Effects Of Differently Processed Rehmannia Roots On Yin Deficiency Animals

Rehmanniae Radix is one of the widely used traditional Chinese medicines and comes from the tuberous root of Rehmannia glutinosa Libosch.,and used in three different forms,namely fresh rehmannia root(FRR),dried rehmannia root(DRR)and steamed rehrnannia root(SRR).According to the traditional practices,FRR is collected as the aerial parts die down,and then dried at a temperature of 70-80 ? and used as DRR.SRR is derived from DRR by steaming for several days.In TCM theory,FRR and DRR have a cold property,being used to clear away pathogenic heat,while SRR is slightly warm and has a tonic effect.Our previous studies found that catalpol was decomposed gradually during the postharvest processing of Rehmannia root,and Maillard reaction occurred during the steam processing of the root.The results suggested that the change of related components might be the material basis for its different efficacy.However,the comparative study of the efficacy of three different processed products has not been reported.In this paper,the contents of catalpol and 5-HMF in three processed products were comparatively analyzed,and the yin-nourishing actions of FRR,DRR and SRR were evaluated by using two kinds of animal models of yin deficiency for the first time.The main works and results are as follows:(1)The contents of catalpol and 5-HMF were determined by HPLC.The contents of catalpol in FRR,DRR and SRR were 0.315%,0.184%and 0.019%,respectively;The contents of 5-HMF were 0.002%,0.005%and 0.436%,respectively.(2)Effects of differently processed Rehmannia roots on dexamethasone induced yin-deficient rats.A yin deficiency rat model was estabolished by long-term subcutaneous injection of dexamethasone(0.1mg/kg),diet reduction,body weight loss and irritable behavior were found in the model group.Comparing with normal control rats,fasting blood glucose,insulin and liver glycogen content were found significantly increased,and insulin tolerance test(ITT)showed that the rate of glucose degradation after insulin injection was significantly decreased.In oral glucose tolerance test(OGTT),the area under the curve of blood glucose content was significantly decreased compared with control rats,which indicated that glucose malabsorption appeared after glucose administration.Significantly reduced number of leukocytes,especially mononuclear granulocytes and lymphocytes were detected in blood counting,and the number of erythrocytes,hemoglobin and hematocrit were significantly increased.In addition,the index of spleen was significantly decreased,and heart,liver and kidney were significantly increased.It was found that FRR administration can improve the impaired food intake by dexamethasone treatment,and reduce fasting blood glucose and insulin resistance index and improve the impaired glucose absorption as showed in OGTT,return the number of red blood cells,hemoglobin content and hematocrit to normal level,and significantly increased spleen index.However,DRR and SRR were not effective as FRR on dexamethasone treated rats,but they can significantly decrease heart index and CK-MB concentration,whichindicated that they have a cardioprotective effect.(3)Effects of differently processed rehmannia roots on mice with yin-deficient constipation induced by loperamide.Loperamide administration led to a significant decrease in the number and weight of fecal pellets in,and the defecating time of the first black pellet after administration of active charcoal significantly increased.FRR,DRR and SRR can significantly promote small intestinal propulsion rates of the mice;and FRR and SRR could increasewater content in feces.Among the three processed rehmannia roots,SRR has the best effect of defecation.In addition,the three kinds of processed rehmannia roots also significantly increased the fecal water content of normal mice.The results show that:the three differently processed rehmannia roots have different pharmacological activities on the two animal models of yin deficiency.The relationship between the processing and the difference of their efficacy was preliminarily confirmed.The achieved results can provide the references for further understanding their properties and clinical efficacy of FRR,DRR and SRR.