Microbial natural product derivatives safety

The most remarkable property of these derivatives of microbial natural products is the wide margin of safety accorded to treated mammals - the reason being that the drug does not readily cross the blood-brain barrier to any extent (18). Fortunately in mammals, GABA mediated nerves only occur in the central nervous system. 

Plants produce a variety of chemicals to survive attacks by microbial invasion (Grayer and Harbome 1994). These metabolites are either preformed in the plant (prohibitins) or induced after infection (phytoalexins). Since phytoalexins can also be induced by abiotic factors such as UV irradiation, they have been defined as antibiotics formed in plants via a metabolic sequence induced either biotically or in response to chemical or environmental factors. Many of these substances have been identified as flavonoids (Cowan 1999). Extraction of flavonoids and identification of their antimicrobial activity is useful not only for finding new drugs but also for obtaining natural products useful as food additives to improve the shelf life and safety of foods. In fact, an aliment can be deteriorated by spoilage bacteria, that cause and develop unpleasant odours, taste and texture, whereas foodbome pathogenic bacteria may cause diseases with flu-like symptoms such as nausea, vomiting, diarrhoea, and/or fever. Food additives with antimicrobial activity can be used to overcome such problems, but consumers tend to reject the present use of additives obtained by chemical synthesis flavonoids, as additives derived from natural products, can be a valid and preferred alternative (Cowan 1999). 

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