ROS-Specific Neutralization of Bioactive Compounds: An Optical Approach

Reactive oxygen species (ROS) are partially reduced or excited forms of oxygen as byproducts of aerobic metabolism (endogenous sources). When cellular redox homeostasis is chronically affected by ROS overproduction or insufficient antioxidant activity (i.e., oxidative stress), different pathologies develop as a result of inflammation. Bioactive antioxidant compounds have been widely used to counter oxidative stress. However, the analytical methods available to explore their ROS scavenging capacity do not allow a comparison between different ROS species for a compound. In this work, we present an optical approach to evaluate the ROS-specific neutralization capacity of bioactive compounds as a function of the pH value, carrier system, and synergy among several compounds. We analyzed the profile of 11 natural antioxidants against four different ROS of physiological relevance: ¹O₂, OH^-, H₂O₂·, and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup><mml:mrow><mml:mi>O</mml:mi></mml:mrow> <mml:mrow><mml:mn>2</mml:mn></mml:mrow> <mml:mrow><mml:mrow><mml:mo>•</mml:mo></mml:mrow> <mml:mrow><mml:mo>-</mml:mo></mml:mrow> </mml:mrow> </mml:msubsup> </mml:math> . Our results show a specific antioxidant signature for each compound. We also found that liposomes have a great influence on the ROS neutralization properties of the compound together with the structural state driven by pH. Moreover, we observed both positive and negative synergistic effects for some dyads. The relevance and versatility of this method may lead to significant improvements in the drug delivery and formulation of antioxidants in the cosmetic and food industries.