Correlação entre composição química e eficácia antioxidante de óleos essenciais de plantas condimentares por análise de agrupamentos hierárquicos (HCA)

Abstract

The essential oils extracted from herbs and spices have been used to accentuate the sensory characteristics of food and these oils have been tested for antioxidant properties since they have gained great importance due the natural product status, the worldwide acceptance by consumers and the potential multifunctional application. In this work we have aimed to analyze the chemical composition of essential oils extracted from fresh leaves of thyme, lemon grass, wild basil and sweet basil. In addition, we have also interested to test the antioxidant activity by different methodologies such as kidnapping of radical DPPH, oxidation of β- carotene and linoleic acid system. We tested the antioxidant activities of one of the standard major constituents e.g. thymol, citral, eugenol and linalool using as positive controls the synthetic antioxidant ascorbic acid, BHA and BHT. Additionally, we correlated the chemical composition and the concentration of 50% inhibition (IC50) of these essential oils through hierarchical cluster analysis (HCA).The major constituents in essential oils of fresh leaves of thyme, lemon grass, wild basil and sweet basil are thymol, p-cymene and γ-terpinen; geranial, neral and myrcene; eugenol, (γ)-muuruleno and (Z)-β-ocimene; cineol, linalool and camphor, respectively. The samples which show higher antioxidant activities are the eugenol and the essential oil of wild basil. Using the HCA, it is observed essential oils and their standards are grouped due to similarity in the quantities of monoterpenes and phenylpropanoids. This study might be important to find and to analyze new compounds of natural origin which will enable to inhibit oxidation.