| The incidence of diabetes is rising rapidly along with the improvement of people’sliving standards. World health organization announced that347million people havediabetes all over the world. China has become the country with the largest number ofdiabetes, the prevalence is9.7%. Type2diabetes accounts for more than90%of thetotal number of diabetes patients, mainly associated with insufficient insulin secretionand insulin resistance. Treatment for type2diabetes is not dependent on insulin, mainlytreated by oral hypoglycemic drugs, however, current oral hypoglycemic drugs oftenhave many disadvantages such as secondary failure, hypoglycemia and expensive.Therefore, it is necessary to develop new oral hypoglycemic drugs. Many studies showthat there is a close relationship between the occurrence of diabetes and the changes inglycosaminoglycans structure, and chromium supplementation can significantlyimprove glucose metabolism and lipid metabolism in diabetic patients. Marineoligosaccharides have many advantages including abundant resources, low toxicity andgood bioactivity, show good application prospects in drug development. In this paper,the complex prepared from marine acidic oligosaccharide which is similar in structurewith glycosaminoglycans and chromium ions was studied, in order to develop a neworal hypoglycemic drug.First of all, the orthogonal experiments were carried out to optimize the preparationconditions of marine drug HS203from oligomannuronate and chromium, and theoptimal reaction conditions were determined. The structural characterization of HS203was performed by using Nuclear magnetic resonance (NMR) spectroscopy, fullwavelength UV-Vis scanning spectrametry, Infrared spectroscopy and other analyticaltechniques. Then the preparation of its capsule and the quality standards were studied, and the capsule formulations were determined. The stabilities of HS203capsules underaccelerated conditions for six months and room temperature for twenty-four monthswere investigated, the results indicated that the drug was stable and the packagingmaterials also meet the requirements, the drug did not need strict conditions for storage.The hypoglycemic activity and its mechanism of HS203were also studied by usingtype2diabetic animal model in Wistar rats and in KM mice, the results showed thatHS203exhibited good hypoglycemic activity in animal models of diabetes mellitus, andhad no acute hypoglycemic effect, so there was no risk of a transient reduction of bloodglucose. The hypoglycemic activity of HS203was by improving insulin sensitivityindex, and also HS203could protect kidney and pancreas from damage caused byhyperglycemia, it showed good anti diabetic prospect.The acute toxicity test of HS203in mice and beagle dogs was investigated, and theresults indicated that the toxicity of HS203was very little, no animal was dead even atthe highest dose by intravenous injection or intragastric administration, so it showedthat HS203was very safe, and with less toxic side effect. The preliminarypharmacokinetics in rats and toxicokinetic in beagle dogs of HS203were studied usingfluorescent labelling high-performance liquid chromatography with post-columnderivatization method, the results showed that HS203could be metabolized afterintravenous injection in rats, t1/2α was3.35±0.78min. After oral administration, HS203was absorbed slowly in rats but fast in beagle dogs. The toxicokinetic in beagle dogsshowed that the plasma concentration of HS203was significantly higher aftercontinuous oral administration for8days and30days than that in the first day, and theplasma concentration in the male dog was higher than that in the female dog. Theseresults showed that the metabolism was not only associated with species differences, butalso might related to gender.The marine drug HS203will be developed as an oral preparation, and it belongs tonon-starchy carbohydrates, so it is necessary to study its effect to gut microbes. WhetherHS203was degraded or not, and what kinds of degradation products are produced, in order to know the metabolic process in vivo. The anaerobic fermentation system wasused to study the utilization of HS203, the results showed that HS203could be used bythe gut microbes. Polymerase chain reaction-denaturing gradient gel electrophoresis(PCR-DGGE) analysis was used to study the composition of the microbiota afterfermentation of HS203, the results indicated that HS203could significantly affect thecomposition of the microbiota, the intestinal microflora from different person weredistinctly different. The results also showed that the bacterias were mainly Bacteroides,and two strains were found in almost all the samples, they were Bacteroidesxylanisolvens and Clostridium clostridioforme respectively. The short chain fat acidsproduced during anaerobic fermentation process were determined. The isolation ofmicrobes was studied by using the gradient dilution and plate paint isolation methods,two strains could degrade HS203were isolated, they were Bacteroides xylanisolvensand Bacteroides ovatus, these results indicated that Bacteroides played an important rolein the use of HS203and its oligosaccharides.In conclusion, the preparation, the properties and stability of marine oligosaccharidedrug HS203and its capsule were studied in this paper. And then the hypoglycemicactivity in animal models of diabetes and the acute toxicity test were investigated, thepharmacokinetics and the toxicokinetic in different animals were also studied. In the last,the effect on intestinal microflora of HS203was investigated by using anaerobicfermentation system. These useful data offered the basis for developing it to be apromising anti-type2diabetes marine oligosaccharide drug in the future. |
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