Hypoxanthine is a naturally occurring purine derivative and a reaction intermediate in the metabolism of adenosine and in the formation of nucleic acids by the salvage pathway. Hypoxanthine is a necessary additive in the certain cell, bacteria, and parasite cultures as a substrate and nitrogen source. For example, it is commonly a required reagent in malaria parasite cultures, since Plasmodium falciparum requires a source of hypoxanthine for nucleic acid synthesis and energy metabolism.

Brucine is an alkaloid resembling strychnine but it is much less potent than strychnine. Brucine was first discovered in 1819 by Pelletier and Caventou in the bark of the Strychnos nux vomica tree. Brucine causes paralysis of the peripheral nerve endings and produces violent convulsions. Since brucine is a large chiral molecule, it has been used as an enantioselective recognition agent using in chiral resolution. While brucine has been shown to have good anti-tumor effects, on both hepatocellular carcinoma and breast cancer, its narrow therapeutic window has limited its use as a treatment for cancer. Brucine is also used in traditional Chinese medicine as an anti-inflammatory and analgesic agent, as well as in some Ayurveda and homeopathy drugs. Like strychnine, brucine also functions as antagonist at the glycine receptor and paralyzes the inhibitory neurons

3-Tyrosine, in contrast to the para isomer, is readily racemized. The majority of the load was metabolized to m-hydroxyphenylacetic acid but m-hydroxymandelic acid and 3,4-dihydroxyphenylacetic acid were also detected. Low circulating levels of m-tyrosine in the plasma suggest that most of the load is held due to a first pass effect somewhere in the enterohepatic system and that this portion of the load is not in equilibrium with the plasma m-tyrosine. The metabolism of a m-tyrosine may give further insight into the deficiencies of the phenylalanine hydroxylating system found in the various phenotypes of phenylketonuria. 3-Tyrosine has been used experimentally as a substitute for L-DOPA in the treatment of Parkinsonism. 3-tyrosine mimics the action of Dopa in two experimental animal models. It was also obvious from the experiments with d,l- and l-m-tyrosine that only the l-isomer (3-Tyrosine) is active.

Pyrene is a polycyclic aromatic hydrocarbon. Pyrene is a carcinogenic agent and is absorbed by the skin. It is a skin irritant, a suspected mutagen, and an equivocal tumor-causing agent. Pyrene (Py) and various metabolites with a Py chromophore are powerful probes often used in biophysical and biochemical sciences due to their high fluorescent quantum yields and relatively long fluorescence lifetimes. Bioaccumulation of this chemical may occur in crustacea, fish, milk, algae and molluscs.