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Secondary metabolites affect body functions resulting to either onset and progression of disease or its prevention and alleviation. Examples of harmful metabolites include the poisons palytoxin and the red tide toxin. Among those which are beneficial are the antibiotic penicillin, ethanol and lactic acid for the preparation and preservation of foods and beverages, the pain relievers morphine and aspirin, the alkaloid reserpine, quinine anti-malarial agent, and the antitumor taxol. Meanwhile, fragrances and dyes are also beneficial byproducts of secondary metabolites
Secondary metabolites, including antibiotics, are produced in nature and serve survival functions for the organisms producing them. The antibiotics are a heterogeneous group, the functions of some being related to and others being unrelated to their antimicrobial activities. Secondary metabolites serve: (i) as competitive weapons used against other bacteria, fungi, amoebae, plants, insects, and large animals; (ii) as metal transporting agents; (iii) as agents of symbiosis between microbes and plants, nematodes, insects, and higher animals; (iv) as sexual hormones; and (v) as differentiation effectors. Although antibiotics are not obligatory for sporulation, some secondary metabolites (including antibiotics) stimulate spore formation and inhibit or stimulate germination. Formation of secondary metabolites and spores are regulated by similar factors. This similarity could insure secondary metabolite production during sporulation. Thus the secondary metabolite can: (i) slow down germination of spores until a less competitive environment and more favorable conditions for growth exist; (ii) protect the dormant or initiated spore from consumption by amoebae; or (iii) cleanse the immediate environment of competing microorganisms during germination.
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