Search results for "TYR"

Development of predictive retention-activity models of butyrophenones by biopartitioning micellar chromatography

2001

The predictive and interpretative capability of quantitative chromatographic retention-biological activity models is supported by the fact that in adequate experimental conditions the solute partitioning into the chromatographic system can emulate the solute partitioning into lipid bilayers of biological membranes, which is the basis of drug and metabolite uptake, passive transport across membranes and bioaccumulation. The use of retention data obtained in biopartitioning micellar chromatography (BMC) has been demonstrated to be helpful in describing the biological behaviour of different kinds of drugs. In this chromatographic system, polioxyethylene 23 lauryl ether Brij35 micellar mobile p…

Crotofolane Diterpenoids and Other Constituents Isolated from Croton kilwae

2023

Six new crotofolane diterpenoids (1-6) and 13 known compounds (7-19) were isolated from the MeOH- CH2Cl2 (1:1, v/v) extracts of the leaves and stem bark of Croton kilwae. The structures of the new compounds were elucidated by extensive analysis of spectroscopic and mass spectrometric data. The structure of crotokilwaepoxide A (1) was confirmed by single -crystal X-ray diffraction, allowing for the determination of its absolute configuration. The crude extracts and the isolated compounds were investigated for antiviral activity against respiratory syncytial virus (RSV) and human rhinovirus type-2 (HRV-2) in HEp-2 and HeLa cells, respectively, for antibacterial activity against the Gram-posit…

Modified ent-Abietane Diterpenoids from the Leaves of Suregada zanzibariensis

2022

The leaf extract of Suregada zanzibariensis gave two new modified ent-abietane diterpenoids, zanzibariolides A (1) and B (2), and two known triterpenoids, simiarenol (3) and β-amyrin (4). The structures of the isolated compounds were elucidated based on NMR and MS data analysis. Single-crystal X-ray diffraction was used to establish the absolute configurations of compounds 1 and 2. The crude leaf extract inhibited the infectivity of herpes simplex virus 2 (HSV-2, IC50 11.5 μg/mL) and showed toxicity on African green monkey kidney (GMK AH1) cells at CC50 52 μg/mL. The isolated compounds 1–3 showed no anti-HSV-2 activity and exhibited insignificant toxicity against GMK AH1 cells at ≥100 μM. p…

Die Hemmung der Aufnahme vonα-Methylnoradrenalin in das Herz durch sympathomimetische Amine

1965

Hearts of rabbits were isolated and perfused with Tyrode solution containing 10 ng/ml (−)-α-methyl noradrenaline. The uptake by the heart ofα-methyl-noradrenaline was calculated by estimating the amount of amine removed from the perfusion fluid while passing through the heart. In control experiments the mean removal ofα-methyl noradrenaline was 43,7 ± 1,6% of the amount infused. The rate of removal remained constant throughout the time period of the experiment, i.e. 20 min.

Phenylalanine Hydroxylase Participation in the Synthesis of Serotonin and Pteridines in Drosophila melanogaster

1997

Abstract Phenylalanine hydroxylase is involved in the synthesis of serotonin and pteridines, probably catalysing the hydroxylation of tryptophan and a tetrahydropterin oxidase reaction, respectively. Supplementation of the wild-type Drosophila diet with either L-Phe or L-Trp induced a significant increase in the phenylalanine hydroxylase concentration, while L-Tyr supplementation had no effect. The level of serotonin in adult heads of the PAH-defective mutant Henna recessive-3 was significantly lower than that obtained for the wild-type strain. A 4-fold increase in the concentration of phenylalanine hydroxylase is observed during the pharate adult head development. It occurs in parallel wit…

Valproate and GABAergic system effects.

2003

Bond-Based 2D Quadratic Fingerprints in QSAR Studies: Virtual and In vitro Tyrosinase Inhibitory Activity Elucidation

2010

In this report, we show the results of quantitative structure–activity relationship (QSAR) studies of tyrosinase inhibitory activity, by using the bond-based quadratic indices as molecular descriptors (MDs) and linear discriminant analysis (LDA), to generate discriminant functions to predict the anti-tyrosinase activity. The best two models [Eqs (6) and (12)] out of the total 12 QSAR models developed here show accuracies of 93.51% and 91.21%, as well as high Matthews correlation coefficients (C) of 0.86 and 0.82, respectively, in the training set. The validation external series depicts values of 90.00% and 89.44% for these best two equations (6) and (12), respectively. Afterwards, a second …

Effects of plant alkylphenols on cytokine production, tyrosine nitration and inflammatory damage in the efferent phase of contact hypersensitivity

2007

Background and purpose: The phenolic compounds isoprenylhydroquinone glucoside (IHG), 3,5-dicaffeoylquinic acid (DCA), and its methyl ester (DCE) have previously been shown to inhibit both contact hypersensitivity (CHS) and peroxynitrite reactivity. The present work seeks to establish a relationship between the anti-inflammatory effect and the release of cytokines and tyrosine nitration in skin. Experimental approach: Murine CHS was developed by means of sensitization and challenge with dinitrofluorobenzene (DNFB) or oxazolone. Ear swelling was measured 24 and 96 h after challenge. Interleukin (IL)-1b, IL-4, and tumour necrosis factor (TNF)-a were measured by ELISA; and the expression of in…

Die Wirkung von 1,1-Dimethyl-4-Phenyl-Piperazinium-Jodid am isolierten Vorhof im Vergleich zur Tyramin- und Nicotinwirkung

1962

Unterschiede zwischen Tyramin und Dimethylphenylpiperazin in der Ca++-Abhängigkeit und im zeitlichen Verlauf der Noradrenalin-Freisetzung am isoliert…

1967

On the perfused rabbit heart a constant infusion of tyramine released noradrenaline continuously and independently of the external Ca++ concentration. In contrast, noradrenaline release by DMPP was only transient and required the presence of Ca++.