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.