不同聚合度琼寡糖对肝细胞内外抗氧化活性的影响

通过研究不同聚合度琼寡糖对肝细胞的内外抗氧化活性的影响,对琼寡糖聚合度与活性间的关系进行了评价。利用二苯基苦味酰肼自由基(DPPH·)检测方法研究了琼寡糖的细胞外抗氧化活性,结果表明,琼六糖具较高的淬灭自由基活性的能力。采用二氯荧光素检测方法(DCF)细胞内的活性,结果与细胞外的活性结果相吻合,并抑制H2O2所造成的细胞氧化损伤及死亡。通过选用五种聚合度的琼胶寡糖,研究了其抗氧化活性,从细胞内、外两个水平说明琼六糖均有良好的清除自由基活性的能力,进一步证实琼寡糖的抗氧化作用较强。

AGARO-OLIGOSACCHARIDE ENHANCES THE ANTIOXIDANT PROPERTY OF LIVER CELL IN VITRO AND IN VIVO

The extracellular and intracellular antioxidant activities of agaro-oligosaccharide in different degrees of polymerizations (DPs) were evaluated in this paper with the establishment of a relationship between the activity and DPs. The extracellular antioxidant capability of oligosaccharides was determined by examining 1,1-diphenyl-2-picryl-hydrazyl (DPPH*) radical scavenging activity. Dichlorofluorescein (DCF) assay was used to evaluate the influence of DP of agaro-oligosaccharide on antioxidant capability in normal liver cell system (L-02), which was directly oxidized by exposing to H₂O₂. The cellular cytotoxic impact of H₂O₂ and agaro-oligosaccharide on liver cell L-02 was also assessed with MTT assay. The DPPH* radical scavenging assay indicated that agarohexaose at 1.85 mg/ml concentration showed higher DPPH*-scavenging capability in IC₅₀ than agarooctaose at 2.62 mg/ml. Both agarobiose and agarotetraose showed relatively low scavenging activity at lower concentration below 8 mg/ml. Intracellular test showed that DPs of agaro-oligosaccharides could affect the antioxidation level significantly. Among 5 agaro-oligosaccharides (agarobiose, agarotetraose, agarohexaose, agarooctaose and agarodecaose), agarohexaose had the strongest protection against H₂O₂-induced ROS, and the ROS yield was decreased by half. To exclude the possibility of cellular cytotoxic property of agaro-oligosaccharides, a cell viability assay was carried out without H₂O₂ treatment. The result shows that agaro-oligosaccharides exhibited no cytotoxic effects on human liver cell L-02. In contrast, the oligosaccharides especially the agarobiose could stimulate the growth of liver cells. The liver cell viability exposed to H₂O₂ was as low as 60%. However, by pre-treatrnent with the 5 agaro-oligosaccharides, the viability was enhanced obviously. Therefore, agaro-oligosaccharides especially agarohexaose are potential antioxidants to protect cells damage caused by reactive oxygen species, exhibiting desirable effects on intercellular and extracellular ROS. These findings also stress the importance of these compounds for being potential excellent antioxidant agents.