On the use of acridinium indicators for the chemiluminescent determination of the total antioxidant capacity of dietary supplements

Abstract

Acridinium salts, due to their chemiluminogenic properties, have found several applications in biomedical analysis as labels and indicators, where the assessment of emission intensity is used for the end-point detection. This work presents the use of chemiluminescent indicators in the form of selected acridinium esters in order to determine the antioxidant properties of exemplary formulations, namely quercetin, vitamin C and the dietary supplement, Apiextract. The principle of measurements is based on a change in the kinetics of emission decay derived from the acridinium cations in alkaline solutions of hydrogen peroxide in the presence of an antioxidant (the analyte). The proposed system makes a beneficial alternative to related methods, which mostly rely on the assessment of emission efficiency and use the luminometric standard luminoldue to superior parameters of acridinium chemiluminescence, among othershigh temporary emission efficiency. The features of the proposed method are manifested by a shorter time period of analysis and lower background signals associated with the environmental influences, as compared to typical approaches. The chromatographic (RP-HPLC) analyses of the substrates and products generated during chemiluminogenic oxidation of acridinium cations under assay conditions are also presented.

Prevent or Cure—The Unprecedented Need for Self‐Reporting Materials

“…Nevertheless, recent research into common luminophores, such as dioxetanes, [131, 132] peroxyoxalates (POs), [122, 133–137] acridinium esters, [138–141] luminol, [129, 142] and their respective derivatives, led to the development of a plethora of advanced, promising self‐reporting CL systems. The CL of acridinium esters, for example, can be triggered by antioxidants, enzymes or peroxides and thus finds application in (biomedical) analytics as self‐reporting sensor for these substances [138–141] . In the presence of a trigger, the acridinium esters are oxidized to dioxetanones, which decompose with the release of CO 2 to form the highly emissive 10‐methyl‐9‐acridone, [139, 143] as displayed in Scheme 2 A.…”

“…However, the challenge to gain higher CL quantum yields, tune the emission range, or simplify the CL system is to modify the reaction environment or the luminophore itself in such a way that the CL properties are not diminished accidentally. Nevertheless, recent research into common luminophores, such as dioxetanes,[ 131 , 132 ] peroxyoxalates (POs),[ 122 , 133 , 134 , 135 , 136 , 137 ] acridinium esters,[ 138 , 139 , 140 , 141 ] luminol,[ 129 , 142 ] and their respective derivatives, led to the development of a plethora of advanced, promising self‐reporting CL systems. The CL of acridinium esters, for example, can be triggered by antioxidants, enzymes or peroxides and thus finds application in (biomedical) analytics as self‐reporting sensor for these substances.…”

Vorbeugen oder Heilen – die beispiellose Notwendigkeit von selbstberichtenden Materialien

“…Die Herausforderung, höhere CL‐Quantenausbeuten zu erzielen, den Emissionsbereich einzustellen oder das CL‐System zu vereinfachen, besteht jedoch darin, die Reaktionsumgebung oder den Luminophor selbst so zu modifizieren, dass die CL‐Eigenschaften nicht versehentlich vermindert werden. Nichtsdestotrotz führte die aktuelle Forschung an bekannten Luminophoren wie Dioxetanen, [131, 132] Peroxyoxalaten (POs), [122, 133–137] Acridiniumestern, [138–141] Luminol [129, 142] und deren jeweiligen Derivaten zur Entwicklung einer Fülle an fortschrittlichen, vielversprechenden selbstberichtenden CL‐Systemen. Die CL von Acridiniumestern beispielsweise kann durch Antioxidantien, Enzyme oder Peroxide ausgelöst werden und findet daher in der (biomedizinischen) Analytik als selbstberichtender Sensor für diese Stoffe Anwendung [138–141] .…”

Chemiluminescent self-reporting supramolecular transformations on macromolecular scaffolds

“…4,[6][7][8] Between the different types of self-reporting phenomena, chemiluminescence (CL) has been recognized as a functional tool due to its high sensitivity and wide dynamic range without the requirement of sophisticated equipment. [9][10][11] Besides common luminophores such as dioxetanes, 12 peroxyoxalates 4 or acridinium compounds, 13 luminol has gained significant attention since its discovery by Albrecht in 1928, 14,15 due to its low cost, beneficial properties and wideranging applications. Unfortunately, the quantum yield of luminol is rather low (≈0.01 in aqueous media and ≈0.09 in DMSO), 16 therefore substantial efforts have been devoted to develop new luminol systems with higher CL emission.…”