연근의 생리활성 및 이용실태에 관한 연구

Abstract

The node of lotus rhizome(Nelumbo nucifera G. root) has been used for the remedy of bleeding, blood stagnancy, thirstiness, anti-diabetic and antipyretic activity as a traditional medicine in Korea. In this study, the effects of ethanol extract of lotus root(LRE) on antioxidant capacity and lipid metabolism were investigated. In addition, usage of lotus root at food service, such as school, industry and hospital, in Jeollanamdo-Gwangju areas was also surveyed to provide basic data for dietitians. This study investigated the effects of an ethanol extract of lotus root on alcohol-induced hepatotoxicity in the rat. Sprague-Dawley rats weighing 100～150g, were divided into 6 groups: basal diet group(BD), alcohol(35%, 10 mL/kg/day) treated group(ET), LRE 200 mg/kg/day treated group(BD-LREL), LRE 400 mg/kg/day treated group(BD-LREH), LRE 200 mg/kg/day and alcohol treated group(ET-LREL), and LRE 400 mg/kg/day and alcohol treated group(ET-LREH). Lotus root ethanol extract was fractionated by the following: n-hexane, chloroform, ethylacetate and n-butanol. The antioxidative capacity of the ethylacetate fraction was the highest among fractions. The body weight gain was decreased by alcohol administration, however, was gradually increased to a little lower level than the basal diet group by administering lotus root ethanol extract. The serum alanine aminotransferase(ALT), asparate aminotransferase(AST) and alkaline phosphatase(ALP) activities that were elevated by alcohol were significantly decreased by lotus root ethanol extract administration. These effects of lotus root ethanol extract within the alcohol groups were dose-dependent manners. It was also observed that thiobarbituric acid reactive substances(TBARS) content, xanthine oxidase(XO), superoxide dismutase(SOD), catalase and glutathione peroxidase(GSH-Px) activities in liver that were increased by alcohol were markedly decreased in the lotus root ethanol extract administered groups as compared with the alcohol administrated group. These effects of lotus root ethanol extract within the alcohol groups were dose-dependent manners. The glutathione(GSH) concentration in liver was decreased by alcohol adminstration, however, increased after administering lotus root ethanol extract. Next, this study was also performed to investigate the effects of lotus root ethanol extract on serum and liver lipid metabolism in rats. Lotus root ethanol extract(200 mg/kg/day and 400 mg/kg/day) was administered orally to rats with fed high cholesterol diet for 6 weeks. We divided into 6 groups: normal diet group(NC), high cholesterol diet group(1% cholesterol and 0.25% sodium cholate)(HC), LRE 200 mg/kg treated group(NC-LREL), LRE 400 mg/kg treated group(NC-LREH), high cholesterol diet and LRE 200 mg/kg treated group(HC-LREL), and high cholesterol diet and LRE 400 mg/kg treated group(HC-LREH). The inhibitory effects of lotus root ethanol extract on LDL-cholesterol oxidation and HMG-CoA reductase activity of in vitro were observed. The growth rate and liver weight of the high cholesterol diet group was higher than the normal diet group, whereas the groups administered lotus root ethanol extract were gradually decreased. There was a signigicant increase in the activities of serum ALT, AST and ALP in the high cholesterol diet group. The administration of lotus root ethanol extract decreased serum ALT, AST and ALP activities in dose dependent manners. The high cholesterol diet group was increased serum triglyceride, total cholesterol, free cholesterol and LDL-cholesterol levels, and decreased atherogenic index, HDL-cholesterol and phospholipid levels as compared with the normal diet group. Lotus root ethanol extract administrated groups were increased HDL-C/T-C, HDL-cholesterol and phospholipid levels, and decreased serum triglyceride, total cholesterol, free cholesterol, and LDL-cholesterol levels as compared with the high cholesterol diet group. The hepatic concentrations of total lipid, total cholesterol and triglyceride were also lower in lotus root ethanol extract administrated groups than in the high cholesterol diet group. We also surveyed dietitians' perception on usuage of lotus root. This study was carried out through a questionnaire and the subjects was 131 school dietitans, 72 industry dietitans and 45 hospital dietitans in Jeollanamdo-Gwangju areas. According to the survey, most dietitians perceived that minimally processed ready-to-use lotus root would helpful for the institutional food service. Most respondents applied lotus root to their menu planning and used lotus root for food service meal less than 10 times per years. Lotus root jorim was estimated the most preferred cooking method. Major reasons for their using lotus root were health food and characteristic food, and reasons for non-use of lotus root were simple cooking method, high price and less preference. It is needed to study for the development of cooking method of lotus root proper to preference of student, adolescent and patient in food service. In addition, for patients' nutrition and well-being through institutional food service meal, it is necessary to prepare database of vegetables such as lotus root. Taken together, these results suggest that ethanol extract of lotus root may have a possible protective effect on liver function in hepatotoxicity-induced rat by alcohol administration, fatty liver in hyperlipidemia-induced rat by a high cholesterol diet. The development of cooking recipe with lotus root and their antioxidative and hyperlipidermic effects of lotus root on patients need to be investigated further.