Lipid quinones are important compounds found in all aerobic organisms, plants and animals, they intervene as cofactors in various enzymatic reactions including electron acceptor function.

The various structures of lipid quinones enable the following classification :

1 - presence of a naphthoquinone nucleus :

- Vitamin K group which can be divided into

- phylloquinone or vitamin K1 (mono-unsaturated isoprenoid chain)

- menaquinone group or vitamin K2 (poly-unsaturated isoprenoid chain)

- other naphthoquinones

2 - precence of a benzoquinone nucleus :

- Ubiquinone group or coenzyme Q (methoxylated and methylated nucleus)

- Plastoquinone group (methylated nucleus)

3 - presence of a heterocyclic quinone nucleus

4 - presence of a hydroquinone nucleus