Figure 4.

Nomenclature diagram of the different components of milk thistle seed and silymarin. ²⁴ Isosilybin B seems to be the most powerful anticancer fraction. ²⁵ Silymarin and Silibinin are different concepts, however some older publications use both terms interchangeably. Silibinin is the more active form of the silymarin extract. Only silymarin extracts are available in pharmacies while researchers usually use silibinin for their experiments. Standard silymarin extracts usually contain 33.5% silybin, 13% silychristin, 8.35% isosilybin, 3.5% silydianin ²⁶ (see Figure 5).