ABSTRACT
Objective:To observe the effect of Puerariae Lobatae Radix on type 2 diabetes mellitus (T2DM) rats and related mechanism. Method:Ninety SD rats were divided into normal group, model group, metformin group, Puerariae Lobatae Radix high dose group, Puerariae Lobatae Radix medium dose group and Puerariae Lobatae Radix low dose group, 15 rats in each group. The rats in abnormal group were fed with high-fat and high sugar diet for 4 weeks, and then T2DM model was established by intraperitoneal injection of 40 mg·kg-1 streptozotocin (STZ). Puerariae Lobatae Radix high-dose group was intragastrically administered with 2.1 g·kg-1 of Puerariae Lobatae Radix extract powder, Puerariae Lobatae Radix medium-dose group was intragastrically administered with 1.4 g·kg-1 of Puerariae Lobatae Radix extract powder, Puerariae Lobatae Radix low-dose group was intragastrically administered with 0.7 g·kg-1 of Puerariae Lobatae Radix extract powder, 0.2 g·kg-1 of metformin hydrochloride in metformin group, distilled water once a day in normal group and model group. After 8 weeks, fasting blood glucose (FBG), glycosylated serum protein (GSP), insulin (FINS), triglyceride (TG), cholesterol (TC) were measured, and insulin resistance index （HOMA-IR） was calculated. The expression of tumor necrosis factor -α(TNF-α) was observed by immunohistochemistry. Western blot was used to detect the protein expression of glucose regulatory protein 78 （GRP78）, activated transcription factor 6 （ATF6） in pancreatic tissue. Result:Compared with normal group, the contents of FBG, GSP, TG, TC, FINS, TNF-α in model group were significantly increased (P<0.05), the HOMA-IR was significantly increased (P<0.05), the protein expressions of GRP78 and ATF6 in pancreatic tissue were significantly increased (P<0.05). Compared with model group, the contents of FBG, GSP, TG, TC, FINS and TNF-α in the metformin group and Puerariae Lobatae Radix high, medium and low dose groups were significantly decreased (P<0.05), HOMA-IR decreased significantly (P<0.05), and the expression of GRP78 and ATF6 protein in pancreatic tissue decreased significantly (P<0.05). Conclusion:Puerariae Lobatae Radix can significantly improve insulin resistance in T2DM rats, inhibit the expression of inflammatory factor TNF-α in pancreatic tissue, reduce the protein expression of GRP78 and ATF6 in pancreatic tissue.
ABSTRACT
Ligustrazine is an important active ingredient of the traditional Chinese medicine Chuanxiong Rhizoma, but its content is a controversial topic. The endophytes of medicinal plants have the ability to produce the same active substances as the host, so this report focused on the endophytic Bacillus subtilis, to study the origin of ligustrazine in Chuanxiong Rhizoma preliminarily by inoculating the isolated endophytic B. subtilis to the Chuanxiong Rhizoma medium for solid state fermentation. Tissue grinding method was used to isolate the endogenetic B. subtilis. The morphological features, conventional physiological and biochemical reactions and 16S rRNA molecular techniques were combined to identify the endogenetic strains. Then, the strains that grew well in the medicinal matrix of Chuanxiong Rhizoma were screened out for further fermentation studies. The solid-state fermentation was performed at 37 °C for 30 d using Chuanxiong Rhizoma fermentation medium (40 g Chuanxiong Rhizoma powder, 100 mL sterile water, 121 °C, sterilization for 25 minutes). UPLC was used to detect the contents of ligustrazine, acetoin in the Chuanxiong Rhizoma fermentation medium and Chuanxiong Rhizoma. All the five strains were Gram-positive and had spores. Phylogenetic analysis of the 16S rRNA sequence showed that the endophytes were B. subtilis. The results of UPLC showed that ligustrazine was detected in the Chuanxiong Rhizoma fermentation medium inoculated with endogenetic B. subtilis LB3, LB3-2-1, LB4, LB5 and LB6-2, while not detected neither in blank Chuanxiong Rhizoma fermentation medium nor in Chuanxiong Rhizoma. This study showed that the endogenetic B. subtilis of Ligusticum chuanxiong Hort. can make use of Chuanxiong Rhizoma fermentation medium to produce ligustrazine. Endogenetic B. subtilis has a certain correlation with the accumulation of ligustrazine in Rhizoma Chuanxiong. We speculate that the ligustrazine may be derived from the catabolism of endogenetic B. subtilis in Ligusticum chuanxiong.