This section is from the book "A Text Book Of Materia Medica, Being An Account Of The More Important Crude Drugs Of Vegetable And Animal Origin", by Henry G. Greenish. Also available from Amazon: A Text Book of Materia Medica : Being an Account of the More Important Crude Drugs of Vegetable and Animal Origin.
Part of the drug is said to be derived from G. cuneifolia and its variety paludosa; the leaves of this plant are cuneate and less coriaceous than those of G. camporum.
G. robusta, Nuttall, and G. squarrosa (Pursh), Dunal are closely allied species and were formerly regarded as yielding the commercial drug.
Before the flowerheads expand they secrete a white, sticky resin; in May and June the whole plant is resinous, and then the leaves and flowering tops are collected and dried.
The commercial drug consists of the slender upper part of the flowering stem, together with the flowerheads and a few leaves.
The stems, often 50 cm. in length, are rounded, yellow in colour, and smooth. They bear alternate, pale green leaves which, however, are easily broken off, and therefore frequently lie loose in the package.
The leaves are oblong or spathulate, 3 to 5 cm. long, with a serrate margin; they are rigid, brittle, smooth, sessile, and sometimes amplexicaul, and have a glabrous, minutely dotted surface.
The flowerheads are sub-conical, yellowish, hard and resinous, and are surrounded by several rows of lanceolate-acuminate, imbricated, recurved bracts. They contain numerous compressed fruits, each of which is crowned by a pappus consisting of two stiff, thick bristles, and when mature is bi-auriculate or more rarely uni-dentate at the summit.
The drug has a slight odour and a somewhat balsamic taste.
The student should observe
(a) The stalky appearance of the drug,
(b) The resinous character, especially of the flowerheads,
(c) The pale green, rigid, brittle leaves.
'The chief constituents of grindelia are amorphous resins (up to 21 per cent.). These include a soft, greenish resin soluble in petroleum spirit and two dark coloured resins, one of which is soluble in ether. To these resins the activity of the drug appears to be due (Power and Tutin, 1905). The drug also contains a considerable quantity of laevoglucose, tannin (1.5 per cent.), and a trace of volatile oil. It leaves about 8 per cent. of ash.
Two glucosides resembling the glucosides of quillaja bark and senega root, an alkaloid and a crystallisable acid, robustic acid, are also said to be contained in the drug, but later researches have not confirmed these statements.
The action of grindelia resembles that of atropine. The drug has the reputation of being almost a specific for certain forms of asthma, and has been recommended in cystitis and catarrh of the bladder. It is not much used in this country.