The fruit coatings of Fagara xanthoxyloides, Lam. (Xanthoxylum senegalense, DC.)3), yield upon distillation with water vapor 0,37 to 2,4 p.c. of a volatile oil4) which is brownish in color and possesses a faint acid reaction. d15o0,9229; [a]D15° - 1,20°; A. V. 2,19; E. V. 58,51.
When treated with acid sodium sulphite, methyl-/7-nonyl ketone (m. p. of oxime 45 to 46°; m. p. of semicarbazone 120 to 121°) was isolated. Presumably it was admixed with decylic aldehyde.
Of acids, the oil was found to contain n-caprinic acid (m. p. of amide 98°) which occurs in the free as well as the combined state. The saponification liquid also contained acetic acid and a solid acid that was not investigated.
The following additional constituents were also identified, viz., dipentene (m. p. of tetrabromide 124 to 125°); linalool (m. p. of citryl-B-naphthocinchoninic acid 198 to 199°); a sesquiterpene with the following properties: b.p. 170 to 180° (14 mm.); d14o 0,9214; [a]D + 4° 16'. A chlorhydrate of this sesquiterpene was not obtained.
1) See this, p. 630.
2) Th. Peckolt, Ber. d. deutsch. pharm. Ges. 9 (1899), 340.
3) The root bark, likewise the fruits are used for medicinal purposes by the native Togos.
4) H. Priess, Berichte d. deutsch. pharm. Ges. 21 (1911), 227.
By treating the oil with potassium hydroxide solution, a substance melting at 143 to 144°, the lactone xanthotoxin, was obtained. This substance can be obtained in larger amounts by extracting the carpels with alcohol. The nitro compound of xanthotoxin, C12H704N02, melts at 230°, the dibromide, after recrystallization from xylene, at 164°. If to the alcoholic solution of xanthotoxin potassium hydroxide be added, a water-soluble salt is formed, the solution being colored yellow at the same time.
The constitution of this substance has been determined by H. Thorns1). By treating the methyl alcoholic solution of xantho-toxin with methyl iodide, he obtained methyl xanthotoxinic acid (m. p. 114 to 117°) and methyl xanthotoxinic methyl ester (m. p. 44°). Fused with potassium hydroxide it yielded a pyro-gallol carboxylic acid thus revealing the xanthotoxin to be a pyrogallol derivative.
In addition to xanthotoxin, the alcoholic extract contains a second lactone, bergaptene2) which is isomeric with xanthotoxin and which is derived from phloroglucinol.
Both substances are fish poisons, but the narcotic action of the xanthotoxin is much greater than that of the bergaptene.
From a botanical point of view the occurrence of xantho-toxin and bergaptene in Fagara xanthoxyloides and of bergap-tene in the fruits of Citrus Bergamia, the plant from which the bergamot oil is obtained, is very interesting since both plants belong to sub-families of the same family, viz., the former to the Rutaceae-Xanthoxyleae and the latter to the Rutaceae-Aurantioideae.
According to H. Thorns3), the oil from the root bark contains a solid constituent, which separates upon standing.
1) Berl. Berichte 44 (1911), 3325; 45 (1912), 3705.
2) Comp. Pomeranz, Monatsh. f. Chem. 12 (1891), 379.
3) Chem. Ztg. U (1910), 1279.
This substance, which H. Thorns and F. Thumen1) have likewise isolated from the root bark by extraction with benzene, is fagaramide. It melts at 119 to 120° and has been identified as the isobutylamide of piperonyl acrylic acid. They obtained it synthetically by the action of piperonyl acrylic acid chloride on isobutylamine in ethereal solution.