A hypothesis on peculiar pharmacological behaviour of biologically active natural compounds

A hypothesis is presented to explain the bioactivity of natural extracts, often higher than that of the synthetic bioactive components. This view is different from that based on synergy of the different chemical entities present in the natural substrate. It is based on the occurrence of molecular interactions originating from the high complexity of the natural matrix, following the rules of supramolecular chemistry. The formation of complexes between the active compound and other molecules (or oligoelements) present in the natural environment (leading to conformations more effective for interaction with the receptor) may be justified by 1H and 13C nuclear magnetic resonance (NMR) data. Examples are presented and discussed, suggesting that differences observed between the spectra of the pure compounds and those due to the same molecular species in the natural extracts may depend on some interactions with other molecular species or interactions with oligoelements.