Over centuries the majorities of drugs have been of a natural source, containing herbs, animal products and inorganic materials in their composition. The development on chemistry allowed isolating and characterizing bioactive ingredients, coming from the plant kingdom and even culture studies of microorganisms were developed.
About 200.000 natural products are known to date and in the last years, due to the technological development and the databases awareness, isolation and structural elucidation of products require less time than ever. Only 5 – 15 % of these natural plants have been studied to identify the presence of bioactive natural products.
There are data that confirm the importance of natural products in the development of new drugs. More than a 50 % of successful products (between 1981 and 2005) are part of this products family. The answer to this achievement lies in nature itself.
Natural products are biologically validated as they have grown up along with living organisms to join the proteins involved in biological processes.
What are and how are natural products produced?
The most important molecules for life are proteins, carbohydrates, fats and nucleic acids. Despite the extremely different characteristics on the diversity of living organisms, routes for changing and synthesizing these substances are essentially and remain the same for all with very minor modifications. These processes are known as primary metabolism and the compounds, involved in the different routes, are known as primary metabolites.
Secondary metabolism is the name for the set of processes that involve compounds with much more limited and specific distribution, according to the living organism. The compounds involved in the metabolism are called secondary metabolites and are specific to these species and defined as NATURAL PRODUCTS from a technical point of view.
The biosynthesis of natural products starts with photosynthesis, which takes place in the upper plants, seaweed and some bacteria. It is an endothermic process that requires sunlight. Those organisms that are unable to absorb light, get their energy from the degradation of carbohydrates. There are three major chemical intermediates such as acetyl-CoA, shikimic acid and mevalonic acid. These compounds are converted through biosynthesis into the main groups of natural products such as fatty acids, anthraquinones, terpenes, steroids, alkaloids, coumarins, lignans, etc.