Design, synthesis and in vivo evaluation of 1,4-dioxo-2-butenyl aryl amine derivatives as a promising anti-inflammatory drug prototype.

Inflammation is a natural response of the organism to an infection, trauma, or cellular stress. Pain is the first symptom of acute and chronic inflammation. The standard class of medication to treat inflammatory pain is the nonsteroidal anti-inflammatory drug (NSAID). These drugs are associated with severe side effects such as gastric ulcers, gastritis, or internal bleeding. One of NSAIDs, Dipyrone® (metamizole) is largely used in many European and South American countries despite its dubious effectivity and its withdrawal from the market of several countries. Here, aiming to identify a new anti-inflammatory drug prototype based on Dipyrone® structure, a set of 27 molecules were virtually screened, and 4 compounds containing the active metabolite 4-aminoantipyrine and 1,4-dioxo-2-butenyl fragment were selected for docking, synthesis, and biological evaluation. The selection was based on the number of H-bonds and π- π stacking interactions between the inhibitor and the amino acids within the binding site of the enzyme. Carrageenan-induced paw edema, acetic acid-induced writhing, and formalin assays were used to evaluate inflammation and pain response. The selected compounds 1-4 inhibited the involvement of biogenic amines in the formation of paw edema. Compounds 1-4 also reduced pain in the inflammatory response phase. It has to be noted that 4-AA may cause agranulocytosis, which should be borne in mind when developing drug candidates of similar structure. Our new drug prototypes based on 4-aminoantipyrine and 1,4-dioxo-2-butenyl moieties open a gate for developing a prototype of nonsteroidal anti-inflammatory drugs.

Antimicrobial and Anticancer Properties of Synthetic Peptides Derived from the Wasp Parachartergus fraternus.

Agelaia-MPI and protonectin are antimicrobial peptides isolated from the wasp Parachartergus fraternus that show antimicrobial and neuroactive activities. Previously, two analogues of these peptides, neuroVAL and protonectin-F, were designed to reduce nonspecific toxicity and improve potency. Here, the three-dimensional structures of neuroVAL, protonectin and protonectin-F were determined by using circular dichroism and NMR spectroscopy. Antibacterial, antifungal, cytotoxic and hemolytic activities were tested for the parent peptides and analogues. All peptides showed moderate antimicrobial activity against Gram-positive bacteria, with agelaia-MPI being the most active. Protonectin and protonectin-F were found to be toxic to cancerous and noncancerous cell lines. Internalization experiments revealed that these peptides accumulate inside both cell types. By contrast, neuroVAL was nontoxic to all tested cells and was able to enter cells without accumulating. In summary, neuroVAL has potential as a nontoxic cell-penetrating peptide, while protonectin-F needs further modification to realize its potential as an antitumor peptide.