Bernhard Vogler

Abaco Bush Medicine: Chemical Composition of the Essential Oils of Four Aromatic Medicinal Plants from Abaco Island, Bahamas

ABSTRACT The leaf essential oils of four aromatic plants used in traditional “bush” medicine on Abaco Island, Bahamas, were obtained by hydrodistillation and analyzed by GC-MS. The most abundant components of Amyris elemifera (Rutaceae) were limonene (45.0%), linalool (20.8%), (β-caryophyllene (5.6%), 3-hexadecanone (5.3%), caryophyllene oxide (3.9%), and (β-sesquiphellandrene (3.6%). Eugenia axillaris (Myrtaceae) leaf oil was largely composed of α-pinene (15.5%), dihydroagarofuran (9.2%), β-caryophyllene (8.8%), α-humulene (6.9%), 1,8-cineole (6.6%), and germacrene D (6.2%). The leaf essential oil of Lantana involucrate (Verbenaceae) was made up largely of germacrene D (21.1%), α-humulene (15.2%), and β-caryophyllene (13.7%). The most abundant components of Myrica cerifera (Myricaceae) were 1,8-cineole (30.7%), α-terpineol (14.2%), 4-terpineol (9.0%), and β-caryophyllene (6.4%). The antimicrobial activity against Bacillus cereus, Pseudomonas aeruginosa, Escherichia coli, Pseudomonas aeruginosa, Candida albicans, and Aspergillus niger, and the in vitro cytotoxicity of the oils on MDA-MB-231, MCF7, Hs 578T, Hep G2, and PC-3 human tumor cells have also been examined. The reported biological activities of the major constituents of A. elemifera leaf oil are consistent with the ethnopharmacological uses of the plant in the Bahamas to reduce fever, treat symptoms of flu, treat sores, and wounds, and its use as a general tonic and bath. L. involucrate leaf oil shows slight antibacterial activity against B. cereus and Staph. aureus and is weakly cytotoxic against our panel of cell lines. The major components in the leaf oil and slight antimicrobial activity are consistent with the ethnobotanical use of L. involucrata to treat itching skin. Neither E. axillaris nor M. cerifera leaf essential oils are appreciably antimicrobial or cytotoxic. In addition, none of the major components from these essential oils show notable activity in our antimicrobial or cytotoxicity assays.

Two triterpene esters from Terminalia macroptera bark

Abstract Investigation of the bark from Terminalia macroptera led to the isolation of two novel esterified triterpenes, identified as 23-galloylarjunolic acid and its β- d -glucopyranosyl ester. In addition terminolic acid, arjunic acid, arjungenin, arjunglucoside 1 , sericic acid and sericoside were isolated and tested in a number of bioassays (antibacterial, antifungal and anthelminthic activity as well as haemolytic property).

Sesquiterpene lactone chemistry of Zaluzania grayana from on-line LC-NMR measurements

On-line LC-NMR measurements were used for the first time to elucidate the sesquiterpene lactone chemistry of a Compositae species, Zaluzania grayana. Structure elucidation of three compounds, visible in HPLC analysis of the constituents of glandular trichomes, was performed on a leaf extract of less than a gram of dried plant tissue by means of direct coupling of the HPLC and NMR instruments. The structures could be assigned to the guaianolide zaluzanin C, a new modified guaianolide and to the 15-hydroxy derivative of costunolide. The taxonomic relevance of the identified compounds is discussed.

Application of high-performance liquid chromatography coupled to nuclear magnetic resonance spectrometry, mass spectrometry and bioassay for the determination of active saponins from Bacopa monniera Wettst.

Reversed-phase high-performance liquid chromatographic separation coupled to (structurally informative) spectroscopic methods like NMR and MS and an efficient bioassay have been used to determine the active compounds from a crude fraction of Bacopa monniera. The fraction containing a mixture of saponins with closely related structures was found to show a significant anthelmintic activity against Caenorhabditis elegans (used as a model test organism for determining anthelmintic activity). The activity was correlated to two dammarane type triterpenoidal saponins containing at least three sugar units. The optimization of separation for 1 mg of the crude sample on column and the sensitivity of on-flow one- and two-dimensional NMR experiments to the high-molecular-mass compounds (M(r) 890-930) has been demonstrated.

Sesquiterpene lactones and a myoinositol from glandular trichomes of Viguiera quinqueremis (Heliantheae; Asteraceae)

The extract of the floral parts of Viguiera quinqueremis afforded, in addition to known compounds, six new sesquiterpene lactones as well as a new myoinositol derivative. All compounds were detected in glandular trichomes which were collected micromechanically from the anther appendages and were analyzed by HPLC. Structure identification was performed by 1H NMR measurements including LC NMR and LC MS experiments.

Identification and quantification of flavonoids and ellagic acid derivatives in therapeutically important Drosera species by LC–DAD, LC–NMR, NMR, and LC–MS

AbstractDroserae herba is a drug commonly used for treatment of convulsive or whooping cough since the seventeenth century. Because of the contribution of flavonoids and ellagic acid derivatives to the therapeutic activity of Droserae herba, an LC–DAD method has been developed for quantification of these analytes in four Drosera species used in medicine (Drosera anglica, D. intermedia, D. madagascariensis, and D. rotundifolia). During elaboration of the method 13 compounds, including three substances not previously described for Drosera species, were detected and unambiguously identified by means of extensive LC–MS and LC–NMR experiments and by off-line heteronuclear 2D NMR after targeted isolation. The most prominent component of D. rotundifolia and D. anglica, 2″-O-galloylhyperoside, with myricetin-3-O-β-glucopyranoside and kaempferol-3-O-(2″-O-galloyl)-β-galactopyranoside, were identified for the very first time in this genus. The LC–DAD method for quantification was thoroughly validated, and enables, for the first time, separation and precise analysis of these analytes in Droserae herba. Simple sample preparation and use of a narrow-bore column guarantee low cost and simplicity of the suggested system, which is excellently suited to quality control of the drug or herbal medicinal products containing this drug. Figure2″-O-galloylhyperoside - a major compound in Drosera anglica and Drosera rotundifolia

Sesquiterpene lactones from glandular trichomes of Viguiera radula (Heliantheae; Asteraceae).

In addition to known compounds, the floral parts of Viguiera radula afforded two new sesquiterpene lactones. All compounds were detected in glandular trichomes, which were micromechanically collected from the anther appendages and analyzed by HPLC. Structure identification was performed by NMR and MS techniques.

Isolation and identification of N-mercapto-4-formylcarbostyril, an antibiotic produced by Pseudomonas fluorescens.

Pseudomonas fluorescens strain G308 isolated from barley leaves produces a novel antibiotic substance that was purified by preparative TLC and HPLC and identified as N-mercapto-4-formylcarbostyril (Cbs) by LC/DAD, IR, LC-ES(+)/MS, LC-ES(-)/MS, GC-EI/MS, LC-HRES(+)/MS, mass isotope ratios analysis, 1H NMR and 13C NMR analysis. The purified new antibiotic compound is effective against many phytopathogenic fungi in vitro. The compound inhibited at 25 ppm spore germination and germ tube growth of the following fungi; Fusarium oxysporum f. sp. lycopersici, Fusarium culmorum, Cladosporium cucumerinum and Colletotrichum lagenarium. At concentrations up to 125 ppm, the compound did not interfere with release of zoospores from sporangia and germination of encysted zoospores of Phytophthora infestans.

Sesquiterpene lactones and flavanones in Scalesia species

Trichome microsampling and HPLC analysis revealed the presence of sesquiterpene lactones and flavonoids in capitate glandular trichomes from the leaf surface of various species of Scalesia. The paucity in plant material of these plants, endemic to the Galapagos Islands, necessitated the use of micropreparative techniques including LC-NMR and LC-MS for structure elucidation. Leaf extracts of Scalesia baurii ssp. hopkinsii, S. stewartii and a combined sample of several species of the genus afforded two eudesmanolides, four guaianolides, four xanthanolides and three flavanones. This is the first report on the terpenoid chemistry of Scalesia and the chemotaxonomic aspects are discussed.

Sesquiterpene lactones in Viguiera eriophora and Viguiera puruana (Heliantheae; Asteraceae)

Extracts of the aerial parts of Viguiera eriophora ssp. eriophora and Viguiera puruana afforded, in addition to known compounds, six new heliangolides and a germacrolide, whose structures were determined by spectral analysis. HPLC analysis and LC NMR experiments revealed the natural occurrence of the compounds in glandular trichomes. The taxonomic relevance of the results is briefly discussed.