Natural Products and Drug Discovery for Neurodegenerative Diseases

Dear Colleagues,

Neurodegenerative diseases (NDs) constitute a large group of pathological conditions, characterized by a progressive loss of neuronal cells, which compromise motor and/or cognitive functions. The most common NDs are Alzheimer’s disease (AD), amyotrophic lateral sclerosis (ALS), Parkinson’s disease (PD), and Huntington’s disease (HD). The causes of these pathologies are multifactorial and not fully understood, but it is well known that factors related to aging and to the overproduction of free radical and reactive oxygen species lead to oxidative stress and to cell death, which are extremely related. Whereas oxidative stress plays an unquestionable and central role in NDs, the control of free radicals and reactive oxygen species levels represents an interesting and promising strategy to delay neurodegeneration and attenuate the associated symptoms.

In this context, several natural bioactive compounds isolated from plants, fungi, and algae, among others, which present antioxidant properties, including vitamins C and E, anthocyanins, and phenolic compounds, are extensively described as potential palliative agents of neurodegenerative symptoms. In vitro and in vivo studies, performed with extracts and fractions of plants and with isolated natural bioactive compounds, provide evidence of the role of these substances in the modulation of the cellular redox balance and in the reduction in the formation of reactive oxygen species originating from oxidative stress, thereby demonstrating their great value as antioxidant agents and cellular protectors.

In antiquity, diverse natural compounds were used to treat several ailments and chronic diseases and were recognized for their therapeutic properties in folklore medicine. These compounds have heterogeneous chemical structure and varied pharmacological activity, being useful in the treatment of diseases of high complexity such as Parkinson’s disease, Alzheimer's disease, and others. Notwithstanding, at the present time, commercial drugs are in many cases aspecific and present side effects that increase pain or malaise in patients. It has been observed that several polyphenolic compounds derived from different natural herbs/plants are associated with successful medical treatment in various human diseases, including neurodegenerative diseases. Thus, extensive use of natural compounds might be a key to generating effective drugs against the treatment of different neurodegenerative diseases. Many researchers are studying to find out the role of different natural compounds and are interested in discovering new natural products with effective medical applications. The interest in these drugs is especially related to the treatment of neurodegenerative disorders such as Alzheimer's disease, Parkison’s disease, ALS, etc. In recent times, some phytodrugs have been methodically tested in in vivo and in vitro models of AD and also in clinical trials. Ginkgo biloba, Curcuma longa, Withania somnifera, and Angelica sinensis extracts have been found to show neuroprotective properties against several human neurodegenerative diseases.

In this Special Issue, we invite researchers to contribute original research and review articles that will help to elucidate the therapeutic potential of natural compounds against various human neurodegenerative disease. We encourage the submission of studies dealing with the use of natural or herbal approaches describing the role of respective compounds as a drug candidate in different neurodegenerative diseases.

Potential topics include but are not limited to the following:

• Different natural compounds with drug therapeutic potential;
• Neuroprotective activity of herbal compounds against different neurodegenerative diseases;
• Antioxidant properties of the natural compounds in various neurodegenerative diseases;
• Mechanism of actions of different natural drugs used in the treatment of different human neurodegenerative diseases;
• Mechanism and action of natural compounds involved in oxidative stress management in neurodegenerative diseases;
• Improved cognitive functions in different animal models by the treatment of herbal extracts.

Dr. Sandeep Singh
Dr. Mahendra P. Singh
Dr. Maria Tikhonova
Dr. Burkhard Poeggeler
Guest Editors

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• natural products
• neurodegenerative diseases
• drug delivery system
• neuroprotection
• antioxidative natural compounds