Studies On The Toxicology, Pharmacokinetics And Immune Function Of Microencapsulated Catechin

[Background] Catechin, a type of tannin is an astringent component contained in green tea. At present, the following actions are confirmed as the physiological function of catechin: anti-acid action, anti-bacterial action and improvement of intestinal bacterium , active oxygen eliminative action, cholesterol regulating action, blood sugar regulating action, antitumor action. But catechin has low bioavailability ,so Biochemical Engineering and Fermentation Technology lab of Hunan Agricultural University made microencapsulated catechin in order to improve the bioavailability of catechin.To supply datas for clinic using of microencapsulated catechin, studies on the toxicology,immune function , pharmacokinetics of microencapsulated catechin is a very meaningful work.[Aim] The study was to observe the acute and subchronic toxicity, immunodulatory effects, pharmacokinetics of microencapsulated catechin in order to supply data for clinic using of microencapsulated catechin.[Methods] 1 .The mice and rats were give orally with microencapsulated catechin in order to observe the acute toxicity test; The rats were give orally with microencapsulated catechin for 12 weeks to observe the subchronic toxicity test . 2. The delayed type hypersensitive (DTH) , HC50 method; cleaning charcoal partical method were chosen to observe the effects of microencapsulated catechin on the immune functions of mice.3. Pharmacokinetic of microencapsulated catechin were studied in rabbits following oral administration of the drug plasma concentrations of catechin were determined by high-performance liquid chromatography.[Results] 1.The rats' LD50 of microencapsulated catechin is 6110mg/ kg ,the mice s LD50 of microencapsulation catechin is 5090 mg / kg.The rats have showed no toxicity reaction in weight ,blood,the internal organs ,liver and kidneys function after the using the microencapsulated catechin.2.Compared with NS group, microencapsulated catechin high dosage group ( 500mg/(kgd)x7d ) , middle dosage group ( 250mg/(kgd)x7d ) and low dosage group( 125mg/(kgd)x7d ) could not increase production of serum hemolysins in mice(P>0.05) ; microencapsulated catechin high dosage group, middle dosagegroup could significantly intensify degrees of oncotic caused by DNFB (P<0.05 P<0.01); microencapsulated catechin high dosage group, middle dosage group could also improved K, a (P<0.01) and increase the viscus index of spleen and thymus (P<0.05 P<0.01) ;Compared with immunosuppressed group, CY+ microencapsulated catechin high dosage group could increase production of serum hemolysins in mice (P<0.05) ;CY+ microencapsulated catechin high dosage group, middle dosage group could significantly intensify degrees of oncotic caused by DNFB(P<0.01); CY+ microencapsulated catechin high dosage group, middle dosage group could improved K, a (P<0.01) and increase the viscus index of spleen and thymus ( P<0.05 P<0.01 ) ;3.The drug concentration-time data were fitted to nonlinear pharmacokinetics after a single oral administration of microencapsulated Catechin. The pharmacokinetic parameters were as follows: A (0.726 + 0.015) mg/L; B (0.891+0.024) mg/L; Vm(1.377+0. 127) ; Km(1.227 + 0. 213) ; t1/2ke ( 1.670 + 0.162) h, Cmax (2.761+0.462) mg/L; C1B (1.435 + 0.267 ) L/h; AUC (2.769 + 0.398) ; Css (3.127+0.459) mg/L.[Conclusion] l.The microencapsulated catechin has actually no toxicity, It indicates that the clinic using of microencapsulated catechin is safe.2.Microencapsulated catechin has an enhanced effect on immunodulatory of normal and immunosuppressed mice.3.After catechin were microencapsulated its characteristics distribution were clear different, half-life is long.