Antioxidants from laurel (Laurus nobilis L.) berries:: influence of extraction procedure on yield and antioxidant activity of extracts

The antioxidant activities of laurel (Laurus nobilis L.) berries extracts were evaluated using a DPPH assay, a beta-carotene/linoleic acid assay and the Rancimat method. Pericarp and kernel of berries were extracted by different extraction methods with solvents of different polarities. Extraction method and extracting solvents significantly affected the yield, total phenolics and antioxidant activity of the extracts. Total phenolic content varied from 142.4 to 168.1 mg gallic acid equivalent (GAE) g(-1) in pericarp extracts and from 233-240.4 mg GEA g(-1) in kernel extracts. Kernel extract by Soxhlet method with 80% ethanol showed the highest scavenging activity of 50.78% at 12 mu g ml(-1) by the DPPH. Fifty percent ethanol extract of pericarp exhibited the strongest antioxidant activity (85.56%) by the beta-carotene/linoleic acid system. Protection Factor of all kernel extracts determined by the Rancimat method was comparable with that of BHT. No correlation was found between the total phenolics and antioxidant activities of the extracts.