There are about twenty species of melilotus species in Asia and Europe.
The MELILOT OFFICINAL or SWEET CLOVER is an herbaceous plant of variable size (30 cm to more than a meter), with erect stems quite stiff, with leaves with three leaflets, and which has small yellow flowers, present during most of the hot season, numerous , in clusters and which attract foraging insects (including bees).
The fruit is a dry, ovoid, straight pod (neither coiled nor twisted) that usually contains a single seed.
Sweet clover gives off a pleasant, sweet scent of cut hay, honey, due to the presence of coumarins in the plant.
Sweet clover lives two years (biennial), it is very resistant to cold and drought but does not support too wet soils.
Sweet clover native to Eurasia has sometimes been introduced accidentally or as a fodder plant in other temperate countries (eg North America) where it is sometimes considered an invasive plant plague.
In Western herbal medicine, the flowering tops of Melilotus officinalis (French pharmacopoeia) are considered medicinal.
CHEMICAL COMPOSITION AND PROPERTIES
FLOWERED AERIAL PARTS OF SWEET CLOVER
The flowering tops contain:
- non-specific flavonoids with anti-inflammatory properties,
- phenolic acids common in many plants: caffeic, salicylic, ferulic and melilotic (more specific to sweet clover),
- coumarins and coumarin derivatives (stricto sensu).
Coumarin and coumarins associated with flavonoids and phenolic acids (the total extract of sweet clover):
- increase venous tone (VEINOTONIC),
- reduce edemas linked to venous and lymphatic insufficiency,
- are DIURETIC and slightly antispasmodic,
- and have ANTI-INFLAMMATORY power (in direct application to areas that are bruised or painful due to inflammation)
COUMARIN AND DICOUMAROL
Under the natural action of fungi (especially when forage containing sweet clover is poorly dried) coumarin is released from melitoside and then transformed into dicoumarol.
Dicoumarol is an anti-vitamin K, therefore an ANTI-COAGULANT, which, beyond a certain blood concentration or accumulation in the body, can induce spontaneous hemorrhages which do not stop and can lead to death.
Dicoumarol inhibits an enzyme which allows the recycling of vitamin K, but it also acts on another intracellular "anti-inflammatory" enzyme, a possible lead for a new family of anti-cancer substances.
The discovery of dicoumarol was made (in 1940) during "hemorrhagic epidemics" in cattle which had consumed poorly dried and lightly fermented hay.
Dicoumarol was very quickly used (at a very controlled dose) in medicine as an anticoagulant to prevent embolism and heart attacks, then was replaced (around 1950) by a derivative that was easier to use, warfarin.
Dicoumarol is now mainly used to kill rodents (RATICIDE) by incorporating it into an attractive food for rats or mice.
WARNING dicoumarol is dangerous for both animals and humans.
VENOUS AND LYMPHATIC INSUFFICIENCY, VARICES, HEMORROIDS and HEMORROIDAL CRISIS, POST-SURGICAL LYMPHOEDEMA
LOWER LIMBS VARICES
The veins whose role is to bring back the blood "used" by the tissues and the organs, towards the heart then the lungs to be re-oxygenated, have an elastic wall but without great tonicity.
The veins that drain venous blood from the lower limbs have valves that prevent blood from flowing back down, if these valves are not tight enough, blood collects in the legs, dilating the superficial veins, which are varicose veins of the lower limbs.
A similar phenomenon appears when a main vein is more or less blocked (thrombo-phlebitis).
The increase in pressure in the veins causes them to dilate, venous and lymphatic exudate (edema of the legs, ankles) or even a slowdown in blood flow with inflammatory phenomenon, sometimes a thrombosis of the varicose veins, skin disorders, difficult ulcerations to heal.
Hemorrhoids are abnormal dilations of the venous network in the anus or in the lower part of the rectum.
The causes are multiple: initial deficiency of the venous network, temporary or permanent increase in abdominal pressure (example: chronic constipation, pregnancy, colitis, etc.)
Hemorrhoids can inflame and become very painful, thicken, or even rupture and cause a small hemorrhage.
Surgical treatment for breast cancer is often accompanied by the removal (dissection) of the lymph nodes in the armpit.
Blocking the flow of lymph can cause permanent and sometimes painful edema of the arm.
EXTRACTS OF MELILOTUS OFFICINALLIS, SWEET CLOVER often associated with other plants (example: blackcurrant , butcher's broom, horse chestnut , red vine , ginkgo , witch hazel):
- STRENGTHEN THE TONE OF VEINS,
- decrease the local permeability of blood vessels,
- locally prevent inflammatory phenomena,
- decrease lymphatic or exudative edema.
DOSAGE EXAMPLES :
- INFUSION of flowering tops: 25 g of dry flowering tops of sweet clover in 1/2 liter of very hot water, let infuse 10 minutes, filter, one cup two to three times a day.
- alcoholic TINCTURE of sweet clover: 50 to 150 drops distributed throughout the day (to be taken rather before meals).
- Sweet clover POWDER: 1 to 3 g per day in two to 3 doses.
There are pharmaceutical specialties that combine extracts of sweet clover with other plants treating venous and lymphatic insufficiency, varicose veins and hemorrhoids.
Rather SHORT TREATMENTS of 2 to 3 weeks are recommended, which can be repeated after an interruption equal to the treatment time.
The intake of sweet clover may be accompanied by an increase in urine output (DIURETIC EFFECT) which can help reduce edema.
ANTISPASMODIC, MILD SEDATIVE
Sweet clover helps alleviate certain "digestive spasms", and calms the irritability of the nervous system; these are traditional but secondary indications sweet clover.
The concentrated infusion of sweet clover (50 g of dry plant for 1/2 liter of boiling water, 10 to 15 minutes of infusion) is useful, once cooled, in local application (compresses) on a gauze or a tampon of cotton:
- to calm inflammation in case of CONTUSION, bruising, muscle STRAIN, sprain,
- in the event of inflammation of the eyelids or "tiredness" of the eyes (it is a traditional indication ).
PRECAUTIONS ET CONTRAINDICATIONS
As indicated above, the treatment sequences are limited to 2 to 3 weeks with a therapeutic rest for as many weeks.
Sweet clover is contraindicated in pregnant women and in people who are on anticoagulant treatment (as a precaution because, theoretically, coumarin does not act on the coagulation time).
Yellow sweet clover is a good HONEY PLANT, very popular with bees.
It has a deep taproot that is interesting in crop rotation to improve soil structure and is also a good green manure.
But it must be mowed before the seeds appear, it is a resistant plant that is a little invasive.
Sweet clover does not require any particular soil, but it grows best in limestone soils because it does not like too wet soils.
It is propagated by seeds, they are sown in spring on thinned and lightly worked soil.
Sweet clover grows quickly, flowers after a few months for the happiness of bees and beekeepers and reseeds naturally.
The seeds can persist in the soil and it is sometimes difficult to get rid of sweet clover.
As a last resort farmers use selective herbicides.
The yellow sweet clover can coexist with the white sweet clover (with white flowers), Melilotus albus, it is a species also introduced in North America and in Australia, more slender but sometimes higher than the yellow sweet clover; it is also a honey plant.
It is not officinal but seems to have the same pharmacological properties and may also be the cause of intoxication of cattle by dicoumarol.
Chinese medicine uses Melilotus suaveolens mainly as an anti-inflammatory, it contains coumarins, flavonoids and tannins.
In India, an annual species with a yellow flower, Melilotus indicus, is found which also contains coumarin.
YELLOW MELILOT, SWEET CLOVER A MEDICINAL PLANT APPRECIATED BY BEES
Sweet clover with yellow flowers and a sweet smell due to the presence of coumarin is indicated to treat venous and lymphatic insufficiency, varicose veins of the lower limbs, hemorrhoids and the complications that accompany them, edema, pain, inflammation.
It is often associated with other plants with the same indications (blackcurrant, red vine, horse chestnut).
Melilots are honey plants very popular with bees and beekeepers.
Copyright 2020: Dr Jean-Michel Hurtel