Do polyketides have some characteristics of porton NMR singals? For example, terpenes have the characteristics of methyl singlets between 0.5 and 1 ppm? Is there a way that you can tell if a crude extract contains polyketides from proton NMR?
Polyketides are a group of secondary metabolites, with great diversity in terms of their structure. You may found macrolides but also small aromatic molecules in this class of compounds. I think that on proton NMR can not be sufficiently diagnostic for these compounds. May be C-NMR more efficient for a preliminary recognition, since carbonyl groups are often contained in polyketides, and may also have particular chemical shifts.