Quercetin
Antioxidants
Glycosides
Plant Extracts
Catechin
Inflammation
Irritants
Sleep
Alzheimer Disease
Ethnobotany
Effect of quercetin on activities of protein kinase C and tyrosine protein kinase from HL-60 cells. (1/1050)
AIM: To study the effect of quercetin (Que) on the activities of cytosol and membrane protein kinase C (PKC) and tyrosine protein kinase (TPK) from HL-60 cells in vitro. METHODS: The number of viable cells was counted by a trypan blue dye exclusion test. PKC activity was assayed by incubating PKC with histone III S and [gamma-32P]ATP. TPK activity was assayed by incubating TPK with poly glutamate.tyrosine (4:1). RESULTS: Que inhibited the proliferation of HL-60 cells in a concentration-dependent manner, its IC50 was 29 (22-37) mumol.L-1 after 48-h treatment; Que strongly inhibited the activity of cytosol PKC and membrane TPK with IC50 31 (20-48) mumol.L-1, 24 (13-45) mumol.L-1, respectively, but did not affect membrane PKC and cytosol TPK from HL-60 cells in vitro. CONCLUSION: The inhibitory effect of Que on the growth of tumor cells is related to its inhibitory effects on PKC and/or TPK. (+info)Quercetin induced apoptosis in human leukemia HL-60 cells. (2/1050)
AIM: To examine whether quercetin (Que) might induce apoptosis in human leukemia HL-60 cells. METHODS: DNA fragmentation was visualized by agarose gel electrophoresis. Inhibition of proliferation was measured with a colorimetric MTT-assay. The DNA degradation was determined using flow cytometry, and the microscopic changes were observed by an electron microscope. RESULTS: Que 15-120 mumol.L-1 elicited typical apoptosis morphological changes including condensed chromatin, nuclear fragmentation, and reduction in volume. DNA fragmentation and DNA degradation in a concentration-dependent manner in HL-60 cells. Que inhibited HL-60 cell proliferation. The values of IC50 and 95% confidence limits were 43 (30-61) mumol.L-1 after 48-h treatment with Que. CONCLUSION: Que induced apoptosis in HL-60 cells. (+info)Quercetin inhibited DNA synthesis and induced apoptosis associated with increase in c-fos mRNA level and the upregulation of p21WAF1CIP1 mRNA and protein expression during liver regeneration after partial hepatectomy. (3/1050)
Quercetin, a widely distributed bioflavonoid, inhibited DNA synthesis in regenerating liver after partial hepatectomy. This inhibition was accompanied by apoptosis, evidenced by in situ end-labeling and gel electrophoresis of DNA fragmentation. Characteristic DNA fragmentation was detected as early as 2 h after injection. Northern blot analysis revealed that quercetin induced the increases in c-fos and p21WAF1CIP1 mRNA levels within 2 h. The expression of p21 protein was also enhanced, while p53 mRNA and protein levels were not affected by quercetin. These results suggest that quercetin-induced apoptosis is associated with the increase in c-fos mRNA level and the upregulation of p21 mRNA and protein expression, probably in a p53-independent pathway. (+info)Protective effect of flavonoids on endothelial cells against linoleic acid hydroperoxide-induced toxicity. (4/1050)
The protective effect of flavonoids against linoleic acid hydroperoxide (LOOH)-induced cytotoxicity was examined by using cultured endothelial cells. When the cells were incubated with both LOOH and flavonoids, most flavonols protected the cells from injury by LOOH. Flavones bearing an ortho-dihydroxy structure also showed a protective effect against the cytotoxicity of LOOH. However, flavanones had no effect. The structure-activity relationship revealed the presence of either the ortho-di-hydroxy structure in the B ring of the flavonoids or 3-hydroxyl and 4-oxo groups in the C ring to be important for the protective activities. The interaction between flavonoids and a-tocopherol was also examined in this system. Flavonoids that were protective against LOOH-induced cytotoxicity had at least an additive effect on the action of alpha-tocopherol against LOOH-induced damage. (+info)Effect of dietary antioxidants on serum lipid contents and immunoglobulin productivity of lymphocytes in Sprague-Dawley rats. (5/1050)
Sprague-Dawley rats were fed alpha-tocopherol, tocotrienol, or quercetin to examine their dietary effects on serum lipid contents and immunoglobulin productivity. In tocotrienol or quercetin groups, serum triglyceride was lower than in the none group. Moreover, in the alpha-tocopherol group, serum IgA level and IgA productivity of MLN lymphocytes were high, while in the tocotrienol group, IgM productivity of spleen lymphocytes and IgA, IgG, and IgM productivity of MLN lymphocytes were high. Thus, we suggested each antioxidant had different effects in rats. (+info)Inhibition of ATPase, GTPase and adenylate kinase activities of the second nucleotide-binding fold of the cystic fibrosis transmembrane conductance regulator by genistein. (6/1050)
In the presence of ATP, genistein, like the ATP analogue adenosine 5'-[beta,gamma-imido]triphosphate (pp[NH]pA), increases cystic fibrosis transmembrane conductance regulator (CFTR) chloride currents by prolonging open times. As pp[NH]pA is thought to increase CFTR currents by interfering with ATP hydrolysis at the second nucleotide-binding fold (NBF-2), the present study was undertaken to investigate the effects of genistein on a fusion protein comprising maltose-binding protein (MBP) and NBF-2 (MBP-NBF-2). MBP-NBF-2 exhibited ATPase, GTPase and adenylate kinase activities that were inhibited by genistein in a partial non-competitive manner with respect to ATP or GTP. Ki values for competitive and uncompetitive inhibition were respectively 20 microM and 63 microM for ATPase, 15 microM and 54 microM for GTPase, and 46 microM and 142 microM for adenylate kinase. For ATPase activity, genistein reduced Vmax by 29% and Vmax/Km by 77%. Additional evidence for complex-formation between genistein and MBP-NBF-2 was obtained by the detection of genistein-dependent alterations in the CD spectrum of MBP-NBF-2 that were consistent with the formation of a higher-ordered state. Addition of MBP-NBF-2 increased the fluorescence intensity of genistein, consistent with a change to a less polar environment. pp[NH]pA partially eliminated this enhanced fluorescence of genistein. These observations provide the first direct biochemical evidence that genistein interacts with CFTR, thus inhibiting NBF-2 activity, and suggest a similar mechanism for genistein-dependent stimulation of CFTR chloride currents. (+info)Dietary flavonols quercetin and kaempferol are ligands of the aryl hydrocarbon receptor that affect CYP1A1 transcription differentially. (7/1050)
Transcriptional activation of the human CYP1A1 gene (coding for cytochrome P450 1A1) is mediated by the aryl hydrocarbon receptor (AhR). In the present study we have examined the effect of the common dietary polyphenolic compounds quercetin and kaempferol on the transcription of CYP1A1 and the function of the AhR in MCF-7 human breast cancer cells. Quercetin caused a time- and concentration-dependent increase in the amount of CYP1A1 mRNA and CYP1A1 enzyme activity in MCF-7 cells. The increase in CYP1A1 mRNA caused by quercetin was prevented by the transcription inhibitor actinomycin D. Quercetin also caused an increase in the transcription of a chloramphenicol reporter vector containing the CYP1A1 promoter. Quercetin failed to induce CYP1A1 enzyme activity in AhR-deficient MCF-7 cells. Gel retardation studies demonstrated that quercetin activated the ability of the AhR to bind to an oligonucleotide containing the xenobiotic-responsive element (XRE) of the CYP1A1 promoter. These results indicate that quercetin's effect is mediated by the AhR. Kaempferol did not affect CYP1A1 expression by itself but it inhibited the transcription of CYP1A1 induced by the prototypical AhR ligand 2,3,7, 8-tetrachlorodibenzo-p-dioxin (TCDD), as measured by a decrease in TCDD-induced CYP1A1 promoter-driven reporter vector activity, and CYP1A1 mRNA in cells. Kaempferol also abolished TCDD-induced XRE binding in a gel-shift assay. Both compounds were able to compete with TCDD for binding to a cytosolic extract of MCF-7 cells. Known ligands of the AhR are, for the most part, man-made compounds such as halogenated and polycyclic aromatic hydrocarbons. These results demonstrate that the dietary flavonols quercetin and kaempferol are natural, dietary ligands of the AhR that exert different effects on CYP1A1 transcription. (+info)Competitive and noncompetitive inhibition of the DNA-dependent protein kinase. (8/1050)
The DNA-dependent protein kinase (DNA-PK) is a serine/threonine protein kinase that is involved in mammalian DNA double-strand break repair. The catalytic subunit of DNA-PK (DNA-PKcs) shares sequence homology in its kinase domain with phosphatidylinositol (PI) 3-kinase. Here, we provide a detailed kinetic analysis of DNA-PK inhibition by the PI 3-kinase inhibitor wortmannin and demonstrate this inhibition to be of a noncompetitive nature, with a Ki of 120 nM. Another inhibitor of PI 3-kinase. LY294002, its parent compound, quercetin, and other derivatives have also been studied. These chemicals are competitive inhibitors of DNA-PK, with LY294002 having a Ki of 6.0 microM. Using an antibody to wortmannin, we found that this compound binds covalently to the kinase domain of DNA-PKcs both in vitro and in vivo. Binding of wortmannin to the active site of DNA-PKcs is inhibited by ATP but not by a peptide substrate. Furthermore, wortmannin is able to bind to DNA-PKcs independently of Ku, and it is not stimulated by the presence of DNA. This suggests that the ATP binding site of DNA-PKcs is open constitutively and that DNA activation of the kinase is mediated via another mechanism. (+info)Quercetin is a type of flavonoid antioxidant that is found in plant foods, including leafy greens, tomatoes, berries, and broccoli. It has been studied for its potential health benefits, such as reducing inflammation, protecting against damage to cells, and helping to reduce the risk of heart disease and cancer. Quercetin is also known for its ability to stabilize mast cells and prevent the release of histamine, making it a popular natural remedy for allergies. It is available in supplement form, but it is always recommended to consult with a healthcare provider before starting any new supplement regimen.
Flavonols are a type of flavonoid, which is a class of plant and fungal metabolites. They are characterized by the presence of a 3-hydroxyflavone skeleton. Flavonols are found in a variety of plants and are known for their antioxidant properties. Some common dietary sources of flavonols include onions, kale, broccoli, apples, tea, and red wine. They have been studied for their potential health benefits, including reducing the risk of chronic diseases such as cancer and cardiovascular disease. Flavonols are also known to have anti-inflammatory, neuroprotective, and antimicrobial properties.
Flavonoids are a type of plant compounds with antioxidant properties that are beneficial to health. They are found in various fruits, vegetables, grains, and wine. Flavonoids have been studied for their potential to prevent chronic diseases such as heart disease and cancer due to their ability to reduce inflammation and oxidative stress.
There are several subclasses of flavonoids, including:
1. Flavanols: Found in tea, chocolate, grapes, and berries. They have been shown to improve blood flow and lower blood pressure.
2. Flavones: Found in parsley, celery, and citrus fruits. They have anti-inflammatory and antioxidant properties.
3. Flavanonols: Found in citrus fruits, onions, and tea. They have been shown to improve blood flow and reduce inflammation.
4. Isoflavones: Found in soybeans and legumes. They have estrogen-like effects and may help prevent hormone-related cancers.
5. Anthocyanidins: Found in berries, grapes, and other fruits. They have antioxidant properties and may help improve vision and memory.
It is important to note that while flavonoids have potential health benefits, they should not be used as a substitute for medical treatment or a healthy lifestyle. It is always best to consult with a healthcare professional before starting any new supplement regimen.
I'm sorry for any confusion, but "onions" are not a medical term. They are a type of vegetable, specifically a variety of bulb vegetables, known scientifically as Allium cepa. Onions are widely used in cooking and have been cultivated for centuries for their unique, pungent flavor and potential health benefits. If you have any questions about onions in a culinary or nutritional context, I'd be happy to try to help answer those!
Antioxidants are substances that can prevent or slow damage to cells caused by free radicals, which are unstable molecules that the body produces as a reaction to environmental and other pressures. Antioxidants are able to neutralize free radicals by donating an electron to them, thus stabilizing them and preventing them from causing further damage to the cells.
Antioxidants can be found in a variety of foods, including fruits, vegetables, nuts, and grains. Some common antioxidants include vitamins C and E, beta-carotene, and selenium. Antioxidants are also available as dietary supplements.
In addition to their role in protecting cells from damage, antioxidants have been studied for their potential to prevent or treat a number of health conditions, including cancer, heart disease, and age-related macular degeneration. However, more research is needed to fully understand the potential benefits and risks of using antioxidant supplements.
Glycosides are organic compounds that consist of a glycone (a sugar component) linked to a non-sugar component, known as an aglycone, via a glycosidic bond. They can be found in various plants, microorganisms, and some animals. Depending on the nature of the aglycone, glycosides can be classified into different types, such as anthraquinone glycosides, cardiac glycosides, and saponin glycosides.
These compounds have diverse biological activities and pharmacological effects. For instance:
* Cardiac glycosides, like digoxin and digitoxin, are used in the treatment of heart failure and certain cardiac arrhythmias due to their positive inotropic (contractility-enhancing) and negative chronotropic (heart rate-slowing) effects on the heart.
* Saponin glycosides have potent detergent properties and can cause hemolysis (rupture of red blood cells). They are used in various industries, including cosmetics and food processing, and have potential applications in drug delivery systems.
* Some glycosides, like amygdalin found in apricot kernels and bitter almonds, can release cyanide upon hydrolysis, making them potentially toxic.
It is important to note that while some glycosides have therapeutic uses, others can be harmful or even lethal if ingested or otherwise introduced into the body in large quantities.
A plant extract is a preparation containing chemical constituents that have been extracted from a plant using a solvent. The resulting extract may contain a single compound or a mixture of several compounds, depending on the extraction process and the specific plant material used. These extracts are often used in various industries including pharmaceuticals, nutraceuticals, cosmetics, and food and beverage, due to their potential therapeutic or beneficial properties. The composition of plant extracts can vary widely, and it is important to ensure their quality, safety, and efficacy before use in any application.
Flavanones are a type of flavonoid, which is a class of plant pigments widely found in fruits, vegetables, and other plants. Flavanones are known for their antioxidant properties and potential health benefits. They are typically found in citrus fruits such as oranges, lemons, and grapefruits. Some common flavanones include hesperetin, naringenin, and eriodictyol. These compounds have been studied for their potential effects on cardiovascular health, cancer prevention, and neuroprotection, although more research is needed to fully understand their mechanisms of action and therapeutic potential.
Phenols, also known as phenolic acids or phenol derivatives, are a class of chemical compounds consisting of a hydroxyl group (-OH) attached to an aromatic hydrocarbon ring. In the context of medicine and biology, phenols are often referred to as a type of antioxidant that can be found in various foods and plants.
Phenols have the ability to neutralize free radicals, which are unstable molecules that can cause damage to cells and contribute to the development of chronic diseases such as cancer, heart disease, and neurodegenerative disorders. Some common examples of phenolic compounds include gallic acid, caffeic acid, ferulic acid, and ellagic acid, among many others.
Phenols can also have various pharmacological activities, including anti-inflammatory, antimicrobial, and analgesic effects. However, some phenolic compounds can also be toxic or irritating to the body in high concentrations, so their use as therapeutic agents must be carefully monitored and controlled.
Polyphenols are a type of phytochemical, which are naturally occurring compounds found in plant-based foods. They contain multiple phenol units and can be classified into several subgroups, including flavonoids, stilbenes, tannins, and lignans. These compounds have been studied for their potential health benefits due to their antioxidant, anti-inflammatory, and immune-modulating properties. They are found in a wide variety of foods such as fruits, vegetables, tea, wine, chocolate, and cereals.
A catechin is a type of plant phenol and antioxidant found in various foods and beverages, such as tea, cocoa, and certain fruits and vegetables. Chemically, catechins are flavan-3-ols, which are a subclass of flavonoids. They have several potential health benefits, including reducing the risk of cardiovascular disease, cancer, and neurodegenerative disorders.
Catechins are known to have anti-inflammatory, antimutagenic, and antidiabetic properties. They can also help improve oral health by inhibiting the growth of harmful bacteria in the mouth. The most well-known catechin is epigallocatechin gallate (EGCG), which is found in high concentrations in green tea and has been extensively studied for its potential health benefits.
In summary, a catechin is a type of antioxidant compound found in various plant-based foods and beverages that may have several health benefits, including reducing the risk of chronic diseases and improving oral health.
Inflammation is a complex biological response of tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. It is characterized by the following signs: rubor (redness), tumor (swelling), calor (heat), dolor (pain), and functio laesa (loss of function). The process involves the activation of the immune system, recruitment of white blood cells, and release of inflammatory mediators, which contribute to the elimination of the injurious stimuli and initiation of the healing process. However, uncontrolled or chronic inflammation can also lead to tissue damage and diseases.
Irritants, in a medical context, refer to substances or factors that cause irritation or inflammation when they come into contact with bodily tissues. These substances can cause a range of reactions depending on the type and duration of exposure, as well as individual sensitivity. Common examples include chemicals found in household products, pollutants, allergens, and environmental factors like extreme temperatures or friction.
When irritants come into contact with the skin, eyes, respiratory system, or mucous membranes, they can cause symptoms such as redness, swelling, itching, pain, coughing, sneezing, or difficulty breathing. In some cases, prolonged exposure to irritants can lead to more serious health problems, including chronic inflammation, tissue damage, and disease.
It's important to note that irritants are different from allergens, which trigger an immune response in sensitive individuals. While both can cause similar symptoms, the underlying mechanisms are different: allergens cause a specific immune reaction, while irritants directly affect the affected tissues without involving the immune system.
Sleep is a complex physiological process characterized by altered consciousness, relatively inhibited sensory activity, reduced voluntary muscle activity, and decreased interaction with the environment. It's typically associated with specific stages that can be identified through electroencephalography (EEG) patterns. These stages include rapid eye movement (REM) sleep, associated with dreaming, and non-rapid eye movement (NREM) sleep, which is further divided into three stages.
Sleep serves a variety of functions, including restoration and strengthening of the immune system, support for growth and development in children and adolescents, consolidation of memory, learning, and emotional regulation. The lack of sufficient sleep or poor quality sleep can lead to significant health problems, such as obesity, diabetes, cardiovascular disease, and even cognitive decline.
The American Academy of Sleep Medicine (AASM) defines sleep as "a period of daily recurring natural rest during which consciousness is suspended and metabolic processes are reduced." However, it's important to note that the exact mechanisms and purposes of sleep are still being researched and debated among scientists.
Alzheimer's disease is a progressive disorder that causes brain cells to waste away (degenerate) and die. It's the most common cause of dementia — a continuous decline in thinking, behavioral and social skills that disrupts a person's ability to function independently.
The early signs of the disease include forgetting recent events or conversations. As the disease progresses, a person with Alzheimer's disease will develop severe memory impairment and lose the ability to carry out everyday tasks.
Currently, there's no cure for Alzheimer's disease. However, treatments can temporarily slow the worsening of dementia symptoms and improve quality of life.
Ethnobotany is the scientific study of the traditional knowledge, practices, and beliefs about plants held by a particular group of people or culture. It involves the documentation and analysis of the ways in which people use plants for medicinal, food, shelter, clothing, dye, ritual, and other purposes. The field of ethnobotany draws on anthropology, botany, ecology, chemistry, and geography to understand the complex relationships between human cultures and their plant resources.
Ethnobotanists may conduct fieldwork with communities to learn about their traditional plant use, documenting this knowledge through interviews, observations, and collections of plant specimens. They may also study the ecological and cultural factors that shape plant use and management, as well as the impacts of globalization, environmental change, and other forces on traditional plant knowledge and practices.
The information gathered through ethnobotanical research can have important implications for conservation, human health, and sustainable development. For example, traditional plant remedies may provide leads for the development of new drugs or therapies, while understanding the cultural significance of plants can help inform efforts to protect biodiversity and support the rights of indigenous peoples and local communities.
Exercise is defined in the medical context as a physical activity that is planned, structured, and repetitive, with the primary aim of improving or maintaining one or more components of physical fitness. Components of physical fitness include cardiorespiratory endurance, muscular strength, muscular endurance, flexibility, and body composition. Exercise can be classified based on its intensity (light, moderate, or vigorous), duration (length of time), and frequency (number of times per week). Common types of exercise include aerobic exercises, such as walking, jogging, cycling, and swimming; resistance exercises, such as weightlifting; flexibility exercises, such as stretching; and balance exercises. Exercise has numerous health benefits, including reducing the risk of chronic diseases, improving mental health, and enhancing overall quality of life.