The nomenclature of natural products is a highly specialized field of biochemistry. Fortunately, some classes of natural products are more amenable to computer analysis than others. Non-ribosomal peptides and heavily post-translationally modified peptides, such as derivatives of the homodetic cycles gramicidin S and the cyclic depsi-peptide valinomycin and the natural product cyclic isopeptides anantin and sungsanpin push the current state-of-the-art in automated natural product naming. Where a compound is structurally related to an existing peptide, perceiving this relationship is required for generating succinct human understandable names. In this talk, we describe the use of databases/dictionaries based upon HELM notation and IUPAC's condensed line notations for specifying 'parent' peptides from which derivatives and analogues can be named. Using the described techniques the name '[5-L-valine]dichotomin C' may be assigned to the cyclic peptide CHEMBL478596. These techniques have been successfully used to identify and correct naming issues in the UniProt and IUPhar/BPS guide to pharmacology databases, which have then been updated by their curators.