# Natural Compounds: A Dynamic Field of Applications
###### Abstract  
Nature represents an amazing source of inspiration since it produces a great diversity of natural compounds selected by evolution, which exhibit multiple biological activities and applications. A large and very active research field is dedicated to identifying biosynthesized compounds, to improve/develop new methodologies to produce/reuse natural compounds and to assess their potential for pharmaceutical, cosmetic and food industries, among others, and also to understand their mechanism of action. Here, the main results presented in each work are highlighted. The applications suggested are mostly related to pharmacological uses and involve mainly pure natural compounds and essential oils. These works are significant contributions and reinforce the dynamic field of natural products applications.  
natural compounds; therapeutic applications; essential oils; antimicrobial; antitumor; SAR 20202  
undesirable side effects of antibiotics and antineoplastic agents used in the clinic [24; 25] have become pressing problems, leading to a continuous search for new inhibitors with new mechanisms of action.  
The application of natural compounds as antioxidant agents is also a hot topic [26; 27; 28; 29], once several diseases are, at least partially, a result of free radicals' imbalance [26; 30; 31]. Overproduction of oxygen free radicals, when associated with the deficiency in antioxidant repair or defence mechanisms, will cause oxidative damage leading to disease development like cancer, inflammation, diabetes, cardiovascular and aging-associated diseases [26; 30; 32; 31].  
Natural products are also applied as an ingredient in cosmetic preparations [33; 34] and in the food industry since they exhibit useful preservative properties [35; 36].  
The limited availability of a natural product is a difficulty when it is a promising molecule for an application. Thus, recently, it has been proposed that several techniques that can improve the natural product yield. It is the case of metabolomics, enable the rapid identification of novel compounds in complex mixtures of natural products, metabolic engineering of cells endowed with the ability of overproduction of new products and metagenomics exploring novel metabolites from microorganisms present in several environments but which remain recalcitrant to culturing [37; 38; 39].  
Natural compounds are privileged structures because of their structural diversity and multiple biological activities. They are undoubtedly the ideal compounds for the rational design of new drugs and the development of new chemical entities with therapeutic potential [8; 14]. Thus, research on natural compounds is necessary and very welcome.  
This Special Issue is dedicated to present the most recent results about the development of natural compounds applications. Ten original research works, organized by applications, and two reviews are included in this Special Issue. Each of them contributes to the knowledge advance, insofar as they present new applications for known products, new methodologies to obtain new products or the evaluation of a given application, with the applications related to health promotion being the most frequently considered.