Horse Chestnut ( Aesculus Hippocastanum)
Horse Chestnuts ( Aesculus Hippocastanum) are favourite trees of gardens, parks and roadways under moist climates. Numerous horticultural varieties have been described. Horse Chestnut is a large deciduous, rapidly-growing tree that can reach a height of 36 meters. It is native to the countries of the Balkan Peninsula, but because of its large, showy flower clusters the tree is cultivated worldwide for its beauty. Flowers are white or pink with a small red spot. Leaves are large, consisting of either five or seven leaflets and the fruit is round with a thick, green, spiny husk containing a glossy brown seed.
Historically, the seed extract was used as a treatment for many ailments, including rheumatism, rectal complaints, bladder and gastrointestinal disorders, fever (first written account in 1720), hemorrhoids (as early as 1886), and leg cramps. Currently, horse chestnut seed extract (HCSE) is widely used in Europe for chronic venous insufficiency, hemorrhoids, post-operative edema, and topically for clearing skin conditions. In the United States, HCSE is gaining wider acceptance as an effective therapy for venous disorders and edema, based on the publication over the last two decades of numerous randomized controlled trials in prominent, peer-reviewed journals.
Active Constituents of Horse Chestnut
The primary active constituent found in horse chestnut seed extract is aescin (also known as escin). Aescin is actually a mixture of triterpene saponins present in two forms, α and β, which are distinguished by their water solubility and melting points.
Recommended Use of Horse Chestnut
Internal use: Horse chestnut seed standardized extract containing 16 to 20 percent aescin—300 milligrams (approximately 50 milligrams of aescin) two to three times daily.
External use: Gel or cream containing 2 percent aescin—apply topically to affected area three to four times daily.
How Horse Chestnut Works
Aescin is a full-service tonic for the veins and capillaries. First and foremost, it helps improve the strength and tone in the walls of the veins and capillaries. Some researchers call this a “vascular tightening” effect probably not much different from the effect we get when we put astringent creams on our face. This improves the return of blood to the heart and discourages the pooling of blood and resulting edema (fluid retention) that is often seen in the ankles and lower legs of persons with CVI. This anti-edema effect is also enhanced by aescin’s ability to help pooled fluid drain from surrounding tissues back into the capillaries. Aescin’s anti-edema and anti-inflammatory actions have contributed to its success as a topical treatment for traumatic injuries such as strains and sprains. Since this is an isolation of one constituent from horse chestnut and not an herbal extract, we’ll concentrate our focus in the next section on use of HCSE for CVI.
Benefits of Horse Chestnut
HCSE administration increases sensitization to calcium ions, decreases permeability of small vessels, and enhances venous contractile activity, thereby improving venous tone and having a “sealing effect” at the sight of injury. The end result is decreased edema and swelling. Aescin’s anti-edematous property is also attributed in part to its inhibition of hypoxia and the resultant reduction of ATP content in endothelial cells. Reduced endothelial ATP levels initiate the release of prostaglandins, platelet activating factor, and neutrophil chemotaxis, leading to venous stasis and edema. Aescin also reduces the adherence and activation of white blood cells, thereby inhibiting edema and protecting the vessels.
The anti-inflammatory properties of aescin have been demonstrated in animal models and suggest it interferes with the release of inflammatory mediators by decreasing leukocyte activation and adhesiveness. In a rat model of pleurisy, aescin administration decreased leukocyte migration into the pleural cavity and inhibited the release of inflammatory mediators. A human study of patients with chronic venous insufficiency showed 5 mg aescin given intravenously twice daily for a week resulted in a 33-percent reduction of leukocyte density, a 50-percent decrease in macrophage numbers, and a 46-percent increase in neutrophils in inflammatory exudates.
Animal studies in dogs and in vitro studies using human saphenous veins demonstrated aescin’s venotonic properties are linked to its ability to enhance production of prostaglandin F2. Prostaglandin F2 inhibits catabolism of venous tissue mucopolysaccharides and improves venous contractility. In dogs, 25-50 mg injected aescin resulted in a dose-related increase in venous pressure of nearly 21 percent, with an increase in final maximum pressure of 30 percent compared to baseline.
In the in vitro study using human saphenous veins, a dose-response curve demonstrated purified β-aescin increased venous tone by 10-20 percent at low concentrations that would correspond to reasonable oral dosing in humans.
Chronic Venous Insufficiency
Chronic venous insufficiency (CVI) is the inability of the veins in the lower leg to carry blood back toward the heart and is usually attributed to either valve damage within the leg veins or deep vein thrombosis blockage, which results in blood leakage and pooling in the legs and feet. CVI is characterized by a tired, “heavy,” achy feeling in the lower legs, dry and/or discolored skin, swelling (edema), varicose veins, or leg ulcers. Some individuals experience pain upon walking or prolonged standing. CVI is typically classified according to severity as follows: stage I: edema; stage II: skin discoloration or varicose veins accompanying edema; and stage III: edema, skin changes, and the presence of leg ulcers (either open or healed). Statistics indicate 20-25 percent of women and 10-15 percent of men suffer from CVI at some time in life, with the incidence increasing with age.
Typically, CVI is treated with compression stockings or wraps to encourage blood flow up the leg; vascular surgery is used when compression stockings fail. With compression therapy, compliance is poor due to discomfort, and surgery is often not a desirable option. A combination therapy of compression stockings and medication to relieve swelling is currently the most typically used therapy in the United States. In Europe, where it has been studied extensively, HCSE is a more popular choice and has been shown in numerous clinical trials to be a highly effective therapy, equal to that of compression stockings.
Results indicate that compression stocking therapy and horse chestnut therapy are equally effective for patients with chronic venous insufficiency and edema. Due to the low rate of side effects observed with HCSE, it seems likely that better patient compliance might be achieved with HCSE than with compression stocking therapy.
Varicose veins are a result of CVI and usually manifest during stage II. Sclerotherapy, laser surgery, or surgical vein stripping are the recommended treatments. In a meta-analysis of five clinical studies on treatment of CVI with HCSE, Suter et al reported on one trial that explored the effect of HCSE on varicose veins. Thirty-nine patients with varicose veins took 1-2 tablets (20 mg aescin each) three times daily and also applied a two-percent aescin gel topically twice daily (average = 4.4 mL daily) for eight weeks. Fifty-eight percent of subjects reported good overall efficacy for the combination treatment. Blue skin discoloration, pain, edema, and leg heaviness were significantly improved at the end of the treatment period compared to baseline.
Venous Stasis Ulcers
Venous stasis ulcers of the lower limb can occur when CVI is left untreated or is refractory to treatment. Because HCSE inhibits several aspects of CVI and has a “sealing effect” on venous tissue, it seems likely HCSE would be an effective treatment for venous stasis ulcers. To date, one clinical trial has been conducted.
Surgeries involving large limbs or lymph nodes often result in post-operative edema in the affected limb. Two clinical trials demonstrate HCSE given intravenously decreases skin temperature and edema in postsurgical patients. In the first trial, patients undergoing surgery for hernia repair, meniscus removal, or lower leg fracture, received intravenous aescin treatment (5-10 mg aescin twice daily) on the day prior to and three days after surgery. The primary endpoint of the trial was skin temperature comparison between the surgical area and the contralateral side. Skin temperature is a relevant indicator of circulation and swelling in the affected limb. In the post-surgical patients receiving intravenous aescin, skin temperature was lower in the operated side than in the post-surgical patients receiving no treatment.
In the second trial, patients undergoing hand surgery received 10 mg intravenous aescin twice daily (duration unknown) or no treatment and were assessed with infrared thermography until symptoms disappeared. In the patients receiving aescin, peak hand temperature difference (between treated side and contralateral side) was noted on the second post-operative day, indicating improvement in skin circulation and swelling, compared to subjects in the non-treated group for whom peak hand temperature difference was not observed until four days post-surgery.
Hemorrhoids are characterized by congestion of internal and/or external veins around the anal canal. Hemorrhoids may be a result of straining during defecation, chronic constipation or diarrhea, anal intercourse, pregnancy, or aging. Two-thirds of healthy people reporting for physical examinations have hemorrhoids. Conventional treatments for hemorrhoids include topical anti-inflammatory agents, astringent creams, rubber band ligation, or surgery when severe. While horse chestnut seed extract has been used effectively to treat hemorrhoids, supportive clinical research is limited.
Inner Ear Perfusion
Based on aescin’s anti-inflammatory and venotonic properties and the vasoprotective antioxidant properties of troxerutin, a natural flavonoid derivative, researchers investigated whether the combination of the two would have an effect on treating inner ear disturbances. Many of these conditions and the resultant loss of hearing are known to be due to circulatory insufficiency in the inner ear.
It is possible that aesculin, a hydroxycoumarin, may potentiate the effect of anticoagulant medications. However, other research suggests this effect is only seen with aesculin, a bark constituent not found in HCSE. Due to lack of clinical research in pregnant or nursing women, HCSE is contraindicated in this patient population.
Side Effects and Toxicity
Side effects with standardized extracts of horse chestnut seed are rare. They can include itching, nausea, upset stomach, and calf spasm. Because of reports of intravenous aescin causing worsening of kidney function in persons with kidney disease, it is probably best for persons with kidney disease to avoid internal use of the extract. Individuals with liver disease should also avoid horse chestnut seed extract.