| Steamed rehmannia root (SRR), Shu Dihuang in Chinese, is one of the traditional chinese herbal medicines mainly used to treat blood deficiency, nourish Yin, supplement marrow and essence. It was prepared from dried rehmaniae radix (DRR) by steaming for one to several days or stewing with rice wine. A side effect of SRR,’Nige’was frequently mentioned in ancient Chinese herbals, i.e., the patients taking SRR will have the feeling of abdominal distension. It was usually processed by using a variety of accessories, such as fructus amomi, pericarpium citri reticulatae, etc., to reduce the side effects.The purported best SRR was produced by steaming DRR for a day and being opened to the sun for another day, and thus repeating for nine times.As to the rice wine-stewed rehmannia root, yeast may also involved for no strict pasteurization was performed in the production of the wine, especially in ancient times. In addition, there have been records in ancient Chinese literatues on fermentation of rehmannia root to treat many ailments and diseases. However, the mechanism underlying this yeast processing remains unknown. In this thesis, SRR was fermented by alcohol yeast to gain yeast-fermented SRR (FSRR). During the fermentation, the main ingredients and DPPH free radical scanvaging activity were monitored. The effects of both SRR and FSRR on type I diabetic rats induced by alloxan were systematically investigated. The main results are as follows:1. Water extract of SRR was fermented with alcohol yeast for48h. It was found that5-HMF in the samples taken at a2-h interval was transformed rapidly at the beginning of the fermentation, while fructose, glucose, galactose and manninotriose was metabolized gradually. However,no significant alteration was detected in DPPH free radical scanvaging activity.2. Two weeks after type I diabetes mellitus induction by intravenous injection of alloxan, the rats were fed with animal chow medicated with high or low doses of SRR or FSRR with standard chow as control. Blood sugar, urine volume and food intake were regularly monitored. Open-field test and tail-immersion test were carried out in the tenth weeks, and then the animals were sacrificed and the blood and the kidneys were collected for the determination of the related parameters. The primary results are as follows:①It was found that neither SRR nor FSRR had a hypoglycemic effect on this diabetic rat.②The diabetic rats had a prolonged tail flick latency in tail-immersion test, reduced defecation in the open-field test, and increased urinary microalbuminuria, K+, Na+and aldosterone; the blood urea nitrogen and TXA2/PGI2increased. FSRR could improve the above abnormities more effectively than SRR.③The urinary urea nitrogen was not changed significantly in the diabetic rats when compared with the normal controls, but it was substatially rised in SRR rats.④Blood creatinine was found distinctly reduced in the diabetic rats; and no improvement was found in FSRR groups, however, it was significantly increased by the supplement of high dose of SRR. On the contrary, the urinary creatinine increased in the diabetic rats, both SRR and FSRR could significantly reduce the parameter.The results of this thesis firstly confirmed that yeast fermentation can improve the preventive effect of SRR on diabetic complications, and the underlying mechanisms may related with the decomposition of sugars and5-HMF. |
