Polyprenols are long-chain isoprenoid alcohols. The general formula of polyprenol is H-(C5H8)n-OH where n is the number of isoprene units. Polyprenol is categorized into three classes: all-trans (Solanesol-type), two-trans and poly-cis (Betulaprenol-type), and three-trans and poly-cis (Ficaprenol-type). Polyprenols serve as natural bioregulators in many plant tissues, despite found in small quantities. Dolichols, which are found in all living creatures, including humans, are their 2,3-dihydro derivatives.