E. V. Buravlev

Separation of racemic ortho-isobornylphenol into enantiomers and evaluation of their antioxidant activity

Racemic ortho-isobornylphenol was separated into enantiomers through diastereomeric camphanates. The absolute configuration of chiral centers of the isolated products was determined by X-ray studies. Antioxidant activity and membrane-protective properties of the enantiomers were studied on the model of H2O2-induced hemolysis of erythrocytes.

Synthesis of new 2,6-diisobornyl-4-methylphenol derivatives

New 2,6-diisobornylphenol derivatives having formyl, hydroxymethyl, and carboxy groups in the para position with respect to the hydroxy group were synthesized. 4-Hydroxy-3,5-diisobornylbenzoic acid was obtained in a moderate yield through intermediate ortho ester and methyl ester.

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.

Comparative study of redox characteristics and antioxidant activity of porphyrins with 2,6-dialkylphenol groups

152 The oxidative stress of an organism is a result of the acceleration of lipid peroxidation (LPO) in cells and the formation of reactive oxygen species and free rad icals. This process leads to destruction of membranes, the emergence of numerous pathologies, and prema ture aging of the organism. The search for new antiox idants, as well as for methods to assess the antioxidant activity, is an important and interesting task [1]. Of particular interest are synthesis and study of properties of polyfunctional compounds with several pharma cophoric centers in the molecule, because such a com bination is able not only to enhance the known physi ological activity but also to cause the appearance of new types of physiological activity [2–4]. Ionol I (2,6 di tert butyl 4 methylphenol) is a known anti oxidant used in the manufacture of foodstuffs (food additive E321). 2,6 Diisobornyl 4 methylphenol (dibornol) IV is currently undergoing preclinical tri als as a promising drug [5]. CHEMISTRY

New tertiary aminomethylphenols having an isobornyl substituent

New tertiary aminomethylphenols having an isobornyl fragment in the ortho position with respect to the phenolic hydroxy group were synthesized by the Mannich reaction.

Simple synthesis of a terpenophenol—chlorin conjugate with an amide bond

A terpenophenol with a butylaminomethyl group was synthesized and conjugated to a chlorin macrocycle through formation of an amide bond without using activating reagents.

ANTI-INFLAMMATORY ACTIVITY OF ISOBORNYLPHENOL DERIVATIVES

Nonsteroidal anti-inflammatory drugs and non-narcotic analgesics are widely used to treat various inflammatory diseases of infectious and noninfectious nature [1]. The development of new drugs based on terpenophenols, which have a unique set of pharmacological properties [2], is highly promising. The literature teaches that phenols with a bicyclic isobornyl moiety exhibit anti-infection activity [3]. The series of studies performed by us on the synthesis and investigation of terpenophenols showed that some alkylphenols exhibit hemorheological properties and improve brain blood flow [4, 5]. Thus, the synthesis of terpenophenols is critical for further studies of their physiological properties. Herein we present results from a study of the anti-inflammatory activity of the synthesized terpenophenols and their aminomethyl derivatives. A series of isobornylphenols (1a–e) with various substituents in the aromatic ring were prepared earlier via alkylation of phenols by the natural monoterpenoid camphene in the presence of the corresponding aluminum phenolates [6–8].

Membrane protective properties of carboxy derivatives based on 2,6-diisobornyl-4-methylphenol

Toxicity, antioxidant activity, and membrane protective properties were studied on mammalian red blood cells for carboxy derivatives and esters of 2,6-diisobornyl-4-methylphenol in comparison with both diastereomers (meso-form and racemate) of this terpenophenol. The studies showed that all the synthesized compounds posses an antioxidant activity, however, the cytotoxicity of derivatives with a free carboxy group might be an obstacle to the use of these compounds in pharmacology. The most promising compound is methyl 4-hydroxy-3,5-diisobornylbenzoate distinguished by a low toxicity and high antioxidant and membrane protective activity, which is comparable to that of 2,6-diisobornyl-4-methylphenol.

Synthesis of novel terpenophenol-chlorin conjugates and evaluation of their membranotropic and membrane-protecting properties

A series of conjugates has been synthesized by the reaction of methylpheophorbide a with ortho-alkylaminomethyl derivatives of 2-isobornyl-4-methylphenol; the terpenophenol fragment in the conjugates is attached to the methylpheophorbide a macrocycle by an amide bond formed upon the amidation of the 13(2)-ester group. A scanning electron microscopy study of the surface structure of erythrocytes incubated with these compounds confirmed their ability to interact with the cell membrane. It was found, based on the ability of the conjugates to inhibit the H2O2-induced hemolysis of erythrocytes and slow down the accumulation of the secondary lipid peroxidation products, that they possess membrane-protecting and antioxidant properties.

Synthesis and membrane protective activity of 4-alkoxymethyl-2,6-diisobornylphenols

Bromination of 2,6-diisobornyl-4-methylphenol gave the corresponding 4-bromomethyl derivative, whose reaction with alcohols resulted in 4-alkoxymethyl-2,6-diisobornylphenols. Their toxicity, membrane protective and antioxidant activity were tested using red blood cells of laboratory mice. The synthesized compounds do not exhibit cytotoxicity at the concentrations of 10 and 100 μmol L–1 and are characterized by high membrane protective and antioxidant activity in the concentrations of 1 and 10 μmol L–1.