Study On Extraction And Anti-obesity Effects In Diet-induced Obesity Rats Of Lipases Inhibitor From Grape Seed

Obesity is one of the most common metabolic pathologies in contemporary society.The incidence and severity of overweight and obesity is rising both in developing and developed country.Obesity has been recognized as an important risk factor that contributes to the development of many disease,such as diabetes, hypertension,heart disease,cerebrovas cular disease cancer,infection,and so on, which seriously affects people’s healthy in mind and body.The magnitude of this health problem and the recent difficulties with several weight-loss therapies emphasize the need for different approaches to find new drugs.So development of drugs to treat obesity is a public health goal of the highest priority.A variety of health-promoting proanthocyanidins,also commonly called condensed tannins,are present in grape solid parts（seeds and skins）.A great deal of research effort is being devoted to testing the putative beneficial effects of grape polyphenols,extracted from grape seeds.Moreno have recently announced that the grape seed extract（GSE） rich in compounds that inhibit lipases may provide a safe,natural,and costeffective weight control treatment.The present study tested the hypothesis that GSE can inhibit the enzymatic activity of pancreatic lipase in vitro,studied the effecting factors of traditional solvent extraction and pulse ultrasonic assistant extraction,and the optimum extraction conditions were investigated.We also investigated the anti-obesity effects of GSE in diet-reduced obesity rats（DIO） to explore its possible action mechanism of the weight loss effect.In this paper,crushed grape seeds were extracted in 95%ethanol for 24h.The organic solvent was then evaporated,and the crude extract was partitioned by petrol ether,chloroform,acetyl acetate and n-Butanol.The solutions were freeze dried to yield extracts.The chloroform part,acetyl acetate part,n-Butanol part and water part inhibited lipases activity with IC₅₀ of 46.316mg/mL,0.950mg/mL,28.541mg/mL, 150.386mg/mL separately.An inhibitory mechanism of lipase inhibitor is proposed using acetyl acetate extract.The inhibition mode of the extract was a non-competitive inhibitor determined by Lineweaver-Burk plot analysis,and the Ki value was 0.94mg/mL.According to lipases inhibitory activities and yield of grape seed extraction,the opimum extraction conditions of lipase inhibitor from grape seed were investigated by using orthogonal experiment as follows:70%ethanol as solvent,the ratio of material to liquor is 1:9,grape seed were extracted for 3h at temperature 35℃.The Lipases inhibitory activities is 73.65%and the yield of extractions is 0.72%.The technology for pulse ultrasonic assistant extraction of lipases inhibitor from grape seed was studied.The optimized technology parameters obtained by combining single-factor experiments with orthogonal experiment are that on time of pulse is 2s, off time is 1s,ultrasonic power is 600W,total extraction time is 30 minutes and the rotation rate of pump for mixing and cycling extractive liquid is 15r/s.Under the optimizing technology parameters,The lipases inhibitory activities is 78.82%and the yield of extractions is 0.79%.Comparing with traditional extraction method,pulse ultrasonic assistant extraction raises Lipases inhibitory activities from 73.65%to 78.82%,the yield from 0.72%to 0.79%;shortens extraction time from 3h to 30min.In this study,GSE（10,30,90mg/kg/d） and Orlistat（10mg/kg/d） were administered intragastrically to diet-induced obese rats for four weeks.The rats’body weight,obese index,weight of fat tissue,fat index（Lee’s） and adipocyte size in the Orlistat-treateded group and three dose of GSE-treateded groups were significantly lower than those in obese model group,respectively.The lowe-dose of GSE-treateded groups decreased the level of triglyceride（TG） significantly.The results show that GSE can prevent and treat obesity of animals in experiment.