Effect Of (-)-Hydroxycitric Acid On Glucose Metabolism And Profile Of Amino Acids In Rats

(-)-hydroxycitric acid is the key component and the major active ingredient present in the fruit rind of Garcinia cambogia.Previous studies had identified that(-)-HCA is a potent competitive inhibitor of adenosine triphosphate-citrate lyase,which is an extra-mitochondrial enzyme catalyzing the cleavage of citrate to oxaloacetate and acetyl-CoA.With the decrease of acetyl-CoA in cell sap,the lipid synthesis was limited.Many studies had reported that the supplement with(-)-HCA can promote weight reduction through suppressed de novo of fatty acid synthesis and reduced food intake,while the precise physiological mechanism of(-)-HCA has not yet been full clarified,especially the effect in energy mechanism and amino acid mechanism.Therefore,present study was conducted to investigate the effect of(-)-hydroxycitric acid on body weight gain,energy metabolism and the variances of amino acids content in serum,liver and muscle of different energy level rats,aims to illustrate the the mechanism of(-)-hydroxycitric acid exerts its action from energy metabolism and amino acid metabolism,also providing the evidence for using(-)-hydroxycitric acid to control body weight.1.Effect of(-)-hydroxycitric acid on glucose metabolism and amino acids profile in male rats with fed normal dietThis study was conducted to investigate the effects of(-)-hydroxycitric acid(HCA)on body weight gain,glucose metabolism and variances of amino acid content in rats.A total of 60 Sprague-dawley rats were randomly allocated to four groups:normal diet control group,low dose of(-)-hydroxycitric acid group,medium dose of(-)-hydroxycitric acid group and high dose of(-)-hydroxycitric acid group,with each group involving 15 rats.The rats were provided with a commercial diet supplement with(-)-hydroxycitric acid(HCA)at 0,1000,2000,3000mg/kg diet for 8 weeks.Results showed that(-)-HCA treatment reduced body weight gain and liver index,increased feed conversion ratio in rats.No statistical differences were observed on serum glucose content,while hepatic glycogen and muscle glycogen contents were increased in NC+L group.The hexokinase activity was significantly elevated in NC+H group,meanwhile,the pyruvate activity was significantly increased in the three(-)-HCA treatment groups.Compared to control group,serum T4 was significantly increased in NC+L and NC+M group,T3 and Leptin contents were significantly increased in NC+L group,insulin content was significantly increased in NC+M and NC+H groups.The protein content in liver and muscle were significantly increased in(-)-HCA treatment groups.Amino acid profile analysis indicated that most of glucogenic amino acid contents in serum were significantly increased,Thr was significantly increased in NC+M group;Thr?Arg?Ala Val?Tyr,Phe,Leu were significantly increased in NC+H group.The amino acid profile analysis in liver indicated that most of glucogenic amino acid contents were significantly increased,Asn,Thr,Trp,Phe were significantly increased in NC+L group;Asp,Glu,Thr,Val were significantly increased in NC+H group;Ile was significantly increased in the three(-)-HCA treatment group.The amino acid profile analysis in muscle indicated that most of glucogenic amino acid contents were significantly decreased,Glu was significantly increased in the three(-)-HCA treatment group;Val,Gln,Tyr,Phe were significantly decreased in NC+L group;Asp and Leu were significantly decreased in NC+M group and also Leu was decreased in NC+H group.These results indicated that(-)-HCA treatment could reduce body weight gain through promoting energy expenditure via its effects on thyroid hormone levels.In addition,(-)-HCA treatment could promote protein synthesis and which action achieved may be due to its altering the metabolic directions of amino acids.2.Effect of(-)-hydroxycitric acid on gulcose metabolism and amino acids profile in rats with fed high-fat dietTo assess the effects of(-)-hydroxycitric acid on the amino acid profile in rats fed high-fat diet,a total of 100 Sprague-dawley rats were randomly allocated to five groups:normal diet control group,high-fat diet control group,high-fat diet with low dose of(-)-hydroxycitric acid group,high-fat diet with medium dose of(-)-hydroxycitric acid group and high-fat diet with high dose of(-)-hydroxycitric acid group,with each group involving 20 rats.The rats in high-fat groups were provided with a commercial diet supplement with(-)-hydroxycitric acid(HCA)at 0,1000,2000,3000mg/kg diet for 8 weeks.The results showed that the body weight gain and BMI and Lee's index in high-fat diet control group were significantly decreased than that in normal diet control group;indicate the high-fat diet in the test could induce the rat being obese.Compared with the high-fat diet control group,(-)-HCA treatment reduced body weight gain liver index BMI and Lee's index,the daily food intake and feed conversion ratio were significantly increased in 2000 and 3000 mg/kg(-)-HCA treatment group.Compared with the high-fat diet control group,hepatic glycogen was significantly increased in the 1000mg/kg(-)-HCA treatment group and the muscle glycogen was significantly increased in 3000mg/kg(-)-HCA treatment group,but there was no significant influence on serum glucose.No statistical differences were observed on hexokinase and pyruvate in(-)-HCA treatment group.Compared with the high-fat diet 'control group,the serum T3 and T4 contents were significantly increased in 3000mg/kg(-)-HCA treatment group,and the serum leptin content significantly increased in 1000mg/kg(-)-HCA treatment group;1000 and 2000mg/kg(-)-HCA could significantly decreased glucagon content.Compared with the high-fat diet control group,the protein content in liver and muscle were significantly increased in(-)-HCA treatment groups.The results of amino acid composition analysis showed that supplementation of(-)-HCA significantly increased Asp,Ser and Gly content in serum when compared to the high-fat diet control group.In addition,supplement of(-)-HCA significantly increased the Ile and Trp content in serum;supplementation with(-)-HCA significantly decreased Asn,Gly,Thr and Ala content in liver,while no statistical difference was observed on the contents of branched chain amino acid in liver,in addition,supplement of(-)-HCA significantly decreased the contents of aromatic amino acid in liver;supplementation with(-)-HCA significantly decreased the content of Asp,Glu,Asn,Ser,Gly,Val,Thr and Ala;the contents of branched chain and Phe were significantly decreased in skeletal muscle.In conclusion,our results indicated that(-)-hydroxycitric acid reduce the body weight gain via regulating the hormone contents and reducing the glucogenic amino acids in the liver and muscle in male rats.