A practical approach to control glycemia in diabetes is to use plant natural products that delay hydrolysis of complex sugars and promote the diminution of the release of glucosyl units into the blood plasma. Polyphenolics have been described as being effective in inhibiting amylases and α-glucosidases. Grape pomace is an important sub product of the wine industry, still rich in many compounds such as polyphenolics. In this context, the purpose of this study was to search for possible effects of a grape pomace extract on salivary and pancreatic αamylases and α-glucosidase, as well as on intestinal glucose absorption. The Merlot grape pomace extract (MGPE) was prepared using a hydroalcoholic mixture (40% ethanol + 60% water). In vitro inhibition was quantified using potato starch (for amylases) and maltose (for α-glucosidase) as substrates. In vivo inhibition was evaluated by running starch and maltose tolerance tests in rats with or without administration of MGPE. Ranking of the extract compounds for its affinity to the α-amylases was accomplished by computer simulations using three different programs. Both α-amylases, pancreatic and salivary, were inhibited by the MGPE. No inhibition on α-glucosidase, however, was detected. The IC 50 values were 90 ± 10 μg/mL and 143 ± 15 μg/mL for salivary and pancreatic amylases, respectively. Kinetically this inhibition showed a complex pattern, with multiple binding of the extract constituents to the enzymes. Furthermore, the in silico docking simulations indicated that several phenolic substances, e.g., peonidin-3-O-acetylglucoside, quercetin-3-O-glucuronide and isorhamnetin-3-O-glucoside, besides catechin, were the most likely polyphenols responsible for the α-amylase inhibition caused by MGPE. The hyperglycemic burst, an usual phenomenon that follows starch administration, was substantially inhibited by the MGPE. Our results suggest that the MGPE can be adequate for maintaining normal blood levels after food ingestion.

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This work describes the synthesis, characterization and application of a pH- and magnetic-responsive PEG hydrogel (HG) nanocomposite as a platform for drug delivery.

The dopaminergic system is involved in a wide range of neuropsychiatric and neurodegenerative disorders. The lack of receptor subtype specificity is related to several pharmacological side effects that are observed during therapy among parkinsonian and schizophrenic patients. It is of paramount importance to search for new compounds that act on dopamine receptors with therapeutic potential, higher clinical effectiveness, and fewer adverse effects. In the present study, we performed a molecular docking study of D2, D3, and D4 receptor interactions with 92 metabolites from Curcuma longa using an in silico approach. We sought to identify compounds for possible drug development. A virtual library of compounds was built using molecules that were identified in the phytochemical characterization of C. longa. Protocols that were validated by redocking were applied to a virtual scan of this library using the Autodock-v4.2.3, Autodock Vina, and Molegro-v6.0 Virtual Docker programs, with four repetitions each. The three-dimensional structures of D2, D3, and D4 receptors in complex with risperidone, eticlopride, and nemonapride were obtained from the Protein Data Bank. Four compounds—stigmasterol, β-sitosterol, cholest-5-en-3-one, and cholestan-3-ol,2-methylene-(3β, 5α)—were the most likely to bind D2, D3, and D4 dopamine receptors, suggesting their potential for possible drug development.

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