Silychristin A = (2R,3R)-3,5,7-trihydroxy-2-((2R,3S)-7-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-3-(hydroxymethyl)-2,3-dihydrobenzofuran-5-yl)chroman-4-one Silychristin B = (2R,3R)-3,5,7-trihydroxy-2-((2S,3R)-7-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-3-(hydroxymethyl)-2,3-dihydrobenzofuran-5-yl)chroman-4-one
Silychristin (also known as silichristin) is a natural product and one of the constituents of silymarin, the standardized, active extract of the fruit of milk thistle, Silybum marianum.[1][2] It is the second most abundant constituent in silymarin, after silybin.[3] Silychristin is a flavonolignan, along with many other silymarin constituents (such as silybin, isosilybin, silydianin, etc.), meaning it is composed up of a flavonoid and a lignan.[3] It is estimated that up to 65–80% of silymarin extract is made up of flavonolignans, like silychristin, which give silymarin its well known potent antioxidant and hepatoprotective properties.[4][5] Silychristin can exist as two stereoisomers, silychristin A (2R, 3S) and silychristin B (2S, 3R). The marianum variety of S. marianum (purple corollas) includes silychristin A as a major flavonolignan constituent, while the lesser known and studied albiflorum variety (white corollas) includes unique flavonolignans, including silyhermin, (–)-silandrin, and (+)-silymonin.[6]
^ abBiedermann, D.; Buchta, M.; Holečková, V.; Sedlák, D.; Valentová, K.; Cvačka, J.; Bednárová, L.; Křenková, A.; Kuzma, M.; Škuta, C.; Peikerová, Ž.; Bartůněk, P.; Křen, V., Silychristin: Skeletal Alterations and Biological Activities. Journal of Natural Products2016, 79 (12), 3086–3092.
^Kawaguchi-Suzuki, M.; Frye, R. F.; Zhu, H.-J.; Brinda, B. J.; Chavin, K. D.; Bernstein, H. J.; Markowitz, J. S., The Effects of Milk Thistle (Silybum marianum) on Human Cytochrome P450 Activity. Drug Metabolism and Disposition2014, 42 (10), 1611–1616.
^Zhu, H.-J.; Brinda, B. J.; Chavin, K. D.; Bernstein, H. J.; Patrick, K. S.; Markowitz, J. S., An Assessment of Pharmacokinetics and Antioxidant Activity of Free Silymarin Flavonolignans in Healthy Volunteers: A Dose Escalation Study. Drug Metabolism and Disposition2013, 41 (9), 1679–1685.
^Ahmed, H. S.; Mohamed, W. R.; Moawad, A. S.; Owis, A. I.; Ahmed, R. R.; AbouZid, S. F., Cytotoxic, hepatoprotective and antioxidant activities of Silybum marianum variety albiflorum growing in Egypt. Natural Product Research2019, 1–5.