Hypolipidemic effect and related gene expression of fucoidan from kelp Laminaria japonica
WANG Junxin, WANG Yafang, HAN Ziqi, HE Yunhai, REN Dandan, WU Long, CONG Haihua, WANG Qiukuan*
National Research & Development Branch Center For Seaweed Processing,Key Laboratory of Fishery Product Processing and Utilization of Liaoning Province,College of Food Science and Engineering,Dalian Ocean University, Dalian
Abstract: The chemical composition and monosaccharide composition of fucoidan from kelp Laminariajaponica (LF) were analyzed by phenol-sulfuric acid method, hydrochloric acid hydrolysis-barium sulfate gravimetric method, and high performance liquid chromatography. Wistar rats with body weight of (150.0±10.0)g were fed basic diet (blank control, group) and the high fat diet containing 10% of pork oil and 2% cholesterol and 0.5% pig bile salt and then orally administrated at kelp fucoidan dose of 100 mg/(kg·d) (low dose) and 300 mg/(kg·d) (high dose)for 12 weeks to evaluate the hypolipidemic activity and mechanism (including histological structure of liver and mRNA expression of related genes of rat) of kelp fucoidan. It was found that the fucoidan (LF) of the kelp was comprised of 75.27% total sugar and 19.58% sulfate group and that the monosaccharides of LF were primarily composed of fucose (41.61%) and galactose (24.90%), with glucose, glucuronic acid, xylose, and fructose. The hypolipidemic test showed that the fucoidan significantly suppressed the total cholesterol (TC) and triglyceride (TG) levels in serum of Wistar rats induced by the high-fat diet, with the best effect in 12 weeks of gastric administration. Wistar rats in the low and high dose groups had significant increase in high density lipoprotein (HDL-C) level and decrease in low density lipoprotein (LDL-C) level after 12 weeks of gavage. The significant inhibitory effects of LF on MDA levels was observed in high-dose group at 8 and 12 weeks, and the significant increase in SOD activity was found in all experimental groups. There was significant increase in GSH-Px activity in Wistar rats in high and low dose LF groups. The decrease in HMG-CoA mRNA expression level and the increase in LCAT mRNA expression level were shown in the livers of Wistar rats in LF low and high dose groups, indicating that the blood lipid-lowering effect of LF is primarily derived from regulation of the synthesis of cholesterol and fatty acids. The decrease in SREBP-1c mRNA expression and the increase in SCD1 mRNA expression further led to slow down lipid synthesis. The histological observation showed significant decrease in liver lipids in the rats fed LF, illustrating the hypolipidemic activity by intragastric administration of LF. The findings indicated that LF inhibited the synthesis of cholesterol and fatty acids, and promoted the decomposition of fat to improve the body’s hyperlipidemia, and that LF can be used as a raw material for development of new hypolipidemic health foods or medicines.
王俊鑫, 王亚芳, 韩梓琪, 何云海, 任丹丹, 武龙, 丛海花, 汪秋宽. 日本真海带褐藻聚糖硫酸酯降血脂功效及其相关基因表达研究[J]. 大连海洋大学学报, 2020, 35(3): 339-346.
WANG Junxin, WANG Yafang, HAN Ziqi, HE Yunhai, REN Dandan, WU Long, CONG Haihua, WANG Qiukuan. Hypolipidemic effect and related gene expression of fucoidan from kelp Laminaria japonica. Journal of Dalian Ocean University, 2020, 35(3): 339-346.