Equisetum Species Research Articles

Styrylpyrone glucosides from Equisetum

Two styrylpyrone glucosides, 3′-deoxyequisetumpyrone ( 3,4- hydroxy-6-(4′- hydroxy-E- styryl)-2- pyron-3-O-β- d-glucopyranoside and 4′-O- methylequisetumpyrone(3,4- hydroxy-6-(3′- hydroxy-4′- methoxy-E- styryl)-2- pyron-3-O-β- d-glucopyranoside ) have been isolated from the rhizomes of Equisetum arvense. The structures of the new derivatives were elucidated spectroscopically. These compounds are accumulated as the main phenolics in rhizomes and gametophytes of all Equisetum species. In these organs, they represent a sink for compounds derived from hydroxycinnamoyl CoA esters and malonyl units, whereas sporophytic shoots contain no styrylpyrones but a considerable variety of flavonoid glycosides.

Interspecific and intraspecific variation of phenolics in the genus Equisetum subgenus Equisetum

The patterns of phenolics in methanolic extracts from the overground sporophytes of all species of the subgenus Equisetum are given. From the interspecific variation in the accumulated flavonoid glycosides and other phenolics, all taxa of the subgenus can be distinguished. The retention characteristics in a standard HPLC method and maxima of the on-line UV spectra of all compounds detected are given. The HPLC method allows the quantification of phenolics in herbal remedies containing Equisetum, as well as in the crude drug material and therefore could be useful for both quality control and chemotaxonomic studies. All species show quantitative and qualitative variations during plant development. As an example, we present chromatograms of different developmental stages of E. arvense and accumulation dynamics of some phenols in that species. Phenolics accumulating in different organs of the plant are distinct. Apart from the spores, only diploid tissues are able to accumulate flavonoids. The haploid vegetative gametophytes accumulate caffeic acid esters and styrylpyrones in high contents. The rhizomes are also free of flavonoids, but contain various styrylpyrones, besides hydroxycinnamoyl esters. Styrylpyrones seem to replace flavonoids in gametophytes and sporophytic rhizomes of Equisetum species.

Vesicular-arbuscular mycorrhizas of Equisetum species in Norway and the U.S.A.: occurrence and mycotrophy

Typical vesicular-arbuscular mycorrhizal structures occurred in the sporophytes of Equisetum species (11 out of 12 species) collected in Norway and U.S.A. Plants growing in wet (hydric) habitats, sampled in the U.S.A. and Norway, had lower levels of colonization by vesicular-arbuscular mycorrhizal fungi than plants growing in mesic/dry-mesic habitats. Colonization levels ranged from 0 to 46% of the root length. Only E. variegatum found growing in a wet habitat in Illinois was consistently non-mycorrhizal. Equisetum species appear to be facultatively mycotrophic; the degree of mycotrophy may depend on habitat conditions. The world-wide warming and change from hydric to mesic conditions, during the late Carboniferous period and thereafter, probably contributed to the demise of the Equisetales. The demise of the Equisetales was less likely influenced by the mycotrophic nature of higher plants, ferns, cycads and pines.

Occurrence of Jasmonic Acid, Related Compounds and Abscisic Acid in Fertile and Sterile Fronds of Three Equisetum Species

In fertile fronds of Equisetum arvense the plant growth regulator jasmonic acid and its metabolite 6epi-7-iso-cucurbic acid were identified by physical methods. Jasmonic acid dominated before spore scattering and 6-epi-7-iso-cucurbic acid thereafter. In fertile fronds of Equisetum sylvaticum 4,5didehydro-jasmonic acid was found to be the major component of the jasmonic acid-like compounds. In fertile and sterile fronds of Equisetum arvense as well as in fertile fronds of Equisetum sylvaticum and Equisetum fluviatile abscisic acid was unequivocally identified. In fertile fronds its level exceeded that of sterile fronds, and it was much higher before spore scattering than thereafter.

GENETIC EVIDENCE FOR DIPLOIDY IN EQUISETUM

Sporophytes and gametophytes of Equisetum arvense, E. laevigatum, and E. telmateia were analyzed using enzyme electrophoresis to estimate isozyme number. Despite their uniformly high chromosome numbers (2n = 216), these three species exhibited isozyme numbers typical of diploid seed plants for the enzymes AAT, ADH, ALD, GDH, [NADP]IDH, LAP, MDH, [NADP]ME, PGI, PGM, SkDH, and 6PGDH. All three species exhibited an additional isozyme for TPI. There is, therefore, no genetic evidence for low base numbers such as x = 9 and x = 12 suggested for Equisetum. Intact chloroplasts were isolated from E. arvense and the chloroplast extract compared electrophoretically to whole plant extracts. The single enzymes observed for LAP, GDH, [NADP]IDH, and [NADP]ME were absent from the chloroplast extract. Isozymes AAT‐1, ALD‐2, MDH‐3, PGI‐1, PGM‐2, SkDH‐2, 6PGDH‐2, TPI‐2, and TPI‐3 were active in the chloroplast fraction; 6PGDH‐1, PGI‐2, PGM‐1, and TPI‐1 were lacking from the chloroplast fraction and were considered cytosolic. Isozymes AAT‐2, MDH‐1, MDH‐2, MDH‐4, and SkDH‐1 were also lacking from the chloroplast fraction but because AAT, MDH, and SkDH have been reported from several subcellular compartments, their localization is unknown. These findings indicate that isozymes in Equisetum species are subcellularly compartmentalized as has also been demonstrated for homosporous ferns, gymnosperms, and angiosperms.

Nitrogen-fixing activities associated with rhizomes and roots of Equisetum species

High rates of nitrogen fixation (acetylene reduction) were associated with Equisetum arvense L. and three other species of the same genus. Excised rhizomes and roots were assayed by incubation under ambient air and N 2-enriched air ( pO 2 0.10atm), using the acetylene reduction method. There was a lag of about 1 day before high activity was observed under a pO 2 of 0.10 atm, but under ambient air the lag was longer and varied from sample to sample. The duration of this lag usually coincided with that required for the establishment of a definite pO 2 level (a threshold value) in the incubation atmosphere. The threshold pO 2 value was about 0.15 atm for E. arvense, E. palustre, and E. hyemale, and 0.10 atm for E. ramosissimum. On incubation of the plant materials, acetylene reduction activity (ARA) increased gradually as the atmospheric pO 2 decreased, and maximum ARA was observed under a definite pO 2 value in the range from 0.04 to 0.01 atm. The highest value was 69nmol C 2H 44 formed g −1 fresh wt h −1 with a sample of E. arvense at pO 2 0.03 atm. When the pO 2 decreased below 0.01 atm, ARA decreased very rapidly and finally ceased. Several strains of N 2-fixing bacteria were isolated from rhizomes and roots of E. arvense and all were classified as members of the family Enterobacteriaceae.

Gametophytes of Equisetum diffusum

Equisetum gametophytes have been studied for many years (Buchtien, 1887; Hauke, 1967, 1968, 1969, 1971, 1977; Duckett, 1970, 1972, 1973, 1977; and literature cited in these references). The gametophytes of all Equisetum species except E. diffusum Don have been described. In a recent monograph of Equisetum subg. Equisetum (Hauke, 1979), I presented an evolutionary sequence of species arranged according to gametophyte specialization which did not parallel the sequence based on sporophyte specialization. Subsequently I was able to obtain viable spores ofE. diffusum and to culture them. The purpose of this paper is to describe gametophytes of Equisetum diffusum and to discuss their evolutionary implications. MATERIALS AND METHODS

A comparative study of crude drugs in Southeast Asia. X. Crude drugs derived from Equisetum species.

This article reports histological study was made for crude drugs derived from Equisetum species. Six samples were examined and all were identified clearly : S 378 muzei( ?? ?? ), KL 489 muxi( ?? ?? ), and188 muzei in Formosa( ?? ??, ?? ?? ) were identified to be E. hiemale L. var. affine (ENGL.) A. A. EATON ; S 400 (S 611) jiegucao( ?? ?? ?? ) andKL 490 bogucao( ?? ?? ?? ) were E. ramosissimum DESF. subsp. debile (ROXB). HAUKE ;30-40 cola de caballowas E. giganteum L.

Distribution of equisetolic acid in the equisetales

Equisetolic acid has been found in the spores and cones of E. telmateia and E. arvense but not in other parts of these species. It could not be detected in five other contemporary Equisetum species, nor in two fossil compressions ( E. columnare, E. lyelli)

Flavonoids of Equisetum species

A survey of Equisetum species found in British Columbia showed that they all contained flavonoid di- and tri-glycosides especially those of kaempferol and, to a lesser extent, those of quercetin. Three other minor flavonoids were identified as gossypitrin, herbacitrin and apigenin-4′-glucoside.