This section is from the book "Botanic Drugs Their Materia Medica, Pharmacology and Therapeutics", by Thomas S. Blair. Also available from Amazon: Botanic Drugs, Their Materia Medica, Pharmacology and Therapeutics.
Gentiana Species universally official; G. lutea nearly universal; G. pannonica in seven countries; G. punctata in five; G. purpurea in six, and Japanese Gentian, G. Scabra, in Japan. G. crinita, G. ochro-leuca, G. Andrewsii, and G. puberula grow in the U. S. Not one of these is official, but they possess similar medicinal properties to the official species. Water extracts the bitter principle of all species. Our native species should be investigated; they are giving satisfactory results in domestic practice.
They consist of glucosides, weak acids, and neutral principles, so far as their medicinal properties are involved. They include gentian, quassia, calumba, chirata, taraxacum, berberis, pareira, serpentaria, cascarilla, and others. They are, as bitters, similar in action. Given by mouth they increase the flow of saliva, inhibiting that of gastric juice for a time and then increasing it. Large doses of the tannin-free bitters increase the flow of the intestinal juices. There is some evidence that they stimulate peristalsis. Pawlow emphasized the psychical factor in increasing stomach secretion, claiming that the bitters so act and, as well, the augmented gastric acids promoting the production of secretin in the duodenum, and inducing pancreatic activity.
Moorhead, in Jour, of Pharmacology and Exper. Ther., Dec, 1915, paralleling Carlston's experiments on healthy animals by similar ones on unhealthy animals, found that the influence of bitters is definite in increasing the quality and quantity of the gastric juice. He contends that this influence is caused reflexly through the nerves of the taste and not by any direct stimulation of the stomach itself.
Thus, the pharmacology of the bitters is predicated upon the influence in disease being definite, while in health there is no definite effect produced, another instance showing that clinical experience is not always negatived by the findings derived by experiments on healthy animals.
The bitters stimulate appetite and digestion, especially in convalescence, in chronic gastritis, in general debility, and in dyspepsia associated with deficient secretion of hydrochloric acid.
The simple bitters should be administered in liquid form only a few minutes before eating. In pill form they serve no useful purpose, so far as is known at present. The tannin-free bitters, more especially in intestinal indigestion, are calumba, chirata, and quassia. Gentisin, in gentian, gives a reaction with ferric chloride, thus giving the erroneous impression that gentian is rich in tannin, which is not the case.
Extract of gentian is used only as a pill excipient. The fl. is given in an average dose of 15 minims; the compound tincture in doses of a fluidrachm or more, but doses of 30 to 45 minims usually serve every useful purpose. The infusion is effective in doses of one-half to one fluidounce. The British Phar. Codex has a concentrated compound infusion, the dose of which is one-half to one fluidrachm, taken well diluted with water. Capsicum, nitrohydrochloric acid, sodium bicarbonate, cardamon, and mild laxatives are combined with gentian. There is no advantage in giving gentian in wines and strongly alcoholic elixirs.