Structure-Activity Relationship Studies of Retro-1 Analogues against Shiga Toxin

One problem, multiple potential targets: Where are we now in the development of small molecule inhibitors against Shiga toxin?

Shiga toxin-producing Escherichia coli (STEC) are a group of enteric pathogens which carry phage-encoded Shiga toxins (Stx). STEC infections begin with severe abdominal pain and non-bloody diarrhoea, which can progress to bloody diarrhoea after approximately 4-days post-infection. In high-risk groups such as children and the elderly, patients may develop haemolytic uremic syndrome (HUS). HUS is characterised by microangiopathic haemolytic anaemia, thrombocytopenia, and in severe disease acute renal failure. Traditional antibiotics have been linked with increased toxin production due to the activation of recA-mediated bacterial stress response, resulting in poorer patient outcomes. Therefore, treatment relies on supportive therapies. Antivirulence strategies have been explored as an alternative treatment for bacterial infections and blockers of virulence factors such as the Type III Secretion System. Recent improvements in the mechanistic understanding of the Stx pathway have led to the design of inhibitors to disrupt the pathway, leading to toxin-mediated ribosome damage. However, compounds have yet to progress beyond Phase III clinical trials successfully. This review explores the progress in developing small molecule inhibitors by collating lead compounds derived from in-silico and experimental approaches.

Iron porphyrin-catalysed C(sp3)–H amination with alkyl azides for the synthesis of complex nitrogen-containing compounds

With the readily prepared iron porphyrin complex as a catalyst and starting with alkyl azides, a panel of nitrogen-containing skeletons representing the families of natural alkaloids and bioactive compounds could be prepared in good yields.

Palladium-catalyzed native α-amino acid derivative-directed arylation/oxidation of benzylic C-H bonds: synthesis of 5-aryl-1,4-benzodiazepin-2-ones

A Pd-catalyzed, native α-amino acid derivative-directed benzylic C-H bond arylation/oxidation with aryl iodides was developed. The natural amino acid auxiliary could serve as a desired building block for formation of 5-aryl-1,4-benzodiazepin-2-ones after removal of the trifluoroacetyl protecting group. The bifunctional reaction probably proceeded through a sequential benzylic arylation/oxidation process.

Role of Recent Therapeutic Applications and the Infection Strategies of Shiga Toxin-Producing Escherichia coli

Shiga toxin-producing Escherichia coli (STEC) is a global foodborne bacterial pathogen that is often accountable for colon disorder or distress. STEC commonly induces severe diarrhea in hosts but can cause critical illnesses due to the Shiga toxin virulence factors. To date, there have been a significant number of STEC serotypes have been evolved. STECs vary from nausea and hemorrhoid (HC) to possible lethal hemolytic-based uremic syndrome (HUS), thrombotic thrombocytopenic purpura (TTP). Inflammation-based STEC is usually a foodborne illness with Shiga toxins (Stx 1 and 2) thought to be pathogenesis. The STEC's pathogenicity depends significantly on developing one or more Shiga toxins, which can constrain host cell protein synthesis leading to cytotoxicity. In managing STEC infections, antimicrobial agents are generally avoided, as bacterial damage and discharge of accumulated toxins are thought the body. It has also been documented that certain antibiotics improve toxin production and the development of these species. Many different groups have attempted various therapies, including toxin-focused antibodies, toxin-based polymers, synbiotic agents, and secondary metabolites remedies. Besides, in recent years, antibiotics' efficacy in treating STEC infections has been reassessed with some encouraging methods. Nevertheless, the primary role of synbiotic effectiveness (probiotic and prebiotic) against pathogenic STEC and other enteropathogens is less recognized. Additional studies are required to understand the mechanisms of action of probiotic bacteria and yeast against STEC infection. Because of the consensus contraindication of antimicrobials for these bacterial pathogens, the examination was focused on alternative remedy strategies for STEC infections. The rise of novel STEC serotypes and approaches employed in its treatment are highlighted.