Why must biofunctional molecules be synthesized

One may think that there is no need for the synthesis of biofunctional molecules, because they always exist in organisms, and can be extracted and isolated. This is quite untrue, because the amounts of biofunctional molecules in organisms are usually very small. Due to their extremely low concentrations effective in organisms, biofunctional molecules can be isolated only in very small amounts, as shown in Table 1.2. It is therefore impossible to isolate hormones, pheromones and other bioregulators in gram quantities. 

The limited availability of biofunctional molecules often makes it difficult to determine their precise stereostructures at the time of isolation. Accordingly, synthesis has become important as a tool to determine the structures of biofunctional molecules unambiguously. Advances in analytical techniques enabled chemists to propose the structures of biofunctional molecules even when they are available in extremely small quantities. Because of that, synthesis has become even more important than ever. 

When we want to use biofunctional molecules practically in agriculture or medicine, of course we have to provide them in quantity. Organic synthesis is a method of choice for their large-scale production together with biotransformation and fermentation. More importantly, organic synthesis can provide useful 

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