In this study the antioxidant activity of methanolic extracts of oregano and sage samples was tested. Samples of oregano belonged to Origanum onites and O indercedens species, whilst samples of sage belonged to Salvia officinalis and S fruticosa species. Two methods were used to evaluate the antioxidant activity of sage and oregano extracts: the crocin test and the Rancimat test. The methanolic extracts were also analysed by HPLC for the qualitative/quantitative determination of phenolic compounds. The total phenolic compound content of oregano samples showed no significant differences between the two species, but rosmarinic acid was present in higher amount in O indercedens. Carvacrol content sharply differentiated flowers from leaves. Samples of O indercedens had a higher antioxidant activity evaluated by the crocin test, whereas no differences were evidenced by the Rancimat test. For sage samples, carnosic acid and methyl carnosate showed a significant difference between the two species, with S fruticosa samples having a higher content than S officinalis samples. Samples of S fruticosa also had a higher antioxidant activity evaluated by the crocin test. The antioxidant activities of sage samples were, on average, higher than those of oregano samples. Some samples of sage had a very high antioxidant activity, with induction times more than 10-fold higher than that of lard used as the reference sample.

Extra-virgin olive oils (EVOO), high in phenolic compounds with antioxidant properties, could be partly responsible for the lower mortality and incidence of cancer and CVD in the Mediterranean region. The present study aims to measure oxidative DNA damage in healthy human subjects consuming olive oils with different concentrations of natural phenols. A randomised cross-over trial of high-phenol EVOO (high-EVOO; 592 mg total phenols/kg) v. low-phenol EVOO (low-EVOO; 147 mg/kg) was conducted in ten postmenopausal women in Florence. Subjects were asked to substitute all types of fat and oils habitually consumed with the study oil (50 g/d) for 8 weeks in each period. Oxidative DNA damage was measured by the comet assay in peripheral blood lymphocytes, collected at each visit during the study period. Urine samples over 24 h were collected to measure the excretion of the olive oil phenols. The average of the four measurements of oxidative DNA damage during treatment with high-EVOO was 30 % lower than the average during the low-EVOO treatment (P¼ 0·02). Urinary excretion of hydroxytyrosol and its metabolite homovanillyl alcohol were significantly increased in subjects consuming high-EVOO. Despite the small sample size, the present study showed a reduction of DNA damage by consumption of an EVOO rich in phenols, particularly hydroxytyrosol.

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The hydrocarbon fraction of 30 virgin olive oils was analyzed, focusing in particular on the sesquiterpenes. The oil samples were of different geographical origins and obtained from different olive varieties. The hydrocarbon fraction was isolated by silica gel column chromatography of the unsaponifiable fraction of the oils. The sesquiterpene hydrocarbons were then fractionated, on the basis of their degree of unsaturation, by AgNO3 TLC and silica gel AgNO3 column chromatography. The composition of the sesquiterpenes was more complex than previously reported. Among the 31 sesquiterpenes detected, 24 have been tentatively identified, by comparison of the linear retention indices on two capillary columns of different polarities and mass spectra with those reported in the literature. The total concentration of the sesquiterpenes in the oils analyzed ranged from about 2 to 37 ppm. Among the sesquiterpenes the more abundant were alpha-farnesene, alpha-copaene, eremophyllene, and alpha-muurolene. The alkenes present in the hydrocarbon fraction were isolated by TLC AgNO3 and characterized by GC-MS of their dimethyl disulfide derivatives. The series of n-Delta9-alkenes from C22 to C27, 8-heptadecene, and 6,10-dimethyl-1-undecene were detected. Among the n-alkanes, those with an odd number of carbon atoms predominated in all of the analyzed oils, the most common being C23, C25, C27, and C29. The concentration of the n-alkenes ranged from about 0.5 to 2 ppm, whereas for the n-alkanes the range was from 30 to 177 ppm.

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