Abrogating Oxidative Stress as a Therapeutic Strategy Against Parkinson's Disease: A Mini Review of the Recent Advances on Natural Therapeutic Antioxidant and Neuroprotective Agents.

Abstract

Reactive oxygen species (ROS) play a vital role in cell signaling when maintained at low concentrations. However, when ROS production exceeds the neutralizing capacity of endogenous antioxidants, oxidative stress is observed, which has been shown to contribute to neurodegenerative diseases such as Parkinson's disease (PD). PD is a progressive disorder characterized by the loss of dopaminergic neurons from the striatum, which leads to motor and nonmotor symptoms. Although the complex interplay of mechanisms responsible is yet to be fully understood, oxidative stress was found to be positively associated with PD. Despite active research, currently proposed regimens mainly focus on regulating dopamine metabolism within the brain, even though these treatments have shown limited long-term efficacy and several side effects. Due to the implication of oxidative stress in the pathophysiology of PD, natural antioxidant compounds have attracted interest as potential therapeutics over the last years, with a more favorable anticipated safety profile due to their natural origin. Therefore, natural antioxidants are currently being explored as promising anti-PD agents. In this mini-review, emphasis was given to presently studied natural antioxidant and neuroprotective agents that have shown positive results in PD animal models. For this purpose, recent scientific articles were reviewed and discussed, with the aim to highlight the most up-to-date advances on PD treatment strategies related to oxidative stress. A plethora of natural compounds are actively being explored against PD, including kaemferol, icaritin, artemisinin, and α-bisabolol, with promising results. Most of these compounds have shown adequate neuroprotective ability along with redox balance restoration, normalized mitochondrial function, and limitation of oxidative damage. In conclusion, natural antioxidants may be the way forward to novel treatments against PD when the limitations of correct dosing and appropriate combinations are resolved.