Tetrahydroquinolinone derivatives as potent P-glycoprotein inhibitors: design, synthesis, biological evaluation and molecular docking analysis.

P-glycoprotein (P-gp) is a transmembrane efflux pump that has been associated with ineffective cancer chemotherapy and multidrug resistance (MDR). Chemical inhibitors of P-gp could have potential cancer therapeutic applications by preventing or reversing MDR. To exploit this, we designed twenty-five tetrahydroquinolinone analogs bearing pyridyl methyl carboxylate at C3 and different substituents at C4 as MDR reversal agents. The inhibitory effects of the synthesized compounds against P-gp were assessed by flow cytometric determination of rhodamine 123 accumulation in P-gp over-expressing MES-SA/DX5 cells. Fluorescence imaging of intracellular rhodamine 123 accumulation in MES-SA/DX5 cells was also performed. Furthermore, the effect of active derivatives on the reduction of doxorubicin's IC50 in MES-SA/DX5 cells was evaluated using MTT assay. Molecular docking was used to confirm the binding mode of some of the synthesized compounds. Five compounds in group A, bearing a 2-pyridyl methyl ester substituent at the C3 position, significantly increased rhodamine accumulation at 25 µM comparable to verapamil, a well-established P-gp inhibitor, while only 2 compounds in group B bearing 3-pyridyl methyl ester at the same position had this effect. This study shows that tetrahydroquinolinones containing methyl pyridine esters could represent an attractive scaffold for the discovery of P-gp inhibitors as MDR reversal agents in cancer cells.

Antioxidant activity of galantamine and some of its derivatives.

Oxidative stress is implicated in the pathogenesis of different human diseases: Alzheimer, Parkinson, Huntington, amyotrophic lateral sclerosis (Lou Gehrig's disease), Down's syndrome, atherosclerosis, vascular disease, cancer, diabetes mellitus type 1 and type 2, age - related macular degeneration, psoriatic arthritis. The aim of current study is to summarize the scientific evidences for the antioxidant and neuroprotective activity of Galantamine and some of its derivatives. Galantamine is a scavenger of reactive oxygen species and causes neuroprotective effect by lowering the oxidative neuronal damage, through the following pathways: 1) prevention of the activation of P2X7 receptors; 2) protection of mitochondrial membrane potential; 3) pre - vention of the membrane fluidity disturbances. Another mechanism is the decreasing of the overproduction of reactive oxygen species, a result from the increasing of acetylcholine level due to: 1) acethylcholinesterase inhibition; 2) allosteric potentiation of α7 - subtype of nicotinic acetylcholine receptors. A close relationship between acethylcholinesterase inhibition and reduced oxidative injury is observed. Through allosteric potentiation of the α7 - subtype of nicotinic acetylcholine receptors, the drug leads to induction of phosphorylation of serine - threonine protein kinase, stimulates phosphoinositide 3 - kinase and elevates the expression of protective protein Bcl - 2. By activation of these important neuroprotective cascades, Galantamine exerts neuroprotection against a variety of cytotoxic agents (ß- amyloid peptide, glutamate, hydrogen peroxide, oxygen and glucose deprivation). The new trend in therapy of Alzheimer's disease will be the investigation and application of compounds such as Galantamine derivatives, which possess acethylcholinesterase and γ- secretase inhibitory activity and antioxidant properties.

Antiradical and antioxidant activities of new bio-antioxidants.

Antioxidants could be promising agents for management of oxidative stress-related diseases. New biologically active compounds, belonging to a rare class of natural lignans with antiangiogenic, antitumoral and DNA intercalating properties, have been recently synthesized. These compounds are benzo[kl]xanthene lignans (1,2) and dihydrobenzofuran neolignans (3,4). The radical scavenging and chain-breaking antioxidant activities of compounds 1-4 were studied by applying different methods: radical scavenging activity by DPPH rapid test, chain-breaking antioxidant activity and quantum chemical calculations. All studied compounds were found to be active as DPPH scavengers but reaction time with DPPH and compounds' concentrations influenced deeply the evaluation. The highest values of radical scavenging activity (%RSAmax) and largest rate constants for reaction with DPPH were obtained for compounds 2 and 3. Comparison of %RSAmax with that of standard antioxidants DL-α-tocopherol (TOH), caffeic acid (CA) and butylated hydroxyl toluene (BHT) give the following new order of %RSA max: TOH (61.1%) > CA (58.6%) > 3 (36.3%) > 2 (28.1%) > 4 (6.7%) > 1 (3.6%) = BHT (3.6%). Chain-breaking antioxidant activities of individual compounds (0.1-1.0 mM) and of their equimolar binary mixtures (0.1 mM) with TOH were determined from the kinetic curves of lipid autoxidation at 80 °C. On the basis of a comparable kinetic analysis with standard antioxidants a new order of the antioxidant efficiency (i.e., protection factor, PF) of compounds 1-4 were obtained: 2 (7.2) ≥ TOH (7.0) ≥ CA (6.7) > 1 (3.1) > 3 (2.2) > ferulic acid FA (1.5) > 4 (0.6); and of the antioxidant reactivity (i.e. inhibition degree, ID): 2 (44.0) >> TOH (18.7) >> CA (9.3) >> 1 (8.4) > 3 (2.8) > FA (1.0) > 4 (0.9). The important role of the catecholic structure in these compounds, which is responsible for the high chain-breaking antioxidant activity, is discussed and a reaction mechanism is proposed. Higher oxidation stability of the lipid substrate was found in the presence of equimolar binary mixtures 2 + TOH, 3 + TOH and 4 + TOH. However, an actual synergism was only obtained for the binary mixtures with compounds 3 and 4. The geometries of compounds and all possible phenoxyl radicals were optimized using density functional theory. For description of the scavenging activity bond dissociation enthalpies (BDE), HOMO energies and spin densities were employed. The best correlation between theoretical and experimental data was obtained for compound 2, with the highest activity, and for compound 4 with the lowest activity. The BDE is the most important theoretical descriptor, which correlates with the experimentally obtained antioxidant activity of the studied benzo[kl]xanthene lignans and dihydrobenzofuran neolignans.

Coumarins as antioxidants.

Coumarins, a well-known class of naturally occurring compounds, display a remarkable array of biochemical and pharmacological actions, some of which suggest that certain members of this group of compounds may significantly affect the function of various mammalian cellular systems. The development of coumarins as antioxidant agents has attracted much attention in recent years. Coumarins afford an opportunity for the discovery of new antioxidants with truly novel mechanisms of action. This review updates and expands the 2006 review by the same author. The review considers and incorporates the most recently published literature on coumarins as related to their antioxidant properties. A lot of coumarins have been identified from natural sources, especially green plants. These natural compounds have served as valuable leads for further design and synthesis of more active analogues. Beyond doubt, a deep understanding of the mechanisms of existing synthetic and natural coumarins will build the basis for the rational design.

Antioxidant therapy: current status and future prospects.

Reactive oxygen species (ROS) are widely believed to cause or aggravate several human pathologies such as neurodegenerative diseases, cancer, stroke and many other ailments. Antioxidants are assumed to counteract the harmful effects of ROS and therefore prevent or treat oxidative stress-related diseases. In this report, recent human studies exploring the efficiency of antioxidants in prevention and treatment of various diseases are reviewed. Few antioxidants including edaravone (for ischemic stroke in Japan), Nacetylcysteine (for acetaminophen toxicity), alfa-lipoic acid (for diabetic neuropathy) and some flavonoids (polyphenolic compounds present in dietary plants), such as micronized purified flavonoid fraction (diosmin and hesperidin) and oxerutins (for chronic venous insufficiency) as well as baicalein and catechins (for osteoarthritis) have found accepted clinical use. However, despite much enthusiasm in the 1980s and 1990s, many well-known agents such as antioxidant vitamins and also more recently developed compounds such as nitrones have not successfully passed the scrutiny of clinical trials for prevention and treatment of various diseases. This has given rise to a pessimistic view of antioxidant therapy, however, the evidence from human epidemiological studies about the beneficial effects of dietary antioxidants and preclinical in vitro and animal data are compelling. We have probably wasted too much time on agents like antioxidant vitamins instead of focusing on more disease specific, target-directed, highly bioavailable antioxidants. We here discuss possible reasons for the lack of success in some clinical trials and seek to provide some suggestions to be considered if antioxidant therapy is to succeed as an effective therapeutic strategy.

Home cage testing of delay discounting in rats.

Testing rodents in their home cages has become increasingly popular. Since human intervention, handling, and transport are minimized, behavior can be recorded undisturbed and continuously. Currently existing home cage systems are too complex if only relatively simple operant-learning tests are to be carried out in rats. For that purpose, a new low-cost computer-controlled operant panel was designed, which can be placed inside the home cage. A pilot study was carried out, using an intolerance-to-delay protocol, classically developed for testing behavioral impulsivity. Male adult rats were tested in their home cages, containing the operant panel provided with nose-poking holes. Nose poking in one hole resulted in the immediate delivery of one food pellet (small-soon, SS), whereas nose poking in the other hole delivered five food pellets after a delay (large-late), which was increased progressively each day (0-150 sec). The two daily sessions, spaced 8 h apart, lasted 1 h each, and the time-out after food delivery was 90 sec. A clear-cut shift toward preference for SS, which is considered a classical index of cognitive impulsivity, was shown at the longest delay. It is noteworthy that rats shifted when the delay interval was longer than the mean intertrial interval-that is, when they experienced more than one delay-equivalent odds against discounting (see Adriani & Laviola, 2006). The shortened training (2 days) and testing (5 days) phases, as allowed by prolonged and multiple daily sessions, can be advantageous in testing rodents during selected short phases of development. Current research is focusing on further validation of this and similar protocols.

Inhibition of Candida albicans extracellular enzyme activity by selected natural substances and their application in Candida infection.

Extracellular enzymes secreted by Candida albicans are claimed to be virulence factors responsible for penetration of the yeast into host cells. Substances able to inhibit lipolytic and proteinase activities of the fungus might be of therapeutic use in some pathologic conditions caused by C. albicans. In the present work, we have tested the influence of the flavonoid compounds apigenin and kaempferol, the indole alkaloid ibogaine, and the protoberberine alkaloid berberine on the in vitro enzyme activity of C. albicans. The substances showed complex suppressive effects concerning the processes of adherence to epithelial cells, secreted aspartyl proteinase activity, and the rate of cell wall protein glycosylation. Apigenin and kaempferol were administered in systemic C. albicans infection, demonstrating an increased number of survivors by kaempferol. The application of apigenin, kaempferol, ibogaine, and berberine in cutaneous infection suppressed the symptoms and accelerated elimination of the yeast from the site of inoculation.

DPPH Radical Scavenging Activity of Several Naturally Occurring Coumarins and Their Synthesized Analogs Measured by the SIA Method.

ABSTRACT Coumarins, naturally occurring compounds derived from benzopyran, have recently been studied extensively for their antioxidant properties. A lot of coumarins have been isolated and identified from natural sources and many others have been synthesized. It is also known that pharmacological and biochemical properties and thus also therapeutic application of simple coumarins depend upon the pattern of their substitution. As a part of studies of biological effects, four naturally occurring coumarins and 18 synthesized analogs of several compounds were assayed for 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) scavenging activity. For this purpose the highly reliable DPPH test modified to be performed by sequential injection analysis (SIA) system was used. This in our laboratory-developed method was originally proposed for antioxidant screening of large series of plant extracts. In this assay, the DPPH test using the SIA method was used for fast and sensitive evaluation of EC(50) of coumarins. The evaluation of EC(50) of a single compound takes only 15 to 30 min. The structure-activity relationships of tested compounds are also established. The results verified 7,8-dihydroxy-4-methylcoumarins as excellent DPPH radical scavengers. Obtained results correspond with those of other studies and suggest the SIA procedure as a suitable method for fast and sensitive antioxidant analysis of various types of compounds.

Effect of infliximab on the glycosylation of IgG of patients with rheumatoid arthritis.

In patients with rheumatoid arthritis (RA) a decrease in the terminal galactose content of N-linked glycans of the Fc region of agalactosyl immunoglobulin G (IgG) (G0) occurs. The aim of this study was to evaluate, for the first time, the effect of infliximab, a new monoclonal antibody for the treatment of RA, on this phenomenon. A total of 19 patients with active RA were treated with intravenous infliximab (3 mg/kg) in combination with methotrexate (MTX) (10-20 mg). IgG was purified from their serum by caprylic acid. Analysis of IgG glycosylation was performed by lectin blotting/immunoblotting and enzyme linked lectin assay (ELLA)/enzyme linked immunosorbent assay (ELISA) using the Griffonia (bandeiraea) simplicifolia lectin II and protein-A/alkaline phosphatase. The purity of IgG samples obtained was higher than 90%. The sensitivity of the lectin/immunoblotting method was of about 0.25 microg of IgG. The inter- and intraassay coefficients of variation (CV) were 1.3% and 9.0% for lectin blotting, and 4.6% and 8.3% for immunoblotting, respectively. The sensitivity of the ELLA/ELISA approach was 0.025 microg/microL and the inter- and intraassay CV were 6.2% and 7.7% for ELLA, and 5.1% and 14.1% for ELISA, respectively. A good linear correlation (r2=0.18, P<0.05) was obtained between the two different experimental approaches. A decrease of G0 was observed in patients who clinically improved (according to the American College of Rheumatology criteria) following the pharmacological treatment. Our data indicate that infliximab can reduce the concentration of G0 in patients with active RA.

Antioxidant and prooxidant effects of quercetin on glyceraldehyde-3-phosphate dehydrogenase.

Anti- and prooxidant properties of quercetin under different conditions were investigated using glyceraldehyde-3-phosphate dehydrogenase, a glycolytic enzyme containing essential cysteine residues. Quercetin was shown to produce hydrogen peroxide in aqueous solutions at pH 7.5, this resulting in the oxidation of the cysteine residues of the enzyme. Quercetin significantly increased oxidation of GAPDH observed in the presence of ferrous ions, particularly when FeSO(4) was added to the solution containing GAPDH and quercetin. The results suggest the formation of hydroxyl radical in the case of the addition of FeSO(4) to a quercetin solution. At the same time, quercetin protects GAPDH from oxidation in the presence of ascorbate and Fe(3+). In the absence of metals, quercetin protects SH-groups of GAPDH from oxidation by the superoxide anion generated by the system containing xanthine/xanthine oxidase.

Immunohistochemical profile of some neurotransmitters and neurotrophins in the seminiferous tubules of rats treated by lonidamine.

Lonidamine (LND) or [1-(2,4-dichlorobenzyl)-1H-indazole-3-carboxylic acid] is an anticancer and antispermatogenic drug that exerts a large number of effects on tumor cells and germ cells. Sexually mature male Sprague-Dawley rats were housed at 22 degrees C on a 12-h light/12-h dark cycle 1 week before the experiments, with free access to food and water. LND was suspended in 0.5% methylcellulose at a concentration of 10 mg/mL and administered orally at the dose of 10 mL/kg (b.w.) as a single dose. Control rats received an equal amount of vehicle. Testes were removed, fixed for 24 h in 2% glutaraldehyde and 2% paraformaldehyde in 0.1 M sodium phosphate (pH 7.2 at 22 degrees C), rinsed with the same buffer, and stored at room temperature. From each sample, a block of tissue was removed by sectioning through the organ. After dehydration in ethanol at increasing concentrations (70-100%), each block was embedded in paraffin and serial 5 mm thick sections were cut using a rotatory microtome. The immunoreactivity for NTs has been observed in spermatogonia of untreated rats, while the rats treated with LND showed an immunohistochemical localization in all the stages of germinal cells. The generally well-expressed immunoreactivity for the neurotrophins receptors in treated rats observed in our study is presumably attributable to alterations of the receptors' structure and/or expression leading to changes of the activity, affinity, localization or protein interactions that may depend on sensitization of ion channels (induced by LND). Neurotrophins (NTs) appear to be interesting proteins for the modulation of sperm maturation and motility with a prominent role for the nerve growth factor (NGF), that may exert an autocrine or paracrine role. We therefore investigated the location and distribution of immunoreactivity for some neurotransmitters (SP, VIP, CGRP, nNOS, Chat), neurotrophins (NGF, BDNF, NT-3) and their own receptors (TrKA, TrKB, TrKC, p75) in the seminiferous tubules of male rats treated by LND in the light of the literature on this topic.

Ibogaine reduces organ colonization in murine systemic and gastrointestinal Candida albicans infections.

In the present study the effect of the indole alkaloid ibogaine on the in vitro lipolytic activity and adherence to epithelial cells of Candida albicans was investigated. The substance was administered intraperitoneally at a dose of 5 mg kg(-1) day(-1) in mice with disseminated and gastrointestinal C. albicans infections. Ibogaine significantly decreased the rate of mortality and the number of C. albicans c.f.u. recovered from the kidney, liver and spleen. Ibogaine interfered with the early stages of both disseminated and gastrointestinal C. albicans infections but did not reduce the number of C. albicans c.f.u. in the organs at the late phase of infections. The development of a specific immune response was not influenced by ibogaine, since the delayed-type hypersensitivity reaction to C. albicans and the production of interferon (IFN)-gamma were similar in control and ibogaine-treated mice. The combined use of amphotericin B plus ibogaine in the treatment of mice with gastrointestinal infection reduced organ colonization more strongly than each substance alone.

Atractylis gummifera L. poisoning: an ethnopharmacological review.

Atractylis gummifera L. (Asteraceae) is a thistle located in the Mediterranean regions. Despite the plant's well-known toxicity, its ingestion continues to be a common cause of poisoning. The toxicity of Atractylis gummifera resides in atractyloside and carboxyatractyloside, two diterpenoid glucosides capable of inhibiting mitochondrial oxidative phosphorylation. Both constituents interact with a mitochondrial protein, the adenine nucleotide translocator, responsible for the ATP/ADP antiport and involved in mitochondrial membrane permeabilization. Poisoned patients manifest characteristic symptoms such as nausea, vomiting, epigastric and abdominal pain, diarrhoea, anxiety, headache and convulsions, often followed by coma. No specific pharmacological treatment for Atractylis gummifera intoxication is yet available and all the current therapeutic approaches are only symptomatic. In vitro experiments showed that some compounds such as verapamil, or dithiothreitol could protect against the toxic effects of atractyloside, but only if administered before atractyloside exposure. New therapeutic approaches could come from immunotherapy research: some studies have already tried to produce polyclonal Fab fragments against the toxic components of Atractylis gummifera.

[Evaluation of the adherence to the asthma guidelines by the administration of a questionnaire in community pharmacies]. / Valutazione dell'adesione alle linee guida per il trattamento farmacologico del paziente asmatico attraverso la somministrazione di un questionario in farmacia.

BACKGROUND: Several studies demonstrate that the adherence to asthma guidelines (GL) is poor, but only a few of them were performed in community pharmacies. Thus, we decided to study this phenomenon by administering a questionnaire (Q) in two pharmacies. METHODS: A Q was developed and administered to 138 patients-customers of two community pharmacies in Rome. RESULTS: The severity of the disease was established based on the frequency of daytime and nocturnal symptoms before therapy, following the stepwise approach recommended by the current GL. We observed up to 90 different treatments, while those listed by the GL, long-term preventive or quick-relief for the four categories of asthma, are only 19. In particular, many of them included antihistaminic drugs and mucoactive agents, pharmacological classes not recommended by the GL, while certain long-term preventive therapeutic schemes did not include glucocorticoids. CONCLUSIONS: The analysis of the effects on daytime and nocturnal symptoms and the interferences of the disease with school and work, showed that the control of asthma was inadequate, probably due to the low adherence to the GL. In conclusion, this small pilot study, which does have several methodological limitations (small population and geographic area, small number of pharmacies involved, the use of a Q to obtain information not easily reported by the patient) confirms the important role played by pharmacists in the analysis of the adherence of pharmacological treatments to official GL.

Corneal toxicity of xylazine and clonidine, in combination with ketamine, in the rat.

PURPOSE: To compare the corneal toxicity of xylazine (XYL)/ketamine (KET) with that of clonidine (CLO)/KET in the rat, in the presence or not of the alpha(2)-adrenergic antagonist yohimbine (YOH). METHODS: XYL (10 mg/kg) and CLO (0.15 mg/kg) were administered subcutaneously in the rat in combination with KET (50 mg/kg), in the presence or not of YOH (2 mg/kg). RESULTS: The corneas immediately lost transparency and luster, but recovered within 120 min. By both light and electron microscopy, a marked stromal edema and alterations of all layers were observed. In addition, XYL/KET altered the permeability of the cornea as indicated by the augmented levels of (14)C-indomethacin, topically administered 30 min after the anesthetic combination. CONCLUSIONS: The mechanism of the corneal toxicity of XYL and CLO in the rat is unclear but we speculate that: (a) proptosis and inhibition of normal blinking did not play a major role because topical application of hyaluronic acid did not protect against it; corneal decompensation, edema and opacification could be due to (b) osmotic or (c) mechanical endothelial stress: the first resulting from the sudden increase of the glucose concentration in the aqueous humor due to the well-known inhibition of insulin release by alpha(2)-adrenergic agonists, and the second from the acute elevation of intraocular pressure caused by these alpha(2)-adrenergic mydriatics in the rat; (d) addition, XYL and CLO could act by directly interacting with local alpha(2)- or, possibly, alpha(1)-adrenergic receptors, whose function is still not clear but probably essential for corneal homeostasis.

Analgesic properties of Epilobium angustifolium, evaluated by the hot plate test and the writhing test.

The analgesic properties of Epilobium angustifolium (Ea), a plant containing flavonoids with anti-inflammatory activity, have not been sufficiently studied so far. Thus, we decided to evaluate, by the classical hot plate test and the writhing test, the analgesic effect of a dry extract of Ea obtained by evaporating a commercially available mother tincture. In the former assay, the effect of Ea (380 mg/kg) was slightly lower than that of morphine (10 mg/kg s.c.). In the writhing test, which is more sensitive for non-steroidal analgesics, the effect of Ea was already significant (P < 0.05) at 95 mg/kg while at doses > or = 190 mg/kg, its activity was similar to that of lysine acetylsalicylate (300 mg/kg). The LD50 of this dry extract of Ea was 1.4+/-0.1 g/kg. Further studies are necessary for the identification of the active principles and the elucidation of their mechanism of action.

Anti-proliferative effect on a prostatic epithelial cell line (PZ-HPV-7) by Epilobium angustifolium L.

Symptomatic benign prostatic hyperplasia (BPH) is a common condition in elderly men and has a significant impact on their daily lives. The drugs prescribed for treatment include alpha1-blockers, 5-alpha-reductase inhibitors and plant preparations. Epilobium angustifolium L. is deemed to be helpful in BPH therapy, although there is less information regarding the mechanism of its biological activity. The present study evaluated the effect of E. angustifolium extract on human prostatic epithelial cells (PZ-HPV-7). The exposure to E. angustifolium extract induced a marked inhibition of cell growth in all tested conditions. The anti-proliferative effect observed in in vitro systems clearly indicates a biologically relevant effect of compounds present in the extract. Considering these results, the use in traditional medicine of E. angustifolium extract against BPH seems to be justified. However, further experimental studies are needed to determine the biochemical mechanism of the action and the clinical value of the E. angustifolium extract.

Two new male contraceptives exert their effects by depleting germ cells prematurely from the testis.

The three currently available male contraceptive approaches are 1) the barrier method such as the condom, 2) hormonal methods by disrupting the pituitary-testicular axis so as to impair spermatogenesis, and 3) immunological methods by preparing vaccines against male-specific antigens. We hereby describe an alternative approach in which attachments of developing germ cells onto the seminiferous epithelium are disrupted, thereby inducing their premature release into the tubular lumen. This in turn leads to infertility. A panel of analogues based on the core structure of 1-(2,4-dichlorobenzyl)-indazole-3-carboxylic acid was synthesized. These compounds were subjected to an in vivo screening assay assessing their effects in inducing the expression of testin, a testicular marker whose expression correlates with the integrity of Sertoli-germ cell junctions. An induction of testin expression in the testis signifies a disruption of Sertoli-germ cell junctions that is followed by depletion of germ cells from the seminiferous epithelium. Two compounds, namely 1-(2,4-dichlorobenzyl)-indazole-3-carbohydrazide (AF-2364) and 1-(2,4-dichlorobenzyl)-indazole-3-acrylic acid (AF-2785), were identified that caused detachment of germ cells, in particular round and elongated spermatids, from the epithelium inducing their premature release into the tubular lumen as confirmed by histological analysis. Adult rats receiving several oral doses of either one of these compounds became infertile within 3-7 wk after the epididymal sperm reserve was exhausted. Depending on the dosing of the administered compound, rats became infertile for 4-14 wk before their fertility gradually bounced back, illustrating the reversibility and efficacy of these new compounds. Also, these compounds did not appear to impair the hypothalamus-pituitary-testicular axis because the serum levels of LH, FSH, and testosterone of the treated animals did not change significantly when compared to control rats. In addition, results of serum microchemistry illustrate that liver and kidney function was not affected in animals treated with both compounds.

Inhibition of heat-induced denaturation of albumin by nonsteroidal antiinflammatory drugs (NSAIDs): pharmacological implications.

The activity of nonsteroidal antiinflammatory drugs (NSAIDs) in rheumatoid arthritis is not only due to the inhibition of the production of prostaglandins, which can even have beneficial immunosuppressive effects in chronic inflammatory processes. Since we speculated that these drugs could also act by protecting endogenous proteins against denaturation, we evaluated their effect on heat-induced denaturation human serum albumin (HSA) in comparison with several fatty acids which are known to be potent stabilizers of this protein. By the Mizushimas assay and a recently developed HPLC assay, we observed that NSAIDs were slightly less active [EC50 to approximately 10(-5)-10(-4) M] than FA and that the HPLC method was less sensitive but more selective than the turbidimetric assay, i.e. it was capable of distinguishing true antiaggregant agents like FA and NSAIDs from substances capable of inhibiting the precipitation of denatured protein aggregates. In conclusion, this survey could be useful for the development of more effective agents in protein condensation diseases like rheumatic disorders, cataract and Alzheimers disease.