Natural Compounds and Their Mechanism of Action: Therapeutic Targets of Neuroprotection and Neurorestoration in Neurodegenerative Diseases

Abstract

Endogenous antioxidant defenses are insufficient; therefore, oxidative stress is generated due to excessive production of reactive species, especially reactive oxygen (ROS) and reactive nitrogen (RNS) species, and degradation of cell structures, lipids, proteins, and genetic material. Oxidative stress is a key mechanism underlying the death of neurons, which is an essential component of the pathophysiology of neurodegeneration. One of the medically prescribed antidotes to this skewed oxidation-antioxidation state is the profession of antioxidants. Recently, natural substances with the properties to both scavenge free radicals and protect cells against oxidative threat as well as possess neuroprotective potential have attracted great interest.

This chapter summarized the state-of-research efforts attempting to identify natural chemical derived from medicinal plants that possess protecting action against neurodegenerative processes at molecular levels by controlling the death of neurons through inhibiting a variety of neurotoxins. Natural regulators of reactive species and mitochondrial activity are lignans, quinones, 1MeTIQ, resveratrol, curcumin, Gingko biloba, alkaloids, glycosides, vitamin C, flavonoids, polyphenols, coumarins, etc. They could decrease the neurotoxic agent-induced oxidative damage and apoptosis, by decreasing ROS/RNS generation, lipid peroxidation, caspase-3 and caspase-9 activities, LDH release, the ratio of Bax/Bcl-2, Ca2+ influx, cytochrome c release, increasing MMP, and restoring reverse endogenous enzymatic activities.

They also prevented mitochondria-dependent apoptosis pathways and modulated the oxidative plunges of several signaling pathways to produce neuroprotective effects against apoptosis. The current study examines the part that reactive species play in neurodegeneration, emphasizing the possible anti-oxidation properties of natural substances as a viable means of creating novel neuroprotective tactics.