The antioxidant activities of laurel (
L.) berries extracts were evaluated using a DPPH assay, a β-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
in pericarp extracts and from 233–240.4 mg GEA g
in kernel extracts. Kernel extract by Soxhlet method with 80% ethanol showed the highest scavenging activity of 50.78% at 12 µg ml
by the DPPH. Fifty percent ethanol extract of pericarp exhibited the strongest antioxidant activity (85.56%) by the β-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.
Chemical compositions, crystalline structures and thermal properties of bombax cotton and natural colored cottons including
laurel green, bottle green and brown cotton were investigated by chemical analysis, SEM, IR spectra and X-ray diffraction.
The results showed that the crystallinity and crystallite sizes of laurel green cotton were lower than those of bottle green
cotton because of the excess content of suberin in the former. The crystallinity of brown cotton was similar to that of white
cotton, and bombax cotton had the lowest crystallinity but its crystallite orientation was the highest. Thermal property of
bottle green cotton was the most stable, whose decomposition temperature was higher of 30°C than that of common white cotton
because of its higher lignin content, and bombax cotton had the lowest thermal degradation temperature. But bottle green cotton
reached the highest decomposition speed and made decomposition finish within a very short time, and bombax cotton was just
Authors:Iveta Placha, Lubica Chrastinova, Andrea Laukova, Klaudia Cobanova, Jana Takacova, Viola Strompfova, Maria Chrenkova, Zuzana Formelova, and Stefan Faix
Baratta, M. T., Dorman, H. J. D., Deans, S. G., Biondi, D. M. and Ruberto, G. (1998): Chemical composition, antimicrobial and antioxidant activity of laurel, sage, rosemary, oregano and coriander essential oils. J. Essent. Oil Res. 10 , 618