Fenugreek is the ripe, dried fruit of an annual leguminous herb. Both seeds and plant of this herb is used in Indian cuisine.
The dried leaves of the fenugreek is used as a quality flavour for meat, fish and vegetable dishes. It acts as a medicine as well as an embalming agent. Fenugreek seeds are rich in vitamin E and is one of the earliest spices known to man.
Fenugreek has a strong, quite peculiar odour reminiscent of maple. It is used in almost all dishes and in pickles. The major producers of Indian Fenugreek are Rajasthan, Gujarat, Uttar Pradesh and Tamil Nadu.
Commercially known as 'Methi', Indian Fenugreek comes in several well-known varieties such as 'Desi' and 'champa'. The spice is exported in its whole and powdered form. The extracted oil of fenugreek is extensively used in perfumery.The major importers of Indian Fenugreek are Saudi Arabia, Japan, Malaysia, USA,UK, Singapore and Sri Lanka.
Trigonella foenum–graecum L. (Leguminosae)
Synonyms and Part Used strong>
Pyridine–type. Gentianine, trigonelline (up to 0.13%), choline (0.05%).
Proteins and amino acids
Protein (23–25%) containing high quantities of lysine and tryptophan. Free amino acids include 4–hydroxyisoleucine (0.09%), histidine, lysine and arginine.
Flavone (apigenin, luteolin) glycosides including orientin and vitexin, quercetin (flavonol).
0.6–1.7%. Glycosides yielding steroidal sapogenins diosgenin and yamogenin (major), with tigogenin, neotigogenin,gitogenin, neogitogenin, smilagenin, sarsasapogenin, yuccagenin; fenugreekine, a sapogenin–peptide ester involving diosgenin and yamogenin; trigofoenosides A–G (furostanol glycosides).
Coumarin, lipids (5–8%), mucilaginous fibre (50%), vitamins (including nicotinic acid) and minerals.
Fenugreek is listed by the Council of Europe as a natural source of food flavouring (category N2). This category indicates that fenugreek can be added to foodstuffs in small quantities, with a possible limitation of an active principle (as yet unspecified) in the final product.
Fenugreek is stated to possess mucilaginous demulcent, laxative, nutritive, expectorant and orexigenic properties, and has been used topically as an emollient and vulnerary. Traditionally, it has been used in the
treatment of anorexia, dyspepsia, gastritis and convalescence, and topically for furunculosis, myalgia,lymphadenitis, gout, wounds and leg ulcers.
1–6 g or equivalent three times daily.
In vitro and animal studies
Hypocholesterolaemic activity has been reported for fenugreek in rats and alloxan–diabetic dogs. Activity has been attributed to the fibre and saponin fractions, and not to lipid or amino acid fractions. Studies have reported a reduction in cholesterol but not triglyceride concentrations,or in both cholesterol and triglyceride concentrations, but without significant alterations in high–density lipoprotein (HDL) and low–density lipoprotein (LDL) concentrations.
Hypoglycaemic activity has been observed in rabbits, rats and dogs, and attributed to the defatted seed fraction (DSF),trigonelline, nicotinic acid and coumarin. Oral administration of DSF reduced hyperglycaemia in four alloxan–diabetic dogs, and reduced the response to an oral glucose tolerance test in eight normal dogs,whereas the lipid fraction had no effect on serum glucose and insulin concentrations.The high fibre content (50%) of DSF was thought to contribute to its antidiabetic effect although the initial rate of glucose absorption was not affected.Nicotinic acid and coumarin were reported to be the major hypoglycaemic components of fenugreek
seeds, following administration to normal and alloxan–diabetic rats.The hypoglycaemic action exhibited by coumarin was still significant 24 hours post administration.In addition, a slight antidiuretic action was noted for coumarin.Trigonelline inhibited cortisone–induced hyperglycaemia in rabbits if administered (250 mg/kg)
concomitantly or two hours before, but not two hours after, cortisone.In addition, trigonelline exhibited significant hypoglycaemic activity in alloxan–diabetic rats (50 mg/kg), lasting 24 hours.
A stimulant action on the isolated uterus (guinea–pig), especially during late pregnancy, has been noted for both aqueous and alcoholic extracts. An aqueous extract is stated to increase the number of heart beats in the isolated mammalian heart.
In vitro antiviral activity against vaccinia virus has been reported for fenugreekine, which also possesses cardiotonic, hypoglycaemic, diuretic, antiphlogistic and antihypertensive properties.
A transient hypoglycaemic effect was observed in 5 of 10 diabetic patients who received 500 mg oral trigonelline whilst fasting.Increasing the dose did not increase this effect, and 500 mg ingested three times a day for five days did not alter the diurnal blood glucose concentration.Hypoglycaemic activity in healthy individuals has been reported for whole seed extracts, with slightly lesser activity exhibited by gum isolate, extracted seeds and cooked seeds.The addition of fenugreek to an oral glucose tolerance test reduced serum glucose and insulin concentrations. Chronic ingestion (21 days) of extracted seeds (25 g seeds daily incorporated into two meals) by
non–insulin–dependent diabetics improved plasma glucose and insulin responses (no control group), and reduced 24–hour urinary glucose concentrations.Furthermore, in two diabetic insulin–dependent subjects, daily administration of 25 g fenugreek seed powder reduced fasting plasma–glucose profile, glycosuria and daily insulin requirements (56–20 units) after eight weeks. A significant reduction in serum cholesterol concentrations in diabetic patients was also noted.
No reported side–effects were located for fenugreek. Acute toxicity values (LD50) documented for fenugreek alcoholic seed extract are 5 g/kg (rat, oral) and 2 g/kg (rabbit, dermal).The alcoholic seed extract is reported to be non-irritating and non–sensitising to human skin and non–phototoxic (mice, pigs). Coumarin is a toxic
seed component.Acute LD50 (rat, oral) values per kilogram documented for various seed constituents are 5 g (trigonelline), 8.8 g (nicotinic acid), 7.4 g (nicotinamide) and 0.72 g (coumarin).
Hypoglycaemic activity has been reported for fenugreek, which may therefore interfere with existing hypoglycaemic therapy. Caution is advisable in patients receiving monoamine oxidase inhibitor (MAOI), hormonal or anticoagulant therapies in view of amine, steroidal saponin and coumarin constituents, respectively, although their clinical significance is unclear. Cardioactivity has been documented in vitro. The absorption of drugs taken concomitantly with fenugreek may be affected (high mucilaginous fibre content).
Pregnancy and lactation
Fenugreek is reputed to be oxytocic and in vitro uterine stimulant activity has been documented. In view of this, and the documented pharmacologically active components, the use of fenugreek during pregnancy and lactation in doses greatly exceeding those normally encountered in foods is not advisable.
Fenugreek seeds contain a high proportion of mucilaginous fibre, together with various other pharmacologically active compounds including steroidal and amine components. The majority of the traditional uses of fenugreek are probably attributable to the mucilage content. In addition, hypocholesterolaemic and hypoglycaemic actions have been documented for fenugreek in both laboratory animals and humans. The mechanism by which fenugreek exerts these actions is unclear. Proposed theories include a reduction in carbohydrate absorption by the mucilaginous fibre,and an effect on cholesterol metabolism, cholesterol absorption and bile acid excretion by the saponin components.Toxicity studies indicate fenugreek seeds to be relatively non–toxic, although the presence of pharmacologically active constituents would suggest that excessive ingestion is inadvisable.