Synthesis and Antioxidant Capacity of Some Derivatives of Sesamol at the C-6 Position.

Several synthetic approaches (aminomethylation, alkylation, condensation, etc.) have been used to synthesize derivatives based on the sesamol (1), natural phenol. The set of methods, including the study of antioxidant activity (AOA) by the ability to inhibit the initiated oxidation of animal lipids, radical scavenging activity, Fe2+ -chelation ability, as well as a comparative assessment of membrane-protective activity under the conditions of H2 O2 -induced hemolysis of mice red blood cells (RBCs), was used to analyze the antioxidant potential of the synthesized compounds. The synthesized derivatives have demonstrated different activity in the listed test systems, and we have identified compounds which appear to be most promising for a detailed study of their pharmacological properties.

Synthesis and Antioxidant Ability of Novel Derivatives Based on para-Coumaric Acid Containing Isobornyl Groups.

A series of novel esters and amides was synthesized on the basis of para-coumaric acid containing isobornyl groups in ortho-positions relative to the phenolic hydroxy group. Antioxidant properties of the obtained compounds were evaluated and compared on in vitro models: radical-scavenging ability, antioxidant activity on a substrate containing the lipids of animal brain, cytotoxicity of red blood cells, antioxidant and membrane-protective properties on the model of oxidative red blood cells hemolysis. Statistically significant relationship was established between the antioxidant activity of the studied compounds in model system containing animal lipids and the parameters reflecting their antioxidant properties on the model of H2 O2 -induced hemolysis of red blood cells. It was determined that an amide with a morpholine fragment has the highest antioxidant activity. The specified derivative significantly surpassed the reference substances (parent acid, BHT) and was not inferior to the effective antioxidant 2,6-diisobornyl-4-methylphenol in terms of its properties.

Novel Aminomethyl Derivatives of 4-Methyl-2-prenylphenol: Synthesis and Antioxidant Properties.

4-Methyl-2-prenylphenol (1) was synthesized from para-cresol and prenol, natural alcohol under the conditions of heterogeneous catalysis. A series of nine new aminomethyl derivatives with secondary and tertiary amino groups were obtained on the basis of compound 1. A comparative evaluation of their antioxidant properties was carried out using in vitro models. It was established that Mannich base with octylaminomethyl group has radical-scavenging activity, high Fe2+ -chelation ability as well as the ability to inhibit oxidative hemolysis of red blood cells.

Antiradical Activity of Porphyrins with a Diisobornylphenol Fragment at the Macrocycle Periphery.

This article focuses on the antiradical activity of a number of 2,6-diisobornylphenol-porphyrin conjugates with various spacers between the porphyrin and phenolic fragments in the model reaction of ethylbenzene oxidation initiated by azoisobutyric acid dinitrile. The study has shown that the electronic effects of the groups directly related to the 2,6-diisobornylphenol fragment exert the predominant influence both on the reactivity of the phenolic hydroxyl group in interaction with free radicals and on the antiradical activity of the molecule as a whole. The antiradical activity of the molecule is generally less affected by the nature of the substituents in the porphyrin macrocycle, mainly due to a change in the stoichiometric inhibition coefficient in the presence of relatively easily oxidizable groups. It was found that the length of the spacer between the porphyrin and phenolic fragments does not affect the antiradical activity of the conjugate.

Novel Mannich bases of α- and γ-mangostins: Synthesis and evaluation of antioxidant and membrane-protective activity.

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 H2O2-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 H2O2-induced oxidative stress conditions.

Synthesis and membrane-protective activity of novel derivatives of α-mangostin at the C-4 position.

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 H2O2-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.