Silybin, a Major Bioactive Component of Milk Thistle (Silybum marianum L. Gaernt.)—Chemistry, Bioavailability, and Metabolism

Abstract

Milk thistle (Silybum marianum) is a medicinal plant that has been used for thousands of years as a remedy for a variety of ailments. The main component of S. marianum fruit extract (silymarin) is a flavonolignan called silybin, which is not only the major silymarin element but is also the most active ingredient of this extract, which has been confirmed in various studies. This compound belongs to the flavonoid group known as flavonolignans. Silybin’s structure consists in two main units. The first is based on a taxifolin, the second a phenyllpropanoid unit, which in this case is conyferil alcohol. These two units are linked together into one structure by an oxeran ring. Since the 1970s, silybin has been regarded in official medicine as a substance with hepatoprotective properties. There is a large body of research that demonstrates silybin’s many other healthy properties, but there are still a lack of papers focused on its molecular structure, chemistry, metabolism, and novel form of administration. Therefore, the aim of this paper is a literature review presenting and systematizing our knowledge of the silybin molecule, with particular emphasis on its structure, chemistry, bioavailability, and metabolism.

Safety and toxicity of silymarin, the major constituent of milk thistle extract: An updated review

“…Silymarin, the major constituent of milk thistle extract (collection of flavonolignans such as silybin A and B, isosilybin A and B, silibinin, silydianin, and silychristin) is found in the seeds, leaves, and fruits of S. marianum (Karimi, Vahabzadeh, Lari, Rashedinia, & Moshiri, ; Luper, ; Napolitano et al, ). Silybin is the major constituent of silymarin and has the most active therapeutic effects among the other flavonolignans (Bijak, ; Dixit, Baboota, Kohli, Ahmad, & Ali, ). Oral bioavailability of silymarin is low due to little solubility in water.…”

“…Oral bioavailability of silymarin is low due to little solubility in water. However, especial formulations were made that increased its solubility and absorption (Bijak, ).…”

Impact of Plant Density and Mepiquat Chloride on Growth, Yield, and Silymarin Content of Silybum marianum Grown under Mediterranean Semi-Arid Conditions

“…is a broadleaved species of the family Asteraceae that is cultivated in several regions worldwide and is one of the most widely used medicinal plants [1]. Currently, it is a very popular herbal remedy used by patients suffering from liver diseases [2,3], and dietary supplements containing silymarin are among the best-selling plant-derived pharmaceuticals in Europe and the USA [4,5]. Silymarin is contained in the extract derived from the seeds of milk thistle and is a complex mixture of at least six flavonolignans (silybin A and B, isosilybin A and B, silychristin, and silydianin) and one flavonoid (taxifolin) [6,7].…”

“…The content of silymarin in seeds can reach up to 7.71% of the seed dry weight [8]. Besides its hepatoprotective action against several liver diseases, silymarin exhibits anticancer activity, anti-inflammatory, antifibrotic and antioxidant properties [2,4,[9][10][11]. A local population ('Agios Georgios') of milk thistle, originating from central Greece, was hand sown on 5 November 2015 and 30 October 2017, for the first and second growing seasons, respectively.…”

Phytochemical profile of Silybum marianum (L.) Gaertn. and Graminis rhizoma and its influence on the bioactivity and shelf life of industrially produced pâté

“…It is a biennial herbaceous plant, flowering in July-August with reddish-purple flowers. This plant grows in southern Europe, southern Russia, Asia Minor, Northern Africa, North and South America, and South Australia but is now naturalised and grown worldwide (Karkanis et al, 2011;Sulas et al, 2016;Bijak, 2017). The milk thistle plant contains 15-30% of triglycerides, especially linoleic, oleic and palmitic acids, about 30% of proteins, sugars, tocopherol, sterols and flavonoids (Abenavoli et al, 2018).…”