Search results for: Ermias Dagne

Items from 1 to 14 out of 14 results

article

Four Lignans from Commiphora erlangeriana

Aman Dekebo, Martin Lang, Kurt Polborn, Ermias Dagne, more

Journal of Natural Products > 2002 > 65 > 9 > 1252 - 1257

article

Furanosesquiterpenes from Commiphora sphaerocarpa and related adulterants of true myrrh

Aman Dekebo, Ermias Dagne, Olov Sterner

Fitoterapia > 2002 > 73 > 1 > 48-55

A new furanosesquiterpene, (1E)-8,12-epoxygermacra-1,7,10,11-tetraen-6-one (3), was isolated from the resin of Commiphora sphaerocarpa together with the known compounds curzerenone (1), furanodienone (2), (1E)-3-methoxy-8,12-epoxygermacra-1,7,10,11-tetraen-6-one (4), (1(10)E,2R*,4R*)-2-methoxy-8,12-epoxygermacra- 1(10),7,11-trien-6-one (5), and dihydropyrocurzerenone (6). Hydrodistillates of the resins...

article

Two octanordammarane triterpenes from Commiphora kua

Aman Dekebo, Ermias Dagne, Lars K. Hansen, Odd R. Gautun, more

Phytochemistry > 2002 > 59 > 4 > 399-403

The resin of Commiphora kwo yielded two new octanordammarane triterpenes namely 15α-hydroxymansumbinone and 28-acetoxy-15α-hydroxymansumbinone, along with the four known compounds, mansumbinone, mansumbinol, (16S, 20R)-dihydroxydammar-24-en-3-one and T-cadinol. These structures were elucidated by spectroscopic techniques, including 1D and 2D NMR spectroscopy, and X-ray analysis.

article

Crystal structures of two furanosesquiterpenes from Commiphora sphaerocarpa

Aman Dekebo, Ermias Dagne, Lars K. Hansen, Odd R. Gautun, more

Tetrahedron Letters > 2000 > 41 > 50 > 9875-9878

The relative stereochemistry of a furanosesquiterpene, reported previously from myrrh, but isolated here from Commiphora sphaerocarpa is determined for the first time as (1(10)E,2R*,4R*)-2-methoxy-8,12-epoxygermacra-1(10),7,11-trien-6-one. Likewise the stereochemistry of furanodienone was established by NMR and X-ray crystallography as (1(10)E,4E)-8,12-epoxygermacra-1(10),4,7,11-tetraen-6-one.

article

Chromones and anthrones from Aloe marlothii and Aloe rupestris

Daniel Bisrat, Ermias Dagne, Ben-Erik van Wyk, Alvaro Viljoen

Phytochemistry > 2000 > 55 > 8 > 949-952

A phytochemical investigation of the leaf exudate of Aloe marlothii has resulted in the isolation of a new chromone (7-O-methylaloeresin A) and a new anthrone (5-hydroxyaloin A 6'-O-acetate). Furthermore 7-O-methylaloesin was isolated as a natural product for the first time from the leaf exudate of Aloe rupestris. The structure elucidation of these compounds was based on spectral data including 2D...

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O-geranylated isoflavones and a 3-phenylcoumarin from Millettia griffoniana

Emanuel Yankep, Zacharias T. Fomum, Daniel Bisrat, Ermias Dagne, more

Phytochemistry > 1998 > 49 > 8 > 2521-2523

Root bark of Millettia griffoniana yielded two new O-geranylated isoflavones and a new 3-phenylcoumarin. Their structures were determined on the basis of spectral evidence as 4'-methoxy-7-O-[(E)-3-methyl-7-hydroxymethyl-2,6-octadienyl]isoflavone, 3',4'-dihydroxy-7-O-[(E)-3,7-dimethyl-2,6-octadienyl]isoflavone and 4-hydroxy-5,6,7-trimethoxy-3-(3',4'-methylenedioxy)phenylcoumarin.

article

A C,O-diglucosylated oxanthrone from Aloe littoralis

Ermias Dagne, Daniel Bisrat, Carles Codina, Jaume Bastida

Phytochemistry > 1998 > 48 > 5 > 903-905

A new C,O-diglucosylated oxanthrone, named littoraloside, has been isolated from the leaf exudate of Aloe littoralis, along with the previously reported compounds, littoraloin, deacetyllittoraloin and 10-hydroxyaloin B. The structure, including the stereochemistry of littoraloside was established on the basis of spectral analyses, as well as by conversion to deacetyllittoraloin and to 10-hydroxyaloin...

article

An O-geranylated isoflavone from Millettia griffoniana

Emmauel Yankep, Z.T. Fomum, Ermias Dagne

Phytochemistry > 1997 > 46 > 3 > 591-593

A new O-geranylated isoflavone, 3',4'-methylenedioxy-7-O-[(E)-3,7-dimethyl-2,6-octadienyl] isoflavone, 7-O-geranylpseudobaptigenin, was isolated in addition to seven other known compounds from the root bark of Millettia griffoniana. The structure of the new compound was elucidated on the basis of spectroscopic data.

article

Anthrones from Aloe microstigma

Ermias Dagne, Daniel Bisrat, Ben-Erik Van Wyk, Alvaro Viljoen, more

Phytochemistry > 1997 > 44 > 7 > 1271-1274

5-Hydroxyaloin A and a new anthrone, named as microstigmin A, were isolated from the leaf exudate of Aloe microstigma. The structure of microstigmin A was determined by spectroscopic techniques as well as by conversion into 5-hydroxyaloin A.

article

Three oxanthrones from Aloe littoralis

Ermias Dagne, Ben-Erik Van Wyk, David Stephenson, Wolfgang Steglich

Phytochemistry > 1996 > 42 > 6 > 1683-1687

The leaf exudate of Aloe littoralis yielded, in addition to the known 10-hydroxyaloin B, two new C-glucoside oxanthrones namely 10-hydroxy-15-O-(2R,3S-nilyl)(6 -O-acetyl)aloin B (littoraloin) and 10-hydroxy-15-O-(2R,3S-nilyl)aloin B (deacetyllittoraloin). Their structures were determined by spectroscopic methods as well as by conversion to the known 10-hydroxyaloin B and nilic acid.

article

Three dihydroanthracenones from Gasteria bicolor

Ermias Dagne, Ben-Erik Van Wyk, Michael Mueller, Wolfgang Steglich

Phytochemistry > 1996 > 41 > 3 > 795-799

The stem and leaves of Gasteria bicolor afforded three new dihydroanthracenones namely 3,4-dihydro-2,6,9-trihydroxy-8-methyl-1(2H)-anthracenone (gasteriacenone A), 3,4-dihydro-2,4,9-trihydroxy-6-methoxy-8-methyl-1(2H)-anthracenone (gasteriacenone B) and 3,4-dihydro-4,6,9-trihydroxy-7-carbomethoxy-8-methyl-1(2H)-anthracenone (gasteriacenone C). Their structures were determined by spectroscopic methods...

article

The Chemotaxonomic Significance of Root Anthraquinones and Pre-anthraquinones in the Genus Lomatophyllum (Asphodelaceae)

Ben-Erik Van Wyk, Abiy Yenesew, Ermias Dagne

Biochemical Systematics and Ecology > 1995 > 23 > 7-8 > 805-808

The roots of seven species of Lomatophyllum were analysed by TLC and HPLC for the presence of nine different anthraquinones and pre-anthraquinones which are all known to be characteristic constituents of the subterranean metabolism of Aloe. Chrysophanol and asphodelin were detected in all the samples analysed. In addition, the 1-methyl-8-hydroxyanthraquinones aloesaponarin I, aloesaponarin II and...

article

Chemotaxonomic Significance of Anthraquinones in the Roots of Asphodeloideae (Asphodelaceae)

Ben-Erik Van Wyk, Abiy Yenesew, Ermias Dagne

Biochemical Systematics and Ecology > 1995 > 23 > 3 > 277-281

The distribution of seven anthraquinones in the roots of some 46 species belonging to the generaAsphodelus, Asphodeline, Bulbine, Bulbinella and Kniphofia was studied by TLC and HPLC. 1,8-Dihydroxyanthraquinones based on a chrysophanol unit are the main constituents of the subterranean metabolism in the subfamily Asphodeloideae. The genera Bulbine, Bulbinella and Kniphofia elaborate knipholone-type...

article

Chemotaxonomic Survey of Anthraquinones and Pre-anthraquinones in Roots of Aloe Species

Ben-Erik Van Wyk, Abiy Yenesew, Ermias Dagne

Biochemical Systematics and Ecology > 1995 > 23 > 3 > 267-275

Root samples from 172 species of Aloe were surveyed by TLC and HPLC for the presence of anthraquinones and pre-anthraquinones. With the exception of the three species of the series Serrulatae, 1,8-Dihydroxyanthraquinones (chrysophanol and asphodelin) were detected in all the species sampled. Compounds derived through the 1-methyl-8-hydroxyanthraquinone pathway, i.e. aloesaponarin I, aloesaponarin...

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