Equisetum species

These are extremely rare natural products. Among the flavones, 6-chloroapigenin is the only compound of this type occurring naturally. It had been isolated in 1980 from an Equisetum species.The flavonol chlorflavonin (5,2 -diOH-3,7,8-triOMe-3 -chloroflavone) had been isolated from Aspergillus Candidas already in 1969. Since then, only the 7-chloroderivatives... 

Fig. 18 TLC synopsis of Equisetum species (see Drug list, 7.1.4, flavonoid pattern ),...

Equiseti herba (8,9) Trade samples are often mixtures of various Equisetum species. In the upper R, range sample 8 shows identical zones with E, arvense, but additional zones in the lower R, range similar to Equisetum species (6,3,4). Drug sample 9 is almost a 1 1 mixture of 1 and 3. 

Adulteration of horsetail with E. palustre, which contains the potentially toxic alkaloid palustrin, is widely reported (Langhammer et al. 1972 Wichtl 2004), and hybrids of E. arvense and other Equisetum species have been reported, further challenging correct identification. The toxicity of palustrin-containing species in humans is not known, as... 

Multiple cases of cattle and horse poisoning by Equisetum species have been reported in the literature, with some reports indicating E. arvense as the causative species (Groh 1930 Hansen 1928 Hudson 1924 Jones 1901 Pammel 1921 Rapp 1954 Rich 1902). A review of these reports indicated that uncertainty in the identification of the species makes the reports difficult to interpret (Mills and Bone 2005). A 1904 study on the toxicity of various species of Equisetum in livestock indicated that E. arvense was nontoxic but that the botanically similar E. palustre demonstrated toxicity (Long 1924). 

Components The shoots contain large amounts of silicic acid in the cell walls (up to 8%). The fatty acids found in H. t. contain 23-30 C-atoms. Secondary constituents of Equisetum species include alkaloids (e.g., palustrine), numerous flavones (e.g., 6-chlo-roapigenin), and flavonols as well as their dihydro derivatives, phenol- and hydroxycinnamic acids (e.g., 2,3-0-di-( )-caffeoyl-mew-tartaric acid in E. ar-vense), indanone derivatives and novel styrylpyrones such as, e.g., equisetumpyrone. The secondary product pattern reveals interspecific and intraspecific differences whereby the latter depend on the state of development. ... 

Table III is a summary of the alkaloids isolated from a number of Equisetum species (see Volume V, p. 307). In addition, all but E. robustum were shown to contain dimethyl sulfone.

A study of four Mexican Equisetum species revealed that ehloroform extracts of E. hymale var. affine had the greatest diuretic activity, more effective than spironolactone, furose-mide, and hydrochlorothiazide. An increase in excretion of sodium, chloride, and potassium, with a rise in urine pH was also... 

E. palustre L., which contains the alkaloid palustrine, is also toxic to livestock. The German Pharmacopoeia requires examination of E. arvense for adulteration with other Equisetum species, especially E. palustre (frohne and pfander). a critical review of the German Pharmacopeial methods, along with... 

Table 2 The effects of water and ethanol extracts from allelopathically active plant species on the germination of Equisetum arvense microspores (amount of red-fluorescing microspores, % of control)... 

Alkaloids are known in the family, but in the present study, only two positive tests were obtained with 12 samples including eight species Equisetum ramosissimum and one unidentified. The rest were negative E. arvense, E. hogoiense, E. laevigalum, Equisetum spp. (2), E. lelmaleia. 

Very little quantitative data have been reported in relation to the concentration of aconitic acid in various plant juices other than from cane sorghum and from sugar cane varieties although the acid has been identified in the juices from many other species of plants. It has been isolated from a variety of species of Aconitum,1-7-11 Delphinium,9 12 and Equisetum,2 3-l2a and also from Achillea millefolium,Adonis vernalis,u,lb Helinus ovatus,16 Sansevieria zeylancia,17 wheat,18 and from barley, maize, oat and rye plants.19 It can indeed be said that aconitic acid, at least qualitatively, is a commonly occurring constituent in the plant kingdom. 

Aconitic Acid occurs in the leaves and tubers of Aconitum napellus L. (Fam. Ranunculaceae) and various species of Achillea and Equisetum, in beet root, and in sugar cane. It may be synthesized by the dehydration of citric acid by sulfuric or methanesulfonic acid. Aconitic Acid from the above sources has the trans configuration. It has a melting point of 195° to 200° with decomposition. It is practically odorless and has a winy taste. It is soluble in water and in alcohol and is slightly soluble in ether. 

In some varieties the fruiting cone is borne on the ordinary stem, in others on a special stem of slightly different form. In the latter the spores are provided with elaters, which, being hygroscopic, coil and uncoil with increase or decrease in the amount of moisture present, thus aiding in the ejection of spores from the sporangia. The number of species is small and included under one genus, Equisetum. (See fig. 158.)... 

Wallace et al. (1977), in describing symptoms of titanium toxicity, reported that chlorotic and necrotic spots occurred on the leaves of bush beans containing about 200 mg Ti kg DM. Titanium levels in plants range from 0.15 to 6.5 mgkg DM, and some species of plants, including horsetail Equisetum sp.) and nettle Urtica sp.), as well as certain diatoms, can accumulate much higher levels of the element (Kabata-Pendias 2000). Various titanium compounds were shown not to be mutagenic in Bacillus subtilis (Nordman and Berlin 1986). 

In order to understand the roles that biomolecules play in the fabrication of nano- and micro-structured biosilica, organic material associated with biosilica was identified, isolated and studied. In addition to some earlier studies, the following recent findings are of particular importance. Several proteins isolated from plants, diatom species (silafFins) and sponges (silicateins) have previously been shown to facilitate the in vitro polymeri tion of silica from a silicon catecholate complex, tetramethoxysilane (TMOS) and tetra-ethoxysilane (TEOS), respectively. Bioextracts from plants Equisetum talmateia and Equisetum arvense have been isolated from biosilica. These... 

Aconitio Acid—CsH.(COOH)3—exists in its Ca salt in the different species of aconitum and of equisetum. It forms white, crystalline crusts, or by slow crystallization w hite plates or prisms odorless sour soluble in water, alcohol and ether fuses at 186° (366°.8 P.). Its salts are soluble and crystalline. It is decomposed by heat into itaconic acid and COa. 

Horse tail (family Equisetaceae). The plant class of the Equisetales belonging to the pteridophytes ferns (Filicatae), reached the apex of its development in the Carbonaceous era with tree-like members but is now extinct except for the family Equisetaceae. This comprises the single genus Equisetum (horse tail) with about 30 species distributed from the tropics to the polar regions. They are all shrub-like, herbaceous plants and can grow up to between 0.1 and a maximum of 12 m ( . giganteum). 

Nicotine belongs to the Solanaceae (nightshade family) alkaloids. It is the principal alkaloid of tobacco, but occurs also as a trace component in Acacia, Sedum, Erythroxylum, Equisetum and Lycopodium species. The two economically most important tobacco species are Nicotiana tabacum (Virginia tobacco), which grows up to 3 metres in height, has reddish flowers and lancet-shaped, pointed leaves, and the 1.2-metre high Nicotiana rustica species (known in South America as Mapacho and in Vietnam as Thuoc Lao), with greenish-yellow flowers and egg-shaped leaves (Fig. 5.204). 

PhilUpson JD, Melville C (1960) An investigation of the alkaloids of some British species of Equisetum. J Pharm Pharmacol 12 506-508 Pictet A, Genequand P (1897) Ueber die Jodmethylate des Nicotins. Ber 30 2117-2125 Pictet A, Rotschy A (1901) Uber neue Alkaloide des Tabaks. Ber 34 696-708 Pictet A, Rotschy A (1904) Synthese des Nicotins. Ber 37 1225-1235 Pinner A (1893) Ueber Nicotin (5.Mitt.) Ber 26 292-305 Pinner A (1895) Ueber Nicotin (9.Mitt.) Ber 28 456-465... 

Equisetum hybrids are extremely variable in morphological features. It has been suggested that hybrid parent species can be verified with analysis of fiavonoid patterns. ... 

Among higher terrestrial plants, horsetail species Equisetum spp.) are well known as strong accumulators of silicon. In addition to X-ray element mapping. 

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