Marmesinin is a natural product of Ammi, Apiaceae. Marmesinin can be used as a reference standard.

SB290157 trifluoroacetate is a potent and selective antagonist of C3a receptor(IC50 of 200 nM). SB 290157 is a competitive antagonist of 125I-C3a radioligand binding to rat basophilic leukemia-2H3 cells expressing the human C3aR (RBL-C3aR, IC50 of 200 nM).

Pyrocatechol its sulfonic acid is often present in the urine of many mammals. Small amounts of catechol occur naturally in fruits and vegetables along with the enzyme polyphenol oxidase. Upon mixing the enzyme with the substrate and exposure to oxygen (as when a potato or apple is cut) the colorless catechol oxidizes to reddish-brown benzoquinone derivatives.