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.
The male fern, Dryopteris Filix-mas, Schott (N.O. Filicineoe), is abundant in Great Britain, and one of the commonest of our indigenous ferns. It produces a circular tuft of fronds attaining a metre in height and arising from a stout rhizome. The lamina is divided pinnately, and bears on its under surface, when in fruit, kidney-shaped or sometimes nearly peltate sori. The petiole bears numerous brown, scarious scales, especially in the lower part.
The rhizome is collected in the autumn; the fronds are cut off, leaving the lower swollen portion, about 3 cm. in length, attached to the rhizome, the roots are removed, and the drug is then dried. Sometimes the rhizome is cut longitudinally to facilitate the drying.
Much is imported from Germany, large quantities being collected in the Harz and Thuringian Mountains.
The drug occurs in pieces up to about 12 or 15 cm. in length, but usually shorter, and 4 cm. in thickness; only about one-half of this is due to the rhizome itself, the rest being formed by the bases of the petioles that have been left attached to it. These, which constitute the major part of the drug, are usually from 2 to 3 cm. in length, from 5 to 15 mm. in thickness, and enlarged near the middle. They are curved, bluntly angular or longitudinally furrowed, and of a dark brown or nearly black colour externally. They are more or less densely covered with dry, brown membranous scales. Examined under the microscope the marginal cells of these scales will be seen to be prolonged at intervals into simple hairlike processes each consisting of two parallel and contiguous cells, but the scale does not bear any glandular hairs, excepting sometimes two at its base; this is an important diagnostic character of the drug (Lauren,
FIG. 215. - a, transverse section of base of petiole of Aspidium Filix-mas. b, transverse section of petiole of A. Filix-foemina; c, the same just below the lamina. Slightly magnified. (Luerssen).
Fig. 216. - A, margin of scale from petiole of A. Filix-mas; B, from that of A. spinulosum. Magnified. (Lauren).
1896). When broken the petioles should be (if recently dried) green internally, and the smooth section should exhibit about eight (usually seven, eight, or nine) steles arranged in a diffuse circle.
The rhizome itself should also be green internally, and exhibit in section about as many principal steles as the petiole. The drug has a disagreeable, nauseous, bitter taste.
The chief constituent of male fern rhizome is about 5 per cent. of a yellow, amorphous substance of acid nature termed filmarone, to which the vermifuge properties of the drug are apparently to be attributed. Filicic acid, aspidinol, flavaspidic acid, flavaspidinol, and albaspidin are also contained in it, as well as fixed oil (6 per cent.), filicitannic acid (7.8 per cent.), resin, and starch. Some of these constituents are formed by the remarkable secreting cells produced by the rhizome and petioles in intercellular spaces in the parenchymatous tissue. The drug yields about 4 per cent. of ash.
Filmarone, which is said to be anthelmintic but not toxic, is insoluble in water, sparingly soluble in alcohol and petroleum spirit, but readily soluble in acetone, chloroform, and ether. Dissolved in acetone or alcohol it slowly decomposes into the comparatively inert filicic acid and aspidinol, both of which substances are present in the drug. This decomposition also takes place in the dried drug, as well as in the liquid extract, causing in the latter case, the formation of a crystalline deposit of filicic acid and deterioration of the preparation. Male fern is said to lose its activity when kept; a good sample should show a green and not brown colour in the transverse section.
Fig. 217. - Male Fern rhizome. Transverse section, magnified 3 diam. y, steles. (Berg).
Filicic acid crystallises in pale yellow plates insoluble in alcohol, and sparingly soluble in ether. Heated with zinc dust and sodium hydroxide methylphloroglucin is produced, a reaction which indicates an analogy with rottlerin and kosin.
Filicin is the name given to an amorphous modification of filicic acid said, to be its anhydride.
Filixnigrins are brown or black, amorphous, inactive substances and are decomposition products of the other constituents of the rhizome.
Although a number of substances have been isolated from male fern rhizome our knowledge of its vermifuge constituent is still far from complete.
Male fern rhizome has a powerful toxic action on tapeworms, which it kills and expels. In large doses it is an irritant poison.
Although the male fern is a common British fern, there are several others that closely resemble it and might be gathered in its place. Of these the most important are A. Filix-foemina, Roth, the lady fern, and D. spinulosa, O. Kuntze, the shield fern.
The rhizome of A. Filix-foemina may be easily distinguished by the number of bundles in the leaf-base, for whilst the male fern has from seven to nine the lady fern has only two large ones. Moreover, the lady fern produces no secreting cells in the parenchyma of rhizome or petiole. It has decided anthelmintic properties, and contains filicic acid and possibly filmarone also. It is seldom, if ever, found in the commercial drug.
The rhizome of D. spinulosa is more difficult to distinguish, as it contains secreting cells similar to those of the male fern, and about the same number of bundles. According to Lauren, the character of the margin of the scales borne by the petiole is distinctive, that of D. Filix-mas bearing hairlike projections, whilst that of D. spinulosa produces glandular secreting cells. The rhizome of D. spinulosa is frequently found mixed with the male fern in German commerce (up to 90 per cent). It is an active vermifuge, and is largely used in Finland. It contains aspidin (polystichin), polystichinin, poly-stichalbin, filicic acid and probably filmarone. The extract prepared from it is said to be twice as active as that from D. Filix-mas.
Fig. 218. - Intercellular spaces in the rhizome of Male Fern, showing the secreting glands, D, and secretion, S. p, cortical parenchyma containing starch-grains. Magnified 240 diam. (Vogl).