Flavonoids and terpenoids from Helichrysum forskahlii

Three new flavonoids, namely helichrysone A (1), helichrysone B (2) and helichrysone C (3) were isolated from the aerial parts of Helichrysum forskahlii, together with 10 known flavonoids, three triterpenes, and one sesquiterpene. The structures of the new flavonoids 1-3 were established by 1D and 2D NMR spectral data. In addition, the antimicrobial activities of the isolated compounds were determined.     

Pseudoguaianolides from the flowers of Parthenium hysterophorus

Chemical investigation on the flowers of Parthenium hysterophorus has resulted in the isolation of four new pseudoguaianolides, hysterones A-D along with the known compounds, parthenin, coronopilin, 2beta-hydroxycoronopilin and tetraneurin-A. The structures of the new compounds were established by interpretation of their spectral (1D and 2D NMR) data. The X-ray crystallographic analysis of hysterones A and C was also carried out.     

Cimiracemates A-D,phenylpropanoid esters from the rhizomes of Cimicifuga racemosa

Four phenylpropanoid esters, cimiracemates A-D (1-4), along with three known compounds, isoferulic acid, ferulic acid and methyl caffeate were isolated from the EtOAc fraction of the rhizome of Cimicifuga racemosa. The structures of the esters were elucidated by means of spectral data, including 2D NMR spectroscopy.     

Stereochenols A and B, two quinones from Stereospermum chelonoides

Two quinones, stereochenols A (1) and B (2) were isolated from a methanol extract of the stem bark of Stereospermum chelonoides, in addition to the known naphthoquinones, sterekunthal B (3) and sterequinone C (4). The structures of these compounds were established by extensive spectroscopic analyses and by comparison of their spectral data with those of related compounds.     

A guaianolide alloside and other constituents from Picris kamtschatica

From Picris kamtschatica two new guaianolide glycosides, including a beta-allopyranosyl analogue of ixerin F, were isolated, in addition to ten known sesquiterpene lactones and six phenolic compounds. This is the first time a sesquiterpene lactone alloside has been described from plants. The compounds were characterized based on mass, 1D and 2D NMR spectral data.     

E/Z-Thesinine-O-4'-alpha-rhamnoside, pyrrolizidine conjugates produced by grasses (Poaceae)

Based on direct infusion mass spectrometry we identified a novel alkaloid as a major component of perennial ryegrass (Lolium perenne). Initial mass spectral data suggested it to be a pyrrolizidine conjugate. As this class of alkaloids has not been described before from grasses, we isolated it to elucidate its structure. The isolated alkaloid proved to be a mixture of two stereoisomers. The structures of the two compounds as determined by 1D and 2D NMR spectroscopy, were E-thesinine-O-4'-alpha-rhamnoside (1) and Z-thesinine-O-4'-alpha-rhamnoside (2). These identifications were supported by the characterisation by GC-MS and optical rotation of (+)-isoretronecanol as the necine base released on alkaline hydrolysis of these alkaloids. 1 and 2 together with the aglycone and a hexoside were also detected in tall fescue (Festuca arundinacea). This is the first report of pyrrolizidine alkaloids produced by grasses (Poaceae).     

Diterpenoid quinones from rosemary (Rosmarinus officinalis L.)

Two new abietane-type diterpenoid o-quinones, 7beta-methoxyabieta-8,13-diene-11,12-dione-(20,6beta)-olide (rosmaquinone A) (1) and 7alpha-methoxyabieta-8,13-diene-11,12-dione-(20,6beta)-olide (rosmaquinone B) (2), together with six known compounds were isolated from the aerial parts of Rosmarinus officinalis L. The structures of the new compounds were determined by extensive spectroscopic analysis, including IR, UV, HR-EIMS, 1D and 2D 400 MHz NMR data (1H, 13C NMR, DEPT, 1H-1H COSY, HMQC, HMBC and NOEs).     

Benzoic acid allopyranosides from the bark of Pseudolarix kaempferi

Two benzoic acid allopyranosides, pseudolaroside A and pseudolaroside B, along with seven known compounds were isolated from the bark of Pseudolarix kaempferi. Their structures were determined by analysis of HR-ESI-MS, 1D and 2D NMR spectroscopic data, chemical analysis and comparison to the literature data.     

Studies on the Lignans of Polygonum orientale

Three lignans were isolated from the aerial parts of Polygonum orientale L. Their structures were elucidated as arctiin (1), lappaol B (2), orientalin (3) by means of the spectral data and chemical methods. Among them, 3 is a novel compound, compounds 1 and 2 were first found in this plant.     

Charminarone,a seco-pseudoguaianolide from Parthenium hysterophorus

A novel sesquiterpenoid, charminarone, the first seco-pseudoguaianolide, has been isolated along with several known compounds from the whole plant of Parthenium hysterophorus. The structure of the new compound has been settled as 1,10-seco-dihydroisoparthenin 1,10-dione from its spectral data as well as from its conversion by reductive coupling reaction with Zn/TiCl(4) reagent to the known compound, anhydrodihydroisoparthenin. The reagent Zn/TiCl(4) has been used here for the first time to construct the seven membered ring of a pseudoguaianolide sesquiterpenoid.     

Bioactive monoterpene glycosides conjugated with gallic acid from the leaves of Eucalyptus globulus

Two monoterpene glycosides, conjugated with gallic acid [globulusin A (1) and B (2)], together with four known compounds, cypellocarpin A (3), eucaglobulin (4), cuniloside (5) and (1S, 2S, 4R)-trans-2-hydroxy-1,8-cineole beta-d-glucopyranoside (6), were isolated from hot-water extracts of the leaves of Eucalyptus globulus. The structures of compounds 1 and 2 were determined by 1D, 2D NMR and MS spectroscopic analyses. The absolute stereochemistry of 1 was determined by correlating the spectroscopic data with those of synthetic compound 6 with a known configuration. Globulusin A (1) and B (2), cypellocarpin A (3) and eucaglobulin (4), scavenged DPPH free radicals and globulusin A (1) showed a higher antioxidant activity than the other tested compounds, with an IC50 of 3.8microM. Globulusin A (1) and eucaglobulin (4) concentration-dependently suppressed inflammatory cytokine production, tumor-necrosis factor-alpha and interleukin-1beta in cultured human myeloma THP-1 cells co-stimulated with phorbol myristate acetate. These compounds also inhibited melanogenesis in cultured murine melanoma B16F1 cells, without any significant cytotoxicity. These results suggested that globulusin A (1) and eucaglobulin (4), which were isolated as antioxidants from E. globulus, also had anti-inflammatory as well as anti-melanogenesis activity.     

Acylated 5,7,2',6'-oxygenated flavone glycosides from Andrographis alata

Five acylated 5,7,2',6'-oxygenated flavone glycosides along with the known 5,2',6'-trihydroxy-7-methoxyflavone-2'-O-beta-d-glucopyranoside have been isolated from the whole plant of Andrographis alata. The structures of the compounds were established from spectral (mainly 1D and 2D NMR) and chemical studies.     

Neolignan and flavonoid glycosides in Juniperus communis var. depressa

Two neolignan glycosides (junipercomnosides A and B) were isolated from aerial parts of Juniperus communis var. depressa along with two known neolignan glycosides and seven flavonoid glycosides. The structures of the isolated compounds were determined by spectral analysis, in particular by 2D-NMR analysis. The significance of distribution of flavonoids in the chemotaxonomy of genus Juniperus was also discussed.     

Stilbenoids in the stem bark of Hopea parviflora

From the bark of Hopea parviflora, two stilbenoids, named (+)-parviflorol and (-)-ampelopsin A, were isolated in addition to three known compounds: (+)-balanocarpol, (-)-epsilon-viniferin and (-)-hopeaphenol. Their structures were determined by analysis of spectral data, including 2D NMR and NOE experiments, respectively.     

Polar acyclic diterpenoids from Bifurcaria bifurcata (Fucales, Phaeophyta)

From the lipophilic extract of the brown alga Bifurcaria bifurcata collected off the Atlantic coast of Southern Brittany (Quiberon, France), five polar linear diterpenoids have been isolated. These metabolites have been identified as hydroxylated derivatives of 13-oxo- and 13-hydroxygeranylgeraniol. Their structures were characterized on the basis of chemical and spectral evidence including two-dimensional NMR experiments and mass spectrometric techniques. The absolute configuration of the 13-position has been determined, for the 13-hydroxygeranylgeraniol derivatives, to be R by means of a modified Mosher's method and therefore that of 13-hydroxygeranylgeraniol (eleganediol) has been revised. Along with these compounds, three related known geranylgeraniol derivatives were also identified, and these data were used for chemotaxonomical purposes.     

ent-Kaurane diterpenoid glycosides from a Malagasy endemic plant,Cussonia vantsilana

Four ent-kaurane diterpenoid glycosides, cussovantosides A-D, were isolated from the dried leaves of Cussonia vantsilana Baker, together with six known compounds. The structures of the compounds were deduced on the basis of their physical and spectral data.     

Polyketides from Penicillium sp. JP-1, an endophytic fungus associated with the mangrove plant Aegiceras corniculatum

Four polyketides, leptosphaerone C (1), penicillenone (2), arugosin I (3) and 9-demethyl FR-901235 (4), as well as five known compounds, bacillosporin A (5), bacillosporin C (6), sequoiamonascin D (7), sequoiatone A (8), and sequoiatone B (9) were isolated from the Penicillium sp. JP-1, an endophytic fungus isolated from Aegiceras corniculatum. Their structures were determined by spectroscopic methods, mainly by 2D NMR spectroscopic analyses. Compound 1 showed cytotoxicity against A-549 cells with an IC50 value of 1.45 microM, while compound 2 showed cytotoxicity against P388 cells with an IC50 value of 1.38 microM.     

Acetophenone C-glucosides and stilbene O-glucosides in Upuna borneensis

Three acetophenone C-glycosides; 2,4,6-trihydroxyacetophenone 3-C-beta-(2'-O-p-hydroxybenzoyl)-glucopyranoside, 2,4,6-trihydroxyacetophenone 3-C-beta-(2'-O-E-coumaroyl)-glucopyranoside, 2,4,6-trihydroxyacetophenone 3-C-beta-(2'-O-E-cinnamoyl)-glucopyranoside, and two resveratrol O-glycosides; piceid 2'-O-p-hydroxybenzoate and, piceid 2'-O-E-ferulate, together with three known compounds were isolated from the acetone soluble part of stem of Upuna borneensis (Dipterocarpaceae). The structures of isolates were determined by spectral analysis including extensive 2D-NMR spectral analyses.     

Extraction, structural characterisation and evaluation of hydroxycinnamate esters of orchard grass (Dactylis glomerata) as substrates for polyphenol oxidase

Polyphenol oxidase (PPO) activity has been reported in orchard grass (Dactylis glomerata); however, to date, no endogenous substrates have been identified. In the present study, we report the isolation and structural elucidation of PPO substrates in this species. The free phenol fraction was extracted, separated by reverse-phase chromatography and six potential substrates, including two hydroxycinnamate esters, were identified by UV spectrometry, electrospray ionisation-tandem mass spectrometry (LC-ESI-MSⁿ) and 1D and 2D NMR analyses (¹H NMR, ¹³C NMR, DEPT, COSY, HMQC and HMBC). Furthermore, three caffeoylquinic acids (3-CQA, 4-CQA and 5-CQA) were identified by comparison of their spectral data (ESI-MS) with those of known compounds and literature data. Five of these compounds were demonstrated to be substrates for orchard grass PPO.     

Koanolides B-D,new sesquiterpene lactones from Koanophyllon gibbosum

Three new germacrane-type sesquiterpene lactones, koanolides B–D (1-3) have been isolated from the aerial parts of Koanophyllon gibbosum (Asteraceae), along with the previously reported sesquiterpene lactone koanolide A and the flavonoid eupatorin. The structures of the new compounds were elucidated using spectroscopic and spectrometric data analyses, including 1D and 2D NMR, and by comparison with known spectral data. The antiproliferative activities of the new compounds were evaluated in a panel of six representative human solid tumor cell lines and showed GI₅₀ values ranging from 1.3 to 16 μM for the new molecules.