Effects Of Functional Factors In The Hull Of Camellia Oleifera Abel. On Obesity And Dyslipidemia

Oiltea camellia (Camellia oleifera Abel.) is an important woody-oil plant in our country, which have more than a thousand years of plant history. Tea oil is abundant in unsaturated fatty acids; its flavor is comparable to olive oil. Camellia fruit hull accounts for 60% of wet weight of the fruit, however, with an extremely low utilization. This paper aimed to separate and identify the active compounds in camellia fruit hull and then evaluate the effect of both extracts and active compounds on obesity and dyslipidemia. The main conclusions are as follows:(1) Oiltea camellia extracts (OCE) were prepared by 50% ethanol-water (v/v) using hot-reflux method. Three compounds were isolated one-step by high-speed counter-current chromatography from OCE; then they were identified as gallic acid (GA), ellagic acid (EA) and 3-O-methylellagic acid 4'-O-p-D-glucopyranoside (MEAG) by IR, UV, ESI-MS and NMR.(2) The contents of GA, EA, MEAG in OCE were measued by HPLC, with a value of 3.67,3.20 and 5.58 mg/g, respectively. Acid hydrolysis and macroporous resin were used to enrich these three compounds. After acid hydrolysis treatment, the contents of gallic acid and ellagic acid increased to about 18-fold and 4-fold of these in OCE. After treamtemt with macroporous resin D101, the content of MEAG in 40% ethanol eluated fraction was about 2.7-fold of that in OCE.(3) FAS inhibition system were used in vitro, the IC50 value of OCE, EA and MEAG on FAS were 2.30,2.50 and 37.73μg/mL, respectively. It indicated that EA was one of characteristic compositions in OCE contributed to the FAS inhibitory effect. The inhibition kinetic results showed that OCE and acetyl-CoA competitively inhibited FAS but these compounds exhibited mixed inhibition against malonyl-CoA and NADPH. Inhibition kinetics of EA and MEAG were different from that of OCE. Both of them exhibited uncompetitive and mixed inhibition for NADPH and acetyl-CoA, respectively. EA and MEAG exhibited mixed and competitive inhibition for malonyl-CoA, respectively. They decreased the FAS activity through inactivation of acetyl/malonyl transferase on FAS.(4) Effects of OCE and its functional factors on proliferation of 3T3-L1 preadipocytes were evaluated. The results indicated that gallic acid could inhibit the proliferation. Treated the preadipocytes with 250 pM GA for 24 h, the inhibiton ratio on preadipocytes proliferation was 66.5%. In 3T3-L1 preadipocytes differentiation experiments, it was found that either oiltea camellia extracts, gallic acid, ellagic acid or MEAG could inhibit preadipocyte differentiation and adipogenesis. Moreover, it was found that MEAG could promote lipolysis in mature adipocytes,10μM MEAG could significantly enhance glycerol releasing.(4) In obese preventive model, mice were oral administration either 100 mg/kg, 200 mg/kg,300 mg/kg OCE or 100 mg/kg gallic acid, respectively, while they were fed a high-fat diet. The results indicated that OCE have anti-obesity effect in a dose dependent mannar.100 mg/kg OCE could significantly reduce the increase rate of mice body weight (P< 0.05).200 mg/kg OCE have comprehensive effects on obesity and dyslipidemia. It significantly decreases TC, TG, but increases HDL-C in serum, reduces perirenal and epididymal fat, inhibits fatty acid synthase activity in liver, and improves lipid accumulation and oxidative stress in liver.100 mg/kg GA could significantly decrease the increase rate of mice body weight and TC in serum, reduce perirenal fat and fatty acid synthase activity in liver, and improve lipid accumulation and oxidative stress in liver.(6) In obesity treatment model, obese mice model were established by feeding them a high-fat diet. Then they were oral administration 100 mg/kg,200 mg/kg,400 mg/kg OCE or 100 mg/kg gallic acid, respectively. The result indicated that 200 mg/kg,400 mg/kg OCE can significantly reduce the body weight of high-fat diet-induced obese mice in about 10 days and 24 days, respectively.400 mg/kg OCE have comprehensive effects on obesiy and dyslipidemia. It significantly decreases TC, TQ reduces perirenal and epididymal fat, inhibits fatty acid synthase activity in liver, and improves lipid accumulation and oxidative stress in liver.(7) According to the series of safety tests, the oral maximum tolerated dose (MTD) of water extracts of oiltea camellia was above 20 g/kg body weight both in rats and in mice, which can be regarded as virtually non-toxic. No mutagenicity was found in Ames test, mouse bone marrow cell micronucleus test and mouse sperm abnormality test. In the subacute study, the SD rats were administered orally at 0.5, 1.0, or 2.0 g/kg for 30 d. There were no treatment-related toxic effects from water extract of oiltea camellia. The histopathological examination of all organs showed that no differences were noted between the control group and treatment group. No significant differences were found in parameters of body weight, food consumption, food utilization, hematology value, clinical chemistry value, and organ/body weight ratio. The level of no observed adverse effect level (NOAEL) for water extract of oiltea camellia was 2.0 g/kg for subacute toxicity study.Oiltea camellia extracts exhibit comprehensive effects in FAS inhibition system, preadipocyte differentiation system, obese preventive model and obesity treatment model, which indicated that OCE can improve dyslipidemia, and could be used for prevention and treatment of obesity.