1. Synthetic chemicals and natural products Synthetic chemicals are made by the use of chemically reactive reagents. Natural Products are synthesized from natural sources. Their synthesis is being conducted by enzymes

2. The chemical factories of compounds

3. historic perspectives 1807 Berzelius introduced the terms organic and inorganic, to refer to chemicals made by living organisms 1833 Persoz and Payen first noted enzyme activity. The concept of vitalism now transferred to enzymes in whole cells. However in 1897 Büchner showed enzyme activity in cell-free solutions so vitalism suffered a final blow. 19 th century. organic molecules gradually split into the study of man-made organic chemicals (the organic chemicals and organic chemistry of today) and organic chemicals made by organisms (=Natural Products and Natural Product Chemistry of today).

4. 1891 Kössel, a German physiological chemist, proposed that the metabolism of organisms could be divided into: Primary metabolism that was the basic biochemistry common to all cells. Secondary metabolism that was the type of biochemistry found only in some species. Thus to physiological chemists, later to be called biochemists, Secondary Metabolites are what chemists call Natural Products.

5. Targeting “undruggable” targets - Trip back to the Nature Hit not Lead compounds Natural products have been evolutionary selected after nature’s combinational chemistry to interact with multiple biological target molecules Propabilistic approaches (combichem) screening of thousands of compounds against a single target The chemical universe is just vast and may contain 10 200 molecules. Map the sub-portion of the chemical space that is of biological relevance. 40% of established drugs are either natural products or derived from natural products