[Photometric micro-titration model of DPPH radicals scavenging activity and its application].

In the present paper, the stoichiometric ratio (R) for the interreaction of DPPH radicals with the antoxidant was employed as a evaluation index for DPPH radicals scavenging activity of antioxidants. This evaluation index was related only with the stoichiometric relationship between DPPH radicals and the antioxidant, not the relationship with the initial DPPH amount and the volume of sample, which could offer a solution for the problem of poor comparability of EC50 under different conditions. A novel photometric micro-titration method was proposed for the determination of the stoichiometric ratio (R) for the interreaction of DPPH radicals with the antoxidant. The titration equation was established based on the absorbance difference (deltaA) of DPPH radicals in the titration process and the added amount of antoxidant. The stoichiometric ratio (R) for the reaction of DPPH radicals with the addition amount of antoxidant was determined by the titration equation obtained, while, the DPPH median elimination concentration (EC50) of antoxidant can be calculated by the stoichiometric ratio (R). The above photometric micro-titration model was verified using rutin as DPPH radicals scavenger. As experiment results, the stoichiometric ratio (R) of DPPH radicals to rutin was determined to be in the range of 1.817-1.846. The calculated value of EC50 was 1.196 x 10(-3), 2.392 x 10(-3), 4.819 x 10(-3) and 7.292 x 10(-3) mg x mL(-1) for 1.12 x 10(-7), 2.24 x 10(-7), 4.48 x 10(-7) and 6.72 x 10(-7) mol of the additon amount of DPPH radicals, respectively. The proposed method has better precision and reliability with smaller amount of sample than conventional method. While, the obtained stoichiometric ratio value (R) of rutin was employed to calculate the rutin median elimination concentration for DPPH EC50) according to the conditions as reported in the literatures, and the calculated results were consistent with that reported in the literatures.

[Effects of tamoxifen on CD147 glycosylation and MMPs in the diabetic rat myocardium].

OBJECTIVE: Over the last few decades, diabetic cardiomyopathy has been identified as a significant contributor in cardiac morbidity. However, the mechanisms of diabetic cardiomyopathy have not been clarified. METHODS: In the present study, a diabetic rat model was induced by the intraperitoneal injection of streptozotocin. The myocardial CD147 expression and extent of glycosylation, as well as thematrixmetalloproteinases(MMPs) expression and activity, were observed in the diabetic and synchronous rats. RESULTS: The results showed that CD147 located on sarcolemma of cardiomyocytes. The myocardial CD147 expression and glycosylation were significantly increased in the diabetic rats as compared with the control. Expression of MMP-2 protein, MMP-2 and MMP-9 activity were also increased in left ventricular myocardium in the diabetic rats. Tamoxifen only inhibited the enhanced expression of myocardial CD147 in the diabetic rats, but not in synchronous control rats. Tamoxifen inhibited glycosylation of myocardial CD147 in both diabetic and control rats. The inhibition of tamoxifen on CD147 glycosylation was stronger than on the expression in the myocardium. The extent of myocardial CD147glycosylation was positively related toMMP-2 and MMP-9 activity. Tamoxifen induced an inhibition of myocardial MMP-2 and MMP-9 activity in the control and diabetic rats. CONCLUSION: These results indicate that myocardial CD147 expression, especially the extent of glycosylation, regulates MMP-2 and MMP-9 activity, then accelerates cardiac pathological remodeling inducing diabetic cardiomyopathy. Tamoxifen inhibits myocardial CD147 glycosylation and further depress the activity of MMPs. Therefore, tamoxifen may protect the diabetic rats against diabetic myocardium.

[Study on the extraction of polyphenol from Scindapsus officinalis with ultrasonic wave technology optimized by central composite design-response surface method].

OBJECTIVE: To optimize ultrasonic extraction technology process conditions of polyphenol from Scindapsus officinalis by the response surface method. METHODS: Based on ethanol concentration, ultrasonic time, the liquid-solid ratio of single factor experiment, the principle of design for 3 star factor 3 level response surface methodology was applied. With FC extraction method for determination of polyphenols, the response surface optimization extraction conditions were studied. RESULTS: The ethanol concentration of 61.14%, ultrasonic wave extracting time of 59.73 min and the ratio of solvent volume of 27.72:1 (Extract 3 times) were selected as the optimum conditions,the extraction yield of polyphenols was 1.352%, with the theoretical 1.361% for the relative error of -0.66%. CONCLUSION: Ultrasonic extraction is a good method for saving time, energy and material,and can be applied to the polyphenols extraction. Central composite design-response surface optimization can get better ecasting results.

[Study on the extraction of breviscapine from Erigeron breviscapus with ultrasonic wave technology optimized by central composite design-response surface method].

OBJECTIVE: To evaluate the effectiveness of ultrasound-assisted extraction and establish the optimized extraction conditions of breviscapine from Erigeron breviscapus. METHODS: On the basis of the single factor and according to the central composite design principles (CCD), the response surface method (RSM) with 3 factors and 3 levels was adopted and the independent variables were ultrasonic wave extracting time, ethanol concentration, and the ratio of solvent volume to Erigeron breviscapus mass, breviscapine extraction yield determinated by HPLC was used as response value. RESULTS: Ultrasonic wave extracting time of 24.5 min, ethanol concentration of 74.7% and the ratio of solvent volume to Erigeron breviscapus mass of 19.8 (mL/g) were selected as optimum conditions. Regression coefficients of binomial fitting complex model was 0. 9549 and the predicted breviscapine extraction yield was 0.641%, while the actual extraction yield was 0.632% (n = 5), with relative error of -1.14%. CONCLUSION: This study confirms the efficiency of ultrasound-assisted extraction as a simple, inexpensive and effective method to improve the extraction of breviscapine from Erigeron breviscapus. The observed and predicted values are close to each other, which proves that the optimization of supersonic extraction process of breviscapine from Erigeron breviscapus by CCD-RSM is reasonable and successful.

[Speciation analysis of eight metal elements in the leaves of Alstonia scholaris by flame atomic adsorption spectrometry].

The eight elements, Cu, Zn, Fe, Mg, Ca, Cr, Mn and Cd, in the leaves of Alstonia scholaris were extracted based on traditional analytical flowchart program and separated into water-soluble state and suspension state by micro porous filtering film. The water-soluble state was divided into organic state and inorganic state based on macro porous adsorption resin. The elements were detected by flame atomic adsorption spectrometry (FAAS). The results show that the extractive rates of the elements were in the range of 9.84%-89.07%, and the immersion-residue ratio in the range of 10.96%-903.4%. Adsorption ration of suspension state was in the range of 3.44%-23.37%. The recovery ratios by standard addition were in the range of 94.5%-111.6%, and the relative standard deviations (RSD) were in the range of 0.29%-2.47%. The precision and accuracy of determining results are satisfactory.

[Effects of Panax notoginseng saponins on antioxidation and preventing DNA damage caused by hydroxyl radical].

Scavening effects of panax notoginseng saponins on active oxygen species in the systems of Fenton reaction, autoxidation of pyrogallol and riboflavine photosensitization were investigated by the mean of spectrophotometry. The inhibition of panax notoginseg saponins on the damage of DNA chain induced by hydroxyl radical by panax notoginseng saponins was observed by the mean of gelose gel electrophoresi and thiobartital spectrophotometry. The results showed that panax notoginseng saponins could scaven * OH, O2*- efficiently and protect DNA chains from being damaged by hydroxyl radical.