Botanical Name: Aesculus hippocastanum, Hippocastanaceae
Common names: Horse Chestnut, Aesculus
Similar species: Aesculus glabra
Plant description: Horse Chestnut is a medium-sized, rapidly growing deciduous tree, 15-17 meters in height, with widely spreading branches that support a rounded crown of foliage. The bark is smooth and gray to almost green in color, and the wood is spongy and soft. The bright green leaves are large, divided into five or seven acuminate leaflets on long stalks, margins irregularly serrated, the size of each leaflet diminishing from the central, terminal leaflet. The flowers are mostly white, borne in pyramidal racemes. The corolla is spreading and composed of 5 oblong, wavy petals, with a small reddish spot above each claw. The calyx is 5-toothed, bright green, and campanulate. The stamens are 7 in number, and support reddish-brown, oblong anthers. The fruit is a prickly, thick, tough capsule with 3-valves, usually containing two brown nuts with an attractive polished skin that surrounds a rough, pale-brown scar where the nut was attached to the placenta.
Habitat, ecology and distribution: Horse Chestnut is indigenous to western Asia (Iran, Northern India), and was brought to Europe in the 16th century as an ornamental.
Part used: Fruit, bark, leaves
History: Although sometimes confused with Sweet Chestnut (Castanea spp.), Horse Chestnut is a very different tree and is not even remotely related to the former. The genus name Aesculus refers to 'food' and was originally applied by Pliny to a species of Acorn (Fagaceae). Thus its designation as Aesculus is somewhat of a misnomer as Horse Chestnuts are hardly edible. Grieve states that the prefix 'Horse' "Šis a corruption of the Welsh gwres, meaning hot, fierce, or pungent. Thus Horse Chestnut is the bitter chestnut, in opposition to the mild, sweet one" (1971). Other opinions state that the name is derived from the use of the fruit in the treatment of horses.
Constituents: Horse Chestnut is noted for its aescin (escin) content, a group of over 30 individual saponin glycosides that were first isolated in 1831, and have since undergone a considerable degree of investigation. Aescin is found in the bark and fruit, but said to be absent from the leaves. It is characterized in fresh plant material by oxidizing and staining the plant tissues brown. Other constituents include the coumarins aesculetin, fraxin and scopolin, a range of flavonol glycosides such as quercetin, astragalin and rutin, condensed tannins (from the hydrolysis of epicatechin), allantoin, phytosterols, lipids, amino acids, cholin and citric acid (Wickes and Felter 1893; Newall et al 1996, 166; Mills and Bone 2000, 449).
Medical Research:
•Venous disease: Horse Chestnut extract and its glycoside aescin have undergone a significant degree of both experimental and clinical investigation of its efficacy in venous disease, particularly chronic venous insufficiency (CVI). CVI is thought to be initiated by an opening of gaps in intercellular gaps in the venular endothelium, resulting in local edema as well as coagulation and thrombosis. Unresolved inflammation allows these gaps to stay open and maintain the disease process. Due to its ability to close the venular endothelial gaps, Horse Chestnut extract has been determined to be a suitable and protective therapy during the early stages of CVI (Ottillinger and Greeske 2001). In a case observation study involving more than 800 general practitioners, more than 5,000 patients with chronic venous insufficiency (CVI) were treated with standardised horse chestnut extract and followed up at regular intervals. All of the symptoms investigated-pain, tiredness, tension and swelling in the leg, as well as itching and the tendency towards edema-all improved markedly or disappeared completely (Greeske et al 1996). The edema-reducing effect of Horse Chestnut seed extract was investigated in randomized placebo controlled parallel double blind study on 40 patients suffering from venous edema in chronic deep vein incompetence. By measuring the leg volume before and after edema provocation, it was shown that Horse Chestnut has a clinical benefit and is useful adjunct to compression therapy that is well tolerated (Diehm et al 1992). A commercial preparation of Horse Chestnut extract called Venostasin, standardized to 50 mg triterpenglycosides, was determined to have tonical effects on the veins, decreasing permeability, with both protective and curative properties. The authors report that the drug was well tolerated (Hitzenberger 1989). Venostasin was also assessed in a randomized placebo-controlled crossover double-blind trial of 22 patients with proven chronic venous insufficiency by measuring the capillary filtration coefficient and the intravascular volume of the lower leg by venous-occlusion plethysmography. Three hours after taking two capsules of Venostasin (600 mg; each capsule containing 50 mg aescin) the capillary filtration coefficient had decreased by 22%, whereas after administration of an identical-looking placebo capsule it rose slightly over three hours (Bisler et al 1986). A pharmaceutical product called Essaven gel and containing aescinate underwent an 8 week randomized, placebo-controlled study to evaluate the effect of local treatment in 30 patients with superficial vein thrombosis (SVT). In patients treated with Essaven gel the decrease in signs and symptoms was significantly larger than in the placebo group, with no intolerance observed (Incandela 2001). The intravenous administration of a Horse Chestnut extract, vitamins B and C, and either strophanthin or digitalis 4 days prior to surgery and for 7 days after was found to significantly reduce the incidence of deep vein thrombosis when compared to similar extracts without Horse chestnut (Kronberger and Golles 1969).
•Diabetes: Essaven gel underwent a 4 week randomized, placebo-controlled study to evaluate the effect of local (foot) treatment in 15 subjects with diabetic microangiopathy. With regular application Essaven gel was found to improve the microcirculation in diabetic microangiopathy, with changes detectable even 1 week after the end of the treatment period (De Sanctis et al 2001).
•Sports injury: A randomised, double blind, placebo controlled, multicentre study was undertaken to determine the clinical efficacy and safety of escin-containing gel in the topical treatment of blunt impact sports injuries. The escin-containing gels were found to produce more rapid pain relief than the placebo gel, without any adverse effects (Wetzel et al 2002).
•Antioxidant: The activity of active-oxygen scavengers such as superoxide anion radicals, hydroxyl radicals, singlet oxygens and lipid peroxides in Horse Chestnut was examined was examined in detail by ESR spin-trapping, malondialdehyde generation, and in a murine dermal fibroblast culture system. Horse Chestnut displayed strong active-oxygen scavenging activity and protective activity against cell damage induced by oxidation. Horse Chestnut was proposed by the authors as an extract for application as anti-aging or anti-wrinkle material for the skin (Masaki et al 1995).
Toxicity: Duke reports an oral LD50 in mice as 134 g/kg (1992). Alpha-aescin was found to be toxic to the bone marrow cells of mice when administered at a dose 80% of the LD50 (Przybojewska et al 1994). Saponin glycosides are known to promote irritation to the mucosa, and Horse Chestnut extract may cause nausea with oral doses. Horse Chestnut pollen was found to display a high allergic sensitization rate (RAST) among urban children (Popp et al 1992).
Herbal action: tonic, astringent, febrifuge, narcotic, and antiseptic
Indications: Venous congestion (e.g. hemorrhoids, varicose veins), rectal itching and irritation, rheumatism, hepatic tenderness, visceral neuralgia, asthma, headache or backache associated with hepatic congestion or venous stasis
Contraindications and cautions: Mills and Bone state that Horse Chestnut extract should not be applied on broken or ulcerated skin (454, 2000). At least one study suggests a possible interaction between Horse Chestnut extract and warfarin therapy (Heck et al 2000).
Medicinal uses: Felter and Lloyd state that the primary indication for Horse Chestnut is visceral pain, secondary to venous congestion, stasis and vascular engorgement. There may be an aching or throbbing pain in the hepatic or rectal regions, with sensations of burning and constriction. Associated symptoms may include back pain, headache, dyspepsia, or asthma. If present, the hemorrhoids will be large and swollen, and may also itch. Bleeding hemorrhoids however is an important contraindication, at least as far as topical preparations are concerned. The kind of venous stasis best associated with Horse Chestnut is that found in the sthenic individual, with peripheral symptoms of heat, and fullness of tissues. In patients with concurrent symptoms of coldness and chill, with constipation, benefit from Horse Chestnut may still be found, but greater attention should be directed to fortifying the digestive apparatus as a whole and countering vital deficiencies. In intermittent fever Horse Chestnut is said to be used to good effect. A powder prepared from the central part of the nuts is recommended as a sternutatory in ophthalmia and headache. The oil of Horse Chestnuts was used in Europe at one time as a local application in neuralgic and rheumatic affections. Cook states that the outer green rinds have a narcotic effect similar to, but about one-third weaker than opium (1869).
Pharmacy and dosage:
•Fresh Plant Tincture: 1:2, 95% alcohol, 20-40 gtt, up to three times daily
•Dry Plant Tincture: 1:5, 50% alcohol, 20-60 gtt, 3-5 mL, up to three times daily
•Decoction: 1:20, 5 mL, four to six times daily
REFERENCES
Bisler H, Pfeifer R, Kluken N, Pauschinger P. 1986. Effects of horse-chestnut seed extract on transcapillary filtration in chronic venous insufficiency. Dtsch Med Wochenschr Aug 29;111(35):1321-9
Cook, WM. H. 1869. The Physiomedical Dispensatory. Cincinnati: self-published. Digitized version available from http://medherb.com/cook/home.htm.
De Sanctis MT, Cesarone MR, Incandela L, Belcaro G, Ricci A, Griffin M. 2001. Four-week treatment with Essaven gel in diabetic microangiopathy--a placebo-controlled, randomized study. Angiology Dec;52 Suppl 3:S49-55
Diehm C, Vollbrecht D, Amendt K, Comberg HU. 1992. Medical edema protection-clinical benefit in patients with chronic deep vein incompetence. A placebo controlled double blind study. Vasa 21(2):188-92
Duke, James A. 1992. Handbook of phytochemical constituents of GRAS herbs and other economic plants. Boca Raton, FL. CRC Press. Digitized database available from http://www.ars-grin.gov/duke/.
Felter, HW and JU Lloyd. 1893. King's American Dispensatory. Digitized version available from http://www.ibiblio.org/herbmed/eclectic/kings/main.html.
Greeske K, Pohlmann BK.Fortschr. 1996. Horse chestnut seed extract--an effective therapy principle in general practice. Drug therapy of chronic venous insufficiency. Med May 30;114(15):196-200
Grieve, Maude. 1971. A Modern Herbal. New York: Dover Publications.
Heck AM, DeWitt BA, Lukes AL. 2000. Potential interactions between alternative therapies and warfarin.. Am J Health Syst Pharm Jul 1;57(13):1221-7
Hitzenberger G. 1989. The therapeutic effectiveness of chestnut extract. Wien Med Wochenschr Sep 15;139(17):385-9
Incandela L, De Sanctis MT, Cesarone MR, Ricci A, Errichi BM, Dugal M, Belcaro G, Griffin M. 2001. Treatment of superficial vein thrombosis: clinical evaluation of Essaven gel--a placebo-controlled, 8-week, randomized study. Angiology Dec;52 Suppl 3:S69-72
Kronberger L, Golles J. 1969. On the prevention of thrombosis with aesculus extract Med Klin 64(26):1207-9
Masaki H, Sakaki S, Atsumi T, Sakurai H. 1995. Active-oxygen scavenging activity of plant extracts. Biol Pharm Bull Jan;18(1):162-6
Mills, Simon and Kerry Bone. 2000. Principals and Practice of Phytotherapy. London: Churchill Livingstone
Newall, Carol A., Linda A. Anderson and J.D. Phillipson. 1996. Herbal Medicines: A Guide for Health-Care Professionals. London: The Pharmaceutical Press.
Ottillinger B, Greeske K. 2001. Rational therapy of chronic venous insufficiency - chances and limits of the therapeutic use of horse-chestnut seeds extract. BMC Cardiovasc Disord 1(1):5
Popp W, Horak F, Jager S, Reiser K, Wagner C, Zwick H. 1992. Horse chestnut (Aesculus hippocastanum) pollen: a frequent cause of allergic sensitization in urban children. Allergy Aug;47(4 Pt 2):380-3
Przybojewska B, Baranski B, Spiechowicz E, Dziubaltowska E, Szymczak W. 1994. Potential carcinogenicity assessment of alpha-aescin and phenbendasol. Acta Pol Pharm 51(1):89-93
Wetzel D, Menke W, Dieter R, Smasal V, Giannetti B, Bulitta M. 2002. Escin/diethylammonium salicylate/heparin combination gels for the topical treatment of acute impact injuries: a randomised, double blind, placebo controlled, multicentre study. Br J Sports Med Jun;36(3):183-8 |
