Phytochemistry (v.60, #8)
Triterpenoids from Parthenium argentatum x P. tomentosa by Galal T. Maatooq; Ali A.H. El Gamal; Todd R. Furbacher; Tracy L. Cornuelle; Joseph J. Hoffmann (755-760).
Four tetracyclic triterpenoids and lupeol were isolated from the hybrid Parthenium argentatum x P. tomentosa. The new triterpenoids were identified as 16, 24-epoxy-3α-hydroxylanost-8-ene (argentatin E); 16, 24-epoxy-25-hydroxycycloart-1, 11, 22-trien-3-one (argentatin F); 16,24-dihydroxycycloart-20, 25-dien-3-one (argentatin G) and 16, 24-dihydroxycycloart-25-en-3-one (argentatin H). The chemical identities of these compounds were confirmed by the different spectrometric measurements.Four tetracyclic triterpenoids and lupeol were isolated from Parthenium argenatum x P. tomentosa. The chemical identities of these compounds were confirmed by the different spectrometric measurements.
Keywords: Triterpenoids; Parthenium argentatum x P. tomentosa; Asteraceae; Lupeol; Argentatins E, F, G and H;
seco-Adianane-type triterpenoids from Dorstenia brasiliensis (Moraceae) by Taketo Uchiyama; Shoji Hara; Mitsuko Makino; Yasuo Fujimoto (761-764).
Two seco-adianane-type triterpenoids, dorstenic acid A and B, were isolated, along with a known isopimarane-type diterpenoid and six coumarins, from the roots of Dorstenia brasiliensis. Their structures were elucidated on the basis of their spectral data. The two triterpenoids showed moderate cytotoxicity against leukemia cells (L-1210 and HL-60).A seco-adianane-type triterpenoid and its deisopropenyl derivative were isolated, along with a known isopimarane-type diterpenoid and six coumarin derivatives, from the roots of Dorstenia brasiliensis. The structures were elucidated by various spectroscopic means.
Keywords: Dorstenia brasiliensis; Moraceae; Dorstenic acid A; Dorstenic acid B; Cytotoxicity; seco-Adianane-type triterpenoid; Psoralen; Coumarin;
Triterpenoids from Viburnum suspensum by Yoshiyasu Fukuyama; Hiroyuki Minami; Hiromi Fujii; Miyako Tajima (765-768).
Three triterpenoids, 3-oxo-11,13(18)-oleanadien-28-oic acid, 24-hydroxy-3-oxo-11,13(18)-oleanadien-28-oic acid, 6β-hydroxy-3-oxo-11,13(18)-oleanadien-28-oic acid have been isolated together with the previously known virgatic acid, vibsanin B and 3-hydroxyvibsanin E from the leaves of Viburnum suspensum. Their structures were determined by spectroscopic methods and by comparison of their NMR spectral data with those of the previously known 11,13(18)-oleanadien-3β-ol.Three oleanane triterpenoids 1–3 were isolated together with the previously known virgatic acid and two vibsane diterpenoids from the leaves of Viburnum suspensum.
Keywords: Viburnum suspensum; Caprifoliaceae; Leaves; Triterpenoid; 11,13(18)-Oleanadiene; Vibsane diterpenoid;
Iridoid glucosides from Thunbergia laurifolia by Tripetch Kanchanapoom; Ryoji Kasai; Kazuo Yamasaki (769-771).
Two iridoid glucosides, 8-epi-grandifloric acid and 3′-O-β-glucopyranosyl-stilbericoside, were isolated from the aerial part of Thunbergia laurifolia along with seven known compounds, benzyl β-glucopyranoside, benzyl β-(2′-O-β-glucopyranosyl) glucopyranoside, grandifloric acid, (E)-2-hexenyl β-glucopyranoside, hexanol β-glucopyranoside, 6-C-glucopyranosylapigenin and 6,8-di-C-glucopyranosylapigenin. Strucural elucidation was based on the analyses of spectroscopic data.From the aerial parts of Thunbergia laurifolia, two iridoid glucosides were isolated, together with seven known compounds.
Keywords: Thunbergia laurifolia; Acanthaceae; Iridoid glucoside; Grandifloric acid; 8-epi-Grandifloric acid; 3′-O-β-Glucopyranosyl-stilbericoside;
Coumarins from the heartwoods of Mansonia gagei Drumm. by Pattara Tiew; Apiruk Puntumchai; Udom Kokpol; Warinthorn Chavasiri (773-776).
Three coumarins and three known mansonones were isolated from the heartwood of Mansonia gagei Drumm. The structures of the three coumarins were elucidated as 3,8-dimethyl-5-isopropyl-6-methoxycoumarin (mansonrin A) 3,8-dimethyl-5-isopropyl-6-hydroxycoumarin (mansorin B) and 2,3-dihydro-3,6,9-trimethyl naphtho[1,8-bc]pyran-7-oxa-8-one (mansorin C) by analyses of physical properties and spectroscopic data. The cytotoxicity of the isolated compounds against brine shrimp Artemia salina Linn. was also evaluated.Three coumarins were isolated from the heartwoods of Mansonia gagei Drumm. The structures were elucidated by spectroscopic means.
Keywords: Mansonia gagei; Sterculiaceae; Coumarin; Mansonone;
Ceriopsins A–D, diterpenoids from Ceriops decandra by Ammanamanchi S.R Anjaneyulu; Vadali Lakshmana Rao (777-782).
Chemical examination of the ethyl acetate solubles of the CH3OH:CH2Cl2 (1:1) extract of the roots of Ceriops decandra collected from Kauvery estuary resulted in the isolation of four new diterpenoids, ceriopsins A–D (1–4). The structures of the new diterpenoids were elucidated by a study of their physical and spectral data as methyl 17-hydroxy-16-oxobeyeran-18-oate (1), methyl 16(R)-16,17-dihydroxybeyeran-18-oate (2), 1β,15(S)-isopimar-7-ene-1,15,16-triol (3), and 8,15(R)-epoxypimarane-1β,16-diol (4).Four diterpenoids, two beyeranoids, ceriopsin A (1) and ceriopsin B (2), one isopimarane, ceriopsin C (3), and a pimarane, ceriopsin D (4) were isolated from the mangrove plant Ceriops decandra.
Keywords: Indian mangrove; Ceriops decandra; Rhizophoraceae; New diterpenoids; Ceriopsins A–D;
Prenylated flavonoids of Erythrina lysistemon grown in Egypt by Sawsan El-Masry; Masouda E Amer; Maged S Abdel-Kader; Hala H Zaatout (783-787).
Three prenylated flavonoid derivatives; 5,7,4′-trihydroxy-8-(3‴-methylbut-2‴-enyl)-6-(2″-hydroxy-3″-methylbut-3″enyl) isoflavone (isoerysenegalensein E), 5,7,2′-trihydroxy-4′-methoxy-5′-(3″-methylbut-2″-enyl) isoflavanone (lysisteisoflavanone), 5, 4′-dihydroxy-6-(3‴-methylbut-2‴-enyl)-2″-hydroxyisopropyl dihydrofurano [4″,5″:8,7] isoflavone (isosenegalensin), together with the four known flavonoids abyssinone V-4′-methylether, alpinumisoflavone, wighteone and burttinone were isolated from the stem bark of Erythrina lysistemon Hutch. (Leguminosae). Structures were elucidated by spectroscopic methods.Three prenylated flavonoid derivatives, together with four known flavonoids, were isolated from the stem bark of Erythrina lysistemon. Two compounds were subjected to cytotoxicity testing.
Keywords: Erythrina lysistemon; Leguminosae; Prenylated flavonoids; Isoerysenegalensein E; Lysisteisoflavanone; Isosenegalensin;
Isoflavonoids from the roots of Erythrina poeppigiana by Hitoshi Tanaka; Tomoko Oh-Uchi; Hideo Etoh; Hiroshi Shimizu; Yoichi Tateishi (789-794).
Five isoflavonoids, 7,4′-dihydroxy-2′-methoxy-8-(γ,γ-dimethylallyl)isoflav-3-ene, 4′-hydroxy-2′-methoxy-6″,6″-dimethylpyran[2″,3″:7,8]isoflav-3-ene, 5,7,4′-trihydroxy-2′-methoxy-5′-(γ,γ-dimethylallyl)isoflavanone, 5,4′-dihydroxy-7,2′-dimethoxy-5′-(γ,γ-dimethylallyl)isoflavanone and 3,9-dihydroxy-4-(γ,γ-dimethylallyl)pterocarpene as well as six known compounds were isolated from the roots of Erythrina poeppigiana. Their structures were established on the basis of spectroscopic evidence.Five isoflavonoids, erypoegins A (1), (B) (2), C (3), D (4) and E (5) together with six known compounds have been isolated from the roots of Erythrina poeppigiana.
Keywords: Erythrina poeppigiana; Leguminosae; Isoflavonoids; Isoflav-3-enes; Isoflavanones; Erypoegins A–E;
Galloylated catechins and stilbene diglucosides in Vitis vinifera cell suspension cultures by Alain Decendit; Pierre Waffo-Teguo; Tristan Richard; Stéphanie Krisa; Joseph Vercauteren; Jean-Pierre Monti; Gérard Deffieux; Jean-Michel Mérillon (795-798).
Suspension cultures of Vitis vinifera were found to produce catechins and stilbenes. From cells grown in a medium inducing polyphenol synthesis, (−)-epicatechin-3-O-gallate, dimeric procyanidin B-2 3′-O-gallate and two resveratrol diglucosides were isolated, together with cis-resveratrol-3,4′-O-β-diglucoside.Suspension cultures of Vitis vinifera were found to produce catechins and stilbenes. When cells were grown in a medium inducing polyphenol synthesis, (−)-epicatechin-3-O-gallate, dimeric procyanidin B-2 3′-O-gallate and two resveratrol diglucosides were isolated, together with a new natural compound that was identified as cis-resveratrol-3,4′-O-β-diglucoside by spectroscopical methods.
Keywords: Vitis vinifera; Vitaceae; Stilbenes; Catechins; Cell suspension culture; (−)-Epicatechin-3-O-gallate; Dimer procyanidin B-2 3′-O-gallate; Resveratrol-3,4′-O-β-diglucoside;
Two chromones from Peperomia vulcanica by James A Mbah; Maguerite H.K Tchuendem; Pierre Tane; Olov Sterner (799-801).
Two chromones: 5-hydroxy-2-(14′-(E)-nonadecenyl) chromone (1) and 5-hydroxy-2-[12′-(3″,4″-methylenedioxyphenyl)dodecanyl] chromone (2), together with six known compounds have been isolated from Peperomia vulcanica Baker & C. H. Wright (Piperaceae). Their structures were determined by spectroscopic analysis including 2D NMR techniques.Two chromones, 5-hydroxy-2-(14′-(E)-nonadecenyl) chromone (1) and 5-hydroxy-2-[12′-(3″,4″-methylenedioxyphenyl)dodecanyl] chromone (2), together with six known compounds have been isolated from Peperomia vulcanica Baker & C.H. Wright (Piperaceae).
Keywords: Peperomia vulcanica; Piperaceae; Chromone; Peperovulcanone A and B;
Chalconoid and stilbenoid glycosides from Guibourtia tessmanii by V Fuendjiep; J Wandji; F Tillequin; D.A Mulholland; H Budzikiewicz; Z.T Fomum; A.M Nyemba; M Koch (803-806).
A dihydrochalcone glucoside and a stilbene rutinoside have been isolated from Guibourtia tessmanii.Phytochemical studies on the stem bark of Guibourtia tessmanii yielded a dihydrochalcone glucoside, 2′,4-dihydroxy-4′-methoxy-6′-O-β-glucopyranoside dihydrochalcone and a new stilbene glycoside, 3,5-dimethoxy-4′-O-(β-rhamnopyranosyl-(1→6)-β- glucopyranoside) stilbene besides the known pterostilbene. Their structures were established on the basis of one and two dimensional NMR spectroscopic techniques, FABMS and chemical evidence.
Keywords: Guibourtia tessmanii; Leguminosae (Caesalpiniaceae); Stem bark; Stilbenoids; Chalconoids; Glycosides;
Acylated flavonol diglucosides from Lotus polyphyllos by Amani M.D El Mousallami; Manal S Afifi; Sahar A.M Hussein (807-811).
Three acylated flavonol diglucosides, kaempferol 3-O-β-(6″-O-E-p-coumaroylglucoside)-7-O-β-glucoside; quercetin 3-O-β-(6″-O-E-p-coumaroylglucoside)-7-O-β-glucoside; isorhamnetin 3-O-β-(6″-O-E-p-coumaroylglucoside)-7-O-β-glucoside were isolated from the whole plant aqueous alcohol extract of Lotus polyphyllos. The known 3,7-di-O-glucosides of the aglycones kaempferol, quercetin and isorhamnetin were also characterized. All structures were established on the basis of chemical and spectral evidence.The three 3-O-β-(6″-O-coumaroylglucoside)-7-O-glucoside of the flavonols kaempferol, quercetin and isorhamnetin were isolated and identified from Lotus polyphyllos.
Keywords: Lotus polyphyllos; Leguminosae; Acylated flavonol diglucosides; Kaempferol 3-O-β-(6″-O-p-coumaroylglucoside)-7-O-β-glucoside; Quercetin 3-O-β-(6″-O-p-coumaroylglucoside)-7-O-β-Glucoside; Isorhamnetin 3-O-β-(6″-O-p-coumaroylglucoside)-7-O-β-glucoside;
Xanthone O-glycosides from Polygala tenuifolia by Yong Jiang; Peng-Fei Tu (813-816).
Four xanthone O-glycosides, polygalaxanthones IV–VII were isolated from the roots of Polygala tenuifolia Willd., together with eight known compounds. The structures of the four xanthone O-glycosides were established as 6-O-[α-l-rhamnopyranosyl-(1→2)-β-d-glucopyranosyl]-1-hydroxy-3,7-dimethoxyxanthone (polygalaxanthone IV), 6-O-[α-l-rhamnopyranosyl-(1→2)-β-d-glucopyranosyl]-1,3-dihydroxy-7-methoxyxanthone (polygalaxanthone V), 6-O-(β-d-glucopyranosyl)-1,2,3,7-tetramethoxyxanthone (polygalaxanthone VI), and 3-O-[α-d-rhamnopyranosyl-(1→2)-β-d-glucopyranosyl]-1,6-dihydroxy-2,7-dimethoxyxanthone (polygalaxanthone VII), respectively, on the basis of analysis of spectroscopic evidence.Four xanthone O-glycosides, polygalaxanthones IV–VII were isolated from the roots of Polygala tenuifolia Willd., together with eight known compounds. Their structures were established on the basis of analysis of spectroscopic evidence.
Keywords: Polygala tenuifolia; Polygalaceae; Xanthone O-glycosides; Polygalaxanthones;
Methylenedioxy- and methoxyflavones from Melicope coodeana syn. Euodia simplex by Henrik T Simonsen; Michael D Larsen; Merete W Nielsen; Anne Adsersen; Carl Erik Olsen; Dominique Strasberg; Ulla W Smitt; Jerzy W Jaroszewski (817-820).
Three new natural products, 3,8-dimethoxy-5,7-dihydroxy-3′,4′-methylenedioxyflavone, 3,6,8-trimethoxy-5,7-dihydroxy-3′,4′-methylenedioxyflavone and 3,6,8,3′,4′-pentamethoxy-5,7-dihydroxyflavone were isolated from Melicope coodeana syn. Euodia simplex (Rutaceae) along with 3,6,3′-trimethoxy-5,7,4′-trihydroxyflavone and 3,3′-dimethoxy-5,7,4′-trihydroxyflavone. The structural assignments are based on 1H and 13C NMR data, including discussion of the chemical shifts of C-2 in 3,5-dihydroxy- and 3-methoxy-5-hydroxyflavones. The presence of highly methoxylated and methylenedioxyflavones is characteristic of the genus Melicope, and the present findings support the recent transfer of Euodia simplex to Melicope.The isolation and structural elucidation of several flavonols, including two methylenedioxyflavones, are presented..
Keywords: Euodia simplex; Melicope coodeana; Rutaceae; Methylenedioxyflavones; Methoxyflavones; 13C NMR; Chemotaxonomy; Réunion Island;
Isolation and identification of oligomeric procyanidins from Crataegus leaves and flowers by Ulla Svedström; Heikki Vuorela; Risto Kostiainen; Jari Tuominen; Juha Kokkonen; Jussi-Pekka Rauha; Into Laakso; Raimo Hiltunen (821-825).
Oligomeric procyanidins were isolated from the leaves and flowers of hawthorn (Crataegus laevigata). A trimer, epicatechin-(4β→8)-epicatechin-(4β→6)-epicatechin, and a pentamer consisting of (−)-epicatechin units linked through C-4β/C-8 bonds have been isolated from hawthorn for the first time, in addition to known procyanidins including dimers B-2, B-4 and B-5, trimers C-1 and epicatechin-(4β→6)-epicatechin-(4β→8)-epicatechin, and tetramer D-1. A fraction containing a hexamer was also found.Two procyanidins were isolated from hawthorn and identified as an epicatechin trimer with 4β→8 and 4β→6 bonds 6, and an epicatechin pentamer with 4β→8 bonds 9.
Keywords: Crataegus laevigata; Rosaceae; Hawthorn; Oligomeric procyanidins; Condensed tannins; ESI–MS;
Isoflavone glycosides from Derris scandens by Vatcharin Rukachaisirikul; Yaowapa Sukpondma; Chaweewan Jansakul; Walter C. Taylor (827-834).
Five isoflavone glycosides, named derriscandenosides A–E (1–5), were isolated from the stems of Derris scandens, together with ten known compounds comprising one isoflavone, two benzoic acid derivatives, three glucosyl isoflavones and four rhamnosyl-(1→6)-glucosyl isoflavones. The structures of the glycosides were assigned on the basis of spectroscopic data, especially of the acetate derivatives. Three known rhamnosyl-(1→6)-glucosyl isoflavones isolated from a crude fraction were retested for hypotensive activity with varying results.Five isoflavone glycosides, named derriscadenosides A–E were isolated from the stems of Derris scandens. The structures of the glycosides were assigned on the basis of spectroscopic data, especially of the acetate derivatives.
Keywords: Derris scandens; Leguminosae; Isoflavone glycosides; Isoflavone glucosides; Rhamnosyl-(1→6)-glucosyl isoflavones; Hypotensive activity;
Kaempferol triosides from Silphium perfoliatum by Nabil H El-Sayed; Małgorzata Wojcińska; Krystyna Drost-Karbowska; Irena Matławska; Jeffrey Williams; Tom J Mabry (835-838).
Two apiose-containing kaempferol triosides, together with nine known flavonoids were isolated from the leaves of Silphium perfoliatum L. Their structures were elucidated by acid hydrolysis and spectroscopic methods including UV, LSI MS, FAB MS, CI MS, 1H, 13C and 2D-NMR, DEPT, HMQC and HMBC experiments. The two new compounds were identified as kaempferol 3-O-β-d-apiofuranoside 7-O-α-l-rhamnosyl-(1‴′→6‴)-O-β-d-galactopyranoside and kaempferol 3-O-β-d-apiofuranoside 7-O-α-l-rhamnosyl-(1⁗→ 6‴)-O-β-d (2‴-O-E-caffeoylgalactopyranoside).Two kaempferol triosides containing apiose and nine other known flavonoids were isolated from the aerial parts of Silphium perfoliatum L. Their structures were elucidated by spectroscopic methods including UV, LSI MS, FAB MS, CI MS, 1H, 13C and 2D-NMR, DEPT, HMQC and HMBC experiments.
Keywords: Silphium perfoliatum L.; Asteraceae; Kaempferol triosides; Kaempferol caffeoyltrioside; Apiose-containing kaempferol triosides;
Coumaronochromones and flavanones from Euchresta formosana roots by Wen-Li Lo; Fang-Rong Chang; Tian-Jye Hsieh; Yang-Chang Wu (839-845).
Four coumaronochromones, formosanatins A–D (–4), and a flavanone, euchrenone a16 (), along with four known compounds, euchretins E and G, euchrestaflavanone A, and daidzein, were isolated from the roots of Euchresta formosana. The structures of – were established by spectroscopic analyses.Four coumaronochromones, formosanatins A–D (1–4), and a flavanone, euchrenone a16 (5), along with four known compounds were isolated and characterized from the roots of Euchresta formosana. The structures of these compounds were established by spectral evidence.
Keywords: Euchresta formosana; Leguminosae; Roots; Coumaronochromones; Formosanatins A–D; Flavanone; Euchrenone a16;
Alkaloids from Narcissus angustifolius subsp. transcarpathicus (Amaryllidaceae) by Josep Labraña; Alex King'ori Machocho; Vladimir Kricsfalusy; Reto Brun; Carles Codina; Francesc Viladomat; Jaume Bastida (847-852).
Seven alkaloids have been isolated from fresh bulbs of Narcissus angustifolius subsp. transcarpathicus (Amaryllidaceae). Nangustine, reported here for the first time, is the first 5,11-methanomorphanthridine alkaloid with a C-3/C-4 substitution. The structure and stereochemistry of this new alkaloid, as well as those previously known, have been determined by physical and spectroscopic methods. Spectroscopic data of pancracine have been completed. The in vitro assay activity against the parasitic protozoa Trypanosoma brucei rhodesiense, Trypanosoma cruzi, Leishmania donovani and Plasmodium falciparum was carried out with the compounds nangustine and pancracine.Seven alkaloids have been isolated from bulbs of Narcissus angustifolius subsp. transcarpathicus (Amaryllidaceae). Nangustine is reported for the first time. The in vitro assay activity against several parasitic protozoa was carried out with nangustine and pancracine.
Keywords: Narcissus angustifolius subsp. transcarpathicus; Amaryllidaceae; Bulbs; Alkaloids; Pseudolycorine; 8-O-Demethylhomolycorine; Cherylline; Ungeremine; Vasconine; Pancracine; Nangustine; Antiprotozoal activity;
The biosynthesis of β-carboline and quinolizidine alkaloids of Alangium lamarckii by Sudha Jain; Archana Sinha; Dewan S Bhakuni (853-859).
The incorporation of tryptamine, dopamine, N-deacetylisoipecoside, N-deacetylipecoside into alangimarckine, deoxytubulosine and ankorine and of strictosidine and vincoside into alangimarckine and deoxytubulosine in young Alangium lamarckii Thw. (Alangiaceae) has been studied and specific utilisation of N-deacetylisoipecoside demonstrated. Parallel experiments with nordeoxytubulosine and deoxytubulosine suggested that O-methylation precedes condensation of protoemetine with tryptamine and further the reduction of ethylene side chain takes place before condensation. Hydroxylation at C-8 in the trans-quinolizidine moiety is the terminal step in the biosynthesis of alangimarckine.Incorporation of labelled precursors into 17, 20 and 6 in Alangium lamarckii Thw. is reported. It is shown that O-methylation precedes condensation of protoemetine nucleus with tryptamine, reduction of the ethylene side chain occurs before condensation and C-8 hydroxylation in transquinolizidine part is the terminal step in the biosynthesis of 17.
Keywords: Alangium lamarckii Thw.; Alangiaceae; Antimicrobial; Biosynthesis; Alkaloids; Deoxytubulosine; Alangimarckine; Ankorine;
Brominated metabolites from an Okinawan Laurencia intricata by Minoru Suzuki; Yoshinori Takahashi; Yasuko Mitome; Taiji Itoh; Tsuyoshi Abe; Michio Masuda (861-867).
Two halogenated C15 acetogenins, itomanallenes A and B, with a terminal bromoallene moiety along with a halogenated sesquiterpene, itomanol, have been isolated from the red alga Laurencia intricata collected in Okinawan waters. Their structures were deduced from 1D and 2D NMR experiments including 1H–1H COSY, HSQC, HMBC, and NOESY methods. The alcohol corresponding to itomanallene B seems to be a plausible precursor of itomanallene A, which has an unusual 2,10-dioxabicyclo[7.3.0]dodecene skeleton. Itomanol was found to be a selinane-type bromosesquiterpenoid, and is the first example of a selinane to be isolated from Japanese Laurencia species.Two brominated C15 acetogenins and a brominated sesquiterpene were isolated from an Okinawan Laurencia intricata.
Keywords: Laurencia intricata; Rhodomelaceae; Red alga; C15 acetogenin; Sesquiterpene; Halogenated compound; Chemotaxonomy;
Unguisin C, a GABA-containing cyclic peptide from the fungus Emericella unguis by Joan Malmstrøm; Anne Ryager; Uffe Anthoni; Per Halfdan Nielsen (869-872).
Besides the known unguisins A and B, a new cyclic heptapeptide, unguisin C, containing a GABA-derived moiety in the ring, was isolated from the fungus Emericella unguis. The structure was determined by 1D and 2D NMR techniques. Marfey's method was used to determine the absolute stereochemistry. Precursor-directed biosynthesis of the unguisins was performed by supplementation of the culture medium with amino acids (l-Ala, l-Ser, l-Phe and l-Leu). A related cyclic heptapeptide, unguisin D, was detected by HPLC and characterized by sequence analysis using LC-QITMS.Unguisin C was isolated from the fungus Emericella unguis. As in the previously identified unguisines A and B, a GABA-derived moiety was incorporated in a cyclic heptapeptide. Precursor-directed synthesis indicated conservation of the common key substructure Trp-GABA-Ala-Val in all the cyclic heptapeptides produced.
Keywords: Emericella unguis; Fungus; Cyclic peptides; GABA; Unguisin C; Unguisin D;
Cyanogenic allosides and glucosides from Passiflora edulis and Carica papaya by David S. Seigler; Guido F. Pauli; Adolf Nahrstedt; Rosemary Leen (873-882).
Leaf and stem material of Passiflora edulis (Passifloraceae) contains the new cyanogenic glycosides (2R)–β-d-allopyranosyloxy-2-phenylacetonitrile (1a) and (2S)–β-d-allopyranosyloxy-2-phenylacetonitrile (1b), along with smaller amounts of (2R)–prunasin (2a), sambunigrin (2b), and the alloside of benzyl alcohol (4); the major cyanogens of the fruits are (2R)–prunasin (2a) and (2S)–sambunigrin (2b). The major cyanogenic glycoside of Carica papaya (Caricaceae) is 2a; only small amounts of 2b also are present. We were not able to confirm the presence of a cyclopentenoid cyanogenic glycoside, tetraphyllin B, in Carica papaya leaf and stem materials. In detailed 1H NMR studies of 1a/b and 2a/b, differences in higher order effects in glucosides and allosides proved to be valuable for assignment of structures in this series. The diagnostic chemical shifts of cyanogenic methine and anomeric protons in 1a/b are sensitive to anisotropic environmental effects. The assignment of C-2 stereochemistry of 1a/b was made in analogy to previous assignments in the glucoside series and was supported by GLC analysis of the TMS ethers.Leaf and stem material of Passiflora edulis (Passifloraceae) contains the cyanogenic glycosides(2R)–β-d-allopyranosyloxy-2-phenylacetonitrile (1a) and (2S)–β-d-allopyranosyloxy-2-phenylacetonitrile (1b) in addition to (2R)–prunasin (2a) and (2S)–sambunigrin (2b); the major cyanogens of the fruits are 2a and 2b. The major cyanogenic glycoside of Carica papaya (Caricaceae) is 2a; while only very small amounts of 2b are present. We were not able to confirm the presence of a cyclopentenoid cyanogenic glycoside, tetraphyllin B, in Carica papaya leaf and stem materials.
Keywords: (2R)–β-d-Allopyranosyloxy-2-phenylacetonitrile; (2S)–β-d-Allopyranosyloxy-2-phenylacetonitrile; Benzyl alcohol alloside; Cyanogenic glycosides; Prunasin; Sambunigrin; d–Allose; Passiflora edulis; Passifloraceae; Carica papaya; Caricaceae;