Semen Plantaginis is the dried, ripe seed of Plantago afra L., P. indica L., P. ovata Forsk., or P. asiatica L. (Plantaginaceae) (1–4).
Plantago afra L.
P. psyllium L. (2).
Plantago indica L.
P. arenaria Waldstein et Kitaibel, P. ramosa Asch. (1, 2, 5).
Plantago ovata Forsk.
P. ispaghula Roxb. (4).
Selected vernacular names
Psyllium seed, plantain seed, flea seed, Flohsamen, semences de psyllium (6).
P. afra L.
Flohsamen, Spanish psyllium (6).
P. indica L.
Flashsamen, fleavort plantago, French psyllium, Spanish psyllium seed, whorled plantago (6).
P. ovata Forsk.
Ashwagolam, aspaghol, aspagol, bazarqutuna, blond psyllium, ch'-ch'ientzu, ghoda, grappicol, Indian plantago, Indische Psylli-samen, isabgol, isabgul, isabgul gola, ispaghula, isphagol, vithai, issufgul, jiru, obeko, psyllium, plantain, spogel seeds (1, 6–9).
Plantago afra L.
An annual, erect, glandular-hairy caulescent herb, with an erect branching stem (0.2–0.4 m in height); it possesses whorls of flattened linear to linear-lanceolate leaves from the upper axils of which flowering stalks as long as the leaves arise. The stalks terminate in ovate-elliptical spikes up to 12mm long. The upper bracts ovate-lanceolate up to 4 mm in length and somewhat similar in character to the lower bracts, but with chloroplastids fewer in the midrib of the proximal portion. The flowers are tetramerous with a calyx of 4 similar persistent, lanceolate sepals, each with green midrib and hyaline lamina, a hypocrateriform corolla of 4 gamopetalous hyaline petals inserted below the ovary, the tube surrounding the ovary and a portion of the filiform, hairy style, the limb with 4-lanceolate, acuminate lobes. The fruit is membranous, 2-celled and 2-seeded (6).
Plantago asiatica L.
Usually wrinkled and contracted leaf and spike, greyish green to dark yellowgreen in colour; when soaked in water and smoothed out, the lamina is ovate or orbicular-ovate, 4–15cm in length, 3–8cm in width; apex acute, and base sharply narrowed; margin slightly wavy, with distinct parallel veins; glabrous or nearly glabrous; petiole is rather longer than the lamina, and its base is slightly expanded with thin-walled leaf-sheath; scape is 10–50cm in length, one-third to one-half of the upper part forming the spike, with dense florets; the lower part of inflorescence often shows pyxidia; roots usually removed, but, if any, fine roots are closely packed (6).
Plantago indica L.
An annual caulescent herb attaining a height of 0.3–0.5m with an erect or diffuse, hairy, frequently branched stem with whorls of linear to filiform leaves, from the axils of the upper ones of which spring peduncles, which are longer than the leaves and more or less umbellate. The lower bracts are transversely obovate below, lanceolate above, with a herbaceous midrib and hyaline margin, glandular hairy; the upper bracts broadly ovate with obtuse summits and also have herbaceous midribs and hyaline margins. The calyx is persistent, hairy, of 2 large spatulate anterior segments and 2 smaller, lateroposterior, lanceolate segments. The corolla is hypocrateriform of 4 petals, the limbs oblong with acute to mucronate summits; the tube of the corolla covering the pyxis and portions of the style. The pyxis is membranous, 2-celled, 2-seeded, and dehisces about or slightly below the middle (6).
Plantago ovata Forsk.
An annual, acaulescent herb, the stem of which is very ramified and bears linear leaves that are lanceolate, dentate, and pubescent. The flowers are white and grouped into cylindrical spikes. The sepals are characterized by a distinct midrib extending from the base to the summit; the petal lobes are oval with a mucronate summit. The seeds are oval and clearly carinate, measure 2–3mm, and are a light grey-pink with a brown line running along their convex side (6, 7).
Plant material of interest: seeds
Plantago afra L.
Hemianatropous, silky to the touch; ovate to ovate-elongate, larger at one end than the other; concavo-convex; light to moderate brown, dark brown along the margin, very glossy. Length 1.3–2.7 mm, rarely up to 3mm, and width 0.6– 1.1 mm; the convex dorsal surface somewhat transparent, exhibiting a longitudinal brown area extending nearly the length of the seed and representing the embryo lying beneath the seed coat, and a transverse groove nearer the broader than the narrower end and over the point of union of the hypocotyl and cotyledons; the concave ventral surface with a deep excavation, in the centre of the base of which is an oval yellowish white hilum (1, 6).
Plantago asiatica L.
Flattened ellipsoidal seed, 2–2.25 mm in length, 0.7–1mm in width, 0.3–0.5mm in thickness; externally brown to yellow-brown and lustrous. Under a magnifying glass, the surface of the seed is practically smooth; the dorsal side protrudes like a bow and the ventral side is somewhat dented; micropyle and raphe not observable. A hundred seeds weigh about 0.05 g (3).
Plantago indica L.
Ovate-oblong to elliptical; dark brown to maroon, often dull, rough and reticulate, 1.6–3.0 mm in length and 1.0–1.5 mm in width; concavo-convex, the dorsal surface has a longitudinal light brown area extending lengthwise along the centre and beneath the seed coat and has a median transverse groove, dent, or fissure; the ventral surface with a deep concavity, the edge of which is somewhat flattened and frequently forms a sharp indented angle with the base of the cavity, the latter showing a pale brown to occasionally whitish oval hilum (1, 6).
Plantago ovata Forsk.
Boat-shaped with ovate outline, pinkish grey to brown in colour along the margin with opaque reticulate surface, 2–2.3mm long, 1–1.5mm wide and 1mm thick, usually with central reddish brown oval patch extending about a third of the length of the seed. The convex dorsal surface has a longitudinal brown area extending nearly along the length of the seed that represents the position of the embryo lying beneath the seed-coat, and a transverse groove nearer to the broader than to the narrower extremity and over the points of union of the hypocotyl and cotyledons. The ventral surface shows a deep brown furrow that does not reach to either end of the seeds, in the centre of which is an oval yellowish white hilum, from which extends to the chalazal end a slightly elevated dark brown raphe. The seed is albuminous with oily endosperm; the embryo is straight, formed of two large plano-convex cotyledons and a small radicle in the narrow end and directed towards the micropyle. The seed is mucilaginous and upon soaking in water, the seed-coat swells and the seed becomes enveloped with a colourless mucilage. The weight of 100 seeds is about 0.1 g. A longitudinal cut, perpendicular to the ventral surface and passing through the hilum, shows a thin dark brown testa within which is a narrow endosperm surrounding a large oval lanceolate cotyledon and large pyramidal radicle directed towards the micropyle (1, 4, 6).
Odourless with mucilage-like taste.
Plantago afra L.
The transverse sections of the seed cut through the central region possess a reniform outline and present for examination a spermoderm, endosperm, and embryo. The spermoderm shows an outer epidermis of mucilaginous epidermal cells with more or less obliterated walls in glycerine mounts; the radial and inner walls swell and disintegrate to form a clear mucilage upon irrigation of the mount with water; and a pigment layer with brown amorphous content. The endosperm composed of irregular-shaped, thick-walled cells with walls of reserve cellulose. The outer layer of this region consists of palisade cells 15–40 µm in height. Aleurone grains and fixed oils are found in the endosperm cells (5).
Plantago asiatica L.
Transverse section reveals a seed-coat consisting of three layers of epidermis composed of cells containing mucilage, a vegetative layer, and a pigment layer of approximately equidiameter cells; in the interior, endosperm thicker than seed-coat, enclosing 2 cotyledons (6).
Plantago indica L.
The transverse section of the seed shows a similar structure to that described above for P. afra, but the palisade cells of the endosperm are up to 52µm in height (6).
P. ovata Forsk.
The transverse cut through the central region possesses a reniform or a concaveconvex outline and shows a testa, an endosperm, and 2 plano-convex cotyledons. Each cotyledon shows aleurone strands. On the convex surface a small raphe. The testa formed of one integument showing outer epidermis consisting of polygonal tabular cells with straight thin anticlinal walls covered with smooth cuticle. They are 52–68µm long, 30–52µm wide and 27–32µm thick. The middle (nutrient) layer is formed of collapsed thin cellulosic parenchyma, usually more than one layer, about 5 or 6 rows. The inner epidermis consists of polygonal cells with straight thin anticlinal walls, containing reddish brown contents; they are 16–38µm long, and 11–20µm wide and 2–3µm thick. The endosperm is formed of irregularly shaped thick cellulosic parenchyma showing an epidermis which is palisade-like, cells containing aleurone grains without inclusion, and fixed oil. The embryo formed of thin-walled cellulosic parenchyma containing fixed oil and aleurone grains. Each cotyledon shows 3 pleurone strands (4).
Powdered plant material
The most commonly used P. ovata powder is greyish brown showing glossy particles, colourless and with mucilage-like taste, characterized by fragments of epidermis formed of thin-walled polygonal cells with smooth cuticle and containing mucilage in the outer tangential and anticlinal walls, staining red with ruthenium red and blue with methylene blue; fragments of the pigment layer which is formed of polygonal cells with thin straight anticlinal walls with brown content traversed by collapsed colourless parenchyma; abundant fragments of endosperm with aleurone grains which are free of content and fixed oil; fragments of embryo tissues showing thin-walled parenchyma containing fixed oil and aleurone grains; few fragments showing spiral vessels attaining 11– 15µm width and few fibres which are elongated with thin pitted walls and pointed ends attaining 80–180µm in length and 8–12µm in width (4).
P. afra and P. indica, west Mediterranean countries (6); P. asiatica, Japan (3). P. ovata, Asia and the Mediterranean countries; the plant is cultivated extensively in India and Pakistan and adapts to western Europe and subtropical regions (4, 6, 8–10).
General identity tests
Macroscopic and microscopic examination (1–4); determining the swelling index (1–4); and test for reducing sugars (3, 4).
The test for Salmonella spp. in Semen Plantaginis products should be negative. The maximum acceptable limits of other microorganisms are as follows (11– 13). Preparations for internal use: aerobic bacteria-not more than 105/g; fungi-not more than 104/g; enterobacteria and certain Gram-negative bacteria -not more than 103/g; Escherichia coli-0/g.
Swelling index of P. afra and P. ovata, not less than 10 (2); of P. indica, not less than 8 (1); of P. asiatica, to be established in accordance with national requirements.
Foreign organic matter
Not more than 0.5% (1).
Not more than 4.0% (1).
Not more than 1.0% (1).
Not more than 14% (2).
To be established in accordance with national requirements. Normally, the maximum residue limit of aldrin and dieldrin in Semen Plantaginis is not more than 0.05 mg/kg (2). For other pesticides, see WHO guidelines on quality control methods for medicinal plants (11) and guidelines for predicting dietary intake of pesticide residues (13).
Recommended lead and cadmium levels are not more than 10 and 0.3mg/kg, respectively, in the final dosage form of the plant material (11).
For analysis of strontium-90, iodine-131, caesium-134, caesium-137, and plutonium-239, see WHO guidelines on quality control methods for medicinal plants (11).
Other purity tests
Tests for water-soluble extractive to be established in accordance with national requirements.
Mucilage (10–30%) (14). Plantago products can be assayed for their fibre content by the method described by the Association of Official Analytical Chemists (14).
Major chemical constituents
Plantago seeds contain 10–30% mucilaginous hydrocolloid, which is localized in the outer seed-coat (husk) and is the major, active principle. The mucilage is composed of a soluble polysaccharide fraction containing mainly arabinoxylans (85%). The polymer backbone is a xylan with 1 → 3 and 1 → 4 linkages, with no apparent regularity in their distribution. The monosaccharides in this main chain are substituted on C-2 or C-3 by L-arabinose, D-xylose, and α-Dgalacturonyl-(1 → 2)-L-rhamnose. In addition, secondary metabolites in the seed include sterols, triterpenes, and aucubin glycosides (4–7, 15).
Seeds, powder, and granules. Store in well-closed containers, in a cool dry place, protected from light (1–4).
Uses supported by clinical data
As a bulk-forming laxative used to restore and maintain regularity (2, 4, 16–20). Semen Plantaginis is indicated in the treatment of chronic constipation, temporary constipation due to illness or pregnancy, irritable bowel syndrome, constipation related to duodenal ulcer or diverticulitis (17–22). It is also used to soften the stools of those with haemorrhoids, or after anorectal surgery (16, 17).
Uses described in pharmacopoeias and in traditional systems of medicine
While Semen Plantaginis is primarily used in the treatment of constipation, it has also been used effectively in the short-term symptomatic treatment of diarrhoea of various etiologies (23, 24).
Uses described in folk medicine, not supported by experimental or clinical data
Other medical uses claimed for Semen Plantaginis include use as an expectorant and antitussive, an antibacterial agent, and a diuretic and in the treatment of rheumatic and gouty afflictions, glandular swelling, and bronchitis (8).
Semen Plantaginis increases the volume of the faeces by absorbing water in the gastrointestinal tract, which stimulates peristalsis (25, 26). The intraluminal pressure is decreased, colon transit is increased, and the frequency of defecation is increased (15, 16, 25).
When mixed with water, the therapeutic efficacy of the drug is due to the swelling of the mucilaginous seed coat which gives bulk and lubrication (7). Semen Plantaginis increases stool weight and water content owing to the water-bound fibre residue and an increased faecal bacterial mass. Clinical studies have demonstrated that ingestion of 18 g of Semen Plantaginis significantly increases faecal fresh and dry weights as compared with weights obtained with placebo (15).
The antidiarrhoeal effects of Semen Plantaginis have been extensively investigated in patients with acute and chronic diarrhoea (23, 24). An increase in the viscosity of the intestinal contents due to the binding of fluid and an increased colonic transit time (decreased frequency of defecation) were observed in patients treated with the drug (23, 24).
Known hypersensitivity or allergy to the plant; faecal impaction or intestinal obstruction; diabetes mellitus where insulin adjustment is difficult (27).
Semen Plantaginis products should always be taken with sufficient amounts of liquid, and at least half an hour after other medications to prevent delayed absorption of the latter. If bleeding or no response occurs after ingesting the drug, or if abdominal pain occurs 48 hours after treatment, treatment should be stopped and medical advice sought. If diarrhoea persists longer than 3 or 4 days, medical attention should be sought (28).
To prevent the generation of airborne dust, users should spoon the product from the container directly into a drinking glass and then add liquid (28). To minimize the potential for allergic reaction, health professionals who frequently dispense powdered Semen Plantaginis should avoid inhaling airborne dust while handling these products.
Semen Plantaginis should be taken with adequate volumes of fluid. It should never be taken orally as the dried powder, because of the possibility of bowel obstruction. In patients who are confined to bed or do little physical exercise, a medical examination may be necessary prior to treatment with the drug.
Bulking agents have been reported to diminish the absorption of some minerals (calcium, magnesium, copper, and zinc), vitamin B12, cardiac glycosides, and coumarin derivatives (29–31). The co-administration of Semen Plantaginis with lithium salts has been reported to reduce the plasma concentrations of the lithium salts and may inhibit their absorption from the gastrointestinal tract (32). Semen Plantaginis has also been reported to decrease both the rate and extent of carbamazepine absorption, inducing subclinical levels of the drug (33). Therefore, ingestion of lithium salts or carbamazepine and Semen Plantaginis should be separated in time as far as possible (33). Individual monitoring of the plasma levels of the drug in patients taking Semen Plantaginis products is also recommended. Insulin-dependent diabetic people may require less insulin (27).
No information available concerning carcinogenesis, mutagenesis, impairment of fertility; drug and laboratory test interactions; nursing mothers, paediatric use, or teratogenic or non-teratogenic effects on pregnancy.
Sudden increases in dietary fibre may cause temporary gas and bloating. These side-effects may be reduced by gradually increasing fibre intake, starting at one dose per day and gradually increasing to three doses per day (28). Occasional flatulence and bloating may be reduced by decreasing the amount of Semen Plantaginis taken for a few days (28).
Allergic reactions to Plantago products in response to ingestion or inhalation have been reported, especially after previous occupational exposure to these products (34–36). These reactions range from urticarial rashes to anaphylactic reactions (rare). One case of fatal bronchospasm has been reported in a Plantagosensitive patient with asthma (34).
The suggested average dose is 7.5 g dissolved in 240 ml water or juice taken orally 1–3 times daily depending on the individual response. The recommended dose for children aged 6–12 years is one-half the adult dose. For children under 6 years, a physician should be consulted. An additional glass of liquid is recommended after ingestion of the drug and generally provides an optimal response. Continued use for 2 or 3 days is needed for maximum laxative benefit.
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