1911 Encyclopædia Britannica/Berberine

BERBERINE, C₂₀H₁₇NO₄, an alkaloid occurring together with the alkaloids oxyacanthine C₁₈H₁₉NO₃, berbamine C₁₈H₁₉NO₃, hydrastine C₂₁H₂₁NO₆, and canadine C₂₀H₂₁NO₄, in Berberis vulgaris; it also occurs in other plants, Berberis aristata, B. aquifolium, Hydrastis canadensis, &c. It is a yellow, crystalline solid, insoluble in ether and chloroform, soluble in 41/2 parts of water at 21°, and moderately soluble in alcohol. It is a monacid base; the hydrochloride, C₂₀H₁₇NO₄·HCl, is insoluble in cold alcohol, ether and chloroform, and soluble in 500 parts of water; the acid sulphate, C₂₀H₁₇NO₄·H₂SO₄ dissolves in about 100 parts of water. Canadine is a tetrahydroberberine.

Its constitution was worked out by W. H. Perkin (J.C.S., 1889, 55, p. 63; 1890, 57, p. 991). This followed from a study of the decomposition products, there being obtained hemipinic acid (CH₃O)₂C₆H₂(COOH)₂, and a substance which proved to be ω-amino-ethyl-piperonyl carboxylic acid, CH₂O₂ : C₆H₂·COOH·CH₂·CH₂NH₂. His formula was modified by Gadamer (Abs. J.C.S., 1902, 1, p. 555), who made the free base an aldehyde, but the salts of an iso-quinolinium type. This formula, which necessitates the presence of two asymmetric carbon atoms in an alkyl tetrahydroberberine, has been accepted by M. Freund and F. Mayer (Abs. J.C.S., 1907, 1, p. 632), who showed that two racemic propyl tetrahydroberberines are produced when propyl dihydroberberine is reduced.