Regulation of the kynurenine metabolism pathway by Xiaoyao San and the underlying effect in the hippocampus of the depressed rat.

ETHNOPHARMACOLOGICAL RELEVANCE: Xiaoyao San (XYS) is a classic Chinese herbal formula for treatment of depression. The present study aimed to investigate the antidepressant effects of XYS in a rat model of chronic unpredictable mild stress (CUMS) and the underlying mechanisms. MATERIALS AND METHODS: A CUMS rat model of depression was established via 4 weeks of unpredictable stimulation. Then the rats were orally administered paroxetine and XYS for 2 weeks with continued stress. Behavioral assessments, including an open field test (OFT), sucrose preference test (SPT) and forced swim test (FST), were conducted to evaluate the antidepressant effects of XYS. The concentrations in rat plasma of tryptophan (Trp) and its metabolic products, including kynurenine (Kyn) and quinolinic acid (QUIN), were determined using high performance liquid chromatography tandem mass spectrometry with electrochemical detection (HPLC-MS/MS). The mRNA and protein levels in rat hippocampus of depression-related brain derived neurotrophic factor (BDNF), cyclic AMP response element binding protein (CREB) and nerve cell adhesion molecule (NCAM) were determined by real-time qPCR and Western blot, respectively. Enzyme Linked Immunosorbent Assay (ELISA) was used to detect the activities of indoleamine 2,3-dioxygenase (IDO) and kynurenine-3-monooxygenase (KMO) in rat plasma. RESULTS: The results showed that a successful CUMS rat model was established through 4 weeks of continuous unpredictable stimulation, as indicated by the significant decrease in locomotor activity and increase in immobility time in the OFT, reduction in body weight and food intake etc. Compared with the normal group, the concentrations of Kyn and QUIN had significantly (p < 0.05) decreased at day 28 in the control group, but then improved after drug treatment with paroxetine and XYS. There were no obvious changes in the activities of IDO and KMO. Compared with the normal group, the mRNA of NCAM, CREB and BDNF were significantly down-regulated (p < 0.001) in the control group, BDNF gene was up-regulated by paroxetine or XYS treatment, NCAM and CREB gene did not change in XYS group, protein expressions of BDNF and CREB were significantly increased, and NCAM was significantly reduced (p < 0.05). CONCLUSIONS: XYS reversed the abnormalities of the tryptophan-kynurenine metabolic pathways in depressed rats and achieved an excellent antidepressant effect. Its direct impact may be observed as changes in biological indicators in rat hippocampus tissue.

[Pharmacokinetic Effect of Acteoside in Blood Deficiency Rats].

Objective: To study the different pharmacokinetics effect of acteoside extracted from Rehmanniae Radix Preparata in normal and blood deficiency rats. Methods: Injected acetyl phenylhydrazine and cyclophosphamide to make blood deficiency rats models subcutaneously,and gave mice the ethand extracts of Rehmanniae Radix preparata by oral administration,the concentration of acteoside in rats at different time points were detected by HPLC method, pharmacokinetic parameters were calculated by 3p87 software. Results: The determination of acteoside in the linear range were 0. 2 ~ 80 µg / m L, the limit of detection and quantification was 0. 03 and 0. 12µg/m L,respectively. Compared with the normal group,the content of AUC0-tand AUC0-∞of corresponding dose in model group rats increased significantly, and the average dwell time and the elimination half-life prolong significantly. Conclusion: This method has high specificity,high sensitivity and simple operation, which can be used for the determination to pharmacokinetic process of acteoside in blood deficiency model.

[In vivo Pharmacokinetics of Notoginsenoside R1 in Ischemia Rats After Acute Myocardial Infarction].

OBJECTIVE: To establish an HPLC-UV method for determining pharmacokinetic difference of notoginsenoside R1 between normal rats and ischemic rats. METHODS: 48 male SD rats were randomly divided into normal group and acute myocardial ischemia( AMI) model group induced by pituitrin and each group was classified into high,middle and low-dose of groups with notoginsenoside R1 (200, 100 and 50 mg/kg) respectively. Blood samples were collected at different points in time after they were administered once by gavage and separated by Waters symmetry C18 column (250 mm x 4.6 mm, 5 µm) under the detective wavelength 203 nm, the mobile phase was acetonitrile-water with icariin as the internal standard and the pharmacokinetic parameters were calculated by DAS 2. 0. RESULTS: Notoginsenoside R1 had good linearity in the ranges of 0.2~125 µg/mL (R2 = 0.9997) with SNR 1:3 and the lowest detection limit was 0.053 µg/mL, the extraction rate, RSDs of within-day and between-day, specificity, accuracy and precision accorded with the require-ment of bio-sample pretreatment. Compared to the normal group, AUC0-t, and AUC0-∞ was significantly increased (P < 0.01) and the terminal half-life was prolonged markedly (P < 0.01) in AMI group. CONCLUSIONS: The method is simple, accurate and had high specificity and sensitivity, that could be applied in quantitative determination of notoginsenoside R1 and research of pharmacokinetics; the relative bioavailability of notoginsenoside R1 is increased significantly in AMI group,which indicates that notoginsenoside R1 has better effect in model rat.