The molecule is a triterpene glycoside that is lanost-8-ene substituted by hydroxy groups at positions 25 and 28, a methylidene group at position 24 and a beta-D-glucopyranosyloxy group at position 3. Isolated from the whole plant of Silybum marianum, it exhibits inhibitory activity against chymotrypsin. It has a role as an EC 3.4.21.1 (chymotrypsin) inhibitor and a plant metabolite. It is a triterpenoid saponin, a tetracyclic triterpenoid, a tertiary alcohol, a beta-D-glucoside and a primary alcohol.
(2R,3S,4S,5R,6R)-2-(hydroxymethyl)-6-[[(3S,4R,5R,10S,13R,14R,17R)-4-(hydroxymethyl)-17-[(2R)-6-hydroxy-6-methyl-5-methylideneheptan-2-yl]-4,10,13,14-tetramethyl-2,3,5,6,7,11,12,15,16,17-decahydro-1H-cyclopenta[a]phenanthren-3-yl]oxy]oxane-3,4,5-triol