The bioautography of lipophilic extracts of some well-known spices showed clear inhibition zones ... more The bioautography of lipophilic extracts of some well-known spices showed clear inhibition zones indicating the presence of antifungal compounds. The extracts of Alpinia galanga (rhizome), Syzygium aromaticum (flower), Pimenta dioica (flower), and Cinnamomum zeylanicum (stem bark) showed the highest activities of inhibit spore germination with EC50 values between 30-112 μg/mL against B. cinerea. The rhizome of Alpinia galanga with a Minimum Inhibitory Concentration (MIC) at 156.3 μg/mL was highly active, whereas Syzygium aromaticum, Pimenta dioica, and Cinnamomum zeylanicum had MIC values at 312.5, 625, and 312.5 μg/mL, respectively. In the case of Pestalotiopsis sp., the extracts of Pimenta dioica, Cinnamomum zeylanicum, Zingiber officinale, and Syzygium aromaticum exhibited EC50 values at 64-200 μg/mL, and showed even less activity against C. gloeosporioides with an EC50 at 401- 894 μg/mL. Similar results were obtained from the MIC values at 625 μg/mL for Cinnamomum zeylanicum, Pi...
Acta Crystallographica Section E Structure Reports Online
The title compound [systematic name: (1S,3aS,4aR,4bS,5S,6R,6aR,10aR,10bR,12aS)-5,6-bis(acetylox... more The title compound [systematic name: (1S,3aS,4aR,4bS,5S,6R,6aR,10aR,10bR,12aS)-5,6-bis(acetyloxy)-1-(3-furyl)-1,5,6,6a,7,10a,10b,11,12,12a-decahydro-4b,7,7,10a,12a-pentamethyloxireno[c]phenanthro[1,2-d]pyran-3,8(3aH,4bH)-dione], C30H36O9, is a limonoid-type triterpene isolated from Aglaia elaeagnoidea (A. Juss.) Benth. (Meliaceae) from Queensland, northern Australia. It contains the gedunin core of four trans-fused six-membered rings with an oxirane ring annelated to the fourth ring. A terminal 3-furyl unity and two acetoxy groups in a mutual cis-disposition supplement the molecule. A comparison between the gedunin cores of the title compound, the parent compound gedunin, and three further gedunin derivatives revealed considerable variations in their conformation stemming from the conformational lability of the first screw-boat ring and the third twist-boat ring. A sensitive measure for the third ring is one C—C—C—C torsion angle, which is 14.2 (2)° in the title compound, bu...
Flavaglines are formed by cycloaddition of a flavonoid nucleus with a cinnamic acid moiety repres... more Flavaglines are formed by cycloaddition of a flavonoid nucleus with a cinnamic acid moiety representing a typical chemical character of the genus Aglaia of the family Meliaceae. Based on biosynthetic considerations 148 derivatives are grouped together into three skeletal types representing 77 cyclopenta[b]benzofurans, 61 cyclopenta[bc]benzopyrans, and 10 benzo[b]oxepines. Apart from different hydroxy, methoxy, and methylenedioxy groups of the aromatic rings, important structural variation is created by different substitutions and stereochemistries of the central cyclopentane ring. Putrescine-derived bisamides constitute important building blocks occurring as cyclic 2-aminopyrrolidines or in an open-chained form, and are involved in the formation of pyrimidinone flavaglines. Regarding the central role of cinnamic acid in the formation of the basic skeleton, rocagloic acid represents a biosynthetic precursor from which aglafoline- and rocaglamide-type cyclopentabenzofurans can be deri...
Stemona alkaloids represent a unique class of natural products exclusively known from the three g... more Stemona alkaloids represent a unique class of natural products exclusively known from the three genera Stemona, Stichoneuron, and Croomia of the monocotyledonous family Stemonaceae. Structurally they are characterized by a central pyrroloazepine core usually linked with two butyrolactone rings. The great diversity, comprising 215 derivatives, is created by the formation of additional CC linkages and oxygen bridges together with ring cleavages and eliminations of the lactone rings. Based on biosynthetic considerations they can be grouped into three structural types represented by the croomine, stichoneurine, and protostemonine skeleton. Due to the formation of characteristic terminal lactone rings and the central pyrrolidine ring pandanamine and pandamarilactonine, isolated from Stichoneuron calcicola, were suggested to represent biogenetic precursors. The taxonomically complex S. tuberosa group can be clearly segregated by the formation of stichoneurines, while the other Stemona species are characterized by protostemonine derivatives. Croomine derivatives are more widespread found in both groups and in the genus Croomia. Of chemotaxonomic significance are the different transformations of protostemonine into stemofolines with a cage-type structure or into pyridoazepines characterized by a six-membered piperidine ring. Stimulated by the great interest in the antitussive activity of Stemona alkaloids, differences in transport mechanisms and potencies via different administrative routes were investigated. Follow-up studies on the significant insecticidal activities focused on the mode of action by using biochemical and electrophysiological approaches. Screening for acetylcholinesterase inhibitory properties revealed a much higher potency for stemofoline derivatives compared to pyridoazepines, but showed also significant activity for isomers of stenine with a stichoneurine skeleton. Evaluating synergistic growth inhibitory effects with cancer chemotherapeutic agents stemofoline exhibited the most potent effect in the reversal of permeability glycoprotein-mediated multidrug resistance. The anti-inflammatory activity of some derivatives was identified as an inhibition of the expression of inflammatory mediators. Comparing the diverse bioactivities of Stemona alkaloids stemofoline-type derivatives are the most versatile compounds representing promising lead structures for further development as commercial agents in agriculture and medicine.
Carbazole alkaloids characterized by a heterocyclic aromatic basic skeleton are known from differ... more Carbazole alkaloids characterized by a heterocyclic aromatic basic skeleton are known from different organisms but do not represent a biogenetically homogenous group. The majority, comprising more than 330 derivatives, is derived from 3-methylcarbazole as common precursor and is designated as phytocarbazoles. They are nearly exclusively known from the four closely related plant genera Bergera (part of Murraya s. l.), Clausena, Glycosmis, and Micromelum of the family Rutaceae. Derived from anthranilic acid and malonyl-CoA the tricyclic basic skeleton is formed via a prenylated 2-quinolone intermediate. The following steps are speculated to involve the formation of 2-prenylindole and cyclization of the prenyl side chain to generate 3-methylcarbazole. Apart from different oxygenations and oxidations of the basic skeleton additional prenylations and geranylations contribute to the great structural diversity of phytocarbazoles which are grouped together according to their C13-, C18-, and C23-basic structures. Of taxonomic significance are the different oxidations of the characteristic C-3 methyl group leading to 3-formyl- and 3-carboxyl derivatives particularly accumulated in Clausena and Micromelum species. Predominant prenylation at C-5 is typical for Glycosmis and Micromelum, whereas in Clausena prenylation at different positions can contribute to an infrageneric grouping. Geranylation represents a characteristic biogenetic trend of Bergera. A wide variety of biological activities ranges from significant antimicrobial, antiprotozoal, and insecticidal properties to anti-inflammatory, antioxidative, antiplatelet aggregative, and anti-HIV activities. Of particular interest is the cytotoxicity of phytocarbazoles against various cancer cell lines, where some derivatives turned out to act as cell cycle inhibitors and apoptosis inducers. Especially the C23 derivative mahanine induced different cell-signaling pathways suggesting that it represents a multi-targeted and multi-functional compound that works on an array of different cancer types and has the potential to inhibit tumor growth in vivo.
Alkamides are natural products formed by connecting straight-chain, mostly unsaturated, aliphatic... more Alkamides are natural products formed by connecting straight-chain, mostly unsaturated, aliphatic acids with various amines by an amide linkage. More than 300 derivatives are known from eight plant families consisting of various combinations of 200 acids with 23 amines. Apart from a few saturated derivatives alkamides with unsaturated acid parts are grouped into compounds with purely olefinic patterns and those with olefinic and acetylenic linkages. Derived from C 18 oleic acid the acid parts are modified either by chain elongations to C 28 or by oxidative shortenings to C 4 acid residues. Substrate and regiospecific desaturases and acetylenases are responsible for their characteristic patterns of unsaturation. Amine parts are derived from various amino acids by decarboxylation. Beside the widespread isobutylamines alkamides with six-and five-membered ring amines and those with phenylalanine derived amines are characteristic for the Asteraceae and Piperaceae while benzylamines are restricted to the Brassicaceae. Within the Asteraceae 2-methylbutylamine distinguishes the tribe Heliantheae from Anthemideae characterized by ring amines. Alkamides with elongated olefinic acid parts are mainly found in Piperaceae and Brassicaceae while acetylenic acid parts are typical for Asteraceae. A wide variety of biological activities ranges from the characteristic pungent/ tingling property and high insecticidal toxicity to significant antifungal, antibacterial, antiprotozoal, molluscicidal, cercaricidal, and acaricidal activity. They also act as plant growth-promoting substances. Position and stereochemistry of the double bonds are essential for the different qualities of the pungent taste. Medically alkamides possess anti-inflammatory and analgesic properties and are responsible for immunomodulatory and cannabinomimetic effects.
ABSTRACT Leaf extracts from 40 Valerianella species were hydrolyzed and subjected to 2-D chromato... more ABSTRACT Leaf extracts from 40 Valerianella species were hydrolyzed and subjected to 2-D chromatography. Luteolin and its methyl ethers, diosmetin and chrysoeriol, are evidently typical for the genus. The distribution of these derivatives and of 6-hydroxyluteolin parallel recent cytological and morphological findings and support a new systematic arrangement. Asiatic species form flavonols, while the North American and Mediterranean-Oriental groups appear progressively more advanced by the appearance of flavones and some 6-hydroxylation.Zusammenfassung`Laubblattextrakte von 40 Valerianella-Arten wurden hydrolysiert und zweidimensional chromatographiert. Luteolin und seine beiden Methyläther Diosmetin und Chrysoeriol sind für die Gattung charakteristisch. Die unterschiedliche Verteilung dieser Derivate und die Bildung von 6-Hydroxyluteolin stützt neue cytologische und morphologische Befunde und ergibt Ansätze für eine neuartige systematische Gliederung. In der asiatischen Artengruppe werden noch Flavonole gebildet, während die nordamerikanischen und mediterran-orientalischen Gruppen durch Reduktion der Flavonole bzw. 6-Hydroxylierung fortschreitend abgeleiteter erscheinen.
Fifteen prenylated or geranylated flavanones and flavanonols were isolated from the leaf extracts... more Fifteen prenylated or geranylated flavanones and flavanonols were isolated from the leaf extracts of different Glycosmis species collected in Thailand and Malaysia. All structures were elucidated by spectroscopic methods, especially 1D and 2D NMR. Six compounds were described for the first time and two were only known so far as synthetic products. The chemotaxonomic significance of flavanoid accumulation within the genus Glycosmis is highlighted.
The genus Artemisia comprises about 400 species mainly distributed in the northern hemisphere. It... more The genus Artemisia comprises about 400 species mainly distributed in the northern hemisphere. It is the largest and most widely distributed of approximately 100 genera (18) in the tribe Anthemidae (Compositae). Within the genus there is a great variety of life forms from dwarf herbaceous representatives to tall shrubs occurring in a wide range of habitats between arctic alpine regions to dry deserts. Most of the Artemisias are characterized by the presence of strong aromatic odours mainly based on mono- and sesquiterpenes which are accumulated both in glandular hairs and schizogenous secretory canals.
The bioautography of lipophilic extracts of some well-known spices showed clear inhibition zones ... more The bioautography of lipophilic extracts of some well-known spices showed clear inhibition zones indicating the presence of antifungal compounds. The extracts of Alpinia galanga (rhizome), Syzygium aromaticum (flower), Pimenta dioica (flower), and Cinnamomum zeylanicum (stem bark) showed the highest activities of inhibit spore germination with EC50 values between 30-112 μg/mL against B. cinerea. The rhizome of Alpinia galanga with a Minimum Inhibitory Concentration (MIC) at 156.3 μg/mL was highly active, whereas Syzygium aromaticum, Pimenta dioica, and Cinnamomum zeylanicum had MIC values at 312.5, 625, and 312.5 μg/mL, respectively. In the case of Pestalotiopsis sp., the extracts of Pimenta dioica, Cinnamomum zeylanicum, Zingiber officinale, and Syzygium aromaticum exhibited EC50 values at 64-200 μg/mL, and showed even less activity against C. gloeosporioides with an EC50 at 401- 894 μg/mL. Similar results were obtained from the MIC values at 625 μg/mL for Cinnamomum zeylanicum, Pi...
Acta Crystallographica Section E Structure Reports Online
The title compound [systematic name: (1S,3aS,4aR,4bS,5S,6R,6aR,10aR,10bR,12aS)-5,6-bis(acetylox... more The title compound [systematic name: (1S,3aS,4aR,4bS,5S,6R,6aR,10aR,10bR,12aS)-5,6-bis(acetyloxy)-1-(3-furyl)-1,5,6,6a,7,10a,10b,11,12,12a-decahydro-4b,7,7,10a,12a-pentamethyloxireno[c]phenanthro[1,2-d]pyran-3,8(3aH,4bH)-dione], C30H36O9, is a limonoid-type triterpene isolated from Aglaia elaeagnoidea (A. Juss.) Benth. (Meliaceae) from Queensland, northern Australia. It contains the gedunin core of four trans-fused six-membered rings with an oxirane ring annelated to the fourth ring. A terminal 3-furyl unity and two acetoxy groups in a mutual cis-disposition supplement the molecule. A comparison between the gedunin cores of the title compound, the parent compound gedunin, and three further gedunin derivatives revealed considerable variations in their conformation stemming from the conformational lability of the first screw-boat ring and the third twist-boat ring. A sensitive measure for the third ring is one C—C—C—C torsion angle, which is 14.2 (2)° in the title compound, bu...
Flavaglines are formed by cycloaddition of a flavonoid nucleus with a cinnamic acid moiety repres... more Flavaglines are formed by cycloaddition of a flavonoid nucleus with a cinnamic acid moiety representing a typical chemical character of the genus Aglaia of the family Meliaceae. Based on biosynthetic considerations 148 derivatives are grouped together into three skeletal types representing 77 cyclopenta[b]benzofurans, 61 cyclopenta[bc]benzopyrans, and 10 benzo[b]oxepines. Apart from different hydroxy, methoxy, and methylenedioxy groups of the aromatic rings, important structural variation is created by different substitutions and stereochemistries of the central cyclopentane ring. Putrescine-derived bisamides constitute important building blocks occurring as cyclic 2-aminopyrrolidines or in an open-chained form, and are involved in the formation of pyrimidinone flavaglines. Regarding the central role of cinnamic acid in the formation of the basic skeleton, rocagloic acid represents a biosynthetic precursor from which aglafoline- and rocaglamide-type cyclopentabenzofurans can be deri...
Stemona alkaloids represent a unique class of natural products exclusively known from the three g... more Stemona alkaloids represent a unique class of natural products exclusively known from the three genera Stemona, Stichoneuron, and Croomia of the monocotyledonous family Stemonaceae. Structurally they are characterized by a central pyrroloazepine core usually linked with two butyrolactone rings. The great diversity, comprising 215 derivatives, is created by the formation of additional CC linkages and oxygen bridges together with ring cleavages and eliminations of the lactone rings. Based on biosynthetic considerations they can be grouped into three structural types represented by the croomine, stichoneurine, and protostemonine skeleton. Due to the formation of characteristic terminal lactone rings and the central pyrrolidine ring pandanamine and pandamarilactonine, isolated from Stichoneuron calcicola, were suggested to represent biogenetic precursors. The taxonomically complex S. tuberosa group can be clearly segregated by the formation of stichoneurines, while the other Stemona species are characterized by protostemonine derivatives. Croomine derivatives are more widespread found in both groups and in the genus Croomia. Of chemotaxonomic significance are the different transformations of protostemonine into stemofolines with a cage-type structure or into pyridoazepines characterized by a six-membered piperidine ring. Stimulated by the great interest in the antitussive activity of Stemona alkaloids, differences in transport mechanisms and potencies via different administrative routes were investigated. Follow-up studies on the significant insecticidal activities focused on the mode of action by using biochemical and electrophysiological approaches. Screening for acetylcholinesterase inhibitory properties revealed a much higher potency for stemofoline derivatives compared to pyridoazepines, but showed also significant activity for isomers of stenine with a stichoneurine skeleton. Evaluating synergistic growth inhibitory effects with cancer chemotherapeutic agents stemofoline exhibited the most potent effect in the reversal of permeability glycoprotein-mediated multidrug resistance. The anti-inflammatory activity of some derivatives was identified as an inhibition of the expression of inflammatory mediators. Comparing the diverse bioactivities of Stemona alkaloids stemofoline-type derivatives are the most versatile compounds representing promising lead structures for further development as commercial agents in agriculture and medicine.
Carbazole alkaloids characterized by a heterocyclic aromatic basic skeleton are known from differ... more Carbazole alkaloids characterized by a heterocyclic aromatic basic skeleton are known from different organisms but do not represent a biogenetically homogenous group. The majority, comprising more than 330 derivatives, is derived from 3-methylcarbazole as common precursor and is designated as phytocarbazoles. They are nearly exclusively known from the four closely related plant genera Bergera (part of Murraya s. l.), Clausena, Glycosmis, and Micromelum of the family Rutaceae. Derived from anthranilic acid and malonyl-CoA the tricyclic basic skeleton is formed via a prenylated 2-quinolone intermediate. The following steps are speculated to involve the formation of 2-prenylindole and cyclization of the prenyl side chain to generate 3-methylcarbazole. Apart from different oxygenations and oxidations of the basic skeleton additional prenylations and geranylations contribute to the great structural diversity of phytocarbazoles which are grouped together according to their C13-, C18-, and C23-basic structures. Of taxonomic significance are the different oxidations of the characteristic C-3 methyl group leading to 3-formyl- and 3-carboxyl derivatives particularly accumulated in Clausena and Micromelum species. Predominant prenylation at C-5 is typical for Glycosmis and Micromelum, whereas in Clausena prenylation at different positions can contribute to an infrageneric grouping. Geranylation represents a characteristic biogenetic trend of Bergera. A wide variety of biological activities ranges from significant antimicrobial, antiprotozoal, and insecticidal properties to anti-inflammatory, antioxidative, antiplatelet aggregative, and anti-HIV activities. Of particular interest is the cytotoxicity of phytocarbazoles against various cancer cell lines, where some derivatives turned out to act as cell cycle inhibitors and apoptosis inducers. Especially the C23 derivative mahanine induced different cell-signaling pathways suggesting that it represents a multi-targeted and multi-functional compound that works on an array of different cancer types and has the potential to inhibit tumor growth in vivo.
Alkamides are natural products formed by connecting straight-chain, mostly unsaturated, aliphatic... more Alkamides are natural products formed by connecting straight-chain, mostly unsaturated, aliphatic acids with various amines by an amide linkage. More than 300 derivatives are known from eight plant families consisting of various combinations of 200 acids with 23 amines. Apart from a few saturated derivatives alkamides with unsaturated acid parts are grouped into compounds with purely olefinic patterns and those with olefinic and acetylenic linkages. Derived from C 18 oleic acid the acid parts are modified either by chain elongations to C 28 or by oxidative shortenings to C 4 acid residues. Substrate and regiospecific desaturases and acetylenases are responsible for their characteristic patterns of unsaturation. Amine parts are derived from various amino acids by decarboxylation. Beside the widespread isobutylamines alkamides with six-and five-membered ring amines and those with phenylalanine derived amines are characteristic for the Asteraceae and Piperaceae while benzylamines are restricted to the Brassicaceae. Within the Asteraceae 2-methylbutylamine distinguishes the tribe Heliantheae from Anthemideae characterized by ring amines. Alkamides with elongated olefinic acid parts are mainly found in Piperaceae and Brassicaceae while acetylenic acid parts are typical for Asteraceae. A wide variety of biological activities ranges from the characteristic pungent/ tingling property and high insecticidal toxicity to significant antifungal, antibacterial, antiprotozoal, molluscicidal, cercaricidal, and acaricidal activity. They also act as plant growth-promoting substances. Position and stereochemistry of the double bonds are essential for the different qualities of the pungent taste. Medically alkamides possess anti-inflammatory and analgesic properties and are responsible for immunomodulatory and cannabinomimetic effects.
ABSTRACT Leaf extracts from 40 Valerianella species were hydrolyzed and subjected to 2-D chromato... more ABSTRACT Leaf extracts from 40 Valerianella species were hydrolyzed and subjected to 2-D chromatography. Luteolin and its methyl ethers, diosmetin and chrysoeriol, are evidently typical for the genus. The distribution of these derivatives and of 6-hydroxyluteolin parallel recent cytological and morphological findings and support a new systematic arrangement. Asiatic species form flavonols, while the North American and Mediterranean-Oriental groups appear progressively more advanced by the appearance of flavones and some 6-hydroxylation.Zusammenfassung`Laubblattextrakte von 40 Valerianella-Arten wurden hydrolysiert und zweidimensional chromatographiert. Luteolin und seine beiden Methyläther Diosmetin und Chrysoeriol sind für die Gattung charakteristisch. Die unterschiedliche Verteilung dieser Derivate und die Bildung von 6-Hydroxyluteolin stützt neue cytologische und morphologische Befunde und ergibt Ansätze für eine neuartige systematische Gliederung. In der asiatischen Artengruppe werden noch Flavonole gebildet, während die nordamerikanischen und mediterran-orientalischen Gruppen durch Reduktion der Flavonole bzw. 6-Hydroxylierung fortschreitend abgeleiteter erscheinen.
Fifteen prenylated or geranylated flavanones and flavanonols were isolated from the leaf extracts... more Fifteen prenylated or geranylated flavanones and flavanonols were isolated from the leaf extracts of different Glycosmis species collected in Thailand and Malaysia. All structures were elucidated by spectroscopic methods, especially 1D and 2D NMR. Six compounds were described for the first time and two were only known so far as synthetic products. The chemotaxonomic significance of flavanoid accumulation within the genus Glycosmis is highlighted.
The genus Artemisia comprises about 400 species mainly distributed in the northern hemisphere. It... more The genus Artemisia comprises about 400 species mainly distributed in the northern hemisphere. It is the largest and most widely distributed of approximately 100 genera (18) in the tribe Anthemidae (Compositae). Within the genus there is a great variety of life forms from dwarf herbaceous representatives to tall shrubs occurring in a wide range of habitats between arctic alpine regions to dry deserts. Most of the Artemisias are characterized by the presence of strong aromatic odours mainly based on mono- and sesquiterpenes which are accumulated both in glandular hairs and schizogenous secretory canals.
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