why are some molecules produced by microbes known as bioactive molecules??? give ex.

Those molecules that can have an effect on a living organism are called as bioactive molecules. Examples of bioactive molecule, cyclosporin A, that is used as an immunosuppressive agent in organ-transplant patients, is produced by the fungus Trichoderma polysporum. Statins produced by the yeast Monascus purpureus have been commercialised as blood-cholesterol lowering agents. It acts by competitively inhibiting the enzyme responsible for synthesis of cholesterol.