Free Radical Threshold Value: A New Universal Body Constant.

Area of Science:

• Biochemistry
• Free radical biology
• Oxidative stress research

Background:

• Reactive oxygen species (ROS) and lipid oxygen species (LOS) form the body's free radical ground state.
• The balance between ROS and LOS influences physiological and pathological processes.
• Understanding free radical effects requires defining thresholds for their impact.

Purpose of the Study:

• To present evidence for a universal free radical threshold value (FRTV).
• To define the borderline between advantageous and adverse free radical effects.
• To experimentally verify the FRTV in human skin and porcine liver.

Main Methods:

• Quantitative Electron Spin Resonance (ESR) x-band spectroscopy.
• In vitro experiments on ex vivo human skin and fresh porcine liver.
• Irradiation of tissues with UV + VIS, UVB + UVA, and VIS light.

Main Results:

• A universal FRTV of approximately 3.5 × 10^12 rad/mg ROS/LOS was calculated and experimentally verified.
• The FRTV was confirmed in both human skin and porcine liver tissues.
• A ROS > LOS ratio was found to be beneficial, while LOS > ROS was deleterious, consistent across tissues relative to the FRTV.

Conclusions:

• The FRTV represents a critical biological constant.
• This threshold differentiates beneficial from harmful free radical activity.
• The findings suggest a new universal body constant for free radical management.