Oxidative stress protection by newly synthesized nitrogen compounds with pharmacological potential

Abstract

In this study we used new nitrogen compounds obtained by organic synthesis whose structure predicted an antioxidant potential and then an eventual development as molecules of pharmacological interest in diseases involving oxidative stress. The compounds, identified as FMA4, FMA5, FMA7 and FMA8 differ in the presence of hydroxyl groups located in the C-3 and/or C-4 position of a phenolic unit, which is possibly responsible for their free radicals' buffering capacity. Data from the DPPH discoloration method confirm the high antiradical efficiency of the compounds. The results obtained with cellular models (L929 and PC12) show that they are not toxic and really protect from membrane lipid peroxidation induced by the ascorbate-iron oxidant pair. The level of protection correlates with the drug's lipophilic profile and is sometimes superior to trolox and equivalent to that observed for alpha-tocopherol. The compounds FMA4 and FMA7 present also a high protection from cell death evaluated in the presence of a staurosporine apoptotic stimulus. That protection results in a significant reduction of caspase-3 activity induced by staurosporine which by its turn seems to result from a protection observed in the membrane receptor pathway (caspase-8) together with a protection observed in the mitochondrial pathway (caspase-9). Taken together the results obtained with the new compounds, with linear chains, open up perspectives for their use as therapeutical agents, namely as antioxidants and protectors of apoptotic pathways. On the other hand the slight pro-oxidant profile obtained with the cyclic structures suggests a different therapeutic potential that is under current investigation.

Neuroprotective effect of safranal, an active ingredient of Crocus sativus , in a rat model of transient cerebral ischemia

“…After centrifuging at 3000 rpm for 10 min, the absorbance of the supernatant was read against the blank at 535 nm. The amount of the produced MDA was calculated using the molar absorption coefficient of 1.56 × 10 5 M -1 cm -1 and expressed in nmol/g tissue [29].…”

Antioxidant activity of synthetic diarylamines: A mitochondrial and cellular approach

“…Cells obtained from ECACC were grown in 75 cm 2 tissue culture flasks, in DMEM medium supplemented with 10% (v/v) heat-inactivated fetal bovine serum (FBS) and 1% (v/v) of an antibiotic/antimycotic solution containing 10,000 units of penicillin, 10 mg streptomycin and 25 lg amphotericin B per ml. The PC12 cell line, established from a rat adrenal pheochromocytoma is a neuronal cell model, usually used to study phenomena related with oxidative stress (Pereira et al, 1999;Silva et al, 2006). The PC12 cells were grown in RPMI-1640, supplemented with 10% (v/v) heat-inactivated horse serum, 5% (v/v) heat-inactivated FBS and 1% (v/v) antibiotic/antimycotic solution (as described above).…”

“…The method used for TBARS measurements was previously described (Agostinho et al, 1997;Silva et al, 2006) with some modifications. PC12 cells were plated in poly-D-lysine coated 6-well plates at a density of 1.3 Â 10 6 cells/ml (2 ml for each well) and left for adhesion overnight.…”

“…However, their use as active principles of drugs is very controversial. For that purpose, compounds obtained by organic synthesis have many advantages relatively to the natural ones: (1) their structures, precisely defined, can be manipulated in order to improve their activity and direct them to a specific target; (2) after establishment of the synthesis procedure, they can be produced in a large scale and (3) they can be obtained with a high degree of purity (Silva et al, 2006).…”

“…As a complement of these studies in mitochondria, we evaluated the compounds effect on whole cells. The neuronal model of PC12 was used to assess the effect of these diarylamines on ascorbate/iron-induced lipid peroxidation, usually associated with neurodegenerative diseases (Pereira et al, 1999;Benedi et al, 2004;Silva et al, 2006). Furthermore, we determined the diarylamines' radical scavenging ability and metal ions chelating capacity (Fe 3+ in particular), in order to better understand their mechanism of action.…”