Identification and determination of the fatty acid composition of Quercus brantii growing in southwestern Iran by GC-MS.

This article reports the fatty acid composition of the oil extracts from Quercus brantii fruits growing in Kohgiloye va Boyer Ahmad province in southwestern Iran. The oil from Q. brantii fruits was extracted with hexane in Soxhlet apparatus and subsequently identified and determined by using gas chromatography-mass spectroscopy. The results revealed that the major fatty acids were oleic acid (52.99-66.14%), linoleic acid (10.80-11.11%), palmitic acid (8.08-10.06%), stearic acid (0.74-1.57%), α-linolenic acid (0.19-0.35%), erucic acid (0.12-0.15%) and arachidic acid (0.12-0.13%). The total proportion of unsaturated and saturated oil was 64.60-77.27% and 9.17-11.75%, respectively. Results indicate that the fruits of Q. brantii contained 0.19-0.35% omega-3, 10.92-14.77% omega-6 and 53.14-66.26% omega-9. Therefore, Q. brantii can be introduced as rich sources of fatty acid in food dietary and medical health.

Different patterns of DNA methylation of the two distinct O6-methylguanine-DNA methyltransferase (O6-MGMT) promoter regions in colorectal cancer.

Colorectal cancer (CRC) is the third most common cancer worldwide. Colorectal cancer incidence differs widely among different geographic regions. In addition to mutational changes, epigenetic mechanisms also play important roles in the pathogenesis of CRCs. O6-methylguanine-DNA methyltransferase (O(6)-MGMT) is a DNA repair protein and in the absence of MGMT activity, G-to-A transition may accumulate in the specific genes such as K-ras and p53. To identify which CpG sites are critical for its downregulation, we analyzed the methylation status of the MGMT gene promoter in two sites in CRC patients. Then we compared the frequency of their methylation changes with the results of our previously reported K-ras gene mutation, APC2 and p16 methylation. MGMT methylation was examined in 92 tumor samples. A methylation specific PCR (MSP) method was performed for two loci of MGMT gene which described as MGMT-A and MGMT-B. The prevalence of MGMT-A, and MGMT-B methylation was 49/91 (53.8%), and 83/92 (90.2%), respectively. We detected high frequency of MGMT-B but not MGMT-A methylation in tumor tissues with APC2 methylation. Our results showed that MGMT-B methylation is significantly associated with K-ras gene mutation rather than MGMT-A (p = 0.04). Simultaneously, an inverse correlation was found between p16 and MGMT-B methylation simultaneously (p = 0.02). Our study indicated that hypermethylation of the specific locus near the MGMT start codon is critical for cancer progression. MGMT-B assessment that is associated with K-ras mutation can have a prognostic value in patients with CRC.