Antioxidant activity of extracts from plants growing in Sardinia.

The present work was carried out to study the effect of some plant methanol extracts and essential oils on lipid peroxidation in simple in vitro systems. The tested extracts were obtained from four plants, commonly known in the Mediterranean area, indigenous to Sardinia: Artemisia arborescens L., Calycotome villosa L., Daphne gnidium L. or naturalized in the island, Eucalyptus globulus Labill. The activity of the extracts was investigated during both autoxidation and iron or EDTA-mediated oxidation of linoleic acid at 37 degrees C in the absence of solvent, and compared with that of BHT, alpha-tocopherol and EDTA. During linoleic acid autoxidation all the extracts were active, showing an antioxidant activity in the order: BHT >alpha- tocopherol >Daphne gnidium (methanol extract) >Eucalyptus globulus (essential oil) >Calycotome villosa (essential oil) >Artemisia arborescens (essential oil and methanol extract) >Calycotome villosa (methanol extract). None showed any prooxidant activity. During the iron-catalysed oxidation of linoleic acid the oils were not active, while all the methanol extracts showed some efficiency in preventing the oxidation process. All the extracts were also tested on cell cultures to investigate their cytotoxic activity or their ability to inhibit the growth of some pathogenic microorganisms.