Marcus Vinicius Cardoso Trento

Inhibition of proteases and phospholipases A2 from Bothrops atrox and Crotalus durissus terrificus snake venoms by ascorbic acid, vitamin E, and B-complex vitamins

The enzyme inhibition by natural and/ or low-cost compounds may represent a valuable adjunct to traditional serotherapy performed in cases of snakebite, mainly with a view to mitigate the local effects of envenoming. The objective of this study was to evaluate possible interactions between vitamins and enzymes that comprise Bothrops atrox and Crotalus durissus terrificus venoms, in vitro. Proteolysis inhibition assays (substrates: azocasein, collagen, gelatin and fibrinogen), hemolysis, coagulation, hemagglutination were carried out using different proportions of vitamins in face of to inhibit minimum effective dose of each venom. The vitamins were responsible for reducing 100% of breaking azocasein by C.d.t. venom, thrombolysis induced by B. atrox and fibrinogenolysis induced by both venoms. It is suggested the presence of interactions between vitamin and the active site of enzymes, for example the interactions between hydrophobic regions present in the enzymes and vitamin E, as well as the inhibitions exercised by antioxidant mechanism.

Anticancer Properties of Essential Oils: An Overview

BACKGROUND Essential oils are complex mixtures of low molecular weight compounds extracted from plants. Their main constituents are terpenes and phenylpropanoids, which are responsible for their biological and pharmaceutical properties, such as insecticidal, parasiticidal, antimicrobial, antioxidant, anti-inflammatory, analgesic, antinociceptive, anticarcinogenic, and antitumor properties. Cancer is a complex genetic disease considered as a serious public health problem worldwide, accounting for more than 8 million deaths annually. OBJECTIVE The activities of prevention and treatment of different types of cancer and the medicinal potential of essential oils are addressed in this review. CONCLUSION Several studies have demonstrated anti-carcinogenic and antitumor activity for many essential oils obtained from various plant species. They may be used as a substitution to or in addition to conventional anti-cancer therapy. Although many studies report possible mechanisms of action for essential oils compounds, more studies are necessary in order to apply them safely and appropriately in cancer therapy.

The protective effect exerted by ascorbic acid on DNA fragmentation of human leukocytes induced by Lachesis muta muta venom: CARDOSO TRENTO et al.

The objective of this study was to evaluate the genotoxic and mutagenic effects of the toxins present in Lachesis muta mutas venom on human peripheral blood leukocytes and the protective potential of ascorbic acid on DNA fragmentation. The venom of L. muta muta was incubated in different concentrations (1, 2.5, 5, 7.5, 10, 15, 20, 30, 40, 50, 60, and 120 µg/mL) with human blood to evaluate DNA fragmentation using the comet, agarose gel electrophoresis, and micronucleus assays. In these concentrations evaluated, the venom of L. muta muta induced genotoxicity (comet assay and agarose gel electrophoresis) and mutagenicity (micronucleus test), but they were not cytotoxic, as they did not change the rate of cell proliferation after cytokinesis blockade with cytochalasin B. The ascorbic acid significantly inhibited the genotoxicity induced by L. muta muta venom in the proportions evaluated (1:0.1 and 1:0.5, venom/ascorbic acid ‐ w/w). Thus, future studies are needed to elucidate the protective mechanisms of ascorbic acid on the genotoxic effects induced by toxins present in snake venoms.

Protective effect of β-D-glucan and glutamine on the genomic instability induced by Cytarabine/Ara-C in BALB/c mice

Prophylactic antibiotics and growth promoters have been substituted, mainly for livestock, by immunomodulators and intestinal health promoters - such as β-D-glucans and glutamine. The aim of this study was to verify the beneficial effects of β-D-glucans and glutamine against Cytarabine/Ara-C, evaluating the DNA damage in leukocytes, the leukogram, and the mitotic index of intestinal crypts cells. Balb/C mice received treatment with β-D-glucan (80 mg/Kg), glutamine (150 mg/Kg), or both, for 21 days. On the last two days of this period, Ara-C was administered (1.8 mg/animal) by intraperitoneal injection every 12 h. The animals submitted to the treatment with Ara-C presented the highest genotoxic index, a significant leukopenia, and a decrease in the mitotic index of the intestinal crypts cells. Treatment with β-D-glucan protected the leukocytes against DNA fragmentation induced by Ara-C. Glutamine alone promoted maintenance of the mitotic index and, in association with β-Dglucan, reduced leukopenia. Thus, the use of β-D-glucan and glutamine proved to be beneficial to intestinal tropism. This can happen once the damage to the genetic material, prevented by the treatments with β-D-glucan and glutamine, can result in genotoxicity. Not only this, but it might be capable of turning into a mutagenesis, with consequential physiopathological alterations.

Snake venom disintegrins: an overview of their interaction with integrins

Disintegrins are non-enzymatic proteins that interfere on cell-cell interactions and signal transduction, contributing to the toxicity of snake venoms and play an essential role in envenomations. Most of their pharmacological and toxic effects are the result of the interaction of these molecules with cell surface ligands, which has been widely described and studied. These proteins may act on platelets, leading to hemorrhage, and may also induce apoptosis and cytotoxicity, which highlights a high pharmacological potential for the development of thrombolytic and antitumor agents. Additionally, these molecules interfere with the functions of integrins by altering various cellular processes such as migration, adhesion and proliferation. This review gathers information on functional characteristics of disintegrins isolated from snake venoms, emphasizing a comprehensive view of the possibility of direct use of these molecules in the development of new drugs, or even indirectly as structural models.

Toxicological Aspects of the Essential Oil from Cinnamodendron dinisii

The objective of this study was to determine cytotoxic activity, hemolytic activity, and to evaluate the ability of the essential oil from Cinnamodendron dinisii to induce DNA fragmentation of human lymphocytes. The essential oil was obtained by hydrodistillation. Cytotoxic activity was determined by the MTT method. Hemolytic activity was evaluated by spectrophotometric quantification of hemoglobin released by erythrocytes. Damage to lymphocyte DNA molecules was assessed by the Comet assay. The essential oil under study showed high cytotoxic activity on Vero cells (CC50 = 35.72 μg/mL) and induced hemolysis in both hematocrits, besides leading to the oxidation of hemoglobin released. The genotoxic activity of C. dinisii essential oil was also observed, which induced concentration‐dependent DNA fragmentation of human lymphocytes and, at 50 μL/mL, it was more active than the positive control. The essential oil from C. dinisii has a toxic action, suggesting a special attention in the application of this oil to health‐promoting activities; however, among its components, there are molecules with potential for future application in anticancer therapies.

BIO010 In vitro effects of extracts of sea anemones on the DNA of human lymphocytes.

Sea anemones produce toxins such as hemolysins, neurotoxins and other enzymes that induce various effects such as cardiotoxicity, dermatitis, itching, local swelling, erythema, paralysis, pain and necrosis. Some toxins isolated from Anemonia, Stichodactyla, Anthopleura and Bunodosoma sea anemone genera are active on ion channels and receptors, acting on the central nervous system and on immune-mediated responses. Thus, sea anemones are promising sources of molecular models of medical-scientific interest, but the possible action of their toxins on the mammalian genome has not yet been reported.