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O Potterat

Publications and source records attributed to O Potterat.

10 recordsLinked to original sources
PubMed2001

Flavonoids and phenylpropanoid derivatives from Campanula barbata.

Four new phenylpropanoid derivatives, barbatosides A-D, and a new catechin, barbatoflavan, were isolated from the whole plant of Campanula barbata L. (Campanulaceae) and identified as wahlenbergioside-3'-O-glucoside, wahlenbergioside-3'-O-(2'''-(p-methoxycinnamoyl))-glucoside, wahlenbergioside-3'-O-(4'''-(trans-p-coumaroyl))-glucoside, wahlenbergioside-3'-O-(4"'-(cis-p-coumaroyl))-glucoside and 3-acetyl-5-methoxy-7,3',4'-trihydroxy-8-O-glucoside-flavan-3-ol, respectively, by spectroscopic methods. In addition, four flavonols were isolated and identified as kaempferol-3-O-glucoside, kaempferol-3-O-rutinoside, quercetin-3-O-glucoside and quercetin-3-O-rutinoside. Barbatoflavan demonstrated scavenging properties towards the DPPH radical.

Asteraceae↗
PubMed2000

Liquid chromatography-electrospray time-of-flight mass spectrometry for on-line accurate mass determination and identification of cyclodepsipeptides in a crude extract of the fungus Metarrhizium anisopliae.

Electrospray ionisation time-of-flight mass spectrometry (ESI-TOF-MS) has been used for the detection and identification of destruxins (cyclodepsipeptides) in a crude extract of the fungus Metarrhizium anisopliae. HPLC-MS analyses were performed with a post-column addition of erythromycin as a reference compound (lock mass procedure). Seven destruxin derivatives could be identified on-line from their accurate masses (deviation from calculated values <5.5 ppm) through elemental composition calculations. As a highly sensitive and accurate method, ESI-TOF-MS proved to be very powerful for the analysis and dereplication of natural products in complex mixtures.

Chromatography, High Pressure Liquid↗
PubMed2000

A stilbene and dihydrochalcones with radical scavenging activities from Loiseleuria procumbens.

A new dihydrochalcone, 6''-acetylphloridzosid, was isolated from the whole plant of Loiseleuria procumbens (L.) Desv. and identified as 2'-O-(6''-O-acetylglucopyranosyl)-4,4',6'-trihydroxydihydrochal cone by spectroscopic methods. In addition, one stilbene and three other dihydrochalcones were identified as (E)-piceid, phloretin (2',4,4',6'-tetrahydroxydihydrochalcone), phloridzosid (2'-O-glucopyranosyl-4,4',6'-trihydroxydihydrochalcone) and asebotin (2'-O-glucopyranosyl-4'-methoxy-4,6'-dihydroxydihydrochalcone), respectively. Some of these compounds showed scavenging properties towards the 2,2-diphenyl-1-picrylhydrazyl radical and antioxidant properties in a test with lysozyme.

Chalcone↗
PubMed1998

Use of on-flow LC/1H NMR for the study of an antioxidant fraction from Orophea enneandra and isolation of a polyacetylene, lignans, and a tocopherol derivative.

The CH2Cl2 extract of the leaves of Orophea enneandra displayed antifungal, antioxidant, and radical scavenging properties in bioautographic TLC assays. To obtain rapid information on the active compounds, on-flow LC/1H NMR and LC/UV/MS analyses of the antioxidant fraction were performed. The on-line information led rapidly to the partial identification of three closely related lignans, one tocopherol derivative, and one polyacetylene. This approach necessitated, however, large quantities to be injected to obtain satisfactory on-flow LC/1H NMR spectra, and isolation of the compounds was necessary to obtain complete NMR data. These compounds were isolated and identified as (-)-phylligenin (1), (-)-eudesmin (2), (-)-epieudesmin (3), polycerasoidol (4), and oropheic acid (5), a new polyacetylene. Their activities against the 2, 2-diphenyl-1-picrylhydrazyl radical and the fungus Cladosporium cucumerinum were investigated. This paper indicates the possibilities and limits of on-flow LC/1H NMR in this type of study.

Acetylene↗
PubMed1996

Xanthones from Hypericum roeperanum.

Four new xanthones have been isolated from the roots of Hypericum roeperanum. Their structures have been established by a combination of spectroscopic and chemical methods as 1,6-dihydroxy-5-methoxy-4',5'-dihydro-4',4',5'-trimethylfurano- (2',3':3,4)-xanthone (5-O-methyl-2-deprenylrheediaxanthone B), 1,6-dihydroxy-5-methoxy-6',6'-dimethylpyrano-(2',3':3,4)-xanthone (5-O-methylisojacareubin), 1,3,5,6-tetrahydroxy-2-(2',2'-dimethyl-4'-isopropenyl)-cyclopen tanylxanthone (5-O-demethylpaxanthonin) and 1,3,5,6-tetrahydroxy-4-trans-sesquilavandulylxanthone (roeperanone). In addition, 2-hydroxyxanthone, 5-hydroxy-2-methoxyxanthone, 1,5-dihydroxy-2-methoxyxanthone, 2-deprenyl rheediaxanthone B, isojacareubin and calycinoxanthone D have been isolated and characterized. Some of the isolated xanthones exhibited antifungal activity against Candida albicans.

Antifungal Agents↗
PubMed1996

Kanchanamycins, new polyol macrolide antibiotics produced by Streptomyces olivaceus Tii 4018. II. Structure elucidation.

Kanchanamycins are a new group of polyol macrolide antibiotics isolated from Streptomyces olivaceus Tü 4018. They all share a common bicyclic carbon skeleton formed by a 36-membered lactone ring and a 6-membered hemiacetal ring. A feature unusual for that class of macrolides is the terminal urea moiety observed in kanchanamycin A. The structures of the kanchanamycins were determined by electrospray MS and modern 2D NMR techniques. Due to substantial overlap of the signals intensive use of inverse detected heteronuclear correlation experiments (HSQC, HMBC, 2D-HSQC-TOCSY) was made.

Anti-Bacterial Agents↗
PubMed1995

Antibacterial phloroglucinols and flavonoids from Hypericum brasiliense.

Three known phloroglucinols (japonicine A, uliginosin A and isouliginosin B) and a new phloroglucinol (hyperbrasiol A) have been isolated from a petrol extract of the leaves and flowers of Hypericum brasiliense. Their structures were established by spectroscopic methods (UV, DCI-MS, 1H and 13CNMR, including SINEPT, HMBC, HSQC, DQFCOSY experiments). The substitution pattern of hyperbrasilol A was confirmed by X-ray crystallography. All four phloroglucinols were antibacterial against Bacillus subtilis in a TLC bioautographic assay. The flavonoids, kaempferol, luteolin, quercetin, quercitrin, isoquercitrin, hyperoside and guaijaverin, were isolated from a methanol extract of the same organs.

Anti-Bacterial Agents↗
PubMed1988

Isolation of biologically active plant constituents by liquid chromatography.

Strategies are outlined for the separation of biologically active products of plant origin. The techniques involved include low-pressure liquid chromatography, semi-preparative high-performance liquid chromatography, flash chromatography and droplet counter-current chromatography. Their application to the isolation of compounds from Sesamum angolense (Pedaliaceae), Psorospermum febrifugum (Guttiferae) and Cordia goetzei (Boraginaceae) is described.

Anthracenes↗