Search results for "DISCOVERY"

2017

The 6-epimer of the plakortide H acid (1), along with the endoperoxides plakortide E (2), plakortin (3), and dihydroplakortin (4) have been isolated from a sample of the Caribbean sponge Plakortis halichondrioides. To perform a comparative study on the cytotoxicity towards the drug-sensitive leukemia CCRF-CEM cell line and its multi-drug resistant subline CEM/ADR5000, the acid of plakortin, namely plakortic acid (5), as well as the esters plakortide E methyl ester (6) and 6-epi-plakortide H (7) were synthesized by hydrolysis and Steglich esterification, respectively. The data obtained showed that the acids (1, 2, 5) exhibited potent cytotoxicity towards both cell lines, whereas the esters s…

Experimental Inhibition of Fibrillogenesis and Neurotoxicity by amyloid-beta (Aβ) and Other Disease-Related Peptides/Proteins by Plant Extracts and H…

2012

Amyloid-β (Aβ) fibrillogenesis and associated cyto/neurotoxicity are major pathological events and hallmarks in diseases such as Alzheimer’s disease (AD). The understanding of Aβ molecular pathogenesis is currently a pharmacological target for rational drug design and discovery based on reduction of Aβ generation, inhibition of Aβ fibrillogenesis and aggregation, enhancement of Aβ clearance and amelioration of associated cytotoxicity. Molecular mechanisms for other amyloidoses, such as transthyretin amyloidosis, AL-amyloidosis, as well as α-synuclein and prion protein are also pharmacological targets for current drug therapy, design and discovery. We report on natural herbal compounds and e…

New oxygenated eudesmanolides from artemisia herba-alba

1990

Abstract The aerial parts of Artemisia herba-alba Asso subsp.valentina Lam. (Asteraceae) yielded the new eudesmanolides 1-11 and the new sesquiterpene-monoterpene adducts 12-13. The absolute configuration of compound 6 was confirmed with the aid of X-ray diffraction analysis. Some aspects of the thermal and photochemical reactivity of 2,4-cyclohexadienones are discussed.

Über die mikrobiologische Umwandlung N-haltiger Substrate. 4. Mitt.: Über die mikrobiologische Umwandlung von 5-Hydroxyindol durch Claviceps purpurea…

1968

Aus 5-Hydroxyindol wird durch den Claviceps purpurea-Stamm 47 A 5-Hydroxytryptophan und ω-N-Acetyl-5-hydroxy-tryptophan, durch Cordyceps militaris ω-N-Acetyl-5-hydroxytryptophan und ω-N-Acetyl-serotonin, durch Aspergillus oryzae nur ω-N-Acetyl-serotonin in der Schuttelkultur gebildet. 5-Hydroxyindole, added to submerged cultures, is converted into 5-hydroxytryptophan and ω-N-acetyl-5-hydroxytryptophan by Claviceps purpurea strain 47 A; into ω-N-acetyl-5-hydroxytryptophan and ω-N-acetyl-serotonin by Cordiceps militaris; and only into-ω-N-acetyl-serotonin by Aspergillus oryzae.

Antimykotische Wirkstoffe, Mitt. Chlor-(1-piperazinyl)-1,3,5-triazine

1988

Aus der Umsetzung von Cyanurchlorid (1) mit den Piperazinderivaten 2a–c bei –20 bis 10° gehen die Dichlor-(1-piperazinyl)-1,3,5-triazine 3a–c hervor. Bei der erhohten Reaktionstemperatur von 40° erfolgt aus 1 und den Piperazinderivaten 4a–b Bildung der 2-Chlor-4,6-bis(piperazinyl)-1,3,5-triazine 5a–b. Zu gemischt substituierten Chlor-1,3,5-triazinen 9 fuhrt die nacheinander erfolgende Umsetzung von 1 mit 2 verschiedenen cyclischen sekundaren Aminen (6 und 8). Die Strukturtypen 3, 5 und 9 zeigen in den 1H-NMR-Spektren zwei fur Piperazinringe charakteristische Signalgruppen im Bereich 2.4–4.0 ppm. Unter den neu entwickelten Verbindungen finden sich Vertreter mit sehr starker antimykotischer W…

Natural and hemisynthetic neoclerodane diterpenoids from Scutellaria and their antifeedant activityElectronic supplementary information (ESI) availab…

2002

Covering: Up to June 2001. Previous review: on the clerodanes, Nat. Prod. Rep., 1992, 9, 243.

Aktivit�tsbestimmung der Isoenzyme der Aldolase im menschlichen Serum mit Hilfe pr�zipitierender Antik�rper

1975

Die Isoenzyme der Aldolase im Serum wurden mit Hilfe prazipitierender Antikorper bestimmt. Das Isoenzymmuster bei 130 gesunden Personen, aus einem Normwertprogramm ausgewahlt, ergab folgende Werte: Gesamt-Aldolase 0,8, 1,6, 2,5 U/L, Isoenzym A 0,6, 1,2, 1,9 U/L, Isoenzym B 0,0, 0,2 0,7 U/L und Isoenzym C 0,0, 0,1, 0,4 U/L ausgedruckt als $$\bar x$$ ±2s. Der Vergleich der Histogramme zeigt, das die Werteverteilung bei Messung der Gesamtaldolase sich bei Gesunden und Hepatitis-Kranken uberschneidet. Bei Messung der Aldolase B kommt es zu keiner Uberschneidung der Werteverteilung. Eine Differenzierung zwischen Gesunden und Kranken mit akuter Hepatitis ist moglich.

Selective derivatisation of resorcarenes: 1. The regioselective formation of tetra-benzoxazine derivatives

1997

Abstract Four 5,6-benzo-1,3-oxazine rings are formed by the condensation of resorcarenes with various aliphatic or aromatic primary amines and formaldehyde. From four possible regioisomers only the C4 symmetrical compound is isolated in yields of up to 90%. Semiempirical calculations confirm its relative stability, which is due to the possible formation of four intramolecular OH…O hydrogen bonds. The regioselectivity of the reaction is further established for two examples by single crystal X-ray analysis. A solvent molecule is included in the extended cavity.

Two new metabolites from the endophytic fungus Xylaria sp. isolated from the medicinal plant Curcuma xanthorrhiza

2015

Abstract The endophytic fungus Xylaria sp. was isolated from healthy leaves of Curcuma xanthorrhiza, collected on the island of Timor, Indonesia. Two new compounds (1 and 2), together with the known resacetophenone (3), were isolated and their structures were elucidated on the basis of comprehensive NMR and mass spectral analyses. The enantiomers of rac-1 were separated by chiral HPLC and their HPLC-ECD spectra were recorded to determine the absolute configuration on the basis of TDDFT-ECD calculations. The (3R,3aR, 9aR) absolute configuration of the optically active 2 was established by comparing the experimental solution ECD spectrum with the TDDFT ones computed for the gas phase and solu…

A remarkable selectivity in the N-functionalization of polyaza[n]paracyclophanes. Synthesis of N-(4-picolyl)-substituted 2,6,9,13-tetraaza[14]paracyc…

1997

Abstract Interaction of cationic host species, in particular Zn 2+ salts, with polyaza[n]paracyclophanes (i.e. 2,6,9,13-Tetraaza[14]paracyclophane, B323 (1a) ) directs their selective N-functionalization. In this way compounds mono- or difunctionalized with ArCH 2− groups at the benzylic nitrogen atoms can be easily obtained. Direct reaction with the alkylating agent, in the absence of the Zn 2+ species, produces, in general, very complex mixtures of mono- and polyalkylated compounds except when 4-picolyl chloride is used. In this case, mono-, di-, tri- and tetra N-substituted derivatives of D323 can be isolated depending on the amount of the alkylating agent used. In this case, the mono- a…