Chapter 9 - Toxic or harmful components of aromatic plants in animal nutrition

Abstract

“All things are poison, and nothing is without poison; only the dose makes the poison” (Paracelsus, 1493–1541). This quote laid down the principle of contemporary toxicology, however, centuries ago. Benefits could arise according to adequate posology and pharmacokinetics of molecules. Phenols as aromatic compounds are regarded as putative defensive molecules. In large concentrations they are confined to certain plant taxa such as Pinaceae, Rosaceae, and Lamiaceae, but not of systematic value. Beyond phytochemical positive effects, polyphenols as tannins or cyclic terpenes as coumarin, or cyanogenic glycosides as prunasin, probably co-evolved in aromatic plants to establish mechanisms of chemical defense against herbivory and pathogens. Consequently, as biologically active in feedstuffs for mammalian grazers and browsers, aromatic plants deserve to be explored in detail for the assessment of potential harm. At present, the debate about aromatic plant consumption associated with dosage of active compounds and related toxic effects is open and contradicting.