The plant is mentioned in ancient Arabic and Persian texts from as far back as the 10th century and from there was introduced to India where it is widely found. The name isapghulliterally means 'horse's ear'
It is native to the Mediterranean regions of western Asia and widely cultivated in India, Pakistan, Russia, China and elsewhere on a commercial scale.
The plant is a softly hairy annual herb, with leaves that are narrowly linear or filiform up to 2S cm long, with an acute apex and an entire or faintly toothed margin. The flowers occur in cylindrical or oval spikes up to 4 cm long. The capsules are ellipsoid and up to 8 cm long, containing the seeds, which are ovoid or oblong, smooth and yellowish?brown with deep red husks.
Seed and husks.
The dried seeds and husk are used as a demulcent, emollient and laxative in the treatment of chronic constipation, amoebic and bacillary dysentery and diarrhoea due to irritant conditions of the gastrointestinal tract; in colds and coughs, bronchitis, rheumatism, kidney disorders and urethritis. They are also applied as a poultice.
The husked seed kernels are mixed with guar and used as cattle feed.
The main component of the mucilage of the seed is a large, linear, highly branched polymer comprising d-galactose, d-glucose, lignin, (1 ,2)-I-rhamnose, d-xylose, I-arabinose, d-mannose with uronic acid side chains.
Other parts of the plant contain monoterpene alkaloids such as boshniakine (indicaine) and boshniakinic acid (plantagonine), the iridoid aucubin and tannins.
Laxative effects: The mucilage in the husk is responsible for this activity. It swells to a jelly?like mass with cold water, thereby increasing in volume, and this relieves constipation by stimulating intestinal peristalsis mechanically. The intraluminal pressure is decreased and colon transit therefore accelerated. The toxins present in the gut are absorbed by the mucilage and are prevented from being absorbed in the system to some extent. The mucilage remains unaffected by the digestive enzymes and bacteria. Only a small part of the fibre is degraded by colon bacteria.
Antihaemorrhoidal effects: In a placebo?controlled trial in 50 patients with bleeding internal haemorrhoids P. ovata was found to be helpful in alleviating symptoms. Parameters measured before and after the treatment included the degree of haemorrhoidal prolapse, the number of congested haemorrhoidal cushions and the amount of bleeding from the haemorrhoids. The average number of bleeding episodes decreased significantly over 15 days in the study group and in the last 10 days of treatment a further reduction was observed. The number of congested haemorrhoidal cushions also diminished after treatment. No differences were found in the control group. No modification of the degree of prolapse was observed after treatment. The addition of a preparation of P. ovata therefore improved most of the symptoms of internal bleeding haemorrhoids, although the effect was not immediate.
Pharmacological activity: The ethanolic extract of the seeds exhibits cholinergic activity, lowering the blood pressure in anaesthetised animals.
Protection of mucosa: A decrease in ?-glucuronidase activity of colon bacteria has been observed, which inhibits cleavage of toxic compounds from their liver conjugates. The bacterial conversion of primary bile acids to the more toxic secondary ones was reduced in a study performed in rats.
Antidiarrhoeal activity: The mucilage in P. ovata combines with the excess fluid in the intestines, thereby increasing the viscosity of the intestinal contents. Hence, transit time and defaecation frequency are normalised.1O Cholesterol-lowering activity: Levels of cholesterol in blood were lowered by P. ovata due to binding with bile acids and increasing their faecal excretion, thereby resulting in further synthesis of bile salts from cholesterol.
Glucose-lowering activity: Levels of blood glucose are lowered by P. ovata due to delaying the intestinal absorption in the intestine.
No harmful or deleterious effects during pregnancy or lactation have been reported. This is understandable as the constituents are not absorbed.13 However, in rare cases hypersensitivity reactions may occur.