Lee Young A, Cho Eun Ju, Tanaka Takashi, Yokozawa Takako
Institute of Natural Medicine, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan.
J Nutr Sci Vitaminol (Tokyo). 2007 Jun;53(3):287-92. doi: 10.3177/jnsv.53.287.
The present study was carried out to evaluate the promising potential of polymers and oligomers from proanthocyanidins of persimmon peel as antioxidants and therapeutic agents for diabetes. Both polymers and oligomers showed the scavenging effect of 2,2-diphenyl-l-picrylhydrazyl, with IC50 values of 4.35 and 2.41 microg/mL, respectively, and they also showed a protective activity against protein oxidation induced by 2,2'-azobis (2-amidinopropane) dihydrochloride. In particular, oligomers exerted a stronger activity against free radicals than polymers. In addition, to investigate their protective potential against diabetes-related pathological conditions, their inhibitory activities on digestive enzymes and advanced glycation endproduct (AGE) formation were evaluated. Polymers showed a strong inhibitory activity against alpha-amylase, while oligomers had a relatively weak effect. This suggests that the inhibition of alpha-amylase activity would probably depend on the degree of polymerization. On the other hand, against alpha-glucosidase activity and AGE formation, oligomers exerted a stronger protective effect than polymers. The present study suggests that polymers and oligomers from proanthocyanidins of persimmon peel could play a role as antidiabetic agents with antioxidative effects. Moreover, oligomers rather than polymers from proanthocyanidins of persimmon peel may be expected to be a more promising antioxidative and antidiabetic agent in relation to utilization in biological systems.
本研究旨在评估柿子皮原花青素中的聚合物和低聚物作为抗氧化剂和糖尿病治疗剂的潜在前景。聚合物和低聚物均表现出对2,2-二苯基-1-苦基肼的清除作用，IC50值分别为4.35和2.41微克/毫升，并且它们还对2,2'-偶氮二（2-脒基丙烷）二盐酸盐诱导的蛋白质氧化具有保护活性。特别是，低聚物对自由基的活性比聚合物更强。此外，为了研究它们对糖尿病相关病理状况的保护潜力，评估了它们对消化酶和晚期糖基化终产物（AGE）形成的抑制活性。聚合物对α-淀粉酶表现出较强的抑制活性，而低聚物的作用相对较弱。这表明对α-淀粉酶活性的抑制可能取决于聚合度。另一方面，对于α-葡萄糖苷酶活性和AGE形成，低聚物比聚合物发挥更强的保护作用。本研究表明，柿子皮原花青素中的聚合物和低聚物可作为具有抗氧化作用的抗糖尿病药物发挥作用。此外，相对于在生物系统中的应用，柿子皮原花青素中的低聚物而非聚合物可能有望成为更有前景的抗氧化和抗糖尿病药物。
