Asplenetin,a flavone and its glycoside from Launaea asplenifolia

A new flavone, asplenetin, has been isolated from Launea asplenifolia and characterized as 5,7,3′,4′,5′-pentahydroxy-3-(3-methylbutyl)flavone. Its glycoside, asplenetin 5-O-neohesperidoside, is also reported.     

Bitter phenylpropanoid glycosides from Conandron ramoidioides

A new bitter glycoside, conandroside and a known glycoside, acteoside were isolated from Conandron ramoidioides. On the basis of the chemical and spectral evidence, conandroside was shown to be 2-(3′,4′-dihydroxy-phenyl)-ethanol 1-O-β-D-xylosyl-(1 → 3)-β-D-(4-caffeyl)-glucoside.     

A chalcone glycoside from Abies pindrow

The EtOH extract of air-dried stems of Abies pindrow yielded okanin, okanin 4′-O-β-d-glucopyranoside, butein 4′-O-β-d-glucopyranoside, 8,3′4′-trihydroxyflavanone-7-O-β-d-glucopyranoside and a new chalcone glycoside, 2′,3′,4′:3,4-pentahydroxy-chalcone 4′-(l-arabinofuranosyl-α-1→4-d-glucopyranoside-β).     

Two new glycosides from the whole plant of Anemone rivularis var. flore-minore

Phytochemical investigation on the whole plant of Anemone rivularis var. flore-minore led to the isolation of a new labdane-type diterpene glycoside (1) and a new trihydroxyfuranoid lignanoid glycoside (2), together with three known triterpene and triterpenoid glycosides (3–5). The structures of the two new compounds were elucidated as β-d-glucopyranosyl (13S)-13-hydroxy-7-oxo-labda-8,14-diene-18-oate (1) and (7S,7′R,8R,8′S)-7′-butoxy-7,9′-epoxy-4,4′,9-trihydroxy-3,3′-dimethoxylignane 9-O-β-d-glucopyranoside (2), on the basis of extensive spectral analysis and chemical evidence. Compound 1 is characterized by a glucose (Glc) esterified C-18 carboxyl group, which is a rarely encountered labdane-type diterpene glycoside in nature. The two new compounds (1 and 2) reported here are the first examples of diterpene glycoside and lignanoid glycoside found in the genus Anemone, and the known triterpene and triterpenoid glycosides (3–5) are identified for the first time from the title plant.     

An acylated sesquiterpene glycoside from Mortonia gregii

A new glycoside has been isolated from Mortonia gregii and identified by chemical and spectral means as 2-O-β-(2′,6′-diacetyl glucopyranosyl) desacetyl mortonol B.     

The structures of amentoflavone glycosides isolated from Psilotum nudum

On the basis of new spectroscopic evidence, structures are proposed for three amentoflavone glycosides and an apigenin di-C-glycoside previously isolated from Psilotum nudum. The major glycoside is identified as the 7,4′,4′“-tri-O-β-D-glucopyranoside, minor glycosides as the 4′,4′“-di-O-β-D-glucopyranoside and 7,4′“-di-O-β-D-glucopyranoside, and the apigenin di-C-glycoside as vicenin-2. The amentoflavone glucosides are all new natural products.     

Inhibition of the β-carbonic anhydrases from Mycobacterium tuberculosis with C-cinnamoyl glycosides: Identification of the first inhibitor with anti-mycobacterial activity

A small series of C-cinnamoyl glycoside containing the phenol moiety was tested for the inhibition of the three Mycobacterium tuberculosis β-carbonic anhydrases (CAs, EC 4.2.1.1) with activities in the low micromolar range detected. The compounds were also tested for the inhibition of growth of M. tuberculosis H₃₇Rv strain, leading to the identification of (E)-1-(2′,3′,4′,6′-tetra-O-acetyl-β-d-glucopyranosyl)-4-(3-hydroxyphenyl)but-3-en-2-one (1) as the first carbonic anhydrase inhibitor with anti-tubercular activity.     

Chalcones and other flavonoids from Asarum sensu lato (Aristolochiaceae)

Seventy-five taxa belonging to the genus Asarum sensu lato were studied for their composition of flavonoids. Three chalcones and an aurone were found as major components. The chalcones were identified as chalcononaringenin 2′,4′-di-O-glucoside, 4,2′,4′-tri-O-glucoside, 4-O-glucoside, and the aurone as aureisidin 4,6-di-O-glucoside. The glycoside, 2′,4′-di-O-glucoside was detected in all taxa examined, and is a chemotaxonomical feature of Asarum sensu lato. 4,2′,4′-Tri-O-glucoside was found from the taxa classified into the genera Asiasarum, Geotaenium and Heterotropa by Maekawa's system. On the other hand, the glycoside was not detected from three Asarum sensu stricto species, A. caudigerum, A. caulescens and A. leptophyllum. In contrast, aurone, aureusidin 4,6-di-O-glucoside occurred in two Asarum s.s., A. caulescens and A. leptophyllum. Thus, the Asarum s.s. and other Maekawa's genera, Asiasarum, Geotaenium and Heterotropa could distinguish by the presence or absence of some anthochlor pigments. Other flavonoids were isolated from the selected 18 Asarum species. They were characterized as some flavonol 3- or 3,7-O-glycosides based on kaempferol, quercetin and isorhamnetin, flavone, apigenin 6,8-di-C-glycoside, flavanone, naringenin 5,7-di-O-glucoside, and xanthone, mangiferin.     

A chemotaxonomic study of flavonoids from european teucrium species

A survey of aerial tissues of 42 European taxa of the genus Teucrium has revealed the widespread presence of five surface flavonoids: cirsiliol, cirsimaritin, cirsilineol, salvigenin and 5-hydroxy-6,7,3′,4′-tetramethoxyflavone. The latter two compounds are useful taxonomic markers in that salvigenin is characteristic of species of section Polium, while 5-hydroxy-6,7,3′,4′-tetramethoxyflavone is completely confined to species of the other five sections surveyed. Eleven flavone glycosides, four flavonol glycosides and the glycoflavone vicenin-2 were found to occur as vacuolar constituents. One of the flavone glycosides, cirsimaritin 4′-glucoside, only occurs in the species T. arduini, while two others, hypolaetin and isoscutellarein 7-acetyl-allosylglucosides, are characteristic of the closely related T. chamaedrys and T. webbianum. 6-Hydroxyluteolin is widely present as the 7-glucoside and 7-rhamnoside, the latter compound being a new glycoside. In general, the chemical results are correlated with sectional classification and usefully indicate that at least one taxon, T. compactum, is misplaced within the genus. Phyletically, the restriction of flavonol glycosides mainly to section Teucrium suggests that this may be the basic group within the genus.     

Poliumoside,a caffeic glycoside ester from Teucrium belion

A new caffeic glycoside ester, poliumoside, has been isolated from the aerial parts of Teucrium belion. Its structure, [β-(3′,4′-dihydroxyphenyl)-ethyl]-(3,6-O-α-L-dirhamnopyranosyl)-(4-O-caffeoyl)-β-D-glucopyranoside, was established mainly by high-resolution ¹H NMR and ¹³C NMR spectroscopy.     

Phenolic lipids from related marine algae of the order dictyotales

2-(1′-Oxo-dodeca-5′, 8′, 11′, 14′, 17′(all Z)-pentaenyl)-5-methoxy-1, 3-dihydroxybenzene, 2- (1′-oxo-dodeca-5′, 8′, 11′, 14′, 17′(all Z)-pentaenyl)-1, 3, 5-trihydroxybenzene, 2-(17′-hydroxy-1′-oxo-dodeca-5′, 8′, 11′, 14′(all Z)-tetraenyl)-1, 3, 5-trihydroxybenzene and 2-(1′oxo-hexadecyl)-1, 3, 5-trihydroxybenzene have been isolated from the related brown algae Zonaria farlowii, Z diesingiana and Lobophora papenfussii. The structures of these new metabolites are based on extensive spectral analyses and comparisons with model compounds. The isolation of (+)-7, 8-dimethyltocol, from L. papenfussii, is also reported.     

Bitter phenyl propanoid glycosides from campsis chinensis

A new bitter phenyl propanoid glycoside, campneoside I, was isolated, together with acteoside and campneoside II, from the leaves of Campsis chinensis. The stereostructure of campneoside I was established as R,S-β-methoxy-β-(3′,4′-dihydroxyphenyl)-ethyl-O-α-L-rhamnopyranosyl(1 → 3) β-^D-(4-O-caffeoyl)-glucopyranoside on the basis of the spectroscopic studies and chemical evidence.     

Three new glycosides from the whole plant of Clematis lasiandra Maxim and their cytotoxicity

Phytochemical investigation on the whole plant of Clematis lasiandra Maxim led to the isolation of two new phenolic glycosides (1 and 2), one new lignanoid glycoside (3), together with three known lignanoid glycosides (4–6). The structures of the new compounds were elucidated as 4-O-β-d-galactopyranosyl-ethyl-E-caffeate (1), 4-O-β-d-galactopyranosyl-3-hydroxyl-phenylethene (2) and (8R)-3,3′-dimethoxy-4,4′,9,9′-tetrahydroxy-5′,8-lignan 3′-O-β-d-glucopyranoside (3), on the basis of extensive spectral analysis and chemical evidence. The characteristic of the polymerized C-5′–C-8 type lignanoid aglycone in glycoside 3 was found from genus Clematis for the first time. Compounds 1–6 were evaluated for their cytotoxicity against human tumor cell lines HL-60, Hep-G2 and SGC-7901, the new glycosides 1 and 2 showed significant cytotoxicity against those three tumor cell lines with IC₅₀ in the range from 9.73 to 22.31 μM, while lignanoid glycosides 3–6 showed weak cytotoxicity to those test cell lines with IC₅₀ value more than 52.71 μM.     

Synthesis of Homo-C-D4T and Homo-C-Thymidine

Abstract

ß-C-Vinyl glycoside of D-arabinofuranose was converted to the β-C-hydroxymethyl glycoside 12 which was condensed with N-3-benzoyl thymine under Mitsunobu conditions to furnish homo-C-analog 14 of the 2′,3′-dideoxy-2′,3′-didehydrothymidine (D4T). Synthesis of the homo-C-thymidine 18 was accomplished by the same procedure from compound 15.     

Neolignans from stem bark of ocotea veraguensis

The stem bark of Ocotea veraguensis has yielded nine neolignans of which five appear to be novel. The new neolignans, which were identified on the basis of spectral characteristics, are^* (7S,8R,1′S,2′S,3′R,4′S)-Δ^8′-2′,4′-dihydroxy-3,3′5′-trimethoxy-4,5-methylenedioxy-1′,2′,3′,4′-tetrahydro-7.3′,8.1′-neolignan, (7S,8R,1′S,3′S,4′S)-Δ^8′-4,4'-dihydroxy-3,3′,5′-trimethoxy-1′,2′,3′,4′-tetrahydro-2′-oxo-7.3′,8.1′-neolignan, (7S,8S,1′R)-Δ^8′-3′,5′-dimethoxy-3,4-methylenedioxy-1′,4′-dihydro-4′-oxo-7.0.2′,8.1′-neolignan, (7S,8S,1′R )-Δ^8′-1′-methoxy-3,4-methylenedioxy-1′,6′-dihydro-6′-oxo-7.0.4′,8.3′-neolignan and (7S,8S)-Δ^8′-2′,6′-dimethoxy-3,4-methylenedioxy-7.0.3′,8.4′,1′.0.7′-neolignan.     

Methylated Chalcones from Bidens torta

Four new natural products, all methylated chalcones, including an acetylated glycoside, were isolated from Bidens torta. Their structures were determined by spectroscopic methods as okanin 3,4,3′,4′-tetramethyl ether, okanin 3,4,3′-trimethyl ether 4′-glucoside, okanin 4-methyl ether 4′-glucoside and okanin 4-methyl ether 4′-glucoside monoacetate. Okanin 3,4-dimethyl ether 4′-glucoside was also isolated.     

Eusiderins and other neolignans from an Aniba species

A previous report disclosed the presence of benzodioxan and bicyclo[3.2.1]octanoid neolignans in the benzene extract of the trunk wood of an Amazonian Aniba (Lauraceae) species. The chloroform extract of the same material contains additionally two new benzodioxan neolignans [rel-(7S,8R)-Δ^8′-7-hydroxy-3,4,5,5′-tetramethoxy-7.0.3′,8.0.4′-neolignan; rel-(7R,8R)-Δ^7′-3,4,5,5′-tetramethoxy-9′-oxo-7.0.3′,8.0.4′-neolignan], two new bicyclo[3.2.1]-octanoid neolignans [(7R,8S,1′S,2′S,3′S,4′R)-Δ^8′-2′,4′-dihydroxy-3,3′-dimethoxy-4,5-methylenedioxy-1′,2′,3′,4′,5′,6′-hexahydro-5′-oxo-7.3′,8.1′-neolignan; (7R,8S,1′R,2′S,3′S)-Δ^8′-2′-hydroxy-3,3′,5′-trimethoxy-4,5-methylenedioxy-1′,2′,3′,4′-tetrahydro-4′-oxo-7.3′,8.1′-neolignan] and a hydrobenzofuranoid neolignan [(7S,8R,1′S,5′S)-Δ^8′-3,3′,5′-tri-methoxy-4,5-methylenedioxy-1′,4′,5′,6′-tetrahydro-4′-oxo-7.0.2′,8.1-neolignan].     

Conversion of (2Z,4E)-5-(1′,2′-epoxy-2′,6′,6′-trimethylcyclohexyl)-3-methyl-2,4-pentadienoic acid to xanthoxin acid by Cercospora cruenta, a fungus producing (+)-abscisic acid

(±)-(2Z,4E)-5-(1′,2′-epoxy-2′,6′,6′-trimethylcyclohexyl)-3-methyl-2,4-pentadienoic acid was metabolized by Cercospora cruenta, which has the ability to produce (+)-abscisic acid (ABA), to give (±)-(2Z,4E)-xanthoxin acid, (±)-(2Z,4E)-5′-hydroxy-1′,2′-epoxy-1′,2′-dihydro-β-ionylideneacetic acid, (±)-1′,2′-epoxy-1′,2′-dihydro-β-ionone and trace amounts of ABA.     

An unusual porosin type neolignan from Licaria chrysophylla

The trunk wood of Licaria chrysophylla contains rel-(7S, 8R, 1′S, 5′S)-Δ^8′-3,3′,5′-trimethoxy-4,5-methylenedioxy-1′,4′,5′,6′- tetrahydro-4′-oxo-7.1′,8.0.2′-neolignan (chrysophyllin A), which differs from all other known benzofuranoid neolignans by showing 7.1′ (rather than 8.1′) and 8.0.2′ (rather than 7.0.2′) linkages between the propenylphenol and allylphenol derived moieties.     

Neolignans from Nectandra miranda

Seven neolignans, isolated from a C₆H₆ extract of Nectandra miranda (Lauraceae) trunk wood, included the hitherto undescribed (2S, 3S, 3aS)- and (2S, 3S, 3aR)-5-allyl-3a-methoxy-2-(3′, 4′, 5′-trimethoxyphenyl)-3-methyl-2, 3, 3a, 6-tetrahydro-6-oxobenzofurans (respectively mirandin-A and mirandin -B), 7-allyl-6-hydroxy-5-methoxy-2-(3′, 4′, 5′-trimethoxyphenyl)-3-methylbenzofuran and (2R, 3R)-7-methoxy-2-(3′, 4′, 5′-trimethoxyphenyl)-3-methyl-5 -(E)-propenyl-2, 3-dihydrobenzofuran (licarin C).