scholarly journals Review on the Bioactivities of Quercetin

2020 ◽  
Vol 13 (3) ◽  
pp. 181-194
Author(s):  
Shabana ◽  
R. C. Jaysree ◽  
Rajendran . N
Keyword(s):  
Wide Spectrum ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Biological Response ◽  
Cyclic Adenosine Monophosphate ◽  
Black Tea ◽  
Adenosine Monophosphate ◽  
Mutant Gene ◽  
The Body ◽  
High Concentration

Quercetin, the most active bioflavonoid which is produced as a secondary metabolite by plants, is a polyphenol with a wide spectrum of bioactivities. This bioflavonoid is the ―nature‘s biological response modifier‖ as it interferes with the various allergens and other reactive compounds. Apple, oranges, tomatoes, onions, black tea and green tea are good sources of quercetin and it is also available commercially. After absorption in the small intestine and colon, quercetin conjugates with glucuronic acid and binds to albumin and passes to liver and benefits the body by its various bioactivities. Quercetin‘s antioxidant activity enhances the radical scavenging activity and metal chelation of the ions but the prooxidant activity depends on its high concentration. Further, quercetin interferes with the formation of leukotrienes from arachidonic acid showing its anti-inflammatory effect. A combined effect of quercetin and bromelain effectively suppresses the allergic reactions and the excessive inflammation resulting from bruising and tissue damage. The mutualistic effect of vitamin C and quercetin protects each other from getting oxidized. A direct relationship was also found to exist between quercetin's antiviral activity and enhancement of cyclic adenosine monophosphate (cAMP), which is a second messenger involved in many biological processes. Quercetin helps in down regulation of mutant gene p53 and inhibits the growth of cancerous cells by putting a check at G1 phase. This also controls the surpassing of the normal regulatory growth by the tumor cells and inhibits the production of heat shock proteins and thus showing its anticancer properties. Owing to the potential pharmaceutical properties of quercetin, the bioactivities, principle uses and mechanisms involved in the treatment of various diseases were reviewed in this paper. In addition, safety issues involved in the partake of quercetin by humans have also been discussed.

α-Glucosidase Inhibition, Antioxidant and Docking Studies of Hydroxycoumarins and their Mono and Bis O-alkylated/acetylated Analogs

2018 ◽  
Vol 15 (2) ◽  
pp. 127-135 ◽  
Author(s):  
Parvesh Singh ◽  
Nomandla Ngcoya ◽  
Ramgopal Mopuri ◽  
Nagaraju Kerru ◽  
Neha Manhas ◽  
...  
Keyword(s):  
In Silico ◽  
Biological Activities ◽  
Wide Spectrum ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Catalytic Site ◽  
Docking Simulations ◽  
In Silico Docking ◽  
Anti Oxidant

Background: Diabetes Mellitus (DM) is a complex metabolic disease illustrated by abnormally high levels of plasma glucose or hyperglycaemia. Accordingly, several α-glucosidase inhibitors have been developed for the treatment of diabetes and other degenerative disorders. While, a coumarin ring has the privilege to represent numerous natural and synthetic compounds with a wide spectrum of biological activities e.g. anti-cancer, anti-HIV, anti-viral, anti-malarial, anti-microbial, anti-convulsant, anti-hypertensive properties. Besides this, coumarins have also shown potential to inhibit α-glucosidase leading to a generation of new promising antidiabetic agents. However, the testing of O-substituted coumarins for α-glucosidase inhibition has evaded the attention of medicinal chemists. Methods: For O-alkylation/acetylation reactions, the hydroxyl coumarins (A-B) initially activated by K2CO3 in dry DMF were reacted with variedly substituted haloalkanes at room temperature under nitrogen. The synthesized compounds were tested for their α-glucosidase (from Saccharomyces cerevisiae) inhibitory activity and anti-oxidant activity using DPPH radical scavenging activity. In silico docking simulations were conducted using CDocker module in DS (Accelrys) to explore the binding modes of the representative compounds in the catalytic site of α-glucosidase. Results: All the coumarin analogues (A1, B1, A2-A10, B2-B8) including their precursors (A-B) were evaluated for their in vitro α-glucosidase inhibition using acarbose as a standard inhibitor. All the mono O-alkylated coumarins (except A1) showed significant (p <0.05) α-glucosidase inhibition relative to the hydroxyl coumarin (A) with IC50 values ranging between 11.084±0.117 to 145.24± 29.22 µg/mL. Compound 7-(benzyloxy)-4, 5-dimethyl-2H-chromen-2-one (A9) bearing a benzyl group (Ph-CH2-) at position 7 showed a remarkable (p <0.05) increase in the activity (IC50 = 11.084±0.117 µg/mL), almost four-fold more than acarbose (IC50 = 40.578±5.999 µg/mL). The introduction of –NO2 group dramatically improved the anti-oxidant activity of coumarin, while the O-alkylation/acetylation decreased the activity. Conclusion: The present study describes the synthesis of functionalized coumarins and their evaluation for α-glucosidase inhibition and antioxidant activity under in vitro conditions. Based on IC50 data, the mono O-alkylated coumarins were observed to be stronger inhibitors of α-glucosidase with respect to their bis O-alkylated analogues. Coumarin (A9) bearing O-benzyloxy group displayed the strongest α-glucosidase inhibition, even higher than the standard inhibitor acarbose. The coumarin (A10) bearing –NO2 group showed the highest anti-oxidant activity amongst the synthesized compounds, almost comparable to the ascorbic acid. Finally, in silico docking simulations revealed the role of hydrogen bonding and hydrophobic forces in locking the compounds in catalytic site of α-glucosidase.

scholarly journals Ellagic Acid Suppresses the Oxidative Stress Induced by Dietary-Oxidized Tallow

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Alam Zeb ◽  
Adnan Akbar
Keyword(s):  
Oxidative Stress ◽  
Fatty Acids ◽  
Ellagic Acid ◽  
Animal Studies ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Thiobarbituric Acid ◽  
Rabbit Heart ◽  
The Body ◽  
Margaric Acid

Dietary tallow was thermally oxidized at 180°C in an open fryer. The oxidized tallow (OT) and unoxidized tallow were characterized for oxidation parameters and fatty acid composition using GC-MS. Tallow samples were fed to rabbits along with 50, 100, and 150 mg/kg/day of ellagic acid (EA) for three weeks. Results revealed that the peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) significantly increased, while radical scavenging activity (RSA) of the tallow decreased significantly with oxidation. GC-MS analysis showed eight fatty acids in the tallow samples, where palmitic acid (48.5-49.7 g/100 g), linoleic acid (18.7-23.7 g/100 g), stearic acid (13.5-15.6 g/100 g), and margaric acid (6.32-6.42 g/100 g) were the major fatty acids. Animal studies showed that oxidized tallow (OT) alone or in combination with EA significantly altered the body weight of the rabbits. Serum biochemical parameters and renal function tests were affected by OT and ameliorated by EA. The toxic effects of OT on haematological indices were minimized by EA. The supplementation of OT alone had significant effects on the liver structure and functions. The coadministration of EA reduced the toxic properties of OT on the liver, by increasing the antioxidant (GSH) system. The rabbit heart was also affected by the OT, which was ameliorated by EA supplementation. These results suggested that the supplementation of EA was beneficial against the OT-induced oxidative stress and may be considered for foods containing oxidized lipids.

scholarly journals Epac signaling protein ligands as tools for studying their biological activity and creating new original drugs

2020 ◽  
pp. 3-17
Author(s):  
G. V. Mokrov ◽  
T. D. Nikiforova ◽  
S. A. Kryzhanovskiy
Keyword(s):  
Biological Activity ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
The Body ◽  
Physiological Functions ◽  
Signaling Protein ◽  
Protein Ligands ◽  
Biological Target ◽  
Effective Drugs ◽  
Structure And Functions

The review discusses modern views about the structure and functions of Epac proteins (exchange proteins directly activated by cyclic adenosine monophosphate). The involvement of Epac proteins both in the regulation of the physiological functions of the body and in the initiation of various pathological processes allows to consider them as a fundamentally new biological target for creating original, highly effective drugs. Information on existing Epac protein agonists and antagonists was collected, and the influence of Epac ligands structure on the values of their affinity and selectivity was analyzed. Presumptive mechanisms of the interaction of ligands with Epac proteins are presented.

scholarly journals Phytochemical screening and HPLC- UV method quantiϐication of Flavonoids in Coffee Arabica green seeds

2020 ◽  
Vol 11 (SPL4) ◽  
pp. 1895-1904
Author(s):  
Bothiraj K V ◽  
Kalaivani P ◽  
Murugan K ◽  
Vanitha V
Keyword(s):  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Biologically Active ◽  
Coffee Bean ◽  
Green Coffee ◽  
High Concentration ◽  
Antimitotic Activity ◽  
Wide Range ◽  
Anti Inflammatory ◽  
Green Coffee Bean

The green coffee bean is the most commonly used beverages in India and it is one of the most commercialised food products. They have a rich source of biologically active compounds that are important for human health. The coffee tree or a shrub belongs to the family Rubiaceae. Commercially available, two species of green coffee bean are Coffea Arabica and Coffea canephora. Cancer is the most important cause of death. Apart from cancer, quercetin can also prevent Osteoporosis. The phytochemicals present in the green coffee bean can be used as an alternate therapy for cancer due to its antimitotic activity and free radical scavenging activity. Total antioxidant shows IC50 value 45.81. Kaempferol is a potent antioxidant that can defence against free radicals and cure chronic diseases. Flavonoids are phenolic substances that act as an antioxidant, anti-inflammatory, anti-allergenic, antiviral and also have vasodilating actions. Green coffee bean shows a high concentration of Flavonoids in hydroethanolic extraction. The aim of this study is used to analyse the presence of Flavonoids in green coffee bean by using High-performance Liquid Chromatography (HPLC). Flavonoids are potent antioxidant that can bind to a protein. Flavonoids show a wide range of biological and pharmacological activities like anti-allergic, anti-inflammatory, anti-cancer and anti-microbial activity.

scholarly journals Aktivitas Antioksidan Minuman Daun Beluntas Teh Hitam (Pluchea indica Less-Camelia sinensis)

2018 ◽  
Vol 38 (2) ◽  
pp. 200
Author(s):  
Paini Sri Widyawati ◽  
Tarsisius Dwi Wibawa Budianta ◽  
Yesiana Dwi Wahyu Werdani ◽  
Maria Olivia Halim
Keyword(s):  
Free Radical ◽  
Secondary Metabolites ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Reducing Power ◽  
Black Tea ◽  
Free Radical Scavenging ◽  
Free Radical Scavenging Activity ◽  
Scavenging Activity ◽  
Iron Ion

The research was conducted to explore the potency of pluchea leaves-black tea drink as antioxidant at various proportions. The research used a single factor randomized block design of pluchea leaves and black tea proportions, including 100:0; 75:25; 50:50; 25:75; and 0:100% (w/w). Each of it was repeated five times. The parameters observed in this study were secondary metabolites, total phenolic, total flavonoids, free radical DPPH scavenging activity, and iron reducing power. The data were statistically analyzed using Analysis of Variance (ANOVA) at α = 5%, if the analysis showed a significant effect then it was continued with Duncan's Multiple Range Test (DMRT). Data was stated as mean ± standard deviation. The results showed that the secondary metabolites containing in drink from pluchea leaves and black tea at various proportions were alkaloids, flavonoids, phenolics, saponins, tannins, and cardiac glycosides. The increasing of black tea proportion in samples added the intensity of alkaloids, phenolics, flavonoids, saponins, and cardiac glycosides compounds detected, but the tannins were decreased. These secondary metabolites were correlated with total phenolic content (TPC) and total flavonoid content (TFC). The increasing of black tea proportion in drink significantly decreased DPPH free radical scavenging activity and iron ion reducing power, except for 100% black tea proportion. Tannin compounds seems determining antioxidant activity.  Based on coefficient correlation between TPC or TFC and DPPH free radical scavenging activity or iron ion reducing power, the result showed that DPPH free radical scavenging activity was dominantly contributed by TPC and iron ion reducing power was determined by TPC and TFC. ABSTRAKPenelitian ini dilakukan untuk mengetahui potensi minuman daun beluntas teh hitam sebagai antioksidan pada berbagai proporsi. Penelitian ini menggunakan rancangan acak kelompok satu faktor, yaitu proporsi daun beluntas teh hitam meliputi 100:0; 75:25; 50:50; 25:75; dan 0:100% (b/b). Tiap faktor diulang sebanyak 5 kali. Parameter yang diamati pada penelitian ini meliputi kandungan metabolit sekunder, total fenolik (TPC), total flavonoid (TFC), kemampuan menangkal radikal bebas DPPH, dan kemampuan mereduksi ion besi. Data dianalisis secara statistik dengan Analysis of Variance (ANOVA) pada α = 5%, jika terdapat beda signifikan dilanjutkan dengan uji Duncan's Multiple Range Test (DMRT). Data dinyatakan dengan rata-rata ± standar deviasi.  Hasil menunjukkan bahwa metabolit sekunder yang terkandung dalam minuman daun beluntas teh hitam pada berbagai proporsi adalah alkaloid, flavonoid, fenolik, saponin, tannin, dan kardiak glikosida. Peningkatan proporsi teh hitam menambah intensitas senyawa alkaloid, fenolik, flavonoid, saponin, dan kardiak glikosida yang terdeteksi, tetapi kandungan senyawa tannin berkurang. Kandungan metabolit sekunder ini berkorelasi dengan total fenolik (TPC) dan total flavonoid (TFC). Peningkatan proporsi teh hitam dalam minuman menurunkan kemampuan menangkal radikal bebas DPPH dan kemampuan mereduksi ion besi, kecuali pada proporsi teh hitam 100%. Kandungan senyawa tannin dalam minuman menentukan aktivitas antioksidan. Berdasarkan koefisien korelasi antara TPC atau TFC dan kemampuan menangkal radikal bebas DPPH atau kemampuan mereduksi ion besi, hasil menunjukkan bahwa kemampuan menangkal radikal bebas DPPH dominan dikontribusi oleh TPC dan kemampuan mereduksi ion besi ditentukan oleh TPC dan TFC.

Effect of P1-purinergic agonist on thyrotropin stimulation of H2O2 generation in FRTL-5 and porcine thyroid cells

1994 ◽  
Vol 130 (2) ◽  
pp. 180-186 ◽  
Author(s):  
Ulla Björkman ◽  
Ragnar Ekholm
Keyword(s):  
Adenylate Cyclase ◽  
Primary Culture ◽  
Purinergic Receptor ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Camp Accumulation ◽  
High Concentration ◽  
Thyroid Cells ◽  
H2o2 Generation ◽  
Stimulation Of

Björkman U, Ekholm R. Effect of P1-purinergic agonist on thyrotropin stimulation of H2O2 generation in FRTL-5 and porcine thyroid cells. Eur J Endocrinol 1994;130:180–6. ISSN 0804–4643 Our previous studies have shown that the generation of H2O2 in FRTL-5 thyroid cells is regulated via both the adenylate cyclase/cyclic adenosine monophosphate (cAMP) and Ca2+/phosphatidylinositol pathway: thyrotropin (TSH) stimulates H2O2 generation through both pathways, via the former at a low concentration and via the latter at a high concentration. In porcine thyrocytes in primary culture H2O2 generation is stimulated only via the Ca2+/phosphatidylinositol route. In the present study we explored the effect of a P1-purinergic agonist (phenylisopropyladenosine, PIA) on stimulations induced by TSH and by adenosine triphosphate (ATP), an activator of the Ca2+/phosphatidylinositol cascade via the P2-purinergic receptor. In FRTL- 5 cells, PIA potentiated H2O2 generation stimulated by TSH at 10U/l (but not at 1 U/l), Ca2+ mobilization induced by TSH and Ca2+ mobilization induced by ATP at 1 μmol/l (but not 10 μmol/l). Phenylisopropyladenosine strongly inhibited TSH-induced cAMP accumulation in FRTL-5 cells. In pig thyrocytes, PIA had no effect on H2O2 generation stimulated by TSH or ATP and no effect on ATP-stimulated Ca2+ mobilization. Also, PIA did not inhibit TSH-stimulated cAMP accumulation in pig thyrocytes, and by itselfhad no effecton H2O2 generation or Ca2 + mobilization. Thus, in FRTL-5 cells, but not in porcine thyrocytes, PIA modulates TSH-stimulated H2O2 generation by enhancing the Ca2+/phosphatitylinositol route and inhibiting the adenylate cyclase/cAMP route of the TSH signal. The net result of this modulation apparently depends on the balance between inhibition of the cAMP route and enhancement of the Ca2+ route. This may explain the lack of potentiation observed by 1 U/1 TSH. Ragnar Ekholm, Department of Anatomy, Medicinaregatan 3, S-413 90 Göteborg, Sweden

scholarly journals An injectable refrigerated hydrogel for Inducing local hypothermia and neuroprotection against traumatic brain injury

2020 ◽  
Author(s):  
yuhan Han ◽  
ZhengZhong Han ◽  
Xuyang Huang ◽  
Feng Qian ◽  
Jun Jia ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Side Effects ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Controlled Drug Release ◽  
The Body ◽  
Whole Body ◽  
Local Hypothermia ◽  
Whole Body Cooling

Abstract Hypothermia is a promising therapy for Traumatic brain injury (TBI) in the clinic. However, the neuroprotective outcomes of hypothermia-treated TBI are not consistent in clinical studies due to several severe side effects. Here, an injectable refrigerated hydrogel is designed to deliver 3-iodothyronamine (T1AM) to achieve a longer period of local hypothermia for TBI treatment. The hydrogel has four advantages: (1) It can be injected into injured site after TBI, where it forms a hydrogel and avoids the side effects of whole-body cooling. (2) The hydrogel can biodegrade and be used for controlled drug release. (3) Released T1AM can bind to trace amine-associated receptor 1 (TAAR1) to produce cyclic adenosine monophosphate (cAMP), which induces hypothermia. (4) This hydrogel has an increased medical value due to its simple operation and ability to achieve timely treatment. This hydrogel is able to cool the brain to 30.25 ± 2.25 °C for 12 hours while maintaining the body temperature at 36.80 ± 1.75 °C after TBI. More importantly, the hypothermia induced by this hydrogel leads to the maintenance of blood-brain barrier (BBB) integrity, the prevention of cell death, the reduction of the inflammatory response and brain edema, and the promotion of functional recovery after TBI. This cooling method can potentially be developed as a new approach for hypothermia treatment in TBI.

scholarly journals Evaluation of Antioxidant Status in Cold Brewed Tea with Respect to Hot Decoction: Comparative Study Between Green and Black Varieties

2018 ◽  
Vol 9 (07) ◽  
Author(s):  
Chandrima Das ◽  
Sirshendu Chatterjee
Keyword(s):  
Ascorbic Acid ◽  
Antioxidant Status ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Black Tea ◽  
Free Radical Scavenging ◽  
Scavenging Activity ◽  
Significant Difference ◽  
Cold Condition ◽  
Ancient Times

Tea is known as nature low calorie wonder drink. Consumption of hot tea decoction became popular from the ancient times. Currently researchers observed that many secondary metabolites that are heat sensitive might get destroyed on heating. Moreover people, who are permanently live at higher altitude or the members of high altitude expedition team, are deprived of various tea brewing facilities like electricity, fuel etc and hence they have to depend on brewing tea at cold condition only for consumption. In this backdrop present study aims at analysis of antioxidants like polyphenols, flavonoids and free radical scavenging activity of cold brewed tea and compared with its hot decoction. The study highlighted that cold brewed green tea harbour more polyphenolics and flavonoids with respect to its hot decoction. However no significant change being observed between hot and cold decoction of black tea. It is also observed that mg Ascorbic Acid Equivalent per cup of cold and hot tea brew has no significant difference and hence both the brews can be consumed for replenishment of antioxidant requirements

scholarly journals Scavenging of Free Radicals Generated in Biological Tissues Exposed to Ionizing Radiation Using Silver Nanoparticles

2020 ◽  
pp. 2257-2265
Author(s):  
Asia H. Al-Mashhadani ◽  
Omar Salah Ashour
Keyword(s):  
Silver Nanoparticles ◽  
Free Radicals ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Electrical Explosion ◽  
Biological Tissues ◽  
The Body ◽  
Nuclear Radiation ◽  
Body Tissues ◽  
Before And After

Humans are exposed to nuclear radiations every day, and these radiations are both natural and artificial. When the body tissues are exposed to nuclear radiation, free radicals are formed, which are responsible for cancer development. In this research, silver nanoparticles were synthesized by electrical explosion wire method. Nanoparticles were added to deionized water that contained free radicals before and after exposure to gamma rays. The obtained results indicate that the silver nanoparticles have antioxidant potential through possessing free radical scavenging activity, as they can donate electron to free radicals and become neutralize. Then, these nanoparticles were injected to mice before and after their irradiation with gamma ray. The liver and kidney of the mice were shown to be unaffected by gamma irradiation.

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