Salicinum. Salicin, CHO, U.S.P.

Salix and Populus, several species. A glucoside.

Habitat.  Europe, N. Ameri ca; cultivated.

Syn.  White Willow, Common European-, Duck-, Huntington-, Salicin Willow, Withe, Withy; Fr. Saule blanc, Salcine; Ger. Weidenrinde, Salicin.

Sa'lix.  L. see etymology, above, of Salicaceae.

Pop'u-lus. L  Poplar, fr. populus, the people -- being often planted along the public ways in Rome, where it was called arbor populi, tree of the people.

Plants

These two juxta-positioned genera are composed mostly of large trees 15-18 M. (50-60 degrees) high, with flexible branches: Salix leaves, long pointed, entire or glandularly toothed; Populus leaves, broad, more or less heart-shaped, ovate, toothed; flowers May, both in catkins appearing before the leaves, dioecious, buds covered with scales, or a varnish; barks of both of genera resemble; that of Salix slips from the wood more readily.

Constituents

Salicin 1-3 p.c., tannin 12 p.c., extractive matter.

Salicinum. Salicin. -- Obtained by several methods: 1. Add litharge or basic lead acetate to hot concentrated decoction of young bark to remove tannin, gum, extractive; the filtrate contains salicin and some absorbed lead, the latter is separated by adding sulphuric acid and barium sulphide, while salicin, upon concentration of the filtrate, crystallizes out.  When basic lead acetate is used, the free acid should be neutralized with calcium carbonate, and then the filtrate evaporated.  2. Boil bark with milk of lime to remove tannin, evaporate filtrate to soft extract, digest this with alcohol, from which salicin will crystallize after distilling off the alcohol.  It is in colorless, silky, shining, needles or prisms, white, crystalline powder, odorless, very bitter taste, soluble in water (23.5), hot water (3.3), alcohol (88.5), hot alcohol (30) insoluble in chloroform, ether; aqueous solution (1 in 30) neutral. Levorotatory, melts at 200 degrees C. (392 degrees F.).  Tests.  1. Heat small portion in test-tube until brown, add distilled water (few cc.), + a drop of ferric chloride T.S. -- violet color.  2. With sulphuric acid -- red color, disappearing on adding distilled water; incinerate -- ash .05 p.c.  3. Heat gently .1 Gm. with potassium dichromate .2 Gm. + diluted sulphuic acid 2 cc. -- fragrant odor of salicylic aldehyde.  4. Aqueous solution (1 in 50) 10 cc., + 1 cc. tannic acid T.S., picric acid T.S., or mercuric potassium iodide T.S. -- no precipitate (abs. of alkaloids); another 10 cc., + a drop of ferric chloride T.S. -- not violet (abs. of salicylic acid).  Impurities: Heavy metals, alkaloids, salicylic acid.  Should be kept in well-closed containers.  Dose, gr. 10-30 (.6-2 Gm.).

Commercial

The White Willow (Salix al'ba) and Crack Willow (S. frag'ilis) contain most tannin, the Purple Willow (S. purpu'rea) most salicin, it being even in the leaves, although largest quantity in bark of young wood.  Populus al'ba, P. angustifu'lia, P. acumina'ta, P. trem'ula, all yield salicin to a considerable extent.

Preparations

(Unoff.): May give in powder, pill, syrup, water, or with glycyrrhiza extract, in small and frequent doses.

Properties

Tonic, antiperiodic, antipyrretic, antiseptic, antiferment, non-toxic; slower, weaker, less depressing to heart than salicylic acid, like it -- circulates in the blood as sodium salycylate; converted in stomach into glucose and saligenin, eliminated by urine as saligenin, salicylic, salicyluric, salicylous acids.

Uses

Acute rheumatism, fevers; relieves pain, arterial swellings, intermittents (inferior to quinine), coryza, hay fever, influenza, neuralgia, diabetes.

Externally -- gangrenous wounds, eczema, cancer, burns, fetid perspiration -- applied in solution with borax.