The in Vitro Antioxidant Capacities of Hydroalcoholic Extracts from Roots and Leaves of Smallanthus sonchifolius (Yacon) Do Not Correlate with Their in Vivo Antioxidant Action in Diabetic Rats

Leaf and root extracts of Smallanthus sonchifolius (yacon), have antihyper-glycemic activity and antioxidant properties. The present study aims to compare the in vivo hepatic antioxidant activity of hydroalcoholic extracts of yacon leaves and roots in rats with streptozotocin-induced diabetes in terms of their in vitro antioxidant capacity. Rats were treated during 14 days with 1060 mg·Kg-1 root extract or 400 mg·Kg-1 leaf extract. The latter was richer in phenolics and possessed a much higher in vitro antioxidant activity. Both extracts prevented hyperglycemia in diabetic rats. The liver of diabetic rats presented increased levels of protein carbonyls and ROS and decreased activities of antioxidant enzymes. Treatment with both root and leaf extracts restored the protein carbonyl levels to normality. The root extract also restored the ROS levels to normality, but the leaf extract was not effective. The root extract was also more effective in restoring the activity of at least two important antioxidant enzymes (glucose 6-phosphate dehydrogenase and glutathione peroxidase). In terms of the antioxidant load (which was 17 times lower in the root extract treatment), the in vivo action of the root extract was more effective than the leaf extract in reducing the hepatic oxidative stress that accompanies diabetes.

菊薯中异贝壳杉烯酸的抗细菌和抗真菌活性(英文)

AIM: To screen for the antibacterial activity of ent-kaurenoic acid (1) from the dichloromethane extract of Smallanthus sonchifolius leaves against Staphylococcus aureus, Staphylococcus epidermidis, Bacillus subtilis, Escherichia coli, Enterobacter aerogenes, Klebsiella pneumoniae, and Pseudomonas aeruginosa, and for its antifungal activity against Candida albicans, Trichophyton rubrum, and Epidermophyton floccosum. METHODS: Compound 1 was isolated by silica gel chromatography and its structure was elucidated by NMR spectroscopy. For assaying the antibacterial and antifungal activities of 1, the disk diffusion method was used, while the minimum inhibitory concentrations (MICs) were determined by the broth dilution method. RESULTS: With the disk diffusion method, 1 was found to be active against all the Gram-positive organisms tested (S. aureus, S. epidermidis, B. subtilis) at the lowest concentration of 1 000 μg·mL-1, while it was active against the fungus T. rubrum at 10 000 μg·mL-1. No inhibitory activity was observed against C. albicans, E. floccosum and all the Gram-negative test strains. The activity indices (AI) of 1 were noted to be highest against S. aureus and lowest against T. rubrum. Statistically significant differences were found between the mean inhibition zones (IZ) of 1 and the standard drugs (ofloxacin and clotrimazole). The results of the broth dilution MIC determination revealed that 1 exhibited moderate activity against S. aureus and S. epidermidis with MIC values of 125 μg·mL-1 and 250 μg·mL-1, respectively; and weak activity against B. subtilis with a MIC of 1 000 μg·mL-1. The growth of T. rubrum in the MIC assay was not inhibited at the highest tested concentration of 1 (10 000 μg·mL-1). CONCLUSION: The minimum bactericidal concentration (MBC) indicated that the bactericidal activities of 1 occurred at concentrations higher than its growth inhibitory concentrations. Furthermore, the MBC: MIC ratio of 2 : 1 clearly demonstrated the in vitro bactericidal effect of 1 against S. aureus and S. epidermidis.

Calibration and validation of FAO-AquaCrop model to estimate the total biomass and yacon root yield

Due to the current water scarcity in the world,it is extremely important to improve the use of this natural and exhaustible resource in agriculture,by contributing to increase agricultural production and sustainability.Several models of crop growth simulation were developed to predict the edaphoclimatic effects on crop yield.These models are calibrated and validated for a given region using the data generated from field experiments.Therefore,the objective of this study was to calibrate and validate the FAO AquaCrop model for yacon(Smallanthus sonchifolius)crop in a tropical climate.The experiment was conducted in an experimental area located in the municipality of Ibatiba,state of Espírito Santo(Brazil)during the years of 2013 and 2014.The calibration was done using the Autumn planting and validation with the Winter and Spring plantings.For the statistical analysis,the coefficient of determination,Willmott concordance index,bias for the systematic error,root mean square error and the mean absolute error to test the model performance were used.In general,the FAO AquaCrop model predicted the root yield,total biomass and harvest index with acceptable accuracy,and with deviations of less than 6%for total and root biomass.Late planting of yacon showed a reduction in yield as well as total biomass.