidant potential and was a better copper chelator than epigallocatechin gallate, a major polyphenol present in green tea and a well-known antioxidant. This could be attributed to the extra fused ring and larger number of OH groups in theaflavin.

CONCLUSIONS

Our findings introduce another natural compound as a potential nutraceutical in oxidation- and copper-modulated illnesses. This simple and fast approach would also be highly pertinent to the inspection of the health benefits of natural food products. To the best of our knowledge, this is the first report of the electrochemical analysis of Cu (II) chelation with theaflavin. © 2020 Society of Chemical Industry.

Monoalkylated Epigallocatechin-3-gallate (C18-EGCG) as Novel Lipophilic EGCG Derivative: Characterization and Antioxidant Evaluation

Epigallocatechin-3-gallate (EGCG) has the highest antioxidant activity compared to the others catechins of green tea. However, the beneficial effects are mainly limited by its poor membrane permeability. A derivatization strategy to increase the EGCG interaction with lipid membranes is considered as one feasible approach to expand its application in lipophilic media, in particular the cellular absorption. At this purpose the hydrophilic EGCG was modified by inserting an aliphatic C18 chain linked to the gallate ring by an ethereal bond, the structure determined by NMR (Nuclear Magnetic Resonance) and confirmed by Density Functional Theory (DFT) calculations. The in vitro antioxidant activity of the mono-alkylated EGCG (C18-EGCG) was studied by the DPPH and Thiobarbituric Acid Reactive Substances (TBARS) assays, and its ability to protect cells towards oxidative stress was evaluated in Adult Retinal Pigmented Epithelium (ARPE-19) cells. Molecular Dynamics (MD) simulation and liposomal/buffer partition were used to study the interaction of the modified and unmodified antioxidants with a cell membrane model: the combined experimental-in silico approach shed light on the higher affinity of C18-EGCG toward lipid bilayer. Although the DPPH assay stated that the functionalization decreases the EGCG activity against free radicals, from cellular experiments it resulted that the lipid moiety increases the antioxidant protection of the new lipophilic derivative.

Combined Analysis of the Metabolome and Transcriptome Identified Candidate Genes Involved in Phenolic Acid Biosynthesis in the Leaves of Cyclocarya paliurus

To assess changes of metabolite content and regulation mechanism of the phenolic acid biosynthesis pathway at different developmental stages of leaves, this study performed a combined metabolome and transcriptome analysis of Cyclocarya paliurus leaves at different developmental stages. Metabolite and transcript profiling were conducted by ultra-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometer and high-throughput RNA sequencing, respectively. Transcriptome identification showed that 58 genes were involved in the biosynthesis of phenolic acid. Among them, 10 differentially expressed genes were detected between every two developmental stages. Identification and quantification of metabolites indicated that 14 metabolites were located in the phenolic acid biosynthetic pathway. Among them, eight differentially accumulated metabolites were detected between every two developmental stages. Association analysis between metabolome and transcriptome showed that six differentially expressed structural genes were significantly positively correlated with metabolite accumulation and showed similar expression trends. A total of 128 transcription factors were identified that may be involved in the regulation of phenolic acid biosynthesis; these include 12 MYBs and 10 basic helix–loop–helix (bHLH) transcription factors. A regulatory network of the phenolic acid biosynthesis was established to visualize differentially expressed candidate genes that are involved in the accumulation of metabolites with significant differences. The results of this study contribute to the further understanding of phenolic acid biosynthesis during the development of leaves of C. paliurus.

Tributyltin(IV) ferulate, a novel synthetic ferulic acid derivative, induces autophagic cell death in colon cancer cells: From chemical synthesis to biochemical effects

Ferulic acid (FA) is a natural phenolic phytochemical that has low toxicity and exhibits therapeutic effects against various diseases, behaving as an antioxidant. FA also displays modest antitumor properties that have been reported at relatively high concentrations. With the aim of improving the anti-tumor efficacy of FA, we synthesized the novel compound tributyltin(IV) ferulate (TBT-F). The coordination environment at the tin center was investigated spectroscopically. Following synthesis, chemical characterization and computational analysis, we evaluated TBT-F effects in colon cancer cells. The results showed that TBT-F, at nanomolar range concentrations, was capable of reducing the viability of HCT116, HT-29 and Caco-2 colon cancer cells. On the other hand, FA was completely inefficacious at the same treatment conditions. Cell viability reduction induced by TBT-F was associated with G2/M cell cycle arrest, increase in membrane permeabilization and appearance of typical morphological signs. TBT-F-induced cell death seemed not to involve apoptotic or necroptotic markers whereas autophagic vacuoles appearance and increase in LC3-II and p62 autophagic proteins were observed after treatment with the compound. The autophagy inhibitor bafylomicin A1 markedly prevented the effect of TBT-F on colon cancer cells, thus indicating that autophagy is triggered as a cell death process. Taken together, our results strongly suggest that the novel ferulic derivative TBT-F is a promising therapeutic agent for colon cancer since it is capable of triggering autophagic (type-II) cell death that may be important in case of resistance to classic apoptosis.

Parameritannin A-2 from Urceola huaitingii enhances doxorubicin-induced mitochondria-dependent apoptosis by inhibiting the PI3K/Akt, ERK1/2 and p38 pathways in gastric cancer cells

Parameritannin A-2 (PA-2) is a natural product extracted from the stems of the plant Urceola huaitingii. Our previous studies have shown that PA-2 exhibits significant synergistic anticancer effects with doxorubicin (DOX) in HGC27 gastric cancer cell lines. Here we report that our isobolographic analysis confirms the synergistic cytotoxic effects of PA-2 and DOX in HGC27 cells. Flow cytometry and immunoblotting indicate that PA-2 enhances DOX-mediated apoptosis. Importantly, PA-2 enhances the intracellular accumulation of DOX in HGC27 cells. The combination of DOX and PA-2 remarkably increases the release of cytochrome C and the activation of caspase-3 and caspase-9, compared with DOX treatment alone. Moreover, PA-2 attenuates the DOX-induced activation of Akt, ERK1/2 and p38 signaling pathways, providing a molecular mechanism for the synergistic effects of DOX and PA-2 in the induction of apoptosis. In conclusion, our studies demonstrate that PA-2 and DOX synergistically induce mitochondria-dependent apoptosis as PA-2 inhibits the PI3K/Akt, ERK1/2 and p38 pathways in HGC27 cells. These findings suggest that the combination treatment with PA-2 and DOX may represent a potent therapy for gastric cancer.