03929nas|a2200397 i 4500 20260817162802.0 040715s2003 th uzm rtt 00| a1eng d .b11933835 AIT Thesis no.PH-03-8 Bhuiyan, Mohammad Iqbal Hossain Antioxidant activity and protective effect on DNA cleavage of some natural products Pathum Thani, Thailand : Asian Institute of Technology, 2003 45 leaves : ill. Thesis ; no. PH-03-8 A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science Thesis (M.Sc.) - Asian Institute of Technology, 2003 Comparison of antioxidant activity (AOA) of y-oryzonol present in dehusked rice and raw and stabilized rice bran by DPPH radical scavenging and hydroxyl radical scavenging method were done. The AOA of dehusked rice bran oil (DHRBO), raw rice bran oil (RRBO-extracted with hexane) and RRBO* (extracted with hexane : isopropanol (50:50)) and stabilized rice bran oil (SRBO) as measured by 1,1-Diphenyl-2-picryhydrazyl (DPPH) radical scavenging method were in the range of 37-46% at the concentration of 50 mg/ml. The AOA of different crude rice bran samples estimated by deoxyribose oxidation method also did not differ much (24-35%). These results indicated that processing of rice bran in different ways have little effect on AOA of y-oryzonol presents in rice bran oil. The leaves of Thai basil (Ocimum sanctum L) were freeze-dried and extracted with water, methanol, ethyl acetate and hexane. The anioxidant properties of leaf extracts and protective effect on DNA cleavage were tested. The antioxidant properties of basil leaf extracts were compared to the activityof ascorbic acid (AsA) and butylated hydroxyanisole (BHA). DPPH radical scavenging activities of the ethyl acetate fraction (EAFB) and hexane fraction of basil leaf (HFB) exhibited more DPPH radical scavenging activity than that of BHA and AsA at all concentration (0.02-10 mg/ml) tested. The water fraction (WFB) showed much higher DPPH radical scavenging activity than that of other antioxidants at low concentrations (0.02 - 1 mg/ml), while methanol fraction of basil showed little activity. The ethyl acetate and hexane fractions showed around 50 % inhibition of 2-deoxyribose oxidation by scavenging {u2022}OH at 10 mg/ml concentration, which was nearly same as compared to BHA (52.2 %) and AsA (53.46%). The water fraction showed 38.72 % antioxidant activity (AOA) at that concentration. Among the four fractions, water fraction of basil extract showed excellent protective effect on DNA cleavage followed by methanol fraction. The ethyl acetate fraction and hexane fraction had no protective effect. Water fraction of basil at 1.25 mg/ml concentration was found to be the minimum concentration that could prevent DNA strand scission. Antioxidants DNA Rakshit, Sudip Kumar, Chairperson Jindal, Vinod Kumar, Examination Committee Athapol Noomhorm, Examination Committee The Royal Government of Netherlands, Scholarship donor Asian Institute of Technology. Thesis ; no. PH-03-8 Full-Text http://203.159.5.9/ait-thesis/detail.php?q=B08775 .b11933835 mnait u 240418 0 040715 m a u 0 mnait mnarc 22 40 Barcode : 30050120651061 CREATED : 2004-07-15 RECORD # : i12407057 LPATRON : 1026142 LCHKIN : 2016-10-19 # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 15 TOT RENEW : 26 Barcode : 30050160005566 CREATED : 2016-03-24 RECORD # : i1290773x LPATRON : 0 LCHKIN : - # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 0 TOT RENEW : 0 6284 6284 0 0 0 0 MAIN MAIN mnait 2026-08-17 50.00 0 AIT Thesis no.PH-03-8 30050120651061 2026-08-17 16:28:02 3 2026-08-17 22 0 0 0 0 MAIN MAIN mnarc 2026-08-17 0 AIT Thesis no.PH-03-8 30050160005566 2026-08-17 16:28:02 2026-08-17 40