Upon distillation of the flowers of Spiraea Ulmaria, L. (family Rosaceae), Pagenstecher1) in 1835 obtained a heavy oil that sank in water and which he gave to Lowig2) for examination. Dumas3), to whom the oil was shown, recognized the similarity of the oil with salicylic aldehyde (salicyl-hydrogen) recently obtained by Piria from salicin. Ettling4) confirmed the surmise expressed by Dumas by showing that spiraea oil consists of two or three volatile substances, one of which is salicylic aldehyde.
Upon distillation of the flowers, Ettling obtained 0,2 p.c. of oil. According to W. Wicke6), the yield from cultivated double varieties is greater than that from the wild plants. Spiraea oil is heavier than water and at - 18 to - 20° congeals completely.
From the investigations of A. Schneegans and J. G. Gerock6), it becomes apparent that in addition to salicylic aldehyde (formerly designated spiroyl-hydrogen, spiraeic acid, salicyl hydrogen, spiroylic or spiric acid) the oil contains methyl salicylate, also traces of heliotropin (piperonal) and vanillin. Furthermore, Ettling found a small amount of a camphor-like substance that crystallized in white, pearly laminae (paraffin?), and an indifferent oil of the composition C5H8 i. e. that of a terpene or sesquiterpene.
1) Repert. f. d. Pharm. 49 (1835), 337; Pharm. Centralbl. 1835, 137.
2) Lowig, Poggend. Ann. 36 (1835), 383. - Lowig and Weidmann, Pharm. Centralbl. 1839, 129.
3) Liebig's Annalen 29 (1839), 306.
4) Ibidem 29 (1839), 309; 35 (1840), 241.
6) Ibidem 83 (1852), 175.
6) Journ. der Pharm. f. ElsaB-Lothr. 19 (1892), 3 and 55; Jahresb. f. Pharm. 1892, 164.
As demonstrated by Schneegans and Gerock, the flowers themselves contain no salicylic aldehyde as such. This is produced by the action of a ferment on an unknown substance during the process of distillation. This substance is not salicin, as was assumed by Buchner1). In addition to methyl salicylate the flowers contain free salicylic acid.
The statement made by W. Wicke, that the roots of Spiraea Ulmaria, L. contain salicylic aldehyde, is incorrect. According to R. Nietzki2), the oil obtained by the distillation of the roots consists principally of methyl salicylate and of traces of another substance, presumably a hydrocarbon.
According to M. W. Beijerinck3), the roots, rhizomes and lower portions of the herb of Spiraea Ulmaria, Sp. Filipendula and Sp. palmata contain the glucoside gaultherin. Acted upon by the enzyme gaultherase, which is likewise present, it yields methyl salicylate. The older roots and rhizomes of Spiraea Kamtschatica also contain a second glucoside, the spiraein, which, when hydrolyzed by gaultherase, yields salicylic aldehyde.
In the distillate obtained from the herb, W. Wicke proved the presence of salicylic aldehyde.
The herb of Spiraea digitata, lobata and Filipendula, also the flowers of Spiraea Aruncus yield salicylic aldehyde upon distillation. Hydrocyanic acid, but no salicylic aldehyde, is obtained from the herb of Spiraea Aruncus, from the leaves of Spiraea japonica, also from the herb and flowers of Spiraea sorbifolia. Neither salicylic aldehyde nor hydrocyanic acid could be detected in the distillates of Spiraea laevigata, acutifolia, ulmi-folia and opulifolia (Wicke).
1) Liebig's Annalen 88 (1853), 284. 2) Arch, der Pharm. 204 (1874), 429. 3) Chem. Zentralbl. 1899, II. 259.