Journal of Advances in Medical and Biomedical Research
Volume:19 Issue: 77, 2011

Utilization of plants as antioxidants in food processing has a potential for substitution of synthetic antioxidants. In the present work, some unexplored biological activities of Thymus daenensis, commercial thyme essential oils and thymol were comparatively studied.

Ferrous ion chelating was assessed by spectrophotometry by mixing the essential oils with diluted FeSO4 followed by addition of ferrozine. Antioxidative properties were assessed by beta carotene bleaching and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging tests. Gallic acid equivalent of ferric reduction was carried out using FeCl3. Super oxide anion radical scavenging was determined using xanthine oxidase and anti tyrosinase inhibitory activity was determined by a spectrophotometry method using a modified dopachrome method with L-DOPA as the substrate.

Chelating reaction of T. daenensis oil was dose dependent, and its super oxide anion radical scavenging property was higher than the commercial oil. Lipid peroxidation inhibition by T. daenensis oil was stronger and those of the commercial oil and thymol were approximately equal. DPPH free radical scavenging property of T. daenensis oil was higher than trolox, butylated hydroxytoluene and anisol (BHT and BHA). Ferric-reducing antioxidant power (FRAP) of T. daenensis oil was greater. The total phenolics anti tyrosinase IC50 were also determined.

The results point to the nutritional value of these plants in preventing formation of toxic reactive oxygen species, and show that Thymus daenensis, as a good antioxidant, can directly scavenge free radicals. The results from biological properties of Thymus daenensis are indicative of its potentials for use in food and drug industries.

Nowadays, mesenchymal stem cells (MSCs) are considered as a promising tool for treatment of different diseases. Due to the low frequency of MSCs, however, it seems inevitable to expand them in vitro prior to use, which could affect the quality of the cells. In all isolation procedures, the density gradient separation of Ficoll is used for volume reduction and RBC exclusion. In this study, the efficiency of Ficoll density gradient was evaluated.

Human bone marrow samples were laid over Ficoll. Following centrifugation, the upper fraction containing the mononuclear cell layer and the lower fraction (RBC layer) were used for in vitro culture. The number and characteristics of MSCs in both layers were then compared with each other.

Inspection of the cultured cells showed that the lower fraction contained MSC-like cells. These cells had spindle–like appearances and exhibited a high capacity for expansion. Furthermore, they showed a potential for differentiating into adipocyte and osteocyte differentiation. Cytofluorometric analysis showed that these cells were positive for CD73, CD90, and CD105, and negative for CD45, CD34, and CD31. It was also found that this fraction contained 58 ± 22% of the total isolated MSCs.

Density gradient is not a very efficient method for separation of MSCs because it leads to sedimentation of most of the cells to the lower compartment during centrifugation, which results in their exclusion. Therefore, there is a need for developing new methods to obtain larger amounts of MSCs from bone marrow.