Antioxidant and Antiproliferative Activities of the Essential Oils from Thymbra capitata and Thymus Species Grown in Portugal.

Maria Graça Miguel,Javier Vioque,Custódia Gago,Cristina Megías,A. Cristina Figueiredo,Isabel Cortés-Giraldo,Maria Dulce Antunes,A. Sofia Lima

doi:10.1155/2015/851721

Abstract

The antioxidant and antiproliferative activities of the essential oils from Thymbra capitata and Thymus species grown in Portugal were evaluated. Thymbra and Thymus essential oils were grouped into two clusters: Cluster I in which carvacrol, thymol, p-cymene, α-terpineol, and γ-terpinene dominated and Cluster II in which thymol and carvacrol were absent and the main constituent was linalool. The ability for scavenging ABTS•+ and peroxyl free radicals as well as for preventing the growth of THP-1 leukemia cells was better in essential oils with the highest contents of thymol and carvacrol. These results show the importance of these two terpene-phenolic compounds as antioxidants and cytotoxic agents against THP-1 cells.

Highlights

Thymbra capitata and several Thymus species grown in Portugal produce essential oils (EOs) of interest for the food and fragrance industries and are of medicinal value
Earlier studies have shown the antioxidant potential of these EOs, but no previous report addressed the antiproliferative properties of the EOs from T. capitata and Thymus species grown in Portugal
Essential oils were isolated from fresh plant material by hydrodistillation for 3 h, using a Clevenger-type apparatus, according to the European Pharmacopoeia [11], and analyzed by gas chromatography (GC), for component quantification, and gas chromatography coupled to mass spectrometry (GCMS) for component identification, as detailed in Barbosa et al [2]

Summary

Introduction

Thymbra capitata and several Thymus species grown in Portugal produce essential oils (EOs) of interest for the food and fragrance industries and are of medicinal value. Opposite to essential oils of T. capitata, characterized by a great chemical homogeneity with high carvacrol relative amounts, Thymus EOs show many chemotypes [1]. This chemical polymorphism may represent a problem for the required efficacy constancy of an EO, the EOs isolated from T. capitata and from different Portuguese Thymus species have all been shown to possess anti-inflammatory, antimicrobial, antioxidant, antiparasitical, insecticidal, and nematicidal activity, among other biological properties [1,2,3,4,5,6,7,8,9,10]. Earlier studies have shown the antioxidant potential of these EOs, but no previous report addressed the antiproliferative properties of the EOs from T. capitata and Thymus species grown in Portugal. The in vitro antioxidant activity was evaluated with methodologies based on distinct mechanisms: one based on electron transfer and the other on hydrogen atom transfer (Trolox Equivalent Antioxidant Capacity (TEAC) and Oxygen Radical Antioxidant Capacity (ORAC), resp.)

Material and Methods

Antioxidant Activity

Antiproliferative Activity

Results and Discussion

Conclusions