An Examination of Burdock Fruit.

Botanical name: 

A Contribution from the Chemical Laboratory of the Philadelphia College of Pharmacy.


Read at the Pharmaceutical Meeting, February 17,1885.

The following analysis of the fruit of Lappa officinalis, while incomplete, gives, we believe, the important constituents of this drug. The moisture determined in the usual way was found to be 7.30 per cent., and the ash 5.34 per cent.

Ten grams reduced to No. 60 powder were thoroughly exhausted with petroleum spirit. This solution, on evaporation and heating to 110°C., was found to consist of a bland light yellow fixed oil, representing 15.4 per cent. of the fruit.

The following are some of the important characteristic reactions. With fuming nitric acid a brown color and aromatic odor, but not becoming solid. With strong sulphuric acid a brown color, becoming thick and syrupy. Exposed to the air in thin layers the oil solidifies. Alcohol and absolute alcohol do not dissolve it, but hot absolute alcohol, ether, chloroform and benzol are good solvents. The specific gravity is .930, determined with a larger amount of the oil prepared from 75 grams of the drug. That portion of the original ten grams remaining after treatment with petroleum spirit was exhausted with ether which dissolved 1.15 per cent. of a resin soluble in alcohol. Absolute alcohol extracted from the remainder of the drug 12.6 per cent. 8.3 per cent. being insoluble in water, appeared to be resin soluble in dilute alcohol; the remaining 4.3 per cent. were soluble in water and were examined for alkaloids. A small quantity of crystals separated on evaporating the chloroform solution of this aqueous portion, first made alkaline with potassium hydrate. The amount, however, was so small that the 75 grams of the drug remaining after extracting the oil with petroleum spirit were exhausted with dilute alcohol, the alcohol evaporated, and the residue, after rendering alkaline, was shaken repeatedly with chloroform until that solvent contained all the bitter principle. On evaporating the chloroform a residue was obtained which all efforts, so far, have failed to get in a crystalline condition. It is intensely bitter, of a faintly alkaline reaction, gives precipitates with phosphomolybdic acid, Mayer's test, tannic acid, and gives off ammonia on beating with potassium hydrate. It is therefore quite certain that this bitter principle is an alkaloid, and we suggest for it the name of Lappine.

The other constituents were not determined, but they with the bitter principle will be further investigated.

We were induced to make this analysis from an account of the medicinal value of the so-called burdock seed in Dr. Squibb's "Ephemeris," vol. i, page 115.

PHILADELPHIA, Feb. 17,1885.

The American Journal of Pharmacy, Vol. 57, 1885, was edited by John M. Maisch.