RESEARCH ARTICLE Antimicrobial activity, toxi

metabolic processes, these classes of compoundsVeterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South AfricaIn nature, different types of plants produce certain che-micals that are naturally toxic to microorganisms. These chemicals produced by plants play an essential role in the natural defence and well-being of plants, and belong to a wide range of classes which include the flavonoids and isoflavonoids [1]. Flavonoids can be classified into noids are linkages of flavone–flavone, flavanone–flavones or flavanone–flavanone subunits. Naturally occurring fla-vonoids are polyphenolic compounds which can be found in different parts of plants such as flowers, fruits, nuts, seeds, stems and vegetables. They can also be found in wine, honey and commonly consumed beverages such as tea [3,4]. Apart from the phytonutritional role of flavonoids i