| Objective:Optimization of solid state fermentation using Eucommiae Cortex as medicinal substrate by Cordyceps militarise and discussion the antihypertensive activity of the fermentation product.Methods:Single-factor test was adopted by the effects of additive,growth factor,supplemental carbon source,supplemental nitrogen source,initial pH,inoculation amount,cultivation temperature and cultivation time on pinoresinol diglucoside(PDG)and cordycepin yield.And on this basis,Factors affecting cordycepin and PDG production in the fermentation were screened by applying the Plackett-Burman design,and the conditions of cordycepin and PDG production were further optimized by Box-Benhnken design.Then,to study the antihypertensive activity of the fermentation product.High,medial and low doses of fermentation products were administered to spontaneously hypertensive rats(SHR),and the blood pressure,heart rate and weight fluctuation of the rats in each group were observed during the whole administration.Affect the determination of fermentation product in mice serum Ang II,ACE,ET-1,NO,NOS content or activity.Took the heart,the kidney,the aorta of each rat,and damage scoring was performed according to both gross observation and light microscopic evaluation.Results:The optimum conditions of solid state fermentation using Eucommiae Cortex as medicinal substrate by C.militaris as follows:the fermentation medium containing 27%Eucommiae Cortex powder,add 4 g/kg VE,4 g/kg glucose,8 g/kg ammonium sulfate,initial pH=8,inoculate 40%seed solution,25℃ of culture temperature,18d of culture time.Cordycepin and PDG production in the solid state fermentation had reached up to 2.92 μg/g and 90.03 μg/g respectively,which were 60.44%and 52.90%increase than the initial value by this optimal process.In the experiment of reducing blood pressure,the systolic blood pressure(SBP)in high dose of Eucommiae Cortex and fermentation product were lowered significantly after 6 days of administration;the captopril,middle dose of Eucommiae Cortex,middle and low dose of fermentation product were lowered in the 8th day;the low dose ofEucommiae Cortex was only lowered in the 10th day.After long-terl oral treatment,the diastolic blood pressure(DBP)of SHR was decreased slowly.The heart rate(HR)and body weight had no statistics difference.Compared with model group,the high dose of Eucommiae Cortex and fermentation products could significantly increased the NOS activity(P<0.05)and NO concentration(P<0.01)in blood serum,reduced the ET-1 concentration,AngⅡ concentration and ACE activity greatly(P<0.05);the middle and low dose of fermentation product and middle dose of Eucommiae Cortex could reduced the ET-1 concentration(P<0.05),AngⅡ concentration(P<0.05)and ACE activity greatly(P<0.01);the low dose of Eucommiae Cortex could reduced the ACE activity(P<0.05);while captopril significantly reduced ET-1 concentration,Ang Ⅱ concentration and ACE activity greatly(P<0.05).In the aspect of target organ’s corresponding weight,compared with model group,there was no statistically significant difference in the weight of kidney/body weight and the weight of heart/body weight in each administration group.On the pathological morphology,compared with model group,the aortic endothelial cells and smooth muscle cells were arranged slightly neat.The percentage of collagen fibers in kidney and heart was less,which delayed the progression of myocardial interstitial fibrosis and glomerular atrophy.Conclusion:Under optimized conditions,C.militaris can grow well in the Eucommiae Cortex fermentation substrate and transformed the active ingredients.Cordycepin and PDG production in the solid state fermentation were 60.44%and 52.90%increase than the initial value.The fermentation products of Eucommiae Cortex by C.militaris has a good reducing blood pressure efficacy and a protective effect on target organ,and the antihypertensive activity of Eucommiae Cortex itself has a more good effect. |
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