Euodionosides A-G: megastigmane glucosides from leaves of Euodia meliaefolia

From a 1-BuOH-soluble fraction of the MeOH extract of leaves of Euodia meliaefolia, collected in Okinawa, seven megastigmane glucosides, named euodionosides A-G, were isolated together with three known megastgmane glucosides, and two aliphatic and three phenolic compounds. Their structures were elucidated through a combination of spectroscopic analyses and application of the modified Mosher's method.     

Stereochemistry of megastigmane glucosides from Glochidion zeylanicum and Alangium premnifolium

From Glochidion zeylanicum, two megastigmane glucosides, 3- and 9-O-beta-D-glucopyranosides of (3S,5R,6R,7E,9S)-megastigman-7-ene-3,5,6,9-tetrol (1 and 2, respectively), were isolated. Their structures were different from those of kiwiionoside (3) and actinidioionoside (4), isolated from Actinidia chinensis and Actinidia polygama, respectively, in the stereochemistry at the 9-positions. Alangionosides E (5) and O (6), isolated from the leaves of Alangium premnifolium, are also megastigmane glucosides, and the latter is closely related to 1 and actinidioionoside (4). However, the absolute configurations of the 9-position remained to be determined. They were analyzed to be R by means of a modified Mosher's method. Alangionoside E (5) is identical with corchoionoside A in all aspects. The name of corchoionoside A must be retained thereafter.     

Lanceocrepidiasides A-F, glucosides of guaiane-type sesquiterpene from Crepidiastrum lanceolatum

From the aerial parts of Crepidiastrum lanceolatum, six guaiane-type sesquiterpene glucosides, lanceocripidiasides A-F were isolated together with five known sesquiterpene glucosides, ixerin Y, crepidialanceosides A and B, and youngiasides A and D, two known megastigmane glucosides, icariside B1 and corchoionoside A, and benzyl 6'-O-beta-D-apiofuranosyl-beta-D-glucopyranoside. Structures were elucidated by spectroscopic analyses.     

Grevillosides A-F: glucosides of 5-alkylresorcinol derivatives from leaves of Grevillea robusta

From a MeOH extract of leaves of Grevillea robusta, seven compounds (1-7) were isolated. One known compound (7) was identified with a benzyl glucoside, icariside F₂. The structures of the six of these, named grevillosides A-F (1-6), were elucidated on detailed inspection of one- and two-dimensional NMR spectroscopic data as glucosides of 5-alkylresorcinols.     

Antifungal constituents of the stem bark of Bridelia retusa

Antifungal activity guided fractionation of solvent extracts of the stem bark of Bridelia retusa of the family Euphorbiaceae against Cladosporium cladosporioides, furnished new bisabolane sesquiterpenes, (E)-4-(1,5-dimethyl-3-oxo-1-hexenyl)benzoic acid, (E)-4-(1,5-dimethyl-3-oxo-1,4-hexadienyl) benzoic acid, (R)-4-(1,5-dimethyl-3-oxo-4-hexenyl)benzoic acid and (-)-isochaminic acid, together with the known (R)-4-(1,5-dimethyl-3-oxohexyl)benzoic acid (ar-todomatuic acid), 5-allyl-1,2,3-trimethoxybenzene (elemicin), (+)-sesamin and 4-isopropylbenzoic acid (cumic acid). All these compounds showed fungicidal activity on TLC bioautography method at very low concentrations except elemicin.     

Lasianthionosides A-C, megastigmane glucosides from leaves of Lasianthus fordii

From the leaves of Lasianthus fordii, three megastigmane glucosides, lasianthionosides A, B and C, were isolated together with the known iridoid glucoside, asperuloside, deacetylasperuloside and methyl deacetyl-asperulosidate, and a megastigmane glucoside, citroside A. The structures have been elucidated based on spectroscopic analyses and/or X-ray crystallographic analysis.     

Eudesmane and megastigmane glucosides from Laggera alata

Four eudesmane glucosides, alatosides A-D (1-4), and one megastigmane glucoside, alatoside E (5), were isolated from the BuOH fraction of Laggera alata along with six known compounds. Structures of the new compounds were elucidated by a combination of chemical and spectroscopic methods. Alatosides A-E were characterized as: 1alpha-O-(beta-D-glucopyranosyloxyl)-7-epi-eudesma-11-en-2beta,4alpha-diol (1), 2beta-O-(beta-D-glucopyranosyloxyl)-eudesma-4alpha-hydroxyl-11(13)-en-12-oic-acid (2), 5beta-O-(beta-D-glucopyranosyloxyl)-eudesma-4(15),11(13)-dien-12-oic-acid (3), 5alpha-O-(beta-D-glucopyranosyloxyl)-eudesma-3,11(13)-dien-12-oic acid (4) and 3beta-O-(beta-D-glucopyranosyloxyl)-megastigma-9-one (5), respectively. Based on the chemical characteristics of eudesmane derivatives isolated from the Laggera genus, it was suggested that there are probably two different biogenetic pathways for these secondary metabolites in this genus.     

Crotonionosides A-G: megastigmane glycosides from leaves of Croton cascarilloides Räuschel

From the 1-BuOH-soluble fraction of a MeOH extract of leaves of Crotoncascarilloides, collected in Okinawa, Japan, seven megastigmane glycosides, named crotonionosides A-G, were isolated together with three known megastigmane glucosides, dendranthemosides A and B, and citroside A. This structures were elucidated by a combination of spectroscopic analyses, HPLC analyses, and application of the modified Mosher’s method.     

Glaucacyclopeptide A from the seeds of Annona glauca

The seeds of Annona glauca furnished two cyclopeptides one of which is novel. The structure was elucidated on the basis on mass spectrometry, 2D NMR methods and amino acids analysis.     

Generation of primary amide glucosides from cyanogenic glucosides

The cyanogenic glucoside-related compound prunasinamide, (2R)-β-d-glucopyranosyloxyacetamide, has been detected in dried, but not in fresh leaves of the prunasin-containing species Olinia ventosa, Prunus laurocerasus, Pteridium aquilinium and Holocalyx balansae. Experiments with leaves of O. ventosa indicated a connection between amide generation and an excessive production of reactive oxygen species. In vitro, the Radziszewski reaction with H₂O₂ has been performed to yield high amounts of prunasinamide from prunasin. This reaction is suggested to produce primary amides from cyanogenic glycosides in drying and decaying leaves. Two different benzoic acid esters which may be connected to prunasin metabolism were isolated and identified as the main constituents of chlorotic leaves from O. ventosa and P. laurocerasus.     

拟巫山淫羊藿的megastigmane糖苷和苯丙醇类成分

为了解拟巫山淫羊藿(Epimedium pseudowushaneseB. L. Guo)的化学成分,其从地上部分水提物中分离得到2个megastigmane糖苷和4个苯丙醇类化合物。通过波谱分析,分别鉴定为淫羊藿次苷B6(1)、megastigman-5-ene-3,9-diol 3-O-α-L-rhamnopyranosyl-(1→6)-β-D-glucopyranoside (2)、丁香酚芸香糖苷(3)、2-羟基-1-(4-羟基-3,5-二甲氧基苯基)-1-丙酮(4)、2,3-二羟基-1-(4-羟基-3,5-二甲氧基苯基)-1-丙酮(5)、2,3-二羟基-1-(4-羟基-3-甲氧基苯基)-1-丙酮(6)、二氢松柏基醇γ-O-α-L-鼠李糖苷(7)。其中化合物2和7为新化合物,所有化合物均为首次从拟巫山淫羊藿中分离得到。     

Studies on structure-activity relationship of sphaeropsidins A-F, phytotoxins produced by Sphaeropsis sapinea f. sp. cupressi

Six forms of sphaeropsidins (SA-SF), three- and tetra-cyclic unrearranged pimarane diterpenes produced by Sphaeropsis sapinea f. sp. cupressi, as well as eight derivatives obtained by chemical modification of SA-SC, were assayed for their bioactivity. The effect of each compound on plants which are host or non-host of the pathogen was investigated. Activity on some plant pathogenic fungi was also tested. Some structure-activity relationships have been identified for both phytotoxic and antifungal activity. It appears that the integrity of the tricyclic pimarane system, the preservation of the double bond C(8)-C(14), the tertiary hydroxyl group at C-9, the vinyl group at C-13, and the carboxylic group at C-10 as well as the integrity of the A-ring provide these molecules with non selective phytotoxic and antimycotic activity.     

Diterpenoid glucosides from Salvia greggii

The structure of four diterpenoid glucosides, designated as salvigresides A-D (1-4), isolated from the aerial parts of Salvia greggii, have been confirmed by spectroscopic and chemical investigation.     

Constituents from Miliusa balansae (Annonaceae)

The styryl derivatives 3,4-dimethoxy-6-styryl-pyran-2-one and (2E,5E)-2-methoxy-4-oxo-6-phenyl-hexa-2,5-dienoic acid methyl ester were isolated from leaves and branches of Miliusa balansae (Annonaceae). In addition, the geranylated homogentisic acid derivative miliusate, four flavanones and two dihydrochalcones were identified. Their structures were elucidated by spectroscopic means.     

Chromone and chromanone glucosides from Hypericumsikokumontanum and their anti-Helicobacter pylori activities

Chromone glucosides, takanechromones A-C (1, 2 and 5) and chromanone glucosides, named takanechromanones A and B (3 and 4), were isolated from the methanolic extracts of Hypericumsikokumontanum together with 27 known compounds. Their structures were established based on spectroscopic evidence. The isolated compounds and some chromone derivatives were assayed for antimicrobial activity against Helicobacter pylori and cytotoxicity against human cancer cell lines.     

Tricalysiosides H-O: Ent-kaurane glucosides from the leaves of Tricalysia dubia

Eight ent-kaurane glucosides, named tricalysiosides H-O, were isolated from Tricalysia dubia. Tricalysioside H possessed a hydroxyl group at the 1-position, to which the glucose moiety was attached. The structure was first elucidated by means of spectroscopic data analysis and finally confirmed by X-ray crystallography. Since acid hydrolysis of 1 gave D-glucose, the aglycone was proved to have an enantio-kaurane type skeleton. The structures of tricalysiosides I-O were mainly elucidated from analysis of spectroscopic evidence.     

Maltol glucosides from the tuber of Smilax bockii

Two maltol glucosides, bockiosides A and B, along with 10 known compounds, were isolated from the tuber of Smilax bockii (Liliaceae), and their structures were elucidated by spectral experiments, chemical analysis and comparison with literature data.     

New monoterpene glycosides and phenolic compounds from Distylium racemosum and their inhibitory activity against ribonuclease H

Two new monoterpene glycosides, distyloside A-B (1-2), and a new megastigmane glucoside, iso-dihydrodendranthemoside A (3) were isolated from twigs and leaves of Distylium racemosum, along with five known phenolic compounds (4-8). The structures were established via spectroscopic techniques and chemical transformations, and the absolute stereochemistry of 3 was determined by Mosher’s esterification. A homogeneous fluorescence resonance energy transfer (FRET) quenching assay was used to determine the inhibitory activity of isolates (1-8) on the ribonuclease H enzymes from HIV-1, 2, human, and Escherichia coli. Among them, 6″-O-galloylsalidroside (6) showed potent inhibitory effects with an IC₅₀ value of 3.5 μM on HIV-2, and 1.7 μM on human RNase H, respectively.     

Chlorine-containing iridoid and iridoid glucoside, and other glucosides from leaves of Myoporum bontioides

Sixteen compounds were isolated from the MeOH extract of leaves of Myoporum bontioides. The five compounds hitherto unknown, were elucidated to be a chlorine-containing iridoid, named myopochlorin, and an iridoid glucoside, an acylated iridoid glucoside, a linear acetogenin glucoside, and an acyclic monoterpene glucoside, named myobontiosides A-D, respectively, by means of spectroscopic analyses.