Chromenes from Ageratina arsenii and revised structures of two epimeric chromene dimers
TL;DR: Agrostophyllin, the first naturally occurring phenanthropyran derivative, was isolated from the orchid Agroophyllum khasiyanum as mentioned in this paper, and it was shown to be a phenotypic indicator of the presence of humans.
Abstract: Agrostophyllin, the first naturally occurring phenanthropyran derivative, was isolated from the orchid Agrostophyllum khasiyanum . It was shown to b
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TL;DR: Analysis of the aerial part of Ayeratum conyzoides afforded 11 chromenes, sitosterol, (+)-sesamin and caryophyllene oxide, one of which is new and eight of the others obtained for the first time from this species, which has been used both in folk medicine and as an insecticide.
Abstract: -Analysis of the aerial part of Ayeratum conyzoides afforded 11 chromenes, sitosterol, (+)-sesamin and caryophyllene oxide. One chromene is new and eight of the others were obtained for the first time from this species. The ‘C NMR spectral data for four of the chromenes have not been published before. INTRODUCIION Over the last two or three decades, great attention has been focused on the biological activity of natural com- pounds of plant origin for their potential as natural pesticides against phytophagous insects. In Colombia, plants have been used for centuries for their insecticidal. repellent or antifeedant properties in the protection of crops from insect attack [I]. Ageratum conyzoides, a widespread weed in Colombia and elsewhere, known to contain precocene I and precocene II [2,3], has been used both in folk medicine and as an insecticide. A study of the insecticidal activity of various fractions of an n-hexane extract of
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TL;DR: The results show that E. aschenbornianum had gastroProtective activity, that the hexane extract had the highest protective activity, and that encecanescin isolated from this extract was the main active gastroprotective agent.
Abstract: Eupatorium aschenbornianum is considered useful in the treatment of gastric ulcer. In the current study the validity of this practice was tested by using the experimental model of an ethanol induced gastric ulcer in rats. The results show that E. aschenbornianum had gastroprotective activity, that the hexane extract had the highest protective activity (85.65 ± 4.76%), and that encecanescin isolated from this extract was the main active gastroprotective agent. The effect elicited by encecanescin was attenuated by N G -nitro- l -arginine methyl ester, N-ethylmaleimide and indomethacin, which suggests that NO, prostaglandins and sulfydryl groups are involved in the mechanisms of gastroprotective action.
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TL;DR: High-performance liquid chromatography analysis indicated that there are three different chemotypes of white snakeroot from the plant samples analyzed, and elucidation of these chemotypes may explain the sporadic and unpredictable toxicity of white Snakeroot to livestock and humans.
Abstract: Ingestion of white snakeroot (Ageratina altissima) can cause trembles in livestock and milk sickness in humans. The toxicity has been associated with tremetol, a relatively crude, multicomponent lipophilic extract of the plant. In this study, 11 different compounds were isolated from white snakeroot-derived lipophilic extracts from 18 collections. Six of the isolated compounds have not been previously reported to be found in white snakeroot. High-performance liquid chromatography (HPLC) analysis indicated that there are three different chemotypes of white snakeroot from the plant samples analyzed. Elucidation of these chemotypes may explain the sporadic and unpredictable toxicity of white snakeroot to livestock and humans.
26 citations
TL;DR: The isolated chromenes 1 and 3 show a moderate leishmanicidal activity, and the isolated compounds are here reported for the first time in C. pinnatifida.
Abstract: Calea pinnatifida (R. Br.) Less., Asteraceae, is popularly known as “quebra-tudo”, “cipo-cruz” or “aruca”. This species is used in the folk medicine for the treatment of stomach pain, giardiasis and amoebiasis. The aim of this study was to isolate and identify chromenes from leaves of C. pinnatifida and evaluate their leishmanicidal activity. A fraction from leaves of C. pinnatifida was analyzed for their chemical constituents, resulting in the isolation and characterization of four known chromenes: 6-acetyl-7-hydroxy-2,2-dimethylchromene (1), 6-acetyl-7-methoxy-2,2-dimethylchromene (2), 6-(1-hydroxyethyl)-7-methoxy-2,2-dimethylchromene (3) and 6-(1-ethoxyethyl)-7-methoxy-2,2-dimethylchromene (4). Structure identification of isolated compounds involved analysis of spectral data of 1D and 2D-NMR. The isolated compounds are here reported for the first time in C. pinnatifida, and the chromenes 1 and 3 show a moderate leishmanicidal activity.
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References
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TL;DR: In this paper, the authors discuss the biogenetical relationships between the tetrahedron of Helianthella uniflora and the acetophenone derivatives of the genus.
Abstract: Die zum Tribus Heliantheae gehorende Helianthella uniflora enthalt neben Spuren des weitverbreiteten Pentain-ens1 zahlreiche Acetophenon-Derivate(2–12), die alle einen Isopentenyl-Rest als Seitenkette oder als Teil von Ringsystemen besitzen. Die Strukturen ergeben sich aus den spektralen Daten. Ihre biogenetischen Beziehungen werden diskutiert.
New Isopentenyl-acetophenone Derivatives from Helianthella uniflora
Helianthella uniflora belonging to the tribe Heliantheae contains besides traces of the widespread pentayne-ene 1 several acetophenone derivatives all bearing an isopentenyl residue as sidechain or as part of ring systems. The structures are elucidated by their spectral data and the biogenetical relationships are discussed.
99 citations
TL;DR: In this paper, two species of the genus Flourensia have been investigated and their structures have been elucidated by spectroscopic methods, besides the already known characteristic 4-hydroxyacetophenone derivatives.
Abstract: Die Untersuchung von zwei Arten der Gattung Flourensia zeigt, das hier neben bereits bekannten, fur die Tribus charakteristischen Acetylenverbindungen vor allem 4-Hydroxyacetophenon-Derivate vorkommen. 14 Verbindungen (2–4, 8, 11, 13, 14, 18–23 und 25) sind bisher noch nicht isoliert worden. Ihre Konstitutionen werden durch spektroskopische Methoden geklart.
On Constituents of the Genus Flourensia
The investigation of two species of the genus Flourensia yields, besides the already known characteristic acetylenic compounds of the tribe, mainly 4-hydroxyacetophenone derivatives. 14 compounds (2–4, 8, 11, 13, 14, 18–23, and 25) have not been isolated before. Their structures have been elucidated by spectroscopic methods.
60 citations
TL;DR: The roots of Gerbera species contain known polyynes 1 and 2 as discussed by the authors, and two new coumarins (4 and 7) were isolated, the structures being elucidated by spectroscopic data as well as by synthesis.
Abstract: Die Wurzeln mehrerer Gerbera-Arten enthalten die bekannten Polyine 1 und 2. Aus Gerbera crocea wurden zusatzlich das Acetophenon-Derivat 3 und zwei neue Cumarine (4 und 7) isoliert, deren Strukturen durch spektroskopische Daten sowie durch Synthese geklart werden.
Naturally Occuring Coumarin Derivatives, IX1) On the Constituents of the Genus Gerbera
The roots of several Gerbera species contain the known polyynes 1 and 2. In addition from Gerbera crocea the acetophenon derivative 3 and two new coumarins (4 and 7) were isolated, the structures being elucidated by spectroscopic data as well as by synthesis.
41 citations
TL;DR: In this paper, the structure of Encelia canescens was elucidated hy high field 1 H NMR spectroscopy, revealing four new dimeric p-hydroxyacetophenone derivatives, two epimeric chromene dimers and two Epimeric mixed dimers of euparin and encecalin.
Abstract: The investigation of Encelia canescens afforded, in addition to several known compounds, four new dimeric p -hydroxyacetophenone derivatives, two epimeric chromene dimers and two epimeric mixed dimers of euparin and encecalin. Furthermore, derivatives of tremetone and of encecalin were present. The structures were elucidated hy high field 1 H NMR spectroscopy.
18 citations
TL;DR: Ageratina tomentella has been investigated for sesquiterpene lactones, including 11,13-dehydro-8β-tigloyloxy-eleman-12-oic acid as discussed by the authors.
Abstract: An investigation of Ageratina tomentella yielded, besides the two known sesquiterpene lactones hiyodorilactone C acetate and 5″-desoxy-3- epi -4″-hydroxyprovincialin, two new sesquiterpenes, 11,13-dehydro-8β-tigloyloxy-eleman-12-oic acid and 8- epi -8-[5′-(4″-hydroxytigloyloxy)-tigloyloxy]-rupicolin A. The structures of the new compounds were elucidated by spectroscopic methods.
10 citations