Description

Isosilybin A CAS NO 142796-21-2 is a specific, purified diastereoisomer of the flavonolignan silybin, which is the primary active constituent of milk thistle (*Silybum marianum*) extract. This compound is of significant interest for its potent and selective biological activities, particularly in hepatoprotection and antioxidant applications. It is a critical high-purity reference standard and active ingredient for the pharmaceutical, nutraceutical, and advanced research sectors seeking targeted therapeutic effects.

Application

• Pharmaceutical Reference Standard: Used as a certified reference material (CRM) for the identification, assay, and purity testing of milk thistle extracts and finished products in QC/QA laboratories.
• Hepatoprotective Drug Development: Serves as a key active pharmaceutical ingredient (API) or intermediate in the formulation of drugs targeting liver diseases, including hepatitis, cirrhosis, and toxin-induced liver damage.
• Dietary Supplement & Nutraceuticals: Incorporated into high-end, standardized nutraceutical formulations where specific Isosilybin A content is claimed for enhanced liver support and antioxidant benefits.
• Biomedical & Mechanistic Research: Utilized in *in vitro* and *in vivo* studies to investigate its anti-inflammatory, anticancer (particularly prostate cancer), and neuroprotective mechanisms of action.
• Cosmeceutical Ingredients: Applied in advanced skincare products for its potent antioxidant properties, helping to protect skin cells from oxidative stress and UV-induced damage.

Basic Information

Product Name	Isosilybin A
CAS No.	142796-21-2
Molecular Formula	C25H22O10
Molecular Weight	482.44 g/mol
Synonyms	Isosilibinin A; (2R,3R)-3,5,7-Trihydroxy-2-[(2R,3R)-3-(4-hydroxy-3-methoxyphenyl)-2-(hydroxymethyl)-2,3-dihydro-1,4-benzodioxin-6-yl]-2,3-dihydrochromen-4-one; Silybin A isomer; Flavonolignan from Silybum marianum; Silymarin component A; Legalon® constituent
EINECS	Contact for details

Quality Control

Every batch of Isosilybin A is manufactured and analyzed under strict quality management systems. We provide comprehensive specifications and a Certificate of Analysis (COA) for each lot, detailing purity, identity, and impurity profiles as determined by advanced chromatographic methods (HPLC, LC-MS). Our quality commitment ensures the material is suitable for use as a pharmaceutical reference standard and in GMP-compliant applications.

Storage

Preserve in a tightly closed container, protected from light. Store at 2-8°C under an inert atmosphere (e.g., nitrogen or argon) to prevent oxidation. The container should be kept in a cool, dry, and well-ventilated area, separate from strong oxidizing agents.

Specification

Item	Specification
Appearance	Yellow to light brown powder
Identification (HPLC)	Conforms to reference standard
Identification (IR)	Conforms to structure
Assay (HPLC)	≥98.0%
Related Substances (HPLC)	Total impurities ≤2.0%
Single Maximum Unknown Impurity	≤0.5%
Residual Solvents (GC)	Meets ICH Q3C guidelines
Heavy Metals	≤20 ppm
Loss on Drying	≤2.0%
Specific Rotation	Contact for details

Note: Specifications can be tailored. Please contact us for the detailed technical data sheet of a specific grade.