The chemical and biological activities of quinones: overview and implications in analytical detection

Abstract

Quinones are a class of natural and synthetic compounds that have several beneficial effects. Quinones are electron carriers playing a role in photosynthesis. As vitamins, they represent a class of molecules preventing and treating several illnesses such as osteoporosis and cardiovascular diseases. Quinones, by their antioxidant activity, improve general health conditions. Many of the drugs clinically approved or still in clinical trials against cancer are quinone related compounds. Quinones have also toxicological effects through their presence as photoproducts from air pollutants. Quinones are fast redox cycling molecules and have the potential to bind to thiol, amine and hydroxyl groups. The aforementioned properties make the analytical detection of quinones problematic. However, recent advances of the available analytical techniques along with the possibility of using labeled compound facilitate their detection hence allowing a better understanding of their action. This review summarizes the current knowledge with respect to the oxido-reductive and electrophilic properties of quinones as well as to the analytical tools used for their analysis. It includes a general introduction about the physiological, and therapeutical functions of quinones. A number of studies are reported to cover the chemical reactivity in an attempt to understand quinones as biologically active compounds. Data ranging from normal analytical methods to study quinones derived from plant or biological matrices to the use of labeled compounds are presented. The examples illustrate how chemical, biological and analytical knowledge can be integrated to have a better understanding of the mode of action of the quinones.

Harvestman Phenols and Benzoquinones: Characterisation and Biosynthetic Pathway

“…The biological activities of benzoquinones 6 and 8 were very similar against all tested microorganisms, except for C. albicans. The biological activity of the benzoquinones has been assigned to the electrophilic character of the conjugated double bond [27].…”

Anthraquinones as Photoredox Catalysts for the Reductive Activation of Aryl Halides

“…Quinones [8,16,17] occur in nature and are known for their excellent electron-accepting and hydrogen-abstracting abilities. [16,18] Not surprisingly, different quinone derivatives have been used for photo-oxidative transformations under visible light.…”

“…[28] ) are powerful reductants and can transfer electrons to organic substrates with extremely negative reduction potentials (e.g., 1,2-dibromobenzene, an aryl halide substrate with a reduction potential of -1.88 V vs. SCE). [28] Although the radical anions of quinone derivatives are common intermediates in natural and synthetic photochemical energy storage, [16,30] they have not yet been applied in photoredox catalytic reductive transformations. As the excited states of radical anions act as powerful reductants, [12,13,28,29,31] we en- [40] In the inset, the luminescence spectrum (λ Ex = 427 nm) of Aq-OH-H -is shown.…”

A comparison of the effects of 1,4-naphthoquinone and 2-hydroxy-1,4-naphthoquinone (lawsone) on indole-3-acetic acid (IAA)-induced growth of maize coleoptile cells

“…As compounds with remarkable chemical and structural properties, naphthoquinones have been the focus of the attention of scientists for a long time. The biological activity of naphthoquinones is primarily based on two primary mechanisms-one is the covalent modification of biological molecules at their nucleophilic sites, such as the thiols in proteins and glutathione (GSH), in which quinones act as electrophiles, while the other mechanism consists of redox cycling, in which reactive oxygen species (ROS) are generated (reviewed in El-Najjar et al 2011;Klotz et al 2014;Kumagai et al 2012). Naturally occurring naphthoquinones such as juglone (5-hydroxy-1,4-naphthoquinone), lawsone (2-hydroxy-1,4-naphthoquinone), plumbagin (2-methyl-5-hydroxy-1,4-naphthoquinone), naphthazarin (5,8-dihydroxy-1,4-naphthoquinone) and others along with their synthetic derivatives have been studied intensively for many years in biology, medicine, agriculture and industry.…”