Scientific Name(s): Galega officinalis L.
Common Name(s): French lilac, Galega, Goat's rue, Italian fitch, Pestilenzkraut (German), Professor-weed
Medically reviewed by Drugs.com. Last updated on Feb 21, 2022.
Goat's rue and its derivatives have been used in the management of diabetes mellitus to reduce blood sugar levels. Goat’s rue has also been used for its lactogenic effects to increase milk production. It has tonic, liver protectant, and platelet aggregation inhibitory effects, and has been evaluated for its diuretic and weight loss effects. However, limited clinical trials exist to support these uses.
Diabetes: Information is lacking to provide dosing recommendations for goat’s rue in diabetes. Clinical dosing information focuses on metformin, which is derived from goat’s rue.
Galactorrhea: 1 teaspoon (5 mL) of dried herb steeped in 1 cup (240 mL) of water administered twice daily or 1 to 2 mL of tincture administered 3 times daily.
Use caution if administering goat’s rue during surgical procedures due to a potential increased risk of bleeding.
Avoid use. Information regarding safety and efficacy in pregnancy is lacking. Silymarin in combination with galega enhances milk production in breast-feeding mothers.
Hypoglycemic medications: Additive blood glucose–lowering effects may occur if using goat’s rue concomitantly with other hypoglycemic medications such as insulin and sulfonylureas.
Antiplatelet/Anticoagulant medications: Because goat’s rue inhibits platelet aggregation, the risk of bleeding may be increased when given concomitantly with other antiplatelet medications or anticoagulants.
Headache, jitteriness, or weakness may occur. Because of its ability to inhibit platelet aggregation, there may be an increased risk of bleeding and bruising with administration of goat’s rue.
Toxicity has been observed with other guanidine derivatives.
- Fabaceae (bean)
Goat’s rue is a perennial herb found in temperate grassland regions of Asia and Europe. It also grows wild in damp fields in Britain.1 The plant, which prefers damp, low-lying areas and sandy soil, grows to about 1 m in height. It has compound leaves with lance-shaped ends and fruit consisting of a round, indented pod containing many seeds. The flowers are white, lilac, light blue, or pinkish in color and grow on terminal spikes. The dried aerial parts of the plant are harvested during the summer flowering season and used medicinally. The plant has no scent unless bruised, in which case it emits a disagreeable odor, from which the name "goat's rue" may have originated. It has a bitter and astringent taste and can discolor saliva to a yellowish-green hue.2 Goat's rue should not be confused with common rue (Ruta graveolens).2, 3, 4, 5, 6
Goat's rue has been traditionally used as a vermifuge, and for treatment of snakebites and the plague. It is believed to have been used as a diuretic and tonic for typhoid conditions and as a nervous system stimulant.2, 4 Goat's rue has been used as a soak for tired feet and as an herb in cheese making.2 Hill's Universal Herbal (1832) mentions the addition of the dried flowers to boiling water to make an infusion for drinking to induce sweating and reduce fever.2 The plant is widely cultivated as cattle feed.4 Reports of lactogenic effects of the plant exist.7 The name "Galega" is derived from "gala" meaning "milk," and "agein" meaning "production."8
Guanidine derivatives, including galegine (isoamylene-guanidine) and hydroxygalegine, are present in all parts of goat's rue.3, 4 Several older reports confirm the presence of galegine and related compounds.9, 10, 11, 12, 13, 14 A later study discusses the presence of several guanidine derivatives, including galegine and 4-hydroxygalegine flavones, and flavone glycosides.15 The flavonol triglycosides kaempferol and quercetin have been found in the plant,16 as have norterpenoid and sesquiterpenoid glycosides, including the rare norterpenoid glycoside dearabinosyl pneumonanthoside.17 Vasicine and other quinazoline alkaloids have been confirmed in Galega spp.18 Other constituents, including peganine, various flavonoids, saponins, and tannins, are also present in goat's rue.3, 4, 19, 20
Uses and Pharmacology
Animal and in vitro data
An in vitro study demonstrated that ethanolic (95%) extracts of G. officinalis inhibited the growth of Enterococcus faecalis and Yersinia enterocolitica. The aqueous alcoholic (60%) extract of G. officinalis inhibited Enterobacter aerogenes, Staphylococcus aureus, E. faecalis, Bacillus subtilis, Serratia marcescens, and Y. enterocolitica.1
Research reveals no clinical data regarding the antibacterial effects of goat’s rue.
Due to its potential diuretic effects, goat’s rue might be considered for disturbances related to secretion of fluids, such as GI ailments (eg, fermentive dyspepsia, gastrocardiac syndrome, diarrhea). Goat's rue is said to stimulate the adrenal glands and pancreas and to aid in glandular disturbances. However, none of these claims are clinically documented.4, 5
Animal and in vitro data
Research reveals no animal or in vitro data regarding the use of goat’s rue for diuresis.
Research reveals no clinical data regarding the use of goat's rue for diuresis.
Goat's rue has been shown to increase milk production in lactating animals and in breast-feeding mothers.4
Animal and in vitro data
In a clinical study, 100 mothers with preterm infants were randomized to receive a galactogogue containing silymarin-phosphatidylserine and galega at a dosage of 5 g/day or placebo from days 3 to 28 postdelivery. Significantly higher milk production was noted with treatment at 7 days and 30 days compared with placebo (P<0.05). Women receiving the galactogogue produced 200 mL (110 to 380 mL) each day compared with 115 mL (60 to 245 mL) with placebo (P<0.0001). Women receiving the galactogogue produced more milk (6,523±5,298 mL) during the study period compared with those receiving placebo (4,136±4,093 mL, P<0.02). No adverse effects were reported.21
Studies in the 1970s demonstrated that galegine and other guanidine derivatives reduce blood sugar levels.4 Metformin, a biguanide used for the management of type 2 diabetes mellitus, is derived from G. officinalis.10
Animal and in vitro data
In a study evaluating effects of rue leaf preparations, alcoholic extracts of goat's rue exhibited hypoglycemic effects in diabetic rabbits.22 Another report found galegine lowered blood sugar 32% in diabetic rats.23 In another study investigating the mechanism by which fractions of the plant exert hypoglycemic effects, inhibition of glucose transport across monolayers of human intestinal cells occurred in a dose-dependent manner.24 In one study, an extract of G. officinalis normalized leukocyte functionality and reduced apoptosis manifestations in streptozotocin-induced diabetes.25 Another report compared the hypoglycemic actions of a dried leaf infusion of G. officinalis with infusions of other plant products.26 The chromium salt content of goat’s rue may also possess antidiabetic effects.3
A review evaluating several alternative therapies for diabetes, including G. officinalis, reported encouraging results regarding new treatment possibilities in diabetes mellitus but noted the need for further research.27 Goat's rue may be of some value as supportive therapy or in early stages of adult-onset diabetes, with guidance from a physician, but use may not be justified based on severity of the disease, adverse effects/interactions, and the availability of better alternatives.4, 5
Several mechanisms have been postulated regarding G. officinalis’ ability to cause weight loss, based on observations in murine models. Although treatment with G. officinalis was accompanied by a transient decrease in food intake in one study, pair-feeding indicated that the effects on body weight were at least partially independent of changes in food intake. Possible mechanisms include the activation of adenosine monophosphate activated protein kinase, enhanced glucose uptake, and inhibition of acetyl-CoA carboxylase. Fatty acid synthesis inhibition and fatty acid oxidation simulation occurs with the inhibition of acetyl-CoA carboxylase.28
Animal and in vitro data
In studies investigating the effects of goat’s rue on weight, a reversible, marked weight-reducing effect was demonstrated in mice, regardless of food intake. Postmortem examinations revealed a striking absence of body fat in mice administered goat’s rue.29, 30 Modifications to galegine, including replacement of the dimethylallyl group by various benzyl substituents, enhanced weight loss ability.31
Research reveals no clinical data regarding the use of goat's rue for weight loss.
Goat's rue has been used as a tonic, liver protectant,5 and platelet aggregation inhibitor.32, 33, 34, 35 It may also possess antioxidant effects, which can vary according to the type of extract.8, 36 G. officinalis extracts were also noted to have variable cytotoxic activity against glioblastoma and lung adenocarcinoma cell lines. An in vitro study demonstrated that an extract of G. officinalis as well as galegine visually changed the color of melanoma cells and reduced the melanin content.37
Information is lacking to provide dosing recommendations for goat’s rue in diabetes. Clinical dosing information focuses on metformin, which is derived from goat’s rue.
1 teaspoon (5 mL) of dried herb steeped in 1 cup (240 mL) of water administered twice daily.38
1 to 2 mL of tincture administered 3 times daily.38
Pregnancy / Lactation
Avoid use. Information regarding safety and efficacy in pregnancy is lacking. In a study of preterm infants, silymarin in combination with galega enhanced milk production in breast-feeding mothers.21
Additive blood glucose–lowering effects may occur if using goat’s rue concomitantly with other hypoglycemic medications such as insulin and sulfonylureas.24
Headache, jitteriness, or weakness may occur. Because of its ability to inhibit platelet aggregation, there may be an increased risk of bleeding and bruising with administration of goat’s rue.32, 33, 34
Toxic effects of goat’s rue have been reported, with most data derived from studies in sheep. Dyspnea, anoxia, and foaming nasal discharge were observed in ewes ingesting doses as small as 0.8 g/kg/day. Hydrothorax, lung congestion, foamy exudates in the bronchioles and trachea, epicardial and endocardial petechiation, and pericardial effusion were noted in sheep that died. Microscopic alterations in the lungs were also noted.39, 40 In 3 sheep with poisoning from G. officinalis, an asphyxic syndrome occurred and led to death within hours.41 Galegine is suspected to be the cause of toxicity.8
In a murine model, G. officinalis at doses up to 5 g/kg was not associated with increased mortality or toxic symptoms. In the subchronic arm of the study, cholesterol, creatine phosphokinase, lactate dehydrogenase, and total and conjugated bilirubin levels were increased in some groups of rats. Reductions in calcium, albumin, albumin/globulin ratio, hematocrit, and white blood cell and platelet counts occurred in some rats.42
In humans, toxicity has been observed with other guanidine derivatives. Most biguanidine preparations developed in the 1950s have been withdrawn from the market.3 Goat's rue should be used to treat diabetes only under physician supervision due to uncertainty regarding its safety and effectiveness.4, 5
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