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.
Melilotus officinalis, Sweet Clover, Yellow Melilot, official in Austria, Germany, Italy, Mexico, and Norway. It is sometimes called Trifolium officinale, a prominent proprietary preparation being based on it, under the latter name. Trifolium pra-tense, Red Clover, is also used in a proprietary product.
Melilotus is active on account of its content of coumarin; it exists therein only in small quantity. Tonka, Dipterix odorata, official in Japan and Mexico, and used as a substitute for vanilla, also contains coumarin. Liatris odoratissima, to be referred to presently, is a coumarin-bearer.
Coumarin is a pronounced narcotic which produces cerebral intoxication. It also influences the heart, in large doses paralyzing it.
Melilotus alba, White Melilot, is similar in action to the yellow variety.
Liatris odoratissima, Vanilla Plant, Deer's Tongue, before referred to as a coumarin-bearer, is, to my personal knowledge, very largely used in smoking tobacco and our nasty American cigarettes. This weed is gathered and shipped to tobacco warehouses - I have seen it there and demonstrated its presence in fourteen brands of pipe and cigarette tobaccos - where it is incorporated to give a fine aroma and to "dope" the product.
Dr. Laurence Johnson, in "A Manual of the Medical Botany of North America," says of it: "The deleterious effects produced by smoking tobacco thus adulterated are much greater than those produced by the consumption of pure tobacco in even greater excess. The inhalation of a few whiffs of the smoke from a cigarette made of this adulterated material, provided the inhalations are made in quick succession, produces a train of cerebral sensations of an intoxicating character as much different from any effect of tobacco alone as could be imagined; and prolonged use of such cigarettes invariably produces great derangement of the digestive organs, very little resembling the dyspepsia induced by excessive use of tobacco, together with cardiac symptoms often of a distressing character.
"The habit of smoking coumarin in this form appears to become more inveterate, more exacting, than that of the use of tobacco alone, so that the unhappy victim - for such he should be called - is never comfortable except when indulging."
The above throws more light on the pharmacology of coumarin than anything else I have encountered.
Melilotus contains very little coumarin; but whatever action it has is dependent upon it.
It is a little difficult to determine a scientific place for melilotus in therapy; but it has a reputation in the treatment of neuralgia. From my own experiments with the drug, I believe its rational indication to be in painful conditions dependent upon cerebral hyperemia. It has, in my hands, relieved congestive headache and some cases of neuralgia. The drug is evanescent in action. The maximum dose of the fl. is 10 minims; but much smaller doses frequently repeated give better results.
Assuredly melilotus is an active drug; but just how far it is wise to extend its use remains to be seen. Theoretically, it should aid in treating hay-fever.
Red Clover, Trifolium pratense, has a long-established reputation as a vegetable alterative.
As it belongs to the Leguminosae, many of which have active seeds and roots, the root of the red clover may possess active properties; it would be more probable to find activity in the root than in the blossoms. However, the blossoms are used; but always combined with several other drugs, inclusive of potassium iodide. Therefore, who is to say whether red clover blossoms by themselves possess any activity? There are too many agents used in medicine simply because at one time they were ingredients in poly-pharmacy preparations. One of the best illustrations of this is the number of such agents carried over from one pharmacopeia to another, and yet nearly worthless. As an illustration, see the next entry.