1,5-Diazacyclooctanes, as Exclusive Oxidative Polyamine Metabolites, Inhibit Amyloid-β(1-40) Fibrillization

Origin and Fate of Acrolein in Foods

Acrolein is a highly toxic agent that may promote the occurrence and development of various diseases. Acrolein is pervasive in all kinds of foods, and dietary intake is one of the main routes of human exposure to acrolein. Considering that acrolein is substantially eliminated after its formation during food processing and re-exposed in the human body after ingestion and metabolism, the origin and fate of acrolein must be traced in food. Focusing on molecular mechanisms, this review introduces the formation of acrolein in food and summarises both in vitro and in vivo fates of acrolein based on its interactions with small molecules and biomacromolecules. Future investigation of acrolein from different perspectives is also discussed.

Inhibition of amyloid formation of amyloid β (1-42), amylin and insulin by 1,5-diazacyclooctanes, a spermine-acrolein conjugate

Amyloid aggregates of proteins are known to be involved in various diseases such as Alzheimer's disease (AD). It is therefore speculated that the inhibition of amyloid formation can play an important role in the prevention of various diseases involving amyloids. Recently, we have found that acrolein reacts with polyamines, such as spermine, and produces 1,5-diazacyclooctane, such as cyclic spermine (cSPM). cSPM could suppress the aggregation of amyloid β 1-40 (Aβ40), one of the causative proteins of AD. This result suggests the potential inhibitory effect of cSPM against Aβ 1-42 (Aβ42) and other amyloid protein aggregation which are the main pathological features of AD and other diseases. However, the effect on the aggregation of such proteins remains unclear. In this study, the effect of cSPM on the amyloid formation of Aβ42, amylin, and insulin was investigated. These three amyloidogenic proteins forming amyloids under physiological conditions (pH 7.4 and 37℃) served as model and are thought to be the causative proteins of AD, type 2 diabetes, and insulin-derived amyloidosis, respectively. Our results indicate that cSPM can suppress the amyloid aggregation of these proteins and reduce cytotoxicity. This study contributes to a better understanding of means to potentially counteract diseases by the means of polyamine and acrolein.

Application of Acrolein Imines to Organic Synthesis, Biofunctional Studies, and Clinical Practice

N-alkyl unsaturated imines derived from acrolein, a toxin produced during oxidative stress, and biogenic alkyl amines occur naturally and are considered biologically relevant compounds. However, despite the recent conceptual and technological advances in organic synthesis, research on the new reactivity of these compounds is lacking. This personal account discusses research on the reactivity that has been overlooked in acrolein imines, including the discovery of new methods to synthesize biologically active compounds, the determination of new functions of relevant imines and their precursors, i. e., aldehydes and amines, and the application of these methods for clinical diagnosis.

Disease-associated acrolein: A possible diagnostic and therapeutic substrate for in vivo synthetic chemistry

Acrolein, a highly reactive α,β-unsaturated aldehyde, is a compound to which humans are exposed in many different situations and often causes various human diseases. This paper summarizes the reports over the past twenty-five years regarding disease-associated acrolein detected in clinical patients and the role acrolein plays in various diseases. In several diseases, it was found that the increased acrolein acts as a pathogenetic factor. Thus, we propose the utility of over-produced acrolein as a substrate for a promising therapeutic or diagnostic method applicable to a wide range of diseases based on an in vivo synthetic chemistry strategy.

Unexplored Chemical Reactions of Endogenous Acrolein: Detection, Toxicity, and Biological Roles

Acrolein, a highly toxic α, β-unsaturated aldehyde, occurs as pollutant in the environment (e.g., tobacco smoke and exhaust gas) and is ubiquitously generated in biosystems (e.g., the lipid peroxidation process and metabolism of polyamine or amino acids). High accumulation of acrolein in biosystems is often linked pathologically with several oxidative stress-related diseases, including cancer and Alzheimer's disease. Accordingly, acrolein holds great potential as a key biomarker in oxidative stress-related diseases, and direct measurement of acrolein in biological samples is important to provide information for diagnostic and therapeutic purposes. Recently, we have serendipitously discovered the unrecognized reactivity of phenyl azide to acrolein. Phenyl azide can rapidly and selectively react with acrolein in a "click" manner to provide 4-formyl-1,2,3-triazoline through 1,3-dipolar cycloaddition. We have successfully utilized the acrolein-azide click reaction as a simple but robust method for detecting and visualizing acrolein generated by live cells in the context of oxidative stress processes. In addition, we also serendipitously discovered novel cycloaddition reactions of N-alkyl-α,β-unsaturated imines derived from acrolein and biogenic amines (e.g., polyamines, norepinephrine, and sphingosine), to yield 8-membered cyclic compounds. We then examined the biological functions of the cyclic products and revealed for the first time their roles in the oxidative stress mechanism and inhibition of amyloid β(1-40) fibrillization.

Oxidative addition/cycloaddition of arenesulfonamides and triflamide to N-allyltriflamide and N,N-diallyltriflamide

Mono- and diallyltriflamides react with triflamide in the oxidative system t-BuOCl + NaI to give the products of addition and cycloaddition, unlike the reaction of N-allyltriflamide with arenesulfonamides or trifluoroacetamide leading to chlorination and cyclodimerization.

Effect of spermine-derived AGEs on oxidative stress and polyamine metabolism

Spermine-derived AGEs CES- and MOSD-induced oxidative stress proceeds through different pathways.

A Reduction-Based Sensor for Acrolein Conjugates with the Inexpensive Nitrobenzene as an Alternative to Monoclonal Antibody

Acrolein, a highly toxic α, β-unsaturated aldehyde, has been a longstanding key biomarker associated with a range of disorders related to oxidative stresses. One of the most promising methods for detecting acrolein involves the use of antibodies that can recognize the acrolein-lysine conjugate, 3-formyl-3, 4-dehydropiperidines (FDP), within oxidatively stressed cells and tissues from various disease states. We have uncovered here that FDP could reduce nitroarenes in high yields at 100 °C in the presence of excess CaCl2 as a Lewis acid promoter. This unique transformation allowed for the development of a de novo method for detecting levels of FDPs generated from proteins in urine or blood serum samples. Thus we successfully converted a non-fluorescent and inexpensive 4-nitrophthalonitrile probe to the corresponding fluorescent aniline, thereby constituting the concept of fluorescent switching. Its sensitivity level (0.84 nmol/mL) is more than that of ELISA assays (3.13 nmol/mL) and is already equally reliable and reproducible at this early stage of development. More importantly, this method is cost effective and simple to operate, requiring only mixing of samples with a kit solution. Our method thus possesses potential as a future alternative to the more costly and operatively encumbered conventional antibody-based methods.