This study presents a family of pyrazolo[1,5-a]pyrimidin-7-ones as potential antimicrobial agents. Initial screening against Staphylococcus aureus, Escherichia coli, and Candida albicans identified compound 3 as active against S. aureus (MIC50 1.8 mu M). A structure activity relationship study of 35 analogues yielded the more potent analogues (MIC50 1.2 mu M, MIC80 6.4 mu M). Hit compounds were further evaluated against Methicillin-Resistant S. aureus (MRSA) and Pseudomonas aeruginosa, with pyrimidinone 12 showing the strongest activity against MRSA (MIC50 1.88 mu M, MIC80 2.93 mu M). In vivo toxicity assessment using Galleria mellonella larvae indicated that the leading active compounds were non-toxic. Importantly, in an in vivo G. Melonella MRSA infection model, compound 12 improved survival by 25 % compared to untreated controls (95 % vs. 75 %, p < 0.05). These strong in vivo results highlight pyrazolo[1,5-a]pyrimidin-7-ones as promising scaffolds for the development of new antibacterial agents.

Pyrazolopyrimidinones are fused nitrogen-containing heterocyclic systems, which act as a core scaffold in many pharmaceutically relevant compounds. Pyrazolopyrimidinones have been demonstrated to be efficient in treating several diseases, including cystic fibrosis, obesity, viral infection and cancer. In this study using glioblastoma U-251MG cell line, we tested the cytotoxic effects of 15 pyrazolopyrimidinones, synthesised via a two-step process, in combination with cold atmospheric plasma (CAP). CAP is an adjustable source of reactive oxygen and nitrogen species as well as other unique chemical and physical effects which has been successfully tested as an innovative cancer therapy in clinical trials. Significantly variable cytotoxicity was observed with IC50 values ranging from around 11 mu M to negligible toxicity among tested compounds. Interestingly, two pyrazolopyrimidinones were identified that act in a prodrug fashion and display around 5-15 times enhanced reactive-species dependent cytotoxicity when combined with cold atmospheric plasma. Activation was evident for direct CAP treatment on U-251MG cells loaded with the pyrazolopyrimidinone and indirect CAP treatment of the pyrazolopyrimidinone in media before adding to cells. Our results demonstrated the potential of CAP combined with pyrazolopyrimidinones as a programmable cytotoxic therapy and provide screened scaffolds that can be used for further development of pyrazolopyrimidinone prodrug derivatives. (C) 2021 The Authors. Published by Elsevier Masson SAS.

Pyrazolopyrimidinone is a fused nitrogen-containing heterocyclic system, which acts as a core scaffold in many pharmaceutically relevant compounds. Pyrazolopyrimidinones have been demonstrated to be efficient in treating several diseases, including cystic fibrosis, obesity, viral infection and cancer. We have tested the synergistic anti-cancer effects of 15 pyrazolopyrimidinones, synthesised in a two-step process, combined with cold atmospheric plasma (CAP), a novel innovation generating reactive species with other unique chemical and physical effects. We identify two pyrazolopyrimidinones that act as prodrugs and display enhanced reactive-species dependent cytotoxicity when used in combination with cold atmospheric plasma. Synergistic activation was evident for both direct CAP treatment on prodrug loaded tumour cells and indirect CAP treatment of prodrug in media prior to adding to tumour cells. Our results demonstrate the potential of CAP combined with pyrazolopyrimidinones as a programmable cytotoxic therapy against cancer.

A simple one-pot method for the microwave-assisted synthesis of substituted pyrazolo[1,5-a]pyrimidinones, a core scaffold in many bioactive and pharmaceutically relevant compounds, has been established. A variety of substituents was tolerated at the 2 and 5 positions, including functionalized aryls, heterocycles, and alkyl groups.

Metformin is the main drug of choice for treating type 2 diabetes, yet the therapeutic regimens and side effects of the compound are all undesirable and can lead to reduced compliance. The aim of this study was to elucidate the mechanism of action of two novel compounds which improved glucose handling and weight gain in mice on a high-fat diet. Wildtype C57Bl/6 male mice were fed on a high-fat diet and treated with novel, anti-diabetic compounds. Both compounds restored the glucose handling ability of these mice. At a cellular level, these compounds achieve this by inhibiting complex I activity in mitochondria, leading to AMP-activated protein kinase activation and subsequent increased glucose uptake by the cells, as measured in the mouse C2C12 muscle cell line. Based on the inhibition of NADH dehydrogenase (IC50 27µmolL(-1)), one of these compounds is close to a thousand fold more potent than metformin. There are no indications of off target effects. The compounds have the potential to have a greater anti-diabetic effect at a lower dose than metformin and may represent a new anti-diabetic compound class. The mechanism of action appears not to be as an insulin sensitizer but rather as an insulin substitute.