Folate Content of Fast Foods and Processed Foods

A trienzyme extraction method (use of alpha-amylase, protease and folate conjugase) for food folate assay has been used to release folate from the food matrix. In order to reduce the incubation time with three enzymes, folate values were compared between two incubation protocols; separate incubation (SI, incubated with alpha-amylase and conjugase separately for 2 hours after protease treatment) and combined incubation (CI, incubated with alpha-amylase and conjugase together for 2 hours after protease treatment) using 88 food items from 12 kinds of fast foods and processed foods. We found that folate values by CI were comparable to or higher than those by SI, indicating that CI might be a better extraction procedure to shorten the entire incubation time. We measured folate contents in 49 fast foods and 26 processed foods by microbiological assay after CI. Mean folate contents of one serving of various burgers ranged from 43.1 to 62.0 microgram. One serving of French fries, pizza, sandwich and triangled kimbab contained a mean of 53.3, 28.4, 47.4, and 25.7 microgram of folate, respectively. Folate contents of non-alcoholic beverages were very low, ranging from 1.0 to 5.2 microgram/100 g. Some of our values were comparable to the values in the folate database published in Korean Nutrition Society, however, some of the published values were 140 times higher than the measured values in this study. Folate values measured by the more recent modifications here can be used to update Korean folate database to accurately estimate dietary folate intake

Changes of Telomerase Activity and Proliferation by Inhibition of Reverse Transcriptase Activity in Human Cancer Cell / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: Activation of telomerase is proposed to be an essential step in cancer cell immortalization and cancer progression. 3'-azido-2',3'-dideoxythymidine (AZT), a reverse transcriptase inhibitor, was reported to be incorporated in telomeric sequences of immortalized cells in culture and to suppress the activity of telomerase and the cell proliferation. In this study, after induction of cancer cell senescence with long-term treatment of AZT, we investigated the dynamics of telomerase subunits (hTERT, hTR, TEP), transcription factors (c-Myc, Mad1), telomerase activity, and finally, telomere length in a human breast cancer cell line. MATERIALS AND METGODS: Human breast cancer cell (MDA-MB-231) was treated with AZT. Senescence was measured by senescence-associated beta-gal staining and apoptosis was counted by dTd enzyme assay. Telomerase activity (by TRAP assay), expression of telomerase subunit genes (by RT-PCR and real-time PCR) and telomere length (by Southern blot analysis) were measured after the AZT treatment. RESULTS: We found evidences of senescence, apoptosis and growth delay after AZT treatment. In addition, AZT- treated cancer cells showed inhibition of telomerase activity and shortening of telomere length in a dose- and duration-dependent way. Among the telomerase subunits, hTERT and c-Myc were the first factors to change after AZT treatment, subsequently, followed by the changes of hTR, Mad1 and TEP. CONCLUSION: The suppression of hTERT and c-Myc by AZT treatment was the initial genetic phenomenon, subsequently followed by the changes of hTR, Mad1 and TEP.