Investigation of piperidine derivatives in ex vivo models of pain and platelet aggregation.

Piperidine derivatives are known to exhibit analgesic activities and are likely to possess the ability to block the effects of prostaglandins through inhibition of downstream signaling pathways. The present study investigated the activity of five derivatives (PD2-6) of 4-(4'-bromophenyl)-4-piperidinol (PD1), against pain and platelet aggregation mediated by the release of prostaglandins and thromboxane A2, respectively. The results showed that compound PD1 and its two phenacyl derivatives PD3 and PD5 exhibited a highly significant analgesic effect (p < 0.01), whereas PD4 and PD6 also showed significant activity. PD3, the most active analgesic compound when docked to the opioid receptor, had interactions between the oxygen of its nitro group and the amino group of ARG 573, indicating a distance of 1.2563 Å. The antiplatelet data showed that compound PD5 (4-(4'-bromo-phenyl)-4-hydroxy-1-[2-(2″,4″-dimethoxyphenyl)-2-oxo-ethyl]-piperidinium bromide) had an IC(50) = 0.06 mM, which was the most active compound, whereas PD3 was the second most active compound against platelet aggregating factor-induced aggregation with an IC(50) = 80 mM. Acetyl salicylic acid (IC(50) = 150 µM) was used as a positive control.

Characterisation of Plasmodium falciparum aspartic protease inhibition by piperidine derivatives.

Piperidine derivatives are reported to exhibit a variety of pharmacological activities. In this article, synthesis and aspartic protease inhibitory activity of three nitrophenacyl derivatives of N-methyl-4-hydroxy piperidine are reported. Enzyme assays showed that the attachment of a nitro group in the benzene ring plays an important role in the inhibition of plasmepsin-II of Plasmodium falciparum. The compound 1-methyl-1-(4'-nitrophenacyl)-4-hydroxypiperidinium bromide (3), consisting of a nitro group at the para position, was the most active at the concentration of 1.0 µM. The activity of the compounds was evaluated through the observed orientation and diagrammatic representation of nitrophenacyl derivatives of 4-hydroxy piperidine.

Effect of some trace elements on the nucleic acid metabolising enzymes level of germinating wheat seeds.

Wheat seeds were grown in the presence and absence of some trace elements like Co, Cu, Fe, Mn, Mo and Zn in non-toxic limits. The level of enzyme activities involved in nucleic acid metabolism were measured by spectrophotometric methods. The level of certain RNA metabolising enzymes increased manyfold in trace element-treated seeds, while the level of AMP-deaminase was increased manyfold in Co-treated seeds.

Negative ion FAB mass spectroscopy of some ribose alkylated 5'-UMP derivatives.

Characteristic fragment ions obtained in Fast atom bombardment (FAB) mass spectroscopy of ribose alkylated Uridine 5'-monophosphate (5'-UMP) derivatives in negative ion mode are described. All the compounds examined exhibited either [M]- or quasimolecular ion [M - H]- the fragmentations can be used to characterize these nucleotides.