A Concise Review of Common Plant-derived Compounds as a Potential Therapy for Alzheimer's Disease and Parkinson's Disease: Insight into Structure-Activity-Relationship.

Alzheimer's disease (AD) and Parkinson's disease (PD) are the two most common neurological illnesses that affect people in their later years. Memory loss is the hallmark of Alzheimer's disease, while dyskinesia, or loss of mobility, is associated with muscle rigidity and tremors in PD. Both diseases are unrelated, however, they do have a few similarities associated with extrapyramidal abnormalities, particularly stiffness, which has been linked to concomitant PD in many AD patients. Increased levels of IL-1, IL-6, and TNF in the AD and PD patients can be regarded as evidence of systemic inflammation associated with each of these neurodegenerative disorders. One of the primary variables in the progression of neurodegenerative disorders is oxidative stress. Many medicinal plants and their secondary metabolites have been claimed to be able to help people with neurodegenerative disorders like AD and PD. Anti-inflammatory, antioxidant, antiapoptotic, monoamine oxidase inhibition, acetylcholinesterase, and neurotrophic pursuits are among the major mechanisms identified by which phytochemicals exert their neuroprotective effects and potential maintenance of neurological health in old age. In regard to neurodegenerative disorders, numerable plant-based drugs like alkaloids, iridoids, terpenes, and flavones are employed for the treatment. Structure-activity relationships (SAR) and quantitative structure-activity relationships (QSAR) are used to investigate the link between bioactivity and the chemical configuration of substances. The SAR and QSAR of natural plant components employed in AD and PD are discussed in the current review.