Span is a synthetic non-ionic emulsifier, which is prepared by partial esterification of sorbitol or sorbitan with food grade palmitic acid.

Phytic acid exists in all eukaryotic cells. In plants it is known to function as a [PO4]3? storage depot and precursor for other inositol phosphates and pyrophosphates. It can be used clinically as a complexing agent for removal of traces of heavy metal ions. It acts also as a hypocalcemic agent.

HQNO is a natural product isolated from P. aeruginosa,and is a potent inhibitor of electron transport chain(Kd of 64 nM for complex III).