USP Monographs: Plantago Seed

Plantago Seed

» Plantago Seed is the cleaned, dried, ripe seed of Plantago psyllium Linné, or of Plantago indica Linné (Plantago arenaria Waldstein et Kitaibel), known in commerce as Spanish or French Psyllium Seed; or of Plantago ovata Forskal, known in commerce as Blond Psyllium or Indian Plantago Seed (Fam. Plantaginaceae).

Packaging and storage— Preserve in well-closed containers, secure against insect attack (see Vegetable and Animal Substances—Preservation in the General Notices).

Botanic characteristics—

Unground Plantago psyllium Seed— Ovate to ovate-elongate, concavo-convex; mostly from 1.3 to 2.7 mm in length, rarely up to 3 mm, and from 600 µm to 1.1 mm in width. It is light brown to moderate brown, darker along the margin, and very glossy; the convex dorsal surface exhibiting a lighter colored longitudinal area extending nearly the length of the seed and representing the embryo lying beneath the seed coat, and showing a sometimes indistinct transverse groove nearer the broader end. The concave ventral surface has a deep cavity, in the center of the base of which is an oval, yellowish white hilum.

Unground Plantago indica Seed— Ovate-oblong to elliptical, concavo-convex; from 1.6 to 3 mm in length and from 1 to 1.5 mm in width. Externally it is dark reddish brown to moderate yellowish brown, occasionally somewhat glossy, often dull, rough, and reticulate; the convex dorsal surface having a longitudinal lighter colored area extending lengthwise along the center and beneath the seed coat, and a median transverse groove, dent, or fissure. The ventral surface has a deep concavity, the edges somewhat flattened and frequently forming a sharp indented angle with the base of the cavity, the latter showing a light colored oval hilum.

Unground Plantago ovata Seed— Broadly elliptical to ovate, boat-shaped, from 2 to 3.5 mm in length and from 1 to 1.5 mm in width. It is pale brown to moderate brown with a dull surface, the convex surface having a small, elongated, glossy brown spot. The concave surface has a deep cavity, in the center of the base of which occurs a hilum covered with a thin membrane.

Odor and taste— All varieties of Plantago Seed are nearly odorless.

Histology— Plantago Seed is reniform in median transverse sections. Its seed coat has a colorless epidermis of mucilaginous cells whose radial and outer walls break down to form layers of mucilage when brought into contact with water, and a reddish brown to yellow pigment layer in the seeds of Plantago indica and Plantago psyllium, a broad endosperm with thick-walled outer palisade cells, and irregular inner endosperm cells; and a straight embryo extending lengthwise through the center. The endosperm and embryo cells contain fixed oil and aleurone grains, the latter being rounded, oval, pyriform, or irregularly shaped, from 2 to 8 µm in diameter.

Water absorption— Place 1 g of Plantago Seed in a 25-mL graduated cylinder, add water to the 20-mL mark, and shake the cylinder at intervals during 24 hours. Allow the seeds to settle for 12 hours, and note the total volume occupied by the swollen seeds: the seeds of Plantago psyllium occupy a volume of not less than 14 mL, those of Plantago ovata not less than 10 mL, and those of Plantago indica not less than 8 mL.

Total ash