2,3-dihydro derivative of quercetin. Effective free radical scavenger. Taxifolin had an IC50 value of 30.1 nM and a Ki value of 16.7 +/- 3.9 nM non-competitive and not specific: inhibits carbonic anhydrase isoenzymes I and II similarily. Dihydroquercetin is proposed for the treatment of oxidative stress in severe acute respiratory syndrome COVID-19
Alzheimer's disease (AD) is a multifactorial disease and the most common form of dementia. There are no treatments to cure, prevent or slow down the progression of the disease. Natural products hold considerable interest for the development of preventive neuroprotectants to treat neurodegenerative disorders like AD, due to their low toxicity and general beneficial effects on human health with their anti-inflammatory and antioxidant features. In this work we describe regioselective synthesis of 7-O-ester hybrids of the flavonoid taxifolin with the phenolic acids cinnamic and ferulic acid, namely 7-O-cinnamoyltaxifolin and 7-O-feruloyltaxifolin. The compounds show pronounced overadditive neuroprotective effects against oxytosis, ferroptosis and ATP depletion in the murine hippocampal neuron HT22cell model. Furthermore, 7-O-cinnamoyltaxifolin and 7-O-feruloyltaxifolin reduced LPS-induced neuroinflammation in BV-2 microglia cells as assessed by effects on the levels of NO, IL6 and TNFalpha. In all in vitro assays the 7-O-esters of taxifolin and ferulic or cinnamic acid showed strong overadditive activity, significantly exceeding the effects of the individual components and the equimolar mixtures thereof, which were almost inactive in all of the assays at the tested concentrations. In vivo studies confirmed this overadditive effect. Treatment of an AD mouse model based on the injection of oligomerized Abeta25-35 peptide into the brain to cause neurotoxicity and subsequently memory deficits with 7-O-cinnamoyltaxifolin or 7-O-feruloyltaxifolin resulted in improved performance in an assay for short-term memory as compared to vehicle and mice treated with the respective equimolar mixtures. These results highlight the benefits of natural product hybrids as a novel compound class with potential use for drug discovery in neurodegenerative diseases due to their pharmacological profile that is distinct from the individual natural components.
        
Title: Screening and identification of secondary metabolites in the bark of Bauhinia variegata to treat Alzheimer's disease by using molecular docking and molecular dynamics simulations Khare N, Maheshwari SK, Jha AK Ref: J Biomol Struct Dyn, :1, 2020 : PubMed
Acetylcholinesterase (AChE) and Butyrylcholinesterase (BChE) acts as a promising protein targets for which drug as an inhibitor can be designed to treat Alzheimer's Disease. Different flavonoids and alkaloids of Bauhinia variegata were used as an inhibitor to target the protein. The current in silico study was carried out to explore the binding patterns of flavanoids and alkaloids against Acetylcholinesterase (PDB ID: 4PQE) and Butyrylcholinesterase (PDB ID: 1P0I) using molecular docking and molecular dynamics simulations approach. Molecular docking result shows that Dihydroquercetin (CID:439533) binds with the active region of AChE and BChE. Using molsoft, molinspiration, and pkCSM all the properties of the candidate were analyzed. The best compound Dihydroquercetin was compared with Donepezil drug through molecular dynamic simulation studies. The analysis of Molecular Dynamics Simulations showed that AChE and AChE-Dihydroquercetin complex became stable at 3000 ps and there was little conformational change in BChE and BChE-Dihydroquercetin complex. The in silico study finally predicts that Dihydroquercetin may act as a good inhibitor for treating Alzheimer's disease and further in vitro and in vivo studies may prove its therapeutic potential. Communicated by Ramaswamy H. Sarma.
Taxifolin, also known as dihydroquercetin, is a flavonoid commonly found in plants. Carbonic anhydrase (CA, EC 4.2.1.1) plays an important role in many critical physiological events including carbon dioxide (CO2)/bicarbonate ([Formula: see text]) respiration and pH regulation. There are 16 known CA isoforms in humans, of which human hCA isoenzymes I and II (hCA I and II) are ubiquitous cytosolic isoforms. In this study, the inhibition properties of taxifolin against the slow cytosolic isoenzyme hCA I, and the ubiquitous and dominant rapid cytosolic isoenzyme hCA II were studied. Taxifolin, as a naturally bioactive flavonoid, has a Ki of 29.2 nM against hCA I, and 24.2 nM against hCA II. For acetylcholinesterase enzyme (AChE) inhibition, Ki parameter of taxifolin was determined to be 16.7 nM. These results clearly show that taxifolin inhibited both CA isoenzymes and AChE at the nM levels.
Alzheimer's disease (AD) is a multifactorial disease and the most common form of dementia. There are no treatments to cure, prevent or slow down the progression of the disease. Natural products hold considerable interest for the development of preventive neuroprotectants to treat neurodegenerative disorders like AD, due to their low toxicity and general beneficial effects on human health with their anti-inflammatory and antioxidant features. In this work we describe regioselective synthesis of 7-O-ester hybrids of the flavonoid taxifolin with the phenolic acids cinnamic and ferulic acid, namely 7-O-cinnamoyltaxifolin and 7-O-feruloyltaxifolin. The compounds show pronounced overadditive neuroprotective effects against oxytosis, ferroptosis and ATP depletion in the murine hippocampal neuron HT22cell model. Furthermore, 7-O-cinnamoyltaxifolin and 7-O-feruloyltaxifolin reduced LPS-induced neuroinflammation in BV-2 microglia cells as assessed by effects on the levels of NO, IL6 and TNFalpha. In all in vitro assays the 7-O-esters of taxifolin and ferulic or cinnamic acid showed strong overadditive activity, significantly exceeding the effects of the individual components and the equimolar mixtures thereof, which were almost inactive in all of the assays at the tested concentrations. In vivo studies confirmed this overadditive effect. Treatment of an AD mouse model based on the injection of oligomerized Abeta25-35 peptide into the brain to cause neurotoxicity and subsequently memory deficits with 7-O-cinnamoyltaxifolin or 7-O-feruloyltaxifolin resulted in improved performance in an assay for short-term memory as compared to vehicle and mice treated with the respective equimolar mixtures. These results highlight the benefits of natural product hybrids as a novel compound class with potential use for drug discovery in neurodegenerative diseases due to their pharmacological profile that is distinct from the individual natural components.
        
Title: Screening and identification of secondary metabolites in the bark of Bauhinia variegata to treat Alzheimer's disease by using molecular docking and molecular dynamics simulations Khare N, Maheshwari SK, Jha AK Ref: J Biomol Struct Dyn, :1, 2020 : PubMed
Acetylcholinesterase (AChE) and Butyrylcholinesterase (BChE) acts as a promising protein targets for which drug as an inhibitor can be designed to treat Alzheimer's Disease. Different flavonoids and alkaloids of Bauhinia variegata were used as an inhibitor to target the protein. The current in silico study was carried out to explore the binding patterns of flavanoids and alkaloids against Acetylcholinesterase (PDB ID: 4PQE) and Butyrylcholinesterase (PDB ID: 1P0I) using molecular docking and molecular dynamics simulations approach. Molecular docking result shows that Dihydroquercetin (CID:439533) binds with the active region of AChE and BChE. Using molsoft, molinspiration, and pkCSM all the properties of the candidate were analyzed. The best compound Dihydroquercetin was compared with Donepezil drug through molecular dynamic simulation studies. The analysis of Molecular Dynamics Simulations showed that AChE and AChE-Dihydroquercetin complex became stable at 3000 ps and there was little conformational change in BChE and BChE-Dihydroquercetin complex. The in silico study finally predicts that Dihydroquercetin may act as a good inhibitor for treating Alzheimer's disease and further in vitro and in vivo studies may prove its therapeutic potential. Communicated by Ramaswamy H. Sarma.
        
Title: Prospects for the use of regulators of oxidative stress in the comprehensive treatment of the novel Coronavirus Disease 2019 (COVID-19) and its complications Mironova GD, Belosludtseva NV, Ananyan MA Ref: Eur Rev Med Pharmacol Sci, 24:8585, 2020 : PubMed
Some surface proteins of the newly identified severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can bind to the hemoglobin molecule of an erythrocyte, which leads to the destruction of the structure of the heme and the release of harmful iron ions to the bloodstream. The degradation of hemoglobin results in the impairment of oxygen-carrying capacity of the blood, and the accumulation of free iron enhances the production of reactive oxygen species. Both events can lead to the development of oxidative stress. In this case, oxidative damage to the lungs leads then to the injuries of all other tissues and organs. The use of uridine, which preserves the structure of pulmonary alveoli and the air-blood barrier of the lungs in the course of experimental severe hypoxia, and dihydroquercetin, an effective free radical scavenger, is promising for the treatment of COVID-19. These drugs can also be used for the recovery of the body after the severe disease.
Taxifolin, also known as dihydroquercetin, is a flavonoid commonly found in plants. Carbonic anhydrase (CA, EC 4.2.1.1) plays an important role in many critical physiological events including carbon dioxide (CO2)/bicarbonate ([Formula: see text]) respiration and pH regulation. There are 16 known CA isoforms in humans, of which human hCA isoenzymes I and II (hCA I and II) are ubiquitous cytosolic isoforms. In this study, the inhibition properties of taxifolin against the slow cytosolic isoenzyme hCA I, and the ubiquitous and dominant rapid cytosolic isoenzyme hCA II were studied. Taxifolin, as a naturally bioactive flavonoid, has a Ki of 29.2 nM against hCA I, and 24.2 nM against hCA II. For acetylcholinesterase enzyme (AChE) inhibition, Ki parameter of taxifolin was determined to be 16.7 nM. These results clearly show that taxifolin inhibited both CA isoenzymes and AChE at the nM levels.