納豆對活性氧之抗致突變性及抗氧化性

Abstract

本研究以溶解血纖維蛋白活性為指標自市售納豆篩選納豆菌，並進行納豆製備，探討納豆水萃物對活性氧物質抗致突變性研究。使用安氏試驗法之測試菌株Salmonella typhimurium TA102分析納豆水萃物對氧化突變劑tert-butylhydroperoxide ( t-BOOH )及過氧化氫( H2O2 )誘導突變之防禦效果。結果顯示，由6株Bacillus sp.所製備之納豆水萃物(10 mg/mL)，對t-BOOH 和 H2O2之抗致突變性分別為36.8-44.2 %和53.6-59.6 %，而納豆的抗氧化突變性可歸因於其抗氧化能力。以6株納豆菌發酵所製備之納豆水萃物(5 mg/mL )，對過氧化氫之清除能力及螫合亞鐵離子分別為74.2-84.0 %及82.7- 94.3%。在清除DPPH自由基及還原力測定中，以Bacillus sp. CN08製備之納豆水萃物(10 mg/mL)為最佳，其具有38.4 % DPPH自由基清除能力，其還原力相當於30.1μg/mL抗壞血酸。而納豆水萃物(10 mg/mL)清除超氧陰離子的能力為44.5-54.7%。

In this study, several Bacillus spp. with high fibrinolytic activity were isolated from several commercial natto products. Functional natto with high fibrinolytic activity was then made by these Bacillus isolates. The antimutagenic activities of natto water extracts against reactive oxygen species were studied by a modified Ames test using Salmonella typhimurium TA102 as a test strain. Assays for the activities of natto water extracts against mutations induced by peroxide mutagens tert-butylhydroperoxide (t-BOOH, 10 μg/plate) and hydrogen peroxide (H2O2, 6 μmol/plate) toward S. typhimurium TA102 were developed. The results indicated inhibitory effects of natto water extracts (10 mg/mL) preparation from 6 Bacillus spp. on the mutagenicity induced by t-BOOH and H2O2 toward S. typhimurium TA102 were range from 36.8 to 44.2 % and 53.6 to 59.6 %, respectively. The antimutagenic activities of natto water extracts might attribute to their antioxidative activities. Results also showed that scavenging effects on H2O2 and chelating effects on ferrous ions of natto water extracts (5 mg/mL) were 74.2-84.0 % and 82.7- 94.3%, respectively. Scavenging effects on DPPH radical and reducing activity of natto water extracts (10 mg/mL) preparation from Bacillus sp. CN08 showed the highest DPPH scavenging activity and ascorbic acid activity, 38.4 % and 30.1μg/mL, respectively. The scavenging effects on superoxide anions of natto water extracts were ranged from 44.5 to 54.7%.