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In this work, we synthesized a series of new 9,10‐dihydro‐2H,8H‐chromeno[8,7e][1,3]oxazine‐2‐on derivatives which incorporate isobornylcoumarin and 1,3‐oxazine moieties. A structure‐antioxidant activity relationship was analyzed. A comparative evaluation of their radical scavenging activity, antioxidant and membrane‐protective properties was carried out in test with DPPH, as well as on the models of Fe2+/ascorbate‐initiated lipid peroxidation and oxidative hemolysis of mammalian red blood cells. The results suggest that all the obtained coumarin[1,3]oxazine derivatives of 7‐hydroxy‐6‐isobornyl‐4‐methylcoumarin are capable of exhibiting antioxidant activity in various model systems. Compound 7 with a phenyl fragment, combining high radical scavenging activity and the ability to inhibit Fe2+/ascorbate‐initiated peroxidation of animal lipids in a heterogeneous environment, also proved to be the most effective membrane protector and antioxidant in the model of H2O2‐induced erythrocyte hemolysis. [ABSTRACT FROM AUTHOR]

Natural monoterpenes and their derivatives are widely considered as effective ingredients for the design and production of new biologically active compounds with high antioxidant, antimicrobial and anti-protozoa properties. In this study, we synthesized two series of thiotherpenoids "sulfide-sulfoxide-sulfone", with different bicyclic monoterpene skeleton (bornane and pinane) structures. The effect of the obtained compounds on platelet aggregation was investigated by using the molecular docking technique. The obtained data revealed that all the synthesized compounds may act as potential inhibitors of platelet aggregation. Moreover, the studied sulfides have shown high antioxidant activity as revealed by lipid peroxidation (LPO) process inhibition in a non-cellular substrate containing animal lipids. The sulfides were able to inhibit erythrocyte oxidative hemolysis, to reduce the accumulation of secondary LPO products in cells and to prevent the oxidation of native oxyhemoglobin. Additionally, the corresponding sulfones and sulfoxides exhibited insignificant antioxidant activity. However, the sulfides were found to exhibit significant antiaggregant and anticoagulant effects. These findings suggest as well that the sulfides could serve as a leader compound for future research and possible practical applications. [ABSTRACT FROM AUTHOR]

In order to explore the extractives of conifers an effective and environmentally friendly method of extraction with aqueous-alkaline solution allowing to isolate up to 10.4% of extractive substances (ES) from pine wood greenery and up to 6.9% from larch wood greenery was investigated. The component fractional composition of aqueous-alkaline extracts was studied. The antioxidant fraction activity of neutral and acidic components isolated from the produced extracts was evaluated. It was found that these fractions have a high antioxidant activity, where the activity of larch extract components was higher than that of the respective components of pine extract. Due to their rich chemical composition and high biological activity, extracts of pine and larch wood greenery produced by aqueous-alkaline extraction have good application prospects as biologically active preparations. [ABSTRACT FROM AUTHOR]

A series of new C-4- and C-4/C-5-aminomethyl derivatives were synthesized on the basis of α- and γ-mangostins. A comparative evaluation of their chelating ability, radical scavenging activity and hemolytic activity, as well as antioxidant and membrane-protective properties, was carried out on the model of H 2 O 2 -induced hemolysis of mammalian red blood cells. It was shown that γ-mangostin and its C-4/C-5-derivatives were superior to α-mangostin and its derivatives in all the investigated parameters characterizing the antioxidant activity in the test systems used. Most of the synthesized Mannich bases at low concentrations were superior to the original α- and γ-mangostins in the ability to protect mammalian red blood cells under H 2 O 2 -induced oxidative stress conditions. [ABSTRACT FROM AUTHOR]

A set of four C-8-aminomethyl derivatives of quercetin has been synthesized by Mannich reaction. The synthesis was carried out using a simple procedure to give target compounds as hydrochlorides. Study of oxidative hemolysis on mice erythrocytes showed that derivatives with morpholinomethyl or thiomorpholinomethyl groups favorably differ from the original quercetin by the ability to protect cells from acute oxidative stress. Graphical abstract: [ABSTRACT FROM AUTHOR]

Small molecules show low efficacy in antioxidant therapy of cardiovascular diseases. Hemocompatible polymeric antioxidants are a potential alternative. In this work, we synthesize a new polymeric antioxidant based on cationic starch with covalently attached terpenophenol (CSt-DiBP). Water solutions of the resulting compounds show lower viscosity that the initial polymer solutions and have rheopexy properties. CSt-DiBPs are characterized by high antioxidant activity in several test systems and are able to effectively protect erythrocytes under conditions of acute oxidative stress. The analysis of the effect of the compounds on the components of plasma hemostasis and some shaped elements of human blood (in vitro), and the effects on plasma coagulation in experimental animals (in vivo) reveals that the synthesized polymeric antioxidants have high hemocompatibility in vitro and do not affect plasma coagulation in vivo. [Display omitted] • Cationic starch was covalently modified with terpenophenol fragments. • Conjugates are characterized by high radical scavenging and antioxidant activity in systems of varying complexity. • Conjugates strengthen the resistance of red blood cells to acute oxidative stress (in vitro). • Conjugates have good hemocompatibility (in vitro) and do not affect the coagulation of blood plasma (in vivo). [ABSTRACT FROM AUTHOR]

A series of new C-4-derivatives of α-mangostin has been synthesized with the use of Mannich reaction and alkylation with 4-bromomethyl-2,6-dialkylphenols. It has been shown on a model of H 2 O 2 -induced erythrocyte hemolysis that the Mannich bases containing morpholinomethyl and piperidinomethyl fragments differ from parent α-mangostin by their high antioxidant and membrane-protective activity. [ABSTRACT FROM AUTHOR]

• Aluminum oxyhydroxide is a good platform for immobilization of phytophenols. • Gallic, caffeic and ferulic acids retain antioxidant properties on AlOOH surface. • Phenols-modified nanoparticles (NPs) are nontoxic colloidally stable hydrosols. • Mechanism of phenolic acids interaction with AlOOH is proposed. • Modified AlOOH NPs protect erythrocytes and lipids against oxidation. Oxidative stress has been associated with a wide spectrum of diseases in the modern era. Antioxidative therapy has demonstrated significant potential in prevention and therapy of cancer, cardiovascular and neurodegenerative diseases. However, molecular forms of natural phenolic antioxidants lack efficiency due to low bioavailability, compatibility, and stability. The aim of the present study was to preserve and improve the properties of phenolic antioxidants immobilizing them on sol-gel derived γ-AlOOH (pseudoboehmite) nanoparticles. The prepared formulations with gallic, caffeic, and ferulic acids are in the form of hydrosols. Results show that modified AlOOH nanoparticles exhibit good colloidal stability at wide pH range and in presence of background electrolyte. Carboxylic groups of phenols play an active role in interaction with pseudoboehmite slightly changing its surface properties. Modification of AlOOH nanoparticles shifts its isoelectric point from basic to more neutral values, changes pK a values and lowers number of acid-base centers. The studied pseudoboehmite-phenol systems show high radical scavenging activity, pronounced membrane-protective and antioxidant properties on cellular and non-cellular models in vitro , enhancing efficiency of phenolic acids. The prepared nanoantioxidants can be used to develop delivery systems of various therapeutic agents and pave a way to new therapeutic strategies for treatment and prevention of socially significant diseases. [Display omitted] [ABSTRACT FROM AUTHOR]