Plant-Derived Antioxidants in Disease Prevention 2018

Department of Medical Physics and Biophysics, Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, Reymonta 19, 30-059 Krakow, Poland Department of Biophysics, Faculty of Science, Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký University, Šlechtitelů 27, Olomouc 78371, Czech Republic Department of Plant Physiology and Biochemistry, Faculty of Biochemistry, Biophysics, and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387 Krakow, Poland

Plant-derived antioxidants are a large group of natural products with reducing or radical-scavenging capacity. Due to their potent preventive as well as therapeutic actions, these compounds receive a great deal of attention not only from scientists but also from pharmacologists and physicians.
The maintenance of redox homeostasis plays a central role in health and disease prevention. Oxidative stress is generated by an imbalance between reactive oxygen species (ROS) and antioxidants. An excess of ROS leads to the degradation of lipids, proteins, and nucleic acids and thus may lead to the oxidative damage of cells as a consequence of the overexpression of oncogenes, mutagen formation, induction of atherogenic activity, or inflammation. Oxidative stress is suggested to play a major role in the pathogenesis of cardiovascular diseases, neurodegeneration, cancers, immune disorders, diabetes, aging, and others. Plants, especially dietary fruits and vegetables, are a rich source of antioxidants. It is postulated that antioxidants show health benefits through direct reduction of oxidative stress. In the body, an antioxidant network works in concert through several different mechanisms: ROS scavenging, termination of lipid peroxidation, or chelating of metals. Despite the fact that a broad knowledge of antioxidant structures, properties, and biological actions has been gathered, many aspects still require clarification and further studies. Relatively little is known about the cellular mechanisms of their therapeutic potential, interactions with other compounds, appropriate dosage, and effectiveness of treatment (especially their effect in randomized clinical trials). Furthermore, the bioactiveness of a large number of natural compounds remains unknown. Wellknown antioxidants, as well those newly discovered, raise hopes for their use in the prevention and treatment of the abovementioned diseases.
In this special annual issue, an attempt has been made to gather articles that update our understanding about the role of plant-derived antioxidants in disease prevention. These reports fill the gaps in the field of antioxidant research, allow better understanding of their action, and facilitate their future usage in disease prevention and treatment. The special issue compiles eleven (11) excellent articles including two (2) reviews and nine (9) research papers, which show current and recent developments in plant-derived antioxidant research.
The review by A. B. Enogieru et al. summarizes the latest knowledge about the neuroprotective mechanisms of plantderived rutin-a glycoside of the flavonoid quercetin. Rutin has a great potential to be a therapeutic agent in different neurodegenerative diseases. The second interesting review by B. M. Kim describes the therapeutic option of saikosaponins (triterpene saponins) isolated from Bupleurum against a variety of age-related disorders.
ROS play a major role in the pathogenesis of numerous diseases. It is believed that the application of exogenous antioxidants is a promising strategy to suppress oxidative stress Nitrosative stress in the brain is associated with various neurodegenerative disorders. The results obtained suggest that hydroxysafflor yellow A protects neurons from nitrosative stress.
Taken altogether, the data presented in this special annual issue cover a series of topics addressing the role of plantderived antioxidants in different oxidative stress-related disease prevention. We believed that the papers published in this special issue not only enrich our understanding of the physiological action of natural products but also provide promising perspectives on their future usage as therapeutic agents. We are sure that all the information provided in this issue will cover a broad range of interests.

Conflicts of Interest
The authors declare that there is no conflict of interest regarding the publication of this article.