Columbin, or Columba-Bitter was discovered by Wittstock in 1830. It is a neutral bitter principle, crystallizing in colourless rhombic prisms, slightly soluble in cold alcohol or ether, but dissolving more freely in those liquids when boiling. It is soluble in aqueous alkalis and in acetic acid.
The presence of Berberine in calumba was ascertained in 1848 by Bödeker, who showed that the yellow cell-walls of the root owe their colour to it and (as we may add) to Columbic Acid, another substance discovered by the same chemist in the following year. Columbic Acid is yellow, amorphous, nearly insoluble in cold water, but dissolving in alcohol and in alkaline solutions. It tastes somewhat less bitter than columbin. Bödeker surmises that it may exist in combination with the berberine.
Bödeker has pointed out a connection between the three bitter principles of calumba. If we suppose a molecule of ammonia, NH₃, to be added to columbin C₄₂H₄₄O₁₄, the complex molecule thence resulting will contain the elements of berberine C₂₀H₁₇NO₄, columbic acid C₂₂H₂₄O₇, and water 3H₂O.
Among the more usual constituents of plants, calumba contains (in addition to starch) pectin, gum, and nitrate of potassium, but no tannic acid. It yields when incinerated 6 per cent. of ash.
Commerce—Calumba root is shipped to Europe and India from Mozambique and Zanzibar, and exported from Bombay and other Indian ports.
Uses—It is much employed as a mild tonic, chiefly in the form of tincture or of aqueous infusion.
PAREIRA BRAVA.
Radix Pareiræ; Pareira-Brava[111]; F. Racine de Butua ou de Pareira-Brava; G. Grieswurzel.
Botanical Origin—Chondodendron tomentosum Ruiz et Pav. (non Eichler) (Cocculus Chondodendron DC., Botryopsis platyphylla Miers[112]).—It is a lofty climbing shrub with long woody stems, and leaves as much as a foot in length. The latter are of variable form, but mostly broadly ovate, rounded or pointed at the extremity, slightly cordate at the base, and having long petioles. They are smooth on the upper side; on the under covered between the veins with a fine close tomentum of an ashy hue. The flowers are unisexual, racemose, minute, produced either from the young shoots or from the woody stems. The fruits are ¾ of an inch long, oval, black and much resembling grapes in form and arrangement.[113]
The plant grows in Peru and Brazil,—in the latter country in the neighbourhood of Rio de Janeiro, where it occurs in some abundance on the range of hills separating the Copacabana from the basin of the Rio de Janeiro. It is also found about San Sebastian further south.