| Oat β-glucan has the feature of reducing the risk of cardiovascular disease, however, it isnot clear about its metabolic and anti-fatigue effects. In this study, oat β-glucan was isolatedfrom oat bran, which is made from “Ding you si” naked oat. Its purity, molecular weight andstructure were identified. By using fluorescein isothiocyanate labeled β-glucan, itsmetabolism, tissue distribution and excretion in rats were investigated. Also, in vitro anti-oxidant abilities of oat β-glucan（OG）and fluorescent labeling of oat β-glucan（OG-FITC）were evaluated using Trolox equivalent method. Moreover, endurance training model in ratwas used to estimate anti-fatigue effect and the protective mechanism of oat β-glucan. Themain results of this study were obtained as follows:（1）Oat β–glucan was isolated from inactivated enzyme oat bran, the sample was madeby the method of alkali dissolution and aci deposition, purified by adding different enzymeand dialysis by deionized water, then freeze dried. The yield of oat β-glucan was8.22%.Extraction rate was77.40%, and the purity was92.58%. The average molecular weight was1.92×105Da. IR analysis showed that the samples had the characteristic structure of oatβ-glucan.（2）Oat β-glucan （OG） has been successfully labeled with fluorescein isothiocyanateby the covalent coupling between fluorescein isothiocyanate （FITC） and oat β-glucan.OG-FITC was orange red powder, and had the same solubility as OG； substitution degree ofFITC in OG-FITC was0.68%. The average molecular weight （Mw） weight of OG andOG-FITC were192.2kDa and192.4kDa, respectively, suggesting that fluorescence markerFITC had little effect on the molecular weight of OG.（3）Study on pharmacokinetics of oat β-glucan showed that: After rats were orallyadministered with300mg/mg OG-FITC, plasma concentration-time data was used to do thecalculation of pharmacokinetic parameters by using a compartmental model. Results showedthat oat β-glucan in rats were metabolized slowly, and had longer absorption half-life andhigher bioavailability. Oat β-glucan was mainly metabolized in the4-10h, and the excretionrate reached the highest around10h. Oat β-glucan was mainly excreted from feces after oraladministration． （4）Results on tissue distribution indicated that: OG-FITC was widely distributed totissues of most organs in rats2h after intravenous administration of300mg/kgOG-FITC．The concentration in stomach and intestine plasma was the most highest in alltissues, and also was abundant in liver and heart．The concentration in stomach and intestinedegraded rapidly after6h，and increased rapidly in brain, spleen, and skeletal muscle,suggesting that oat β-glucan was involved mainly in the spleen and skeletal musclemetabolism. For most tissues，oat β-glucan concentrations had significantly decreased in24hafter oral administration, while the oat β-glucan concentration in fat was not decreasedsignificantly. This may be associated with the fact that fat was less participated in metabolism.β-Glucan was also be detected in brain，which means β-glucan could cross the blood brainbarrier and participate in the brain’s neural regulation.（5）Evaluation on anti-fatigue effect of oat β-glucan suggested that: Compared withcontrol group （NC）, oat β-glucan group （OG） could increase the exhaustive running time,and reduce serum urea nitrogen and serum creatine kinase of rats significantly （P <0.01）.Also, it could increase the liver glycogen contents, serum free fatty acid content and lactatedehydrogenase enzyme activity, and reduce serum urea nitrogen levels significantly （P <0.05）. Results showed that oat β-glucan has significant anti-fatigue properties, by combinedwith oat β-glucan and moderate intensity training, it could improve the body’s endurance,delay fatigue.（6）Research on antioxidantive of oat β-glucan in vitro and in vivo showed that: Oatβ-glucan has strong antioxidant properties in vitro, which can effectively scaveng DPPH,Hydroxyl free radical, and owned higher oxygen radical absorbing capacities compared withTrolox. The results also showed that the antioxidant properties of β-glucan after fluorescentlabeling treatment did not change significantly. Results in vivo indicated that Oat β-glucancould reduce exercise-induced oxidative stress levels, and decrease cell injury of liver andmuscle tissue in rat model. Compared with the NC group, oat β-glucan treatment （OG）could enhance serum catalase activity significantly （P <0.05）, increase SOD activity ofskeletal muscle homogenates significantly （P <0.01）； and reduce serum hydroxyl radicalcontent （P <0.05） and MDA content in skeletal muscle homogenates significantly （P <0.01）. Oat β-glucan combined with exercise training could reduce exercise-induced oxidativestress levels and decrease cell injury of liver and muscle tissue much better than β-glucanalone in rats.（7）All in all, OG-FITC has excellent properties on stability, effective and exactlyinspection in biology sample test. First, study on pharmacokinetics showed that oat β-glucancan distribute in liver, skeletal muscle and epididymis fat. Second, research on anti-fatigue indicated that oat β-glucan can directly supply energy by improving the content of glycogenin liver and skeletal muscle and serum free fatty acid, and indirecty reduce/remove harmfulmetabolites such as decrease the lactid acid in serum by improve the activity of lacticdehydrogenase and reduce the content of urea nitrogen in serum. Third, the antioxidant of oatβ-glucan can improve adaptment of body on exercise induced oxidative stress, by increase theactivity of antioxidant enzyme and decrease the production of lipid peroxide. In conclusion,oat β-glucan could significantly enhance exercise capacity and prolong occurance ofexercise-induced-fatigue by directly engage in energetic metabolism and improve antioxidantcapacity of rats. |
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