Study On The Antioxidative Effect Of Shudihuang And Its Different Fractions

Rehmannia glutinosa Libosch.is a traditional Chinese medicinal(TCM) herb, and depending on different processing methods,R.glutinosa Libosch has been categorized into three types,named as Radix Rehmanniae Recens(fresh root),Radix Rehmanniae Exsiccata(dried root) and Radix Rehmanniae Preparata(steamed root). Shudihuang,the steamed roots of R.glutinosa(SRG),are used more widely than the others,which has the effects of nourishing body,invigorating the kidney and promoting blood flow.It is often described as a primary herb in formulas to treat a great variety of diseases with the symptom of "kidney deficiency".Oxidative stress has been proposed to impair the antioxidant defense system,leading to oxidative damage by changing the balance between oxidant and antioxidant factors.Oxidative damage has been postulated to be involved in the etiopathogenesis of a diverse variety of diseases,and nearly all of these diseases manifest "kidney deficiency" during their development,which can be treated with SRG in TCM.Hence antioxidation might be one of therapeutic mechanisms of SRG.1.Study on the antioxidative effect of SRG on mice exposed to chronic mild stressSRG has significant effect of antioxidation to a mice model of chronic mild stress(CMS).CMS resulted in elevated gastric ulceration,hepatic malondialdehyde (MDA),together with reduced total antioxidant capability(TAOC),superoxide dismutase andcatalase(SOD) activities,glutathione(GSH) content and catalase activities(CAT).The alterations were improved by SRG in a dose-dependent manner. The differences in the activity of glutathione peroxidase(GSH-Px) were statistically nonsignificant among groups.Meanwhile locomotion reduced by CMS was restored by low dose of SRG(L-SRG,2.5 g/kg body weight) but not by high dose(H-SRG,5 g/kg body weight).Fur state,body and organ weight were found to be insensitive to CMS.Clomipramine the positive drug was similar to SRG especially in antioxidation. SRG is of therapeutic value for CMS,and antioxidation may be one of the mechanisms underlying its action.2.Active fractions of antioxidation of SRG in vitroIt has been investigated the active fractions of antioxidation of SRG in vitro. Water extract of SRG was partitioned into high and low molecular weight fractions (HMW and LMW) by 80%ethanol,the later was extracted by acetoacetate and the polar LMW(PLMW) was obtained.The above samples together with purified primary component manninotriose were dilated to concentrations corresponding to crude drug of 1,2.5,5,10,25,50,100 mg/ml and subjected to the assay of antioxidation in an in vitro model induced by FeSO₄ in rat hepatic homogenate.The data indicate that multifarious components distributed in HMW,hydrophilic and hydrophobic LMW are responsible for the antioxidation of SRG,and the primary active compounds exist in PLMW,but manninotriose displays inactive in antioxidation.In addition,the hydrophobic fraction removed from LMW was considered containing pro-oxidants.3.Study on the establishment of a rat model with the syndrome of "kidney deficiency"It was established the rat model with the syndrome of "kidney deficiency" by CPS.The male Wistar rats were randomly divided into two groups:the stress group and the control group.The stress group was subjected CMS of 5 periods(20days) to make the model with the symptom of "kidney deficiency".Compared with control group,the learning and memory ability wasn't decreased in the experiment of shuttle-box,meanwhile the increase of weight had been lower since the first stress period in stress group.There weren't significant differences in the viscera indexes (adrenal,thymus and brain) except spleen,which was atrophy in stress group.The activities of creatine kinase(CK) and lactic acid dehydrogenase(LDH) were notable increased,the levels of aspartate aminotransferase(AST) and triglyeride(TG) were higher,and there weren't marked distinction in total protein(TP),albumin(A), globulin(G) or glycose(Glu).As far as oxidative indexes were considered,the activity of SOD was declined with increase of MDA content in stress group,and the other oxidative indexes weren't significant differences(CAT,GSH-Px,GSH or Protein).It may cause the syndrome of "kidney deficiency" to subject CMS.