The Potential of Crude and Partially Purified Black Rice Bran Extracts Obtained by Ultrasound-Assisted Extraction: Anti-Glycemic, Cytotoxicity, Cytoprotective, and Antitumoral Effects.

Recovering anthocyanins from black rice bran is a way of valuing this byproduct, by obtaining an extract with biological potential. The objective of this study was to recover anthocyanins using ultrasound-assisted extraction. Some of the extract was partially purified, and both (crude and partially purified) extracts were evaluated for their anthocyanin content, antioxidant activity, antidiabetic and antitumoral activities, cytotoxicity, and oxidative stress. An increase in the laboratory scale was also achieved, making possible to increase the extraction volume up to 20 times without significantly changing the content of anthocyanins (1.85 mg C3G/g DW). It was found that the purified sample presented a 4.2 times higher value of total anthocyanins compared to the crude sample. The best IC50 values for the purified sample were verified by DPPH and ABTS (0.76 and 0.33 mg/mL). The best results for antidiabetic activity were obtained for the partially purified sample: 0.82 µM C3G for α-glucosidase and 12.5 µM C3G for α-amylase. The extracts demonstrated protection (~70%) when subjected to the oxidative stress of L929 cells. An antitumoral effect of 25-30% for both extracts was found in A459 cells. The crude and partially purified extracts of black rice have antidiabetic and anticancer effects and more studies are needed to explore their potential.

Chemo- and regioselective reactions of 5-bromo enones/enaminones with pyrazoles.

Reaction of 5-bromo enones with pyrazoles provided a series of unexpected N,O-aminal derivatives, through a 1,4-conjugated addition at the ß-carbon of the 5-bromo enones instead of the expected nucleophilic substitution of the bromine. This reaction also furnished the 1,3-regioisomer of the pyrazole. A similar reaction of pyrazoles using 5-bromo enaminones furnished only N-alkylated pyrazoles-with high regioselectivity and at good yields-through nucleophilic substitution of the bromine.

NF-kappaB, MEF2A, MEF2D and HIF1-a involvement on insulin- and contraction-induced regulation of GLUT4 gene expression in soleus muscle.

The GLUT4 gene transcriptional activity has a profound impact on the insulin-mediated glucose disposal and it is, therefore, important to understand the mechanisms underlying it. Insulin and exercise modulate GLUT4 expression in vivo, but the net control and involved mechanisms of each one have not been established yet. This paper sought to discriminate, in soleus muscle, the effects of insulin and muscle contraction on GLUT4 gene expression, and the involvement of transcriptional factors: myocite enhancer factor 2 (MEF2 A/C/D), hypoxia inducible factor 1-a (HIF1-a) and nuclear factor-kappa B (NF-kappaB). The GLUT4 mRNA was reduced by fasting (40%), and increased by in vitro incubation with insulin (25%) or insulin plus glucose (40%), which was accompanied by opposite regulations of NF-kappaB mRNA. Differently, in vitro, muscle contraction led to a rapid increase (35-80%) in GLUT4, MEF2A, MEF2D and HIF1-a mRNAs. Additionally, electrophoretic mobility shift assay confirmed changes in the binding activity of nuclear proteins to consensus NF-kappaB, GLUT4-Ebox and GLUT4-AT-rich element probes, parallel to the mRNA changes of their respective transcriptional factors NF-kappaB, HIF1-a and MEF2s. Concluding, insulin- and contraction-induced regulation of GLUT4 expression involves distinct transcriptional factors.