Silymarin is a natural polyphenolic flavonolignan mixture extracted from the seeds of Silybum marianum. It can inhibit tumor cell proliferation and angiogenesis, and improve insulin resistance, thus being widely used in liver disease-related research and adjuvant applications. Studies have shown that silymarin exhibits inhibitory activity against the SARS-CoV-2 main protease, and it has potential research value in the mechanism-related studies of COVID-19.

Silybin A is the major active constituent of silymarin, a standardized extract of the milk thistle seeds, containing a mixture of flavonolignans consisting of silibinin, isosilibinin, silicristin, silidianin and others. Silibinin itself is a mixture of two diastereomers, silybin A and silybin B, in approximately equimolar ratio. Both in vitro and animal research suggest that silibinin has hepatoprotective (antihepatotoxic) properties that protect liver cells against toxins. Silibinin has also demonstrated in vitro anti-cancer effects against human prostate adenocarcinoma cells, estrogen-dependent and -independent human breast carcinoma cells, human ectocervical carcinoma cells, human colon cancer cells, and both small and nonsmall human lung carcinoma cells.

Isosilybin (Isosilibinin) and Silybin might be suitable candidates to design potent PXR antagonists to prevent drug-drug interactions via CYP3A4 in cancer patients.

Silychristin (Silicristin) is a plant growth regulator. Silychristin is an anti-hepatotoxic agent. Silychristin is the inhibitor of horseradish peroxidases and lipoxygenase.

Silydianin (Silidianin) exerts inhibition of UGT in human liver. Silydianin exerts inhibition of OATP1B1, OATP1B3 (unknown origin) expressed in HEK293 cells. Silydianin exerts inhibition of OATP2B1 (unknown origin) expressed in MDCK2 cells.

Isosilybin A is a partial PPARγ agonist, it significantly induced ABCA1 protein expression, it inhibited both monophenolase (IC50=1.7-7.6μM) and diphenolase (IC50=12.1-44.9μM) of tyrosinase. Isosilybin A shows anti-angiogenic efficacy, it has anti-prostate cancer (PCA) activity that is mediated via cell cycle arrest and apoptosis induction.

Silybin B (Silibinin B) is an effective inhibitor of raloxifene 4 '- and 6-glucosalylation, an effective anti-fibrinogenic and anti-oligomeric component of Silymarin, with free radical scavenging activity of 1, 1-diphenyl-2-pyridinyl hydrazine (DPPH), and a protective effect against cisplatin-induced neurotoxicity by alleviating DNA damage and apoptosis. Silybin B can inhibit the growth of human chronic myeloid leukemia K562 cells and induce apoptosis.

Isosilybin B is a flavonolignan extracted from silymarin that exhibits anti-prostate cancer (PCA) activity, inhibits cancer cell proliferation, and contributes to G1-phase blockade and apoptosis.Isosilybin B induces degradation of the androgen receptor.

Silyamandin may have antihepatotoxic and chemopreventive activities.

Silychristin B is a natural product for research related to life sciences. The catalog number is TN5023 and the CAS number is 879325-58-3.