2.2.2.1 Plantago Seed The origin of the word ‘Plantago’ is from the Latin and means sole of the foot, referring to the shape of the leaf. Likewise, ‘Psyllium’ is from the Greek and means fleadescribing the seed.
Synonyms Psyllium seed; Plantain seed; Flea seed; Ispaghula; Isapgol; Isabgul.
Biological Source It is the dried ripe seeds of Plantago psyllium L., or Plantago arenaria Waldst & Kit (P. ramosa Asch.) (Spanish or French psyllium seed) or of Plantago ovata (blond or Indian plantago seed) or of Plantago amplexicaulis belonging to the family: Plantaginaceae.
Geographical Source P. amplexicaulis is grown on the Panjab plains, Malwa and Sind and extending to Southern Europe. P. psyllium is an annual pubescent herb practically native to the Mediterranean countries. It is grown in France and constitutes the main bulk of the American imported psyllium seed. P. ovata is extensively grown in Pakistan; besides it is found to be native to Mediterranean countries and Asia.
Preparation The crops are grown usually on light, well drained sandy loamy soils; and during their entire growth peroid the climate must be cool and dry. The ripe and matured fruits are normally collected after a span of about three months. The seeds are separated by thrashing lightly on a solid support. The dust and foreign particles are removed by sieving and against a current of mederate air-blast.
Description
Colour : Pinkish grey to brown
Odour : No characteristic odour
Taste : Bland and mucilageous
Weight : 100 seeds weigh between 0.15-0.19 g
Figure 3.3 gives an account of the dorsal surface as well as the ventral surface of Ispaghula seed and Psyllium seed along with their overall shape, size and outersurface.
Chemical Constituents Plantago seeds generally comprise of approximately 10% of mucilage invariably located in the epidermis of the testa together with proteins and fixed oil. The mucilage essentially consists of pentosan and aldobionic acid.
Shape : Ovate or boat shaped
Size : Length = 1.8-3.5 mm, Width = 1.0-1.7 mm.
Outersurface: The Convex surface has a central brown oval spot, whereas the Concave surface bears a deep furrow having its hilum covered with a thin whitish membrane.
The various products of hydrolysis are, namely: xylose, arabinose, rhamnose and galacturonic acid.
Chemical Tests
1. Its mucilage gives a distinct red colouration on treatment with Ruthenium Red solution.
2. Swelling Factor*: It establishes the purity of the drug and ranges between 10 to 14. It is easily determined by transferring accurately 1.0g of the drug in a 25 ml measuring cylinder duly filled with 20 ml of water with intermittent shaking. The exact volume occupied by the seeds after a duration of 24 hours of wetting is noted carefully which represents the swelling factor of the seeds under investigation.
Substituents/Adulterants A number of species of Plantago have been studied extensively for their mucilage contents. Interestingly, Plantago rhodosperma which is particularly habitated in Missouri and Lousiana (USA) and Plantago wrightiana are worth mentioning. The former species contains mucilage to the extent of 17.5% whereas the latter contains about 23%. However, these two species compare favourably with the official drug.
In addition to the above, a few species like P. purshii, P. aristata and P. asiatica are also employed as a substitute for plantago seeds.
Uses
1. Plantago seeds are mostly employed as demulscent and in the treatment of chronic constipation.
2. It is also used in amoebic and bacillary dysentary.
3. Mucilage of the isapgol is invariably employed in the preparation of tablets (e.g., granulation)
4. It is used as a stabilizer in the ice-cream industry
5. The crushed seeds are employed as a poultice for rheumatic pain
6. The acid form of polysaccharide is obtained by carefully removing the cations from the mucilage by treatment with cation-exchange resins and spray drying the resultant products. This ‘specialized product’ finds its enormous applications as a tablet disintegrator, as enteric coating substance and finally employed in the sustained release drug formulations.
