Comparative evaluation of 11 essential oils of different origin as functional antioxidants, antiradicals and antimicrobials in foods

aDipartimento delle Risorse Naturali e Culturali, Lab. Biologia farmaceutica & Biotrasformazioni, Università degli Studi di Ferrara, C.so Porta Mare 2, I-44100 Ferrara, Italy

bDipartimento di Scienze Farmaceutiche, Università degli Studi di Ferrara, via Fossato di Mortara 17–19, I-44100 Ferrara, Italy

cFundacion Chankuap’, Macas, Ecuador

dDipartimento di Biologia Evolutiva e Funzionale, Sez. Biologia Vegetale e Orto Botanico, Università degli Studi di Parma, Parco Area delle Scienze 11A, 43100 Parma, Italy


Received 15 March 2004; revised 22 June 2004; accepted 22 June 2004. Available online 28 September 2004.

Abstract
Eleven essential oils, namely, Cananga odorata (Annonaceae), Cupressus sempervirens (Cupressaceae), Curcuma longa (Zingiberaceae), Cymbopogon citratus (Poaceae), Eucalyptus globulus (Myrtaceae), Pinus radiata (Pinaceae), Piper crassinervium (Piperaceae), Psidium guayava (Myrtaceae), Rosmarinus officinalis (Lamiaceae), Thymus x citriodorus (Lamiaceae) and Zingiber officinale (Zingiberaceae), were characterized by means of GC and GC–MS and evaluated for their food functional ingredient related properties. These properties were compared to those of Thymus vulgaris essential oil, used as a reference ingredient. Antioxidant and radical-scavenging properties were tested by means of 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay, β-carotene bleaching test and luminol-photochemiluminescence (PCL) assay. In the DPPH assay, C. odorata, C. citratus, R. officinalis and C. longa showed major effectiveness, with a radical inhibition ranging from 59.6 ± 0.42–64.3 ± 0.45%. In the β-carotene bleaching test, C. odorata (75.5 ± 0.53%), R. officinalis (81.1 ± 0.57%) and C. longa (72.4 ± 0.51%) gave the best inhibition results. Similar results were obtained for the same essential oils in the PCL assay. Antimicrobial properties were obtained on five food-spoilage yeasts: Candida albicans ATCC 48274, Rhodotorula glutinis ATCC 16740, Schizosaccharomyces pombe ATCC 60232, Saccharomyces cerevisiae ATCC 2365, Yarrowia lypolitica ATCC 16617 . C. citratus and T. x citriodorus were the most effective against the tested strains. Suggestions on relationships between chemical composition and biological activities are outlined.