Herb profile/Horsetail/Equisetum arvense

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Horsetail Herb Latin Name Equisetum arvense Pharmacopeial Name Equiseti herba Other Names bottlebrush, common horsetail, field horsetail, shave grass, shavetail grass OverviewHorsetail is a dimorphic perennial plant common throughout the temperate northern hemisphere in Asia, Europe, and North America. Two distinct chemotypes have been identified, one from Europe and the other from Asia and North America, which can be differentiated chemically by the detection of certain characteristic flavonoids unique to each chemotype (Leung and Foster, 1996). The material of commerce comes from Albania, Hungary, Poland, the former Yugoslavia, the United Kingdom, and the former USSR (BHP, 1996; Wichtl and Bisset, 1994). A relative to ferns, horsetails reproduce through spore transport, not by seeds (Tyler, 1993). Horsetail's therapeutic use in Europe dates back to at least ancient Roman and Greek medicine; it was recorded by Greek physician Claudius Galenus (130–200 C.E.). The genus name Equisetum is derived from the Latin equus meaning horse and seta meaning bristle (Grieve, 1979). Nicholas Culpepper, the seventeenth century English herbalist, indicated horsetail juice or decoction as a remedy to stop bleeding, to treat ulcers, wounds, ruptures and inflammations in the skin, as well as for kidney stones and strangury (painful and interrupted urination in drops) (Grieve, 1979). In Indian Ayurvedic medicine, horsetail is used as a treatment for inflammation or benign enlargement of the prostate gland, for urinary incontinence, and for enuresis (involuntary discharge of urine) of children (Karnick, 1994). In the nineteenth century, American Eclectic physicians used it to treat gonorrhea, prostatitis, and enuresis (Ellingwood, 1983). Some of its uses in North American aboriginal medicine are comparable to the Asian and European uses. The Cherokee people prepared the infusion as a kidney aid. The Chippewa Ojibwe people prepared a decoction of the stems as a urinary aid to treat dysuria (painful or difficult urination). The Okanagan-Colville people prepared an infusion of the stems as a diuretic drug to stimulate the kidneys. The Potawatomi people prepared an infusion as a urinary aid for bladder trouble (Moerman, 1998). The approved modern therapeutic applications for horsetail herb are supportable based on its long history of clinical use in well established systems of traditional medicine, phytochemical investigations, and pharmacological studies. Its diuretic actions are mild, according to studies, and are attributed to horsetail's flavonoid and saponin constituents (Bradley, 1992; Tyler, 1993). The plant's actions in healing bones and strengthening connective tissue are thought to be due to silicic acid. The mineral content is significant: silica and silicic acid concentrations in the stems are usually from five to eight percent, which is probably why the hollow weeds were used to scour pots, and why horsetail is also called scouring rush (Tyler, 1993). In Germany, horsetail is official in the German Pharmacopoeia, approved in the Commission E monographs, and the tea form is official in the German Standard License monographs (BAnz, 1998; Braun et al., 1997; DAB, 1998). It is used as a monopreparation and also as a component of various prepared diuretic drugs (Wichtl and Bisset, 1994). For example, it is a component in Kneipp® "Blasen- und Nieren-Tee" (Kidney and Bladder Tea) composed of 30% horsetail herb, 25% giant goldenrod herb (S. gigantea), 20% birch leaf (Betula alba), 10% spiny restharrow root (Ononis spinosa), 5% rose hip shells (Rosa canina), 5% peppermint leaf (Mentha x piperita), and 5% marigold blossoms (Calendula officinalis) (Kneipp®, 1996). In the United States, horsetail is commonly found as a component of dietary supplement products in fluid (infusion or tincture) or solid (capsules and tablets) dosage forms for its mineral nutrient content and/or for its diuretic action. Pharmacopeial grade horsetail herb consists of the dried, green, sterile stems of Equisetum arvense L. in whole, cut or powdered forms. Botanical identity must be carried out by thin-layer chromatography (TLC), macroscopic and microscopic examinations, and organoleptic evaluations. It must contain no more than 3% blackish rhizome fragments and maximum 5% stems or branches from hybrids and/or from other Equisetum species. The fertile cambium may not be present (DAB, 1998; Wichtl and Bisset, 1994). It must contain not less than 15% water-soluble extractive (BHP, 1996; Karnick, 1994). DescriptionHorsetail consists of the fresh or dried, green, sterile stems of E. arvense L. [Fam. Equisetaceae] and its preparations in effective dosage. The herb contains silicic acid and flavonoids. Chemistry and PharmacologyConstituents include 10–20% minerals, of which over 66% are silicic acids and silicates, plus potassium, aluminum, and manganese; 0.3–1% flavonoids, mainly quercetin glycosides (quercetin 3-glucoside and its malonyl esters); phenolic acids, including up to 0.008% di-E-caffeoyl-meso-tartaric acid, plus methyl esters of protocatechuic and caffeic acids; alkaloids (traces of nicotine); polyenic acids and rare dicarboxylic acids; and phytosterols (Bradley, 1992; Hänsel et al., 1992–1994; Leung and Foster, 1996; Meyer-Buchtela, 1999; Wichtl and Bisset, 1994). The Commission E reported mild diuretic properties. The British Herbal Compendium reported weak diuretic, hemostyptic (an astringent that stops bleeding), vulnerary (wound healing) and mild leukocytosis causing (increases leukocyte count in the blood) actions (Bradley, 1992). UsesThe Commission E approved internal use of horsetail herb in irrigation therapy for post-traumatic and static edema and for bacterial infections and inflammation of the lower urinary tract and renal gravel. Externally, horsetail is indicated as supportive to poorly healing wounds. The German Standard License horsetail tea monograph allows the same indications for use as those reported in the Commission E monograph (Braun et al., 1997). In France, it is indicated for use to promote renal and digestive elimination functions and as an adjuvant in slimming diets (Bradley, 1992; Bruneton, 1995; DPM, 1992). The British Herbal Compendium indicates its internal use for inflammation or mild infections of the genito-urinary tract and external use for poorly healing wounds (Bradley, 1992). ContraindicationsNone known. Note: No irrigation therapy in the case of edema due to impaired heart and kidney function. Side EffectsNone known. Use During Pregnancy and LactationNo restrictions known. Interactions with Other DrugsNone known. Dosage and AdministrationUnless otherwise prescribed: 6 g per day of cut herb for infusions and other equivalent galenical preparations for oral administration. For irrigation therapy, ensure an abundant fluid intake. External: Cut herb for decoctions and other equivalent galenical preparations. Internal: Decoction: Pour 150 ml boiling water over 2 g and continue boiling for 5 minutes, then allow to steep for another 10 to 15 minutes before straining; take three times daily (Wichtl and Bisset, 1994). Infusion: Steep 2 g of herb in 150 ml boiled water for 10 to15 minutes; take three times daily (Braun et al., 1997). [Note: 34% of the potentially available flavonoids are yielded into the tea after 5 minutes of steeping and 40% are released after 10 minutes (Meyer-Buchtela, 1999).] Cold Macerate: Soak 2 g of herb in 150 ml cold water for 10 to 12 hours; take three times daily (Meyer-Buchtela, 1999; Wichtl and Bisset, 1994). Fluidextract 1:1 (g/ml): 2 ml, three times daily. Tincture 1:5 (g/ml): 10 ml, three times daily. External: Bath additive: Add 2 g herb per 1 liter hot bathwater and allow to steep one hour before bathing (Hänsel et al., 1992–1994; Meyer-Buchtela, 1999). Decoction: To prepare a decoction for use in making a cataplasm or compress, boil 10 g herb in 1 liter water for 10 to 15 minutes (Braun et al., 1997; Meyer-Buchtela, 1999). Cataplasm: Semi-solid paste prepared from horsetail aqueous decoction for a moist-heat direct application to the skin; used like a poultice to remove deep-seated inflammation. Compress: Saturate a stupe with hot semi-solid preparation containing horsetail aqueous decoction; fold and apply firmly for a moist-heat direct application to the skin to relieve pain or inflammation. Note: The herb in powdered form is not recommended for children or for prolonged use due to the inorganic silica content. Toxicity of the herb was found to be similar to nicotine poisoning in children who chewed the stem (McGuffin et al., 1997). Source:onhealth.webmd.comGet your FREE download of MSN Explorer at http://explorer.msn.com