Suchergebnisse

2-Styrylchromones (2-SC) are a small class of naturally-occurring oxygen-containing heterocycles. Although they are scarce in nature, a large number of 2-SC derivatives has been synthesized and their biological activ ity evaluated, namely as antiallergic, anti-inflammatory, antimicrobial, antioxidant and antitumor agents [l]. As far as we know, the antidiabetic activity of 2-SC is still unexplored. With this rational in mind, a series of 12 polyhydroxylated derivatives of 2-SC (1) were synthethized and used as inhibitors of the carbohydrate hydrolyzing enzyme a-glucosidase. This enzyme catalyzes the final step of the digestive process of starch and break down oligosaccharides to monosaccharides being one of the most currently used therapeutic approaches to decrease postprandial hyperglycemia and consequently to control type 2 diabetes mellitus [2]. The synthesis of polyhydroxylated 2-SC involves a multi-step strategy starting with the condensation of the appropriate 2'-hydroxyacetophenones with cinnamic acid derivatives, base-promoted Baker- Yenkataraman rearrangement of the esters formed, cyclodehydration and finnaly cleavage of the protecting groups to afford the desired polyhydroxylated 2-SC (3]. The in vitro assay to evaluate the inhibitory activity of the compounds under study and the positive control, acarbose, against a-glucosidase was performed by monitoring the hydrolysis of the substrate p-nitrophenyl glucopyranoside into the product p-nitrophenol at 405 nm. In addition, the study of the inhibition type was carried out through nonlinear regression Michaelis-Menton enzymatic kinetics and the corresponding Lineweaver-Burk plot [4]. ; This work received financial support from the European Union (FEDER funds POCI/01 /0145/FEDER/007265) and National Funds (FCT/MEC, Fundayiio para a Ciencia e Tecnologia and Ministerio da Educação e Ciência) under the Partnership Agreement PT2020 UID/ AGR/00690/2013; UID/QUI/50006/2013; UID/QUI/00062/2019, and "Programa Operacional Competitividade e Intemacionalizayiio" (COMPETE) (POCI-01-0145-FEDER-029241), and under the framework of QREN (NORTE-01-0145-FEDER-000024). ; info:eu-repo/semantics/publishedVersion

Chromone and xanthone derivativas are well-known for their outstanding antioxidant properties. ln an effort to develop new antioxidants with improved efficacy, here we cteveloped a new synthetic strategy to prepare hydroxylated chromones 3 and xanthones 4 with extended conjugated rr-systems. The synthetic strategy involved the aldolcondensation of 2-methylchromones 1 with cinnamaldehyde 2 to give chromones 3. Subsequent electrocyclization and oxidation of chromones 3 afforded xanthones 4 (Fig. 1 ). The scavenging activities of both derivativas 3 and 4 were addressed against both reactive oxygen species (ROS) and reactive nitrogen species (RNS). Ali tested compounds exhibited scavenger effects dependent on the concentration, with ICso values found in the micromolar range [1]. ; Sincere thanks are expressed to Faculdade de Farmácia da Universidade do Porto, Universidade de Aveiro, Instituto Politécnico de Bragança, Fundação para a Ciência e a Tecnologia (FCT, Portugal), European Union, QREN, FEDER and COMPETE funding UCIBIOREQUIMTE (FCT UID/Multi/04378/2013) and OOPNA (FCT UID/QUI/00062/2013) Research Units and also to the Portuguesa National NMR Network (RNRMN). ; info:eu-repo/semantics/publishedVersion