| 1. |
- Ashitani, Tatsuya, et al.
(författare)
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Reaction mechanism of direct episulfidation of caryophyllene and humulene
- 2008
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Ingår i: Natural Product Research. - : Informa UK Limited. - 1478-6419 .- 1478-6427. ; 22:6, s. 495-498
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Tidskriftsartikel (refereegranskat)abstract
- Direct episulfidations of caryophyllene or humulene with elemental sulfur were examined by means of gas chromatography. Caryophyllene-6,7-episulfide was formed at an early stage in a reaction of the caryophyllene and elemental sulfur at 120C. Caryophyllene-3,6-sulfide and polymer compounds were formed after the episulfidation. Formations of the these compounds were related to the disappearance of the caryophyllene-6,7-episulfide. Isomerization from the caryophyllene to isocaryophyllene was also observed during the reaction. In the reaction of humulene with elemental sulfur, humulene-6,7-episulfide was initially produced and then converted to humulene-9,10-episulfide. It was assumed that the polymer compound in the reaction of humulene with sulfur was related to the disappearance of the both humulene episulfides.
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| 2. |
- El-Seedi, Hesham R
(författare)
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Antimicrobial triterpenes from Poulsenia armata Miq. Standl.
- 2005
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Ingår i: Natural Product Research. - : Informa UK Limited. - 1478-6419 .- 1478-6427. ; 19:2, s. 197-202
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Tidskriftsartikel (refereegranskat)abstract
- Crude petroleum ether extract from the bark of Poulsenia armata showed antimicrobial activity. Activity-guided fractionation led to the isolation and structure elucidation of two active new triterpene derivatives, the stearate of glut-5-en-3beta-ol (1) and 3beta,28-diacetoxyurs-12-ene (4), for the first time as naturally occurring compounds. Compound 4 has previously been synthesized. The structures were determined by 1D- and 2D-NMR spectroscopy, mass spectrometry and chemical transformations. This is the first report on the chemistry and pharmacology of the genus.
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| 3. |
- Ibrahim, Nabaweya Ali, et al.
(författare)
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Phytochemical investigation and hepatoprotective activity of Cupressus sempervirens L. leaves growing in Egypt.
- 2007
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Ingår i: Natural Product Research. - : Informa UK Limited. - 1478-6419 .- 1478-6427. ; 21:10, s. 857-866
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Tidskriftsartikel (refereegranskat)abstract
- Three phenolic compounds cosmosiin, caffeic acid, and p-coumaric acid were isolated for the first time from the leaves of Cupressus sempervirens L., together with cupressuflavone, amentoflavone, rutin, quercitrin, quercetin, myricitrin. The isolated compounds were identified using (1)H- and (13)C-NMR spectra. The hepatoprotective activity of the MeOH extract was carried out in liver homogenate of normal and CCl(4)-treated rats; a significant decrease in glutamate oxaloacetate transaminase, glutamate pyruvate transaminase, cholesterol level, and triglycerides, while a significant increase in the total protein level, was observed after the oral administration of MeOH extract. The free radical scavenging activity against stable 2,2-diphenyl-2-picrylhydrazyl (DPPH*) was measured for MeOH extract and some of the isolated phenolic compounds in comparison with alpha-tocopherol and butylated hydroxy toluene as standard antioxidants using ESR technique, showed high antioxidant activity for quercetin, rutin, caffeic acid, and p-coumaric acid.
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