【作者】 赵燕；

【导师】 史贤明；

【作者基本信息】 上海交通大学 ， 食品科学， 2007， 硕士

【摘要】 罗汉果是葫芦科(Cucurbitaceae)罗汉果(Siraitia grosvenorii)植物的果实,罗汉果甜甙(Mogrosides)是其主要甜味物质,甜度约为蔗糖的400倍,而热量几乎为零,是理想的低热型甜味剂。少数文献已报道罗汉果甜甙在体外具有一定的清除自由基、抗脂质过氧化以及不被致龋菌利用等作用,但还未见其体内功能评价的相关研究报道。本论文以罗汉果浓缩汁和罗汉果甜甙为材料进行动物实验,系统、全面地评价了罗汉果的抗氧化、调血脂以及防龋齿的功能作用。本论文主要包含了三方面的研究工作:1.抗氧化功能评价。通过饲喂高脂饲料建立高脂血症抗氧化损伤模型小鼠,探讨了罗汉果浓缩汁和罗汉果甜甙对小鼠血清抗氧化酶系统等指标的影响。结果表明:与正常对照组相比,高脂模型组小鼠血清抗氧化酶GSH-Px和CAT的活性以及T-AOC和NO浓度显著降低(P<0.05),MDA显著升高(P<0.05),SOD无显著性变化(P>0.05)。与高脂模型组相比,罗汉果浓缩汁和罗汉果甜甙组的小鼠血清GSH-Px、SOD及CAT的活性分别提高了29.90%和32.44%、15.53%和19.03%、28.63%和29.93%;T-AOC和NO浓度分别提高了49.02%和39.93%、82.58%和70.11%;MDA含量分别下降了40.83%和31.10%,以上指标差异显著(P<0.05),说明罗汉果浓缩汁及罗汉果甜甙均具有抗氧化活性。2.降血脂功能评价。利用高脂血症模型小鼠,研究了罗汉果浓缩汁及罗汉果甜甙对小鼠血清脂质水平的影响。结果表明:高脂模型组TC、TG水平分别高达118.70mg/dl、214.36mg/dl,HDL-C水平降低到54.99mg/dl;与高脂模型组比,罗汉果浓缩汁和罗汉果甜甙组小鼠血清TC水平分别下降了17.32%和27.49%,TG水平分别下降了28.37%和44.49%,HDL-C水平分别升高34.41%和27.30%,以上指标变化差异均显著(P<0.05),说明罗汉果浓缩汁及罗汉果甜甙对高脂模型小鼠血脂代谢具有正调节作用,其中罗汉果甜甙的综合作用效果优于罗汉果浓缩汁。3.防龋齿评价。体外实验研究了罗汉果浓缩汁及罗汉果甜甙对变形链球菌生长、产酸、粘附的影响,体内实验分别评价了罗汉果浓缩汁和罗汉果甜甙对大鼠磨牙的致龋性以及其在致龋因子综合作用下的防龋效果。结果表明:变形链球菌在含罗汉果浓缩汁培养液中的生长速度和粘附性均显著低于蔗糖(P<0.05),但产酸性较高;在含罗汉果甜甙的培养液中几乎不生长繁殖,与木糖醇差异不显著(P>0.05);罗汉果浓缩汁对大鼠磨牙的致龋性显著低于蔗糖(P<0.05),罗汉果甜甙无致龋性,且在高糖饮食等致龋因素作用下还具有预防龋齿的作用。综上所述,罗汉果具有良好的抗氧化、调血脂作用,作为天然甜味剂应用还具有致龋性低等特点。此外,罗汉果在一定程度上能提高动物血清的NO浓度,表明罗汉果可能对血管收缩、血凝失常等因NO缺乏引起的疾病具有一定的预防或治疗作用,这有待于进一步研究证实。更多还原

【Abstract】 Luo Han Kuo is a fruit of Siraitia grosvenorii plant which is a traditional Chinese herb and belongs to Cucurbitaceous plants. It contains sweet components called mogrosides, which are triterpene glycosides with 400 times sweeter than sucrose but with almost no calorie. Therefore, Luo Han Kuo is an ideal sweet additive. It has been reported that Luo Han Kuo mogrosides can scavenge free radicals and inhibit lipid peroxidation; however, these studies were restricted in vitro. So, in this paper, we systematically and comprehensively studied the effects of Luo Han Kuo concentrated juice (SE) and Luo Han Kuo mogrosides (SM) on antioxidation, lipid metabolism mediation and dental caries prevention in vivo, respectively. There were three parts as follows:(1). Evaluation of antioxidation. Hyperlipidemic ICR mice model was established by feeding high fat and high cholesterol diet to induce oxidative damage. The effects of SE (group SE) and SM (group SM) on the antioxidative enzymes in mouse serum and other antioxidative indexes were investigated. It has been shown that the activities of GSH-Px and CAT, contents of NO and T-AOC in hyperlipidemic model group (group M) were significantly lower (P<0.05), the level of MDA significantly higher (P<0.05), the activity of SOD wihout significant difference (P>0.05), compared with Control group (group C). However, compared with group M, the activities of GSH-Px, SOD and CAT of group SE and SM increased by 29.90% and 32.44%,15.53% and 19.03%, 28.63% and 29.93%, T-AOC and the contents of NO increased by 49.02% and 39.93%, 82.58% and 70.11% , the levels of MDA decreased by 40.83% and 31.10%, respectively, these differences were siginificant (P<0.05). It can be concluded that both SE and SM possess antioxidative ability.(2). Evaluation of lipid metabolism mediation. The functions of SE and SM in mediating lipid metabolism were carried out based on the hyperlipidemic ICR mice model. It was found that the levels of TC and TG of group M were 118.70mg/dl and 214.36mg/dl, the level of HDL-C was 54.99mg/dl.Compared with group M, the levels of TC of group SE and SM decreased by 17.32% and 27.49%, the levels of TG decreased by 28.37% and 44.49%, the levels of HDL-C increased by 34.41% and 27.30%, respectively, these differences were significant (P<0.05). It could be concluded that both SE and SM can positively mediate the lipid metabolism of hyperlipidemic mice, and more significant in SM.(3). Dental caries Prevention. The effects of SE and SM on the growing, fermenting and attaching of S.mutans in vitro as well as caries inducing and caries preventing in vivo were studied. The results indicated that the growth and attachment abilities of S.mutans in the medium containing SE were significantly lower than those of sucrose (P<0.05). S.mutans could not grow in the medium containing SM, which had no significant difference compared with that in the medium containing xylitol (P>0.05). The effects of SE in vivo on inducing caries were significantly lower than that of sucrose (P<0.05), the SM did not induce caries and possessed the activity of preventing caries when the mice were suffered from the caries inducing factors such as high sucrose diet and S.mutans.It is concluded that Luo Han Kuo has activities of antioxidation and lipid metabolism mediation. Its low cariogenicity would enlarge its application as a sweet additive. Furthermore, it was also found that Luo Han Kuo could induce the increase of the level of NO in mouse serum, which would show its new ability in preventing and curing the diseases caused by NO deficiency such as vasoconstriction and disorder of blood coagulation, but the mechanisms of these functions need to be further investigated.更多还原