Milk Thistle Extract (Silymarin 80%)

Milk Thistle Extract, Silymarin 80%, is made from the ripe fruits (achenes, traded as seed) of Silybum marianum (L.) Gaertn., family Asteraceae. The fruits are de-hulled and de-fatted, then extracted with food-grade ethanol, methanol, acetone or ethyl acetate and concentrated to a light yellow to yellow-brown free-flowing powder. Silymarin is not one molecule but a flavonolignan complex, CAS 65666-07-1, expressed against silibinin, C25H22O10, MW 482.4, PubChem CID 31553. The complex contains silybin A and silybin B (together silibinin), isosilybin A and isosilybin B, silychristin and silydianin, together with the flavonoid precursor taxifolin. The 80% figure needs reading carefully, and Thovek states the method on every certificate. An 80% silymarin claim is a spectrophotometric (UV) result, and a UV method reads total absorbing flavonoid material without separating the individual flavonolignans. The pharmacopoeial methods are chromatographic and give a materially lower number on the same lot: Ph. Eur. monograph 2071, milk thistle dry extract refined and standardised, sets a nominal silymarin content of 30 to 65 per cent m/m expressed as silibinin, and USP Powdered Milk Thistle Extract requires NLT 90.0% and NMT 110.0% of the labelled silymarin calculated as silybin on the dried basis. A UV 80% and an HPLC 30–65% are not competing claims about the same measurement, and quoting one against the other is the most common source of dispute on this ingredient. Thovek supplies both a UV-80% commodity grade and HPLC-assayed Ph. Eur. and USP grades, priced and documented separately. USP also fixes the internal proportions of the complex, which is what distinguishes a genuine milk thistle extract from a topped-up one: within silymarin, silydianin plus silychristin must be 20.0–45.0%, silybin A plus silybin B 40.0–65.0%, and isosilybin A plus isosilybin B 10.0–20.0%. Thovek reports the full flavonolignan profile by HPLC on request so buyers can audit that ratio. The powder is poorly soluble in water and soluble in ethanol and acetone, so a phospholipid-complexed grade is offered separately for buyers who need dispersibility. Material is fruit-derived, vegan and vegetarian, non-GMO, and free of milk, egg, soy, fish, crustacean, mollusc, peanut, tree nut, sesame, mustard, celery, lupin and gluten. Milk thistle carries the word milk only as a common name for the white leaf veining; it contains no dairy and no milk protein, and a dairy-free declaration is issued as standard because that name causes recurring confusion on finished-product labels.