Takebayashi Jun, Tai Akihiro, Yamamoto Itaru
Department of Immunochemistry, Faculty of Pharmaceutical Sciences, Okayama University.
Biol Pharm Bull. 2002 Nov;25(11):1503-5. doi: 10.1248/bpb.25.1503.
Stoichiometric evaluation of the radical scavenging activity of O-substituted derivatives at the C-2 position of ascorbic acid (AA) was conducted. Their reaction with a stable radical, 1,1-diphenyl-2-picrylhydrazyl (DPPH), under an acidic condition was assessed by the colorimetric method. 2-O-alpha-D-Glucopyranosyl-L-ascorbic acid (AA-2G) and a series of 6-O-acyl-2-O-alpha-D-glucopyranosyl-L-ascorbic acids (6-Acyl-AA-2G) had long-term radical scavenging activity against DPPH. The reaction of AA-2G or 6-Acyl-AA-2G with DPPH was very slow when compared with AA. However, one molecule of these derivatives consumed approximately three molecules of DPPH radicals at the end of the experiment (2 h). In contrast, one molecule of AA scavenged two molecules of DPPH radicals, and the reaction ended in the short time (<10 min). The quantity of radicals quenched by AA-2G and 6-Acyl-AA-2G was superior to that of AA in a long-term reaction.
对抗坏血酸（AA）C-2位O-取代衍生物的自由基清除活性进行了化学计量评估。通过比色法评估了它们在酸性条件下与稳定自由基1,1-二苯基-2-苦基肼（DPPH）的反应。2-O-α-D-吡喃葡萄糖基-L-抗坏血酸（AA-2G）和一系列6-O-酰基-2-O-α-D-吡喃葡萄糖基-L-抗坏血酸（6-酰基-AA-2G）对DPPH具有长期自由基清除活性。与AA相比，AA-2G或6-酰基-AA-2G与DPPH的反应非常缓慢。然而，在实验结束时（2小时），这些衍生物的一个分子消耗了大约三个分子的DPPH自由基。相比之下，一个分子的AA清除两个分子的DPPH自由基，并且反应在短时间内（<10分钟）结束。在长期反应中，AA-2G和6-酰基-AA-2G淬灭的自由基数量优于AA。
