Study On Lipid-lowing And Weight-loosing Activity Of Alkaloids From Lotus Leaf

Nowadays, many researchers have reported that the alkaloids from lotus leaf material have such physiological function as helping losing weight and lipid regulation and the targeted functional composition is mainly focused on the total alkaloids crude extract from lotus leaf. Simultaneously, the researchers always adopted the function evaluation system either form experiments in vivo or experiments in vitro, and the test model is some animal models with diseases or defects related to hyperlipidemia and obesity, or lipase or fat cells, however, the lotus leaf alkaloid monomer’s effect on lipid-lowering and body weight lost in vivo and vitro and its related mechanism is seldom studied.In this paper, total alkaloids of lotus leaf were gained based on the extract methods which had existed in the laboratory, and with the aid of high-speed countercurrent chromatography (HSCCC) and preparation liquid chromatography (Pre——HPLC), four kinds leaf lotus alkaloid monomers were separated and purificated. Then the effect of all alkaloids extract from lotus leaf and the four kinds leaf lotus alkaloid monomers on the mass and lipid regulation in terms of experiments in vivo and vitro were investigated in order to provide theoretical support for taking lotus leaf alkaloids into further application for developing health care products helping controlling body mass and lowering blood lipid level.The main conclusions were as follows:(1) Preparation and determination of total alkaloids and four kinds alkaloid monomers from lotus leaf:the total alkaloids form lotus leaf was extracted by ultrasonic wave assisted extraction technology and then the total alkaloids were separated and purificated by high-speed countercurrent chromatography (HSCCC) and preparation liquid chromatography (Pre—HPLC), four kinds leaf lotus alkaloid monomers were obtained. The content of total alkaloids Was69.4～72.3%, and that of the four kinds leaf lotus alkaloid monomers was above90%. (2) Lipid-lowering efficacy in vivo of lotus leaf alkaloids extract was determined by animal experiment. After adapting to the feeding environment for10days,30experimental rats were randomly divided into6experimental groups according to their serum lipid level and body mass:general diet group, high fat diet with lotus leaf alkaloids extract groups, positive drug group and high fat diet group. Except for the general diet group feeding normal diet, the other five groups feed high fat diet to set up the model of hyperlipidemia rats, this period lasted for40days.Then,the contents of TC(total cholesterol), TG(Triglyceride), LDL-C (low density lipoprotein-cholesterol), HDL-C(high density lipoprotein-cholesterol), AST (aspartate aminotransferase) and ALT (alanine aminotransferase)level in serum were assayed respectively in hyperlipidemia rat which had been fed lotus leaf alkaloids extract20mg/kg bw·d,40mg/kg bw·d,80mg/kg bw·d and positive drugs10mg/kg bw·d for another40days respectively. In addition, body and liver mass, body length, tail length was measured. It turned out that body mass significantly decreased in the high fat diet with lotus leaf alkaloids extract groups compared to that of general diet group. The index of Lee’s, mass of the livers and spleen of rats corresponded to the increase of body mass. Also, the TC, TG, LDL-c, AST and ALT in serum decreased significantly in the hyperlipidemia rat fed with lotus leaf alkaloids extract. Moreover, lotus leaf alkaloids extract could decrease AI and increase ratios of HDL-c/TC and apoAI/apoB.(3) Lipid-lowering efficacy in vitro of total alkaloids and four kinds of alkaloid monomers from lotus leaf was determined by measuring the inhibitory activity against pancreatolipase by monitoring the hydrolysis of p-NPb, which releases the yellow chromogen p-nitrophenol. And the effect of temperature,PH, concentration on inhibitory rate were studied respectively. All the kinds of alkaloids showed the max inhibitory rate on lipase activity when the temperature is37℃, the nuciferine and N-nornuciferine showed the max inhibitory rate on lipase activity when pH=7.4, while theasimilobine and O-nornuciferine is pH=7.4. All kinds of alkaloids’ inhibitory rate on lipase activity in a concentration-dependent manner. Based on the Linweaver-Burk plots, the lipase inhibitor demonstrated uncompetitive inhibition for pancreatic lipase. (4) The effects of total alkaloids and one kind alkaloid monomers from lotus leaf on3T3-L1preadipocytes were investigated. We determined the proliferation of3T3-L1preadipocytes by MTT assays, and calculate the inhibition ratio of total alkaloids and one kind alkaloid monomers from lotus leaf on3T3-L1, we found total alkaloids and one kind alkaloid monomers from lotus leaf significantly inhibited the proliferation of3T3-L1preadipocytes and its inhibition of proliferation in a concentration-dependent and time-dependent manner.