Synthesis of Asparagusic Acid Modified Lysine and its Application in Solid-Phase Synthesis of Peptides with Enhanced Cellular Uptake

May 1,2-Dithiolane-4-carboxylic Acid and Its Derivatives Serve as a Specific Thioredoxin Reductase 1 Inhibitor?

Thioredoxin reductase is an essential enzyme that plays a crucial role in maintaining cellular redox homeostasis by catalyzing the reduction of thioredoxin, which is involved in several vital cellular processes. The overexpression of TrxR is often associated with cancer development. A series of 1,2-dithiolane-4-carboxylic acid analogs were obtained to verify the selectivity of 1,2-dithiolane moiety toward TrxR. Asparagusic acid analogs and their bioisoters remain inactive toward TrxR, which proves the inability of the 1,2-dithiolane moiety to serve as a pharmacophore during the interaction with TrxR. It was found that the Michael acceptor functionality-containing analogs exhibit higher inhibitory effects against TrxR compared to other compounds of the series. The most potent representatives exhibited micromolar TrxR1 inhibition activity (IC50 varied from 5.3 to 186.0 μM) and were further examined with in vitro cell-based assays to assess the cytotoxic effects on various cancer cell lines and cell death mechanisms.

Asparagusic Acid - A Unique Approach toward Effective Cellular Uptake of Therapeutics: Application, Biological Targets, and Chemical Properties

The synthetic approaches towards unique asparagusic acid and its analogues as well as its chemical use, the breadth of its biological properties and their relevant applications have been explored. The significance of the 1,2-dithiolane ring tension in dithiol-mediated uptake and its use for the intracellular transport of molecular cargoes is discussed alongside some of the challenges that arise from the fast thiolate-disulfide interchange. The short overview with the indication of the available literature on natural 1,2-dithiolanes synthesis and biological activities is also included. The general review structure is based on the time-line perspective of the application of asparagusic acid moiety as well as its primitive derivatives (4-amino-1,2-dithiolane-4-carboxylic acid and 4-methyl-1,2-dithiolane-4-carboxilic acid) used in clinics/cosmetics, focusing on the recent research in this area and including international patents applications.

Synthesis and Antimicrobial Evaluation of New Cephalosporin Derivatives Containing Cyclic Disulfide Moieties

Due to a steady increase in microbial resistance, there is a need to increase the effectiveness of antibiotic performance by involving additional mechanisms of their penetration or retention for their better action. Cephalosporins are a successful group of antibiotics to combat pathogenic microorganisms, including drug-resistant strains. In this study, we investigated the effect of newly synthesized cephalosporin derivatives with cyclic disulfide modifications against several Gram-positive and Gram-negative strains as well as against biofilm formation. The incorporation of asparagusic acid was found to be effective in improving the activity of the drug against Gram-negative strains compared to the all carbon-control compounds. Furthermore, we could demonstrate the successful reduction of biofilm formation for Staphylococcus aureus and Pseudomonas aeruginosa at similar concentrations as obtained against planktonic cells. We propose that the incorporation of cyclic disulfides is one additional strategy to improve antibiotic activity and to combat bacterial infections.

Cell-Penetrating Dynamic-Covalent Benzopolysulfane Networks

Cyclic oligochalcogenides (COCs) are emerging as promising systems to penetrate cells. Clearly better than and different to the reported diselenolanes and epidithiodiketopiperazines, we introduce the benzopolysulfanes (BPS), which show efficient delivery, insensitivity to inhibitors of endocytosis, and compatibility with substrates as large as proteins. This high activity coincides with high reactivity, selectively toward thiols, exceeding exchange rates of disulfides under tension. The result is a dynamic-covalent network of extreme sulfur species, including cyclic oligomers, from dimers to heptamers, with up to nineteen sulfurs in the ring. Selection from this unfolding adaptive network then yields the reactivities and selectivities needed to access new uptake pathways. Contrary to other COCs, BPS show high retention on thiol affinity columns. The identification of new modes of cell penetration is important because they promise new solutions to challenges in delivery and beyond.

Activation of disulfide bond cleavage triggered by hydrophobization and lipophilization of functionalized dihydroasparagusic acid

Introduction of a hydrophilic group into dihydroasparagusic acid (DHAA) indicated higher reduction ability of disulfide in protein and lower air oxidation.