Plant sterols (also known as phytosterols) represent a large class of organic plant ste- roid compounds including more than 200 unique molecules with a triterpene structure similar to zoosterols, specifically cholesterol. Sterols are also present in mushrooms and yeast, with ergosterol as the main representative compound. The molecular backbone is composed of a tetracyclic cyclopenta[a]phenanthrene scaffold with variable aliphatic side chains attached to carbon 17 (refer to Figure 1). Sterols (Δ5-sterols) differ from stanols (saturated plant sterols with a 5α reduction) because a double bond is present in
Different isoforms of plant sterols derive from the steroid backbone structure based on various types of lateral residue attached at carbon 29 (R1) and on the presence of double-bonds between two carbons at various positions (delta).