AA-2βG与V_c对DPPH自由基清除作用的比较

Comparative Evaluation of Radical Scavenging Activity Against 1,1-Diphenyl-2-Picrylhydrazyl of Vitamin C and Natural Vitamin C Anal 2-O-β-D-Glucopyranosyl-L-Ascorbic Acid Isolated from Fructus lycii

用DPPH自由基(DPPH.)清除法,比较了不同浓度、不同pH值时Vc和AA-2βG对DPPH.的清除作用.结果表明,AA-2βG与Vc对DPPH·的清除能力均与浓度呈明显量效关系;AA-2βG对DPPH·的清除作用是一个长时间的过程,且清除能力随pH值的升高而下降;在乙醇(φ=60%)-柠檬酸缓冲液(φ=40%,pH=3.0)体系中,AA-2βG对DPPH·的清除能力较Vc强.与Vc相比,AA-2βG具有较高的稳定性和较长的时效性,说明其具有与Vc相似但又不完全相同的抗氧化机制.可为AA-2βG作为稳定的Vc衍生物应用于医药、食品和化妆品等领域提供基础数据,为正确理解枸杞的组效关系,揭示枸杞抗氧化、抗衰老等药效机制提供参考.

2-O-β-D-glucopyranosyl-L-ascorbic acid（AA-2βG） is a natural derivative of Vitamin C（L-ascorbic acid,AA） isolated from Fructus lycii.In this paper,the radical scavenging activity against 1,1-diphenyl-2-picrylhydrazyl（DPPH） of AA-2βG was compared to that of AA in buffer under different pH conditions.The DPPH scavenging assay demonstrated a dose-dependent scavenging activity for both AA-2βG and AA.Different from that seen in the presence of AA,a pH dependent manner and moderately increasing activity of radical scavenging with time was observed in reactions using AA-2βG,AA-2βG showed slow and long-lasting radical-scavenging whereas AA quenched the radical immediately,increasing pH of the buffer resulted in decrease in the scavenging activity.AA-2βG was better than Vc under the optimal conditions of 60% ethanol / 40% citrate buffer solution（pH=3.0）.These results suggest that AA-2βG is an important antioxidant component of Fructus lycii that may share similar but distinct antioxidant mechanistic properties with AA-2βG might have the potential to be used as radical scavengers in foods and medicines.This study furthered our understanding of the mechanisms of pharmacological activities of Fructus lycii on antioxidant and anti-aging properties as a traditional medicine and dietary supplement.