Andresa Heemann Betti

The PT-31 molecule, a potential antipsychotic, has demonstrated promising results when orally administrated to in vivo models. A recent study suggested the genotoxic and mutagenic potential of PT-31 after acute treatment by intraperitoneal route. This study aimed to evaluate PT-31 potential of inducing genotoxic or mutagenic damage after acute oral administration. For that, adult males and females Balb/C mice were treated acutely by oral administration with vehicle or PT-31 in three different doses (10, 20, and 40 mg kg-1). After 24 hours from PT-31 administration, animals were euthanized for performing the comet and micronucleus assays. None of the tested groups of PT-31 presented a significant increase in damage index and MN frequency. However, they presented the following tendency on damage index: females presented a tendency at 40 mg kg-1 and males at 20 mg kg-1. Regarding the MN assay, male mice at the highest dose of 40 mg kg-1 presented a tendency of increased MN frequency. Also, there was a significant increase in PCE/NCE ratio in male mice. Results suggest that the male mice group presented higher susceptibility to damage. The tendency of increased damage to DNA and MN frequency suggests that the molecule PT-31 may induce reparable damage to DNA, and these DNA strand repairs may have originated from the MN. However, significant genotoxic and mutagenic effects were not observed. This study reinforces the atypicality of the molecule as much as its safety by oral route administration.

Schizophrenia is a psychiatric disorder that affects 1% of the world population and is treated with antipsychotics, which may induce important biochemical and hematological alterations. Since it is necessary to verify the safety of new molecules with antipsychotic potential, the present study aimed to evaluate the oral toxicity of PT-31, a putative α₂-adrenoreceptor agonist, after acute (2000 mg/kg) and repeated doses (28 days) gavage treatment, in three different doses: minimum effective dose in animal models (10 mg/kg), twice the dose (20 mg/kg), and four times the dose (40 mg/kg), as recommended by the OECD guidelines. Balb/C female adult mice were used, and biochemical, hematological, and histopathological analyses were performed. PT-31 10 and 20 mg/kg did not cause biochemical alterations related to hepatic and renal toxicity, and neither altered glycemic and lipid profiles. The preclinical dose of PT-31 also did not promote mice histopathological changes in the liver, kidney, and brain. In the hematimetric parameters, PT-31 only increased HGB at 20 mg/kg, and MCH and MCHC at 40 mg/kg. However, all the tested doses of PT-31 showed platelet increase, which must be better investigated. Therefore, further studies are needed to investigate the safety of PT-31 as a potential antipsychotic drug.

Inflammatory processes cause changes in the permeability of the blood brain barrier. Non-steroidal anti-inflammatory drugs (NSAID) are most commonly used to treat these inflammatory processes, including meloxicam, and they can reach the central nervous system (CNS) and cause neurotoxicity. Since there are no studies evaluating the neurotoxicity of NSAID in alternative models of toxicity, the aim of this study was to evaluate the acute neurotoxicity (through nematodes changes in behavior) of meloxicam in an alternative in vivo model, Caenorhabditis elegans, as well as, to determine meloxicam toxicity through LD50 and development assessments. Meloxicam LD50 was high (50.03 mg/mL) and only the highest dose (100 mg/mL) caused a decrease in the nematode body size, indicating low toxicity in this alternative model. Besides, a neurological effect was observed only in the highest dose. Meloxicam showed neurotoxicity only at a very high dose, suggesting low potential to cause toxicity in the CNS. However, further studies are necessary to evaluate meloxicam neurotoxicity.

Meloxicam is the non-steroidal anti-inflammatory drug most used in small animals; however, studies on genotoxicity, oxidative stress, and histopathologic alterations in cardiac tissue are limited, especially at therapeutical doses used in these animals. This study evaluated the toxic effects caused by the treatment involving repeated low at higher doses of meloxicam in mice, by genotoxicity, oxidative stress, and histopathological parameters. Mice (CF1, male) received, by gavage, meloxicam at the therapeutic dose indicated for small animals (0.1 mg/kg) and at higher doses (0.5 and 1 mg/kg) for 28 days. Later, they were euthanized for blood and organ analysis. Oxidative stress was analyzed by the plasma ferric reduction capacity (FRAP) and catalase, and genotoxicity, by the comet assay and the micronucleus test. Heart, liver, lung, and kidney tissues were analyzed by the histology, and stomach and duodenum were analyzed with a magnifying glass. The relative weight of organs did not present significant alterations. However, congestion of duodenum vessels was observed at the three tested doses and caused hyperemia of stomach mucosa at 1 mg/kg. In the heart histology there was a reduction in the number of cardiomyocytes, accompanied by an increase in cell diameter (possible cell hypertrophy) dose-dependent. The highest tested dose of meloxicam also increased the DNA damage index, without alterations in the micronucleus test. Meloxicam did not affect the catalase activity but increased the FRAP (1 mg/kg). Meloxicam at the dose prescribed for small animals could potentially cause cardiac histopathologic alterations and genotoxic effects.

Fluoxetine (FLU), a selective serotonin reuptake inhibitor, is the first line in depression treatment and it is involved in oxidative stress (OE). Thus, this study aimed to analyze the OE parameters in patients diagnosed with depression and treated with FLU. Were evaluated 121 volunteers divided into two groups: 58 fluoxetine users (with major depression) and 63 non-fluoxetine users (control group, without major depression). The OE was evaluated by determining the levels of malondialdehyde (MDA), total antioxidant power (FRAP) and activity of antioxidant enzymes glutathione peroxidase (GPx) and superoxide dismutase (SOD). MDA, FRAP, GPx and SOD were dosed in plasma. The influence of age, smoking, alcoholism, comorbidities, use of another drugs and antioxidants in the OE were evaluated. The results were compared between the groups. In relation to the fluoxetine daily dose, MDA presented higher levels in patients using 20 mg daily FLU when compared to the control group, as well as the activity of the GPx enzyme and the FRAP levels. In this way, the use of fluoxetine may interfere with the OE parameters, causing an increase in OE levels.

Quillaja saponaria Molina represents the main source of saponins for industrial applications. Q. saponaria triterpenoids have been studied for more than four decades and their relevance is due to their biological activities, especially as a vaccine adjuvant and immunostimulant, which have led to important research in the field of vaccine development. These saponins, alone or incorporated into immunostimulating complexes (ISCOMs), are able to modulate immunity by increasing antigen uptake, stimulating cytotoxic T lymphocyte production (Th1) and cytokines (Th2) in response to different antigens. Furthermore, antiviral, antifungal, antibacterial, antiparasitic, and antitumor activities are also reported as important biological properties of Quillaja triterpenoids. Recently, other saponins from Q. brasiliensis (A. St.-Hill. & Tul.) Mart. were successfully tested and showed similar chemical and biological properties to those of Q. saponaria barks. The aim of this manuscript is to summarize the current advances in phytochemical and pharmacological knowledge of saponins from Quillaja plants, including the particular chemical characteristics of these triterpenoids. The potential applications of Quillaja saponins to stimulate further drug discovery research will be provided.