An acylated allose-containing 8-hydroxyflavone glycoside from Veronica filiformis

A novel flavone glycoside has been obtained from the whole plant of Veronica filiformis and identified by means of ¹³C NMR spectroscopy as isoscutellarein 4′-methyl ether 7-O-β-(6?-O-acetyl-2″-O-allosylglucoside). The related isoscutellarein glycoside is also present. This is the first report of 2-allosylglucose as a disaccharide unit of flavonoids. ¹³`C NMR data on some A-ring trioxygenated flavonoids are also presented.     

A flavonol glycoside and A sesquiterpene cellobioside from Trillium tschonoskii

The underground and aerial organs of Trillium tschonoskii afforded two new compounds in addition to dioscin, methyl protodioscin and four 18-norspi     

Triterpenes from the leaves of Pleurostylia opposita

Friedelin, friedelan-3β-ol, sitosterol, α-amyrin, 6β,20-dihydroxylupan-3-one, lup-20(29)-en-3β,6β-diol, 6β,28-dihydroxylup-20(29)-en-3-one and dulcitol were isolated from the leaves of Pleurostylia opposita. The distribution of lupanes in the Celastraceae and their chemotaxonomic significance is discussed.     

Flavonoids from Elaeodendron balae root bark

The root bark of Elaeodendron balae afforded ourateacatechin, ouratea-proanthocyanidin A and a new leucoanthocyanidin derivative elaeocyanidin.     

Polyhydroxyagarofuran derivatives from Austroplenckia populnea

The larvicidal extract of Austroplenckia populnea leaves gave two new polyesters of 8-oxo-1,2,3,4,9,14-hexahydroxydihydroagarofuran, a compound which is typical of Celastraceae species.     

Insecticidal sesquiterpene polyol ester from Celastrus angulatus

An insecticidal sesquiterpene polyol ester, angulatin A, was isolated from the root bark of Celastrus angulatus. Its structure was established as 1,2-diacetoxy-8β,15-diisobutyryloxy-9-benzoyloxy-4β, 6β-dihydroxydihydro-β-agarofuran by spectroscopic methods.     

An acylated flavonol glycoside and hydrolysable tannins from Callistemon lanceolatus flowers and leaves

Introduction –  Callistemon lanceolatus DC. (Myrtaceae) is a plant rich in polyphenols, and is used as anticough, antibronchitis and insecticide in folk medicine. Because of the biological importance of plant polyphenols, particularly tannins, a phytochemical study was of interest to investigate the constitutive poyphenols in the extracts of flowers and leaves. Objective –  To avoid time‐consuming methodology for isolation of a complex mixture of known metabolites, HPLC‐ESI/MS was employed for fast picking up of the new compounds followed by identification of the structures with UV and one‐ and two‐dimensional NMR. Methodology –  Flowers and leaves were separately extracted with hot aqueous methanol under reflux (70°C). Pre‐isolation of the total extracts was achieved through column chromatographic fractionation on polyamide with water–methanol for gradient elution. The main fractions were purified using repeated column chromatography on cellulose and/or Sephadex LH‐20 with suitable eluents. HPLC‐ESI/MS analyses were carried out in the single ion monitoring (SIM) and negative ion modes. The pure compounds in methanol–water (1:1) were analysed by direct infusion ESI/MS. Final structure elucidation was obtained by one‐ and two‐dimensional NMR. Results –  Two new metabolites namely quercetin 3‐O‐β‐D‐glucuronopyranoside n‐butyl ester ( 1 ) and n‐butylgallate 4‐O‐(2′,6′‐di‐O‐galloyl)‐β‐d ‐glucopyranoside ( 4 ) along with nine known ones were identified from the aqueous methanol extracts of flowers and leaves. Conclusion –  The study has shown that Callistemon lanceolatus is rich in polyphenols. HPLC‐ESI/MS may be used, in negative ion mode, as an efficient and rapid analytical tool for investigating complex plant extracts. Copyright © 2008 John Wiley & Sons, Ltd.     

Two new acylated drimane-type sesquiterpene glucosides from Petrorhagia saxifraga

Two new acylated drimane sesquiterpenoid glucosides, saxifragoside A and B, have been isolated from the methanol extract of Petrorhagia saxifraga, a perennial herbaceous plant typical of the Mediterranean vegetation. The structures of these compounds have been elucidated on the basis of extensive 2D NMR spectroscopic analyses, including COSY, TOCSY, NOESY, HSQC, CIGAR-HMBC, H2BC and HSQC-TOCSY, along with Q-TOF HRMS² analysis. As drimane glucosides have already been reported in other plants of Petrorhagia genus, they could represent a useful chemotaxonomic marker for this genus.     

Glaucolide-like sesquiterpene lactones from Cotula cinerea

The aerial parts of Cotula cinerea gave, in addition to widespread compounds, a characteristic diacetylenic spiroketal enolether and several sesquiterpene lactones, three of them being glaucolide-like lactones. The structures were elucidated by highfield ¹H NMR spectroscopy.     

Further sesquiterpene lactones from Calea and Viguiera species

The aerial parts of Calea clematidea gave three new germacranolides, those of Viguiera procumbens two orizabin derivatives and those of V. linearis dihydrobudlein A. In addition to these lactones, several known ones were isolated.     

Two sesquiterpene lactones from Trichogonia gardneri

The structures and stereochemistries of two sesquiterpene lactones from Trichogonia gardneri were established as (6R,7S,8S,9S,IOR)-4E-9,10-dihydroxy-8-tigloxygermacr-4-en-6,12-olide) and (5R*,6R*,7S*,8S*,9R*)-14-acetoxy-3-chloro-9-hydroxy-2-oxo-8-tigloxyguia-1(10),3-dien-6,12-of olide by a combination of NMR spectrometry and X-ray diffraction. The results show that the structures of several sesquiterpene lactones which were isolated previously from related species require revision.     

Ant-repellent sesquiterpene lactones from Eupatorium quadrangularae

The chloroform extract from the leaves of Eupatorium quadrangularae has been systematically fractionated by following biological activity in a bioassay which measures repellency to the leafcutter ant Atta cephalotes (Formicidae, Attini). Several sesquiterpene lactones were isolated, two of which showed significant ant-repellency.     

Antimalarial sesquiterpene lactones from Distephanus angulifolius

Combined use of bioassay-guided fractionation based on in vitro antiplasmodial assay and dereplication based on HPLC-PDA-MS-SPE-NMR led to isolation of (6S,7R,8S)-14-acetoxy-8-[2-hydroxymethylacrylat]-15-helianga-1(10),4,11(13)-trien-15-al-6,12-olid and (5R,6R,7R,8S,10S)-14-acetoxy-8-[2-hydroxymethylacrylat]-elema-1,3,11(13)-trien-15-al-6,12-olid, along with vernodalol, vernodalin, and 11,13β-dihydroxyvernodalin from extract of Distephanus angulifolius. All compounds were identified by spectroscopic methods, including 1D and 2D homo- and heteronuclear NMR experiments. The isolated compounds showed IC₅₀ values in the range 1.6-3.8 μM and 2.1-4.9 μM against chloroquine sensitive D10 and chloroquine resistant W2 Plasmodium falciparum strains, respectively.     

Seven sesquiterpene lactones from Ferreyanthus species

The investigation of two Ferreyanthus species afforded seven germacranolides which have not been isolated previously. Two derivatives of linalol were also present. The structures were elucidated by spectroscopic methods. Chemotaxonomic relationships are briefly discussed.     

Two acylated flavanone glycosides from Nierembergia hippomanica

Two new acylated flavanone glycosides have been isolated from Nierembergia hippomanica and identified by spectral data as pinocembrin 7-O-β-(3?-O-acetyl)neohesperidoside and pinocembrin 7-O-β-(6″-O-acetyl)neohesperidoside.     

The chemistry of toxic principles from Maytenus nemerosa

Maytenus nemerosa has been fractionated systematically by following the toxicity of extracts, partitioned solutions and column chromatographic fractions against cultured KB cells. Several compounds were isolated in this fashion, including 3-oxo-20(29)-lupen-30-al, β-amyrin, 29-hydroxyfriedelan-3-one, 30-hydroxy-20(29)-lupen-3-one, 30-hydroxyfriedelan-3-one and lup-20(29)-ene-3β,30-diol, as well as tingenone, 20-hydroxytingenone and galactitol. 3-Oxo-20(29)-lupen-30-al was shown to be cytotoxic for the first time; the structural basis of this cytotoxicity was investigated, in part, by bioassay of four products obtained by chemical transformation of single, isolated principles.     

The sesquiterpene constituents of Mortonia hidalgensis

The structure of mortonol B, a sesquiterpene constituent of Mortonia hidalgensis, was established as 2β-acetoxy-mortonol A. Mortonol B is propose