- Clinical data 90%
- Efficacy 90%
- Security 90%
- Toxicity 10%
Equiseum calderi Boivin
Whole sterile stems, 20–80 cm long (up to 30 cm long according to the USSR pharmacopoeia 1990 (2)), or fragments of 0.5–2 cm in length, and 3–5 mm in diameter, with 6–18(20) deep longitudinal grooves, light green to greenish-grey, rough to the touch, brittle and crunchy when crushed, hollow and jointed at the nodes, which occur at intervals of about 1.5– 4.5 cm. Vaginas covering the stem nodes are cylindrical, 4–8 mm long, with teeth; the teeth are triangular-lanceolate, dark brown, with whitescaled margins, half as long as vagina, concrescent in groups of 2 or 3. Fracture short, exposing a large central cavity and the vascular canals of the cortex in the stems. Numerous solid branches arranged in whorls, pointing upwards, unbranched, 5–20 cm long, 1–2 mm in diameter, with 4–5 deep grooves. Leaf vaginas on the branches are cylindrical, green and have 4–5 teeth, which represent the extremely reduced leaves; the number of teeth corresponds to the number of grooves on the branches; the teeth are pale green or brownish, oblong-lanceolate, with acuminate apices; half or one third as long as vagina; connected between each other (alternate) scales, forming a specifi c vaginate structure in the nodes of the branches, which is usually called a “sheath”.
Major chemical constituents
Asian and North American varieties contain a large amount of quercetin 3-O-β-d-glucopyranoside (isoquercitrin) and its malonyl esters. Apigeninand luteolin 5-O-glucosides, as well as their malonyl esters are also present. In the European chemotype, the fl avonoids are mainly quercetin 3-Osophoroside together with genkwanin and kaempferol derivatives, among them protogenkwanin 4´-O-β-d-glucopyranoside, genkwanin-5- O-glucoside, kaempferol 3,7-di-O-glucoside, kaempferol-3-O-(6´-Omalonyl-glucoside)-7-O-glucoside, kaempferol-3-O-sophoroside and glycosides of luteolin (among them the 5-glucopyranoside, galuteolin), onitin and onitin-9-O-glucoside. The plant also contains more than 10% inorganic constituents of which two thirds are silicates (which can constitute as much as 15%) and potassium salts. Small amounts of gold (0.03–0.075 ppm) and silver (0.23 ppm) and lanthanides have been reported as well as traces of alkaloids, including nicotine and spermidine-type bases, and palustrine. The sterols β-sitosterol, campesterol, isofucosterol and cholesterol are present. Other constituents reported include methoxypyridine, equisetonin, equisetroside, sapogenin and equisetogenin. In addition, there are saponins, carotenoids, polyenic acids, rare dicarboxylic acids and organic acids (aconitic, arabinonic, caffeic, citric, equisetolic, fumaric, gallic, gluconic, glyceric, malic, malonic, protocatechuic and quinic), and rhodoxanthin, threonic, p-coumaric, 4-hydroxybenzoic and vanillic acid among others. The structures of some characteristic constituents are presented below.
Medicinal uses of Equiseum arvense
Uses supported by clinical data
An open clinical trial has indicated a possible diuretic effect.
Uses described in pharmacopoeias and well-established documents
Equisetum arvense: Used internally for kidney and bladder diseases, oedema and as an adjuvant in slimming diets. It is applied as irrigation therapy for infectious and infl ammatory diseases of the genitourinary tract, and kidney stones. Used externally as supportive treatment for slowhealing wounds.
Uses described in traditional medicine
Symptomatic treatment of chronic swelling of the legs, slow-healing sprains and fractures, irritable skin conditions, gout, rheumatism, arthritis, hepatitis, fractures, sore throat, dermatological problems and haemorrhoids. In folk medicine Herba Equiseti is used as an analgesic, antihypertensive, clotting agent, haemostatic, depurative, astringent, diuretic and anti-infl ammatory. In Indian Ayurvedic medicine it is used for the treatment of infl ammation or benign enlargement of the prostate gland, for urinary incontinence and for enuresis in children.
Antinociceptive and anti-infl ammatory activity An aqueous-ethanol extract of the stems of Equisetum arvense at concentrations of 10, 25, 50 and 100 µg/g, administered intraperitoneally, reduced the writhing induced in mice by acetic acid (49, 57, 93 and 98%, respectively). The results of treatment with the extract were positive but less marked in the formalin and carrageenan paw oedema tests, but were negative in the hotplate test. The antinociceptive and anti-infl ammatory effects of the extract are thus confi rmed in chemical models of nociception in vivo.
Sedative and anticonvulsant effects
In an open-fi eld test in rats, an aqueous-ethanol extract of the aerial parts of Equisetum arvense, at doses of 200 and 400 mg/kg body weight (bw), had anticonvulsant activity. The treatment enhanced the number of falls in the rota-rod test, reducing the time of permanence on the bar. An increase in barbiturate-induced sleeping time was also observed (46% and 74%, at the 200 and 400 mg/kg bw doses, respectively). The extract increased the pentylenetetrazole-induced convulsion latency, diminished the severity of convulsions, reduced the percentage of rats which developed convulsions (25% and 50% at the 200 and 400 mg/kg bw doses, respectively) and protected animals from death, thus confi rming the anticonvulsant effect of the extract.
Intravenous infusion of a hot aqueous extract of the dried aerial parts (dose not stated) to female Wistar rats showed antiurolithiasis activity both in prevention and in treatment of kidney stone formation.
The antibacterial activities of 90–95% ethanol extracts of the dried aerial parts were assessed in vitro. At a concentration of 500 µg/disc, the extracts exhibited weak activity against Bacillus subtilis and Streptococcus faecalis, but were inactive against Escherichia coli, Aerobacter aerogenes, Bacillus globifer, Bacillus mycoides, Proteus morganii, Proteus vulgaris, Pseudomonas aeruginosa, Serratia marcescens and Streptococcus aureus. A methanol extract of the dried leaves at a maximum inhibitory concentration >500 µg/ml was inactive against Mycobacterium avium and Mycobacterium smegmatis in a study using a broth culture method.
The disc diffusion method was also used for the evaluation of the antimicrobial activity of the essential oil from the stems of Equisetum arvense against Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella enteritidis, Aspergillus niger and Candida albicans. A 1:10 dilution of the essential oil was shown to possess a broad spectrum of antimicrobial activity against all strains tested.
A dried extract of the fresh aerial parts was active against Aspergillus fl avus in vitro (concentration not stated). The antifungal activity of an aqueous-ethanol extract of dried stems, at a concentration of 500 g/ ml/agar plate was assessed. The results showed that the extract was inactive against Aspergillus fumigatus, Aspergillus niger, Botrytis cinerea, Penicillium digitatum, Rhizopus nigricans, Trichophyton mentagrophytes, Candida albicans and Saccharomyces pastorianus. A 95% ethanol extract at various concentrations was inactive against Fusarium culmorum, Fusarium solani, Penicillium notatum and Scopulariopsis species. An aqueousmethanol extract of the dried aerial parts inhibited HIV-1 reverse transcriptase activity in cell culture at a concentration of 10%.
An aqueous extract of the dried aerial parts at a concentration of 1 mg/ml signifi cantly inhibited collagen-, thrombin- and ADP-induced platelet aggregation in vitro (91.9%, p < 0.001). This antiaggregatory effect was dose-dependent.
Antioxidant, hepatoprotective and radical scavenging effects
An aqueous extract of the dried aerial parts (30 µl) exhibited radical scavenging effects in cultured lines of microsomes. The antioxidative activity of water and ethanol extracts of the aerial parts was investigated using different methods. The content of total phenolic components was higher in the ethanol extract, but the protein content was higher in the aqueous extract. The extracts had remarkable antioxidative activities, similar to those of 5 mM ascorbic acid. Water extracts showed high superoxide anion radical-scavenging activities. Hydroxyl radicals were effectively scavenged by ethanol extracts. The effects may be due to the presence of vitamins C and E, copper and zinc. Compounds isolated from the methanol extract of the plant (the phenolic petrosin onitin and fl avonoid luteolin) exhibited hepatoprotective activities in vitro against tacrine-induced cytotoxicity in human liver-derived Hep G2 cells, displaying median effective concentrations (EC50) values of 85.8 ± 9.3 µM and 20.2 ± 1.4 µM, respectively. Silybin, used as a positive control, showed an EC50 value of 69.0 ± 3.3 µM. The isolated compounds also showed superoxide scavenging effects (IC50, 35.3 ± 0.2 µM and 5.9 ± 0.3 µM, respectively) and 1,1-diphenyl-2-picrylhydrazyl-2,2-di(4-tert-octylphenyl)–1–picrylhydrazyl free radical scavenging effect (IC50, 35.8 ± 0.4 µM and 22.7 ± 2.8 µM, respectively).
Uterine stimulant activity A weak in vitro uterine stimulant effect of a methanol extract of the aerial parts was observed using isolated uterus (unspecifi ed condition) preparations from female rats at a dose of 5 mg/ml.
A methanol extract of the plant at a median effective dose of 20 µg/ml had a cytotoxic effect in a human leukaemia cell line (L1210). A 10% aqueous extract and a methanol extract at a concentration of 50 µg/ml showed no cytotoxic activity in either HeLa or 9KB cell cultures. Oral administration of the dried entire plant (in rations) at variable concentrations (20% or more) caused an acute vitamin B1 defi ciency (antithiamine activity) in horses within 2–5 weeks, an effect known as equisetosis.
In an open uncontrolled clinical trial, sap from the aerial parts of Herba Equiseti, at a dose of one tablespoon (15 g) three times a day, was tested in patients with cardiac failure and oedema. All patients showed an augmentation of diuresis. In the same study, an infusion of 15 g of the plant in 180 ml of water was given in divided doses (one tablespoon every 2 hours) to a group of patients with oedema. Again, an increase in diuresis was observed in more than 50% of patients.
A cholesterol-rich diet (0.5% cholesterol and 0.15% sodium cholate for 14 days), to which 4% of Herba Equiseti powder had been added, caused dermatitis of the neck, head and back in 65% of rats. The effect was not observed when the rats were fed on a normal diet.
No irrigation therapy (hydrocolon therapy) is recommended in patients with oedema due to impaired heart and kidney function. If signs of hypersensitivity reactions appear, Herba Equiseti must not be used again.
Ingestion of large amounts of Herba Equiseti is not recommended in combination with a cholesterol-rich diet.