IUPAC definition : Natural pigments containing a fundamental skeleton of four pyrrole nuclei united through
the α-positions by four methine groups to form a macrocyclic structure (porphyrin
is designated porphine in Chemical Abstracts indexes).;
Natural pigments containing a fundamental skeleton of four pyrrole nuclei united through
the α-positions by four methine groups to form a macrocyclic structure (porphyrin
is designated porphine in Chemical Abstracts indexes).