Zea. Corn silk. Zea mays.
Zea. N. F. IV (U. S. P. VIII). Corn Silk. Stigmata Maydis. Filament de Mais, Fr. Maispistille, G.—"The fresh styles and stigmas of Zea Mays Linné (Fam. Gramineae)." N. F.
This drug is the so-called "silk" of the ear of ordinary Indian corn or maize, cultivated in the warmer temperate and subtropical countries of the world. It consists of "slender filaments from 10 to 20 cm. in length, and about 0.4 mm. in diameter; of a light green, purplish-red, yellow or light brown color; stigmas bind, the segments very slender, frequently unequal and from 0.4 to 3 mm. in length. Under the microscope, the styles are seen to consist for the most part of parenchyma and two parallel, vascular bundles with narrow, spiral or annular tracheae; the epidermal cells are rectangular, many of these being extended into multicellular hairs, the latter being from 0.2 to 0.8 mm. in length, the basal portion consisting of two to five united cells, the upper portion being usually unicellular; the cells of the hairs are rich in cytoplasm and usually contain a small, spherical nucleus; the purplish-red styles contain a purplish-red cell sap. Digest a small portion of the fresh styles and stigmas in diluted alcohol and filter; a pale purplish-red solution is produced, separate portions of which, on the addition of acids, become distinctly purplish or yellowish-red; on the addition of alkalies, green; on the addition of ferric chloride T.S., olive-green changing to greenish-brown; and on the addition of an aqueous solution of alum, bluish or purplish, the color being quite permanent." N. F. Rademaker and Fischer (A. J. P., 1886, p. 369) determined the presence of 2.25 per cent. of maizenic acid in dried corn silk. It was first described, however, by Vautier. It is freely soluble in water, alcohol and ether, but insoluble, in benzin. Rademaker and Fischer found, in addition to the acid, fixed oil, resin, chlorophyll, sugar, gum, extractive, albuminoids, phlobaphene salt, cellulose and water.
Used as a mild stimulant diuretic, useful in acute and chronic cystitis and in the bladder irritation of uric acid and phosphatic gravel. It has also been employed in gonorrhea, and has been affirmed by Landreux to be a useful diuretic and even cardiac stimulant in the dropsy of heart disease. It probably is, however, of little value.
Concerning the activity of maizenic acid we have little definite knowledge, but it probably represents whatever physiological power the drug possesses; it has been given in the dose of one-eighth of a grain (0.008 Gm.).
Corn silk was official in the U. S. VIII but dismissed from the U. S. IX. It was introduced in the N. F. IV. The fluidextract of zea N. F. is made with a menstruum of diluted alcohol.
Dose, one to three drachms (3.9-11.6 Gm.).