Epigenetic Evaluation of N-(2-hydroxyphenyl)-2-Propylpentanamide, a Valproic Acid Aryl Derivative with Activity Against HeLa Cells.

BACKGROUND: Valproic acid (VPA) is an HDAC inhibitor (HDACI) with an anticancer activity, but is hepatotoxic. N-(2-hydroxyphenyl)-2-propylpentanamide (o-OH-VPA) is a VPA aryl derivative designed in silico as a selective inhibitor of HDAC8 with biological properties against HeLa, rhabdomyosarcoma and breast cancer cell cultures. OBJECTIVE: We studied the epigenetic mechanism of o-OH-VPA as an HDACI and evaluated whether it was toxic to normal cells. METHODS: HeLa cells and primary human fibroblasts were used for this study as carcinogenic and normal cells, respectively. Cell survival was evaluated by MTT assay, whereas viability and doubling time were determined by the Trypan-blue method. HDAC activity was tested using the colorimetric HDAC activity assay. The expression of p21 was analyzed by PCR and HDAC8 expression was also evaluated by real-time PCR. Cell cycle and caspase-3 activity were analyzed by flow cytometry and caspase-3 colorimetric assay, respectively. RESULTS: o-OH-VPA (IC50 = 0.1 mM) was fifty-eight times more effective than VPA (IC50 = 5.8 mM) to reduce HeLa cell survival. Furthermore, o-OH-VPA increased the doubling time of HeLa cells by 33% with respect to the control. o-OH-VPA acted as HDACI in HeLa cells without affecting the HDAC8 expression, arresting the cell cycle of HeLa cells in the G0/G1 phase due to the increase in p21 expression with the inhibition of caspase-3 activity without exhibiting toxicity toward normal cells. CONCLUSION: Our results revealed that o-OH-VPA is an HDACI with a selective effect against HeLa cells but without the known toxicity exerted by most pan-HDACIs on normal cells.

Disruption of motor behavior and injury to the CNS induced by 3-thienylboronic acid in mice.

The scarcity of studies on boron containing compounds (BCC) in the medicinal field is gradually being remedied. Efforts have been made to explore the effects of BCCs due to the properties that boron confers to molecules. Research has shown that the safety of some BCCs is similar to that found for boron-free compounds (judging from the acute toxicological evaluation). However, it has been observed that the administration of 3-thienylboronic acid (3TB) induced motor disruption in CD1 mice. In the current contribution we studied in deeper form the disruption of motor performance produced by the intraperitoneal administration of 3TB in mice from two strains (CD1 and C57BL6). Disruption of motor activity was dependent not only on the dose of 3TB administered, but also on the DMSO concentration in the vehicle. The ability of 3TB to enter the Central Nervous System (CNS) was evidenced by Raman spectroscopy as well as morphological effects on the CNS, such as loss of neurons yielding biased injury to the substantia nigra and striatum at doses ≥200mg/kg, and involving granular cell damage at doses of 400mg/kg but less injury in the motor cortex. Our work acquaints about the use of this compound in drug design, but the interesting profile as neurotoxic agent invite us to study it regarding the damage on the motor system.

Catalytic activity of acetylcholinesterase immobilized on mesoporous molecular sieves.

MCM-41 and FSM-16 were used for enzyme immobilization on account of their good physical and chemical properties. In this work, the catalytic activity of acetylcholinesterase (AChE) immobilized on these materials was investigated, using neostigmina as AChE inhibitor. The results show that AChE was adsorbed on MCM-41 and on FSM-16-TIPB. AChE immobilized on the latter material maintained 70% of its activity and the material did not hydrolyze ACh (as MCM-41) by itself. Therefore, FSM-16-TIPB was the best material, considering also that when neostigmine was applied to AChE immobilized on FSM-16-TIPB, the activity of AChE decreased as occurs in its free from. Hence, this model could be useful in the evaluation of different kinds of AChE inhibitors, allowing the recycling of enzymes and making possible several assays and thereby, lowering cost.

Effects of succinic acid derivatives on ex vivo acetylcholinesterase activity.

In the present study the acetylcholinesterase (AChE) inhibition and acute toxicity of two succinic acid derivatives were compared with tacrine. Administration of a single dose of each of two succinic acid derivatives produced a time and dose-dependent inhibition of brain AChE activity. Although the magnitude of the cholinergic effects observed with the two succinic acid derivatives was similar to that seen with tacrine and other AChE inhibitors, the toxicity study showed that the new inhibitors have less adverse side effects.

The ambrosanolide cumanin inhibits macrophage nitric oxide synthesis: some structural considerations.

Since its role in inflammatory diseases was recognized, nitric oxide (NO) has become an important mediator to evaluate anti-inflammatory agents. Sesquiterpene lactones, which occur in several medicinal plants, inhibit the NO production in macrophage-like cells. This action is probably due to a 1,4 addition reaction between its alpha,beta-unsaturated carbonyl group with sulfhydryl (SH)-containing compounds. For this reason it is believed that these compounds are cytotoxic, which restricts their therapeutic use. In this contribution, the ability of the ambrosanolide-type sesquiterpene lactone cumanin (from the Asteraceae Ambrosia psilostachya) to inhibit NO biosynthesis was evaluated in lipopolisaccharide-induced peritoneal murine macrophages and its cytotoxicity was assessed in the MTT assay. Cumanin showed a potent inhibitory effect in NO production (IC(50) = 9.38+/-0.38 microM) with low cytotoxicity. The 1,4-addition reaction of thiols was slow, which does not explain the inhibition of NO production but does explain the low cytotoxicity of cumanin with respect to other lactones.

Reversible and irreversible inhibitory activity of succinic and maleic acid derivatives on acetylcholinesterase.

Aryl succinic and maleic acid derivatives are potent inhibitors of bovine acetylcholinesterase in vitro. Succinic acid aminophenol derivatives 1b-e and 2b-d act as reversible inhibitors of acetylcholinesterase, while maleic acid aminophenol derivatives 3b-d and 4c-e act as choline subsite-directed irreversible inhibitors, detected by dialysis in the presence of edrophonium. Linear relationships between the logarithm of the velocity of hydrolysis of acetylcholine plotted against the time of incubation at several different inhibitor concentrations were determined. The K(i) for reversible competitive inhibitors was determined. For irreversible inhibitors the K(i) for the dissociation constant of the enzyme-inhibitor complex at the beginning of the recognition process was also determined as well as the inactivation constant of the enzyme-inhibitor adduct formation k(+2) and the bimolecular inhibition constant k(i) for the inhibition of acetylcholinesterase by aminophenol derivatives 3b-d and 4c-e. The conclusions of this study can be summarized as follows for both families: (a) the aromatic moiety played a critical role in the recognition of the active site; (b) in case of the reversible inhibitor, when the ester function took the place of the hydroxyl fragment, there was an important increase in the affinity; and (c) the distance between phenolic hydroxyl and nitrogen was critical because the inhibition is ortho<

[Toxicity and hypotensive effect of L-arginine oxoborolidinone and its modulation by methylene blue. Comparison with L-arginine, nitrite, and nitrate]. / Toxicidad y efecto hipotensor de oxoborolidinona de L-arginina y su modulación por azul de metileno. Comparación con L-arginina, nitrito y nitrato.

Nitric oxide is synthesized by constitutive oxide nitric synthase from the guanidine group of L-arginine. L-arginine, oxoborolidinone of L-arginine, nitrite and nitrate showed dose-dependent hypotensive effects after injection via the femoral vein in Wistar rats. The hypotensive effects were shifted to the right after treatment with methylene blue, which is a synthetic phenothiazine inhibitor of guanylate cyclase. Oxoborolidinone of L-arginine had high hypotensive effects with an effective half dose of 10 eta moles kg-1 and of mumoles kg-1 for methylene blue. Methylene blue also attenuated the toxic effects of all the tested compounds.