Daniela H. de Oliveira

Essential oil of Psidium cattleianum leaves: Antioxidant and antifungal activity

Abstract Context: Psidium cattleianum Sabine (Myrtacea) is rich in vitamin C and phenolic compounds, including epicatechin and gallic acid as the main components. Objective: To evaluate the antifungal and antioxidant capacity in vitro of the essential oil of araçá (EOA). The acute toxicity of the EOA also was evaluated in mice. Materials and methods: The leaves of the P. cattleianum were extracted by steam distillation. The antioxidant capacity was evaluated by in vitro tests [1,1-diphenyl-2-picryl-hydrazyl (DPPH), 2,2-azinobis(3-ethylbenzothiazoline-6-sulfonate) (ABTS), ferric ion reducing antioxidant power (FRAP), linoleic acid oxidation, thiobarbituric acid reactive species (TBARS)], and ex vivo analysis [TBARS, δ-aminulevunilate dehydratase (δ-Ala-D) and catalase activity, non-protein thiols (NPSH), and ascorbic acid levels]. The toxicity was studied in mice by a single oral administration of EOA; and the antifungal activity was performed with five strains of fungi. Results: The EOA exhibited antioxidant activity in the FRAP assay and reduced lipid peroxidation in the cortex (Imax = 32.90 ± 2.62%), hippocampus (IC50 = 48.00 ± 3.00 µg/ml and Imax = 32.90 ± 2.62%), and cerebellum (Imax = 45.40 ± 14.04%) of mice. Acute administration of the EOA by the oral route did not cause toxicological effects in mice (LD50 > 500 µg/ml). The EOA also showed antifungal activity through of the determination minimum inhibitory concentration (MIC) values ranging from 41.67 ± 18.04 to 166.70 ± 72.17 µg/ml for tested strains. Conclusion: The results of present study indicate that EOA possess antioxidant properties, antifungal and not cause toxicity at tested doses.

Synthesis of 4-Arylselanylpyrazoles Through Cyclocondensation Reaction Using Glycerol as Solvent

We describe here a simple method to synthesize 4-arylselanylpyrazoles by reaction of α-arylselanyl-1,3-diketones with arylhydrazines using glycerol as solvent at 60 °C under N2 atmosphere. This is a direct cyclocondensation reaction performed with α-arylselanyl-1,3-diketones and arylhydrazines bearing electron-withdrawing and electron-donating groups affording the corresponding 4-arylselanylpyrazoles in moderate to good yields.

Synthesis, Antimicrobial, and Antioxidant Activities of Chalcogen-Containing Nitrone Derivatives from (R)-citronellal

Background: The main constituents of Cymbopogonnardus (L) Rendle and C. citratus (DC) Stapfessential oils are (R)-citronellal and citral, respectively. Organochalcogen compounds can boost the biological activities of natural products. Methods: Several chalcogen-containing nitrones derived from (R)-citronellal and citral were prepared and evaluated for their antimicrobial and antioxidant activities. The antimicrobial activity was evaluated by the disc diffusion test and the antioxidant properties were evaluated in vitro by DPPH (1,1-diphenyl-2-picryl-hydrazyl), ABTS (2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid), and FRAP (ferric ion reducing antioxidant power) assays. Results: In the antimicrobial assay, (E)-N,3,7-trimethyl-3-(phenylthio)oct-6-en-1-imine oxide 5c exhibited halos between 21.5 mm (Escherichia coli O157:H7) and 26.0 mm (Listeria monocytogenes), while (E)-N,3,7-trimethyloct-6-en-1-imine oxide 5d presented halos between 22.5 mm (E. coli O157:H7) and 31.0 mm (L. monocytogenes). (E)-N,3,7-Trimethyl-2-(phenylthio)oct-6-en-1-imine oxide 5a showed the lowest minimal inhibitory concentration (MIC) value against Bacillus cereus (0.48 mM), and 5c was the most potent bactericide, with a minimal bactericidal concentration (MBC) of 0.52 mM for E. coli O157:H7. In the antioxidant assays, 5c, 5d, and 10 ((E)-3,7-dimethyl-2-(phenylselanyl)oct-6-enal oxime) were the most actives in the DPPH, ABTS, and FRAP assays, respectively. Conclusions: The presence of a phenylthio group in the nitrone increases its antimicrobial activity against Gram-positive and Gram-negative foodborne pathogens in the disk diffusion test and the antioxidant activity in vitro.

Antioxidant and antifungal activities of the flowers’ essential oil of Tagetes minuta, (Z)-tagetone and thiotagetone

ABSTRACT Herein, we describe our results on the determination of the chemical profile of the essential oil (EO) of flowers from Tagetes minuta L. grown in Southern Brazil. The major component of the EO is (Z)-tagetone 1 (70.64% w/w). Thiotagetone 6, a semi-synthetic derivative, was prepared from 1 in 82% yield. Compounds 1 and 6 and the EO were evaluated for their antioxidant and antifungal activities in vitro. All the tested samples presented antioxidant effect in scavenging radical and in the lipid peroxidation assays. A good antifungal activity against Candida lipolityca, Candida parapsilosis, Trichosporon asahii and Sphaceloma ampelinum was observed. (Z)-Tagetone 1 inhibited the mycelia growth of S. ampelinum around 80% at 6 days. No acute toxicity (200 mg/kg) was observed in mice for the EO or the compounds 1 and 6. The lack of toxicity is an indicative for additional studies aiming their potential therapeutic use.

3-(4-Chlorophenylselanyl)-1-methyl-1 H -indole, a new selenium compound elicits an antinociceptive and anti-inflammatory effect in mice

Abstract Several pathologies, such as pain and inflammation, are modulated by different pathways, making it necessary to develop drugs capable of modulating different pathways. Based on that, we investigated the antinociceptive and anti‐inflammatory effect of 3‐(4‐chlorophenylselanyl)‐1‐methyl‐1H‐indole (CMI), as well as the systems involved in these actions. This study evaluated the antinociceptive and anti‐inflammatory effects of CMI [0.0001–10 mg/kg administered intragastrically (i.g.)] in the formalin, glutamate, hot plate, ear edema induced by croton oil and paw edema induced by formalin tests. In addition, to investigate the mechanism of action, mice were pre‐treated with antagonists of adenosinergic, monoaminergic and opioid systems before administration of CMI. The selenium‐containing compound decreased the paw licking and biting time in the formalin and glutamate tests, increased the response latency in hot plate test, without ambulatory changes, evaluated in the open field test. CMI was able to reduce both paw and ear edema induced by formalin and croton oil, respectively. Additionally the antinociceptive effect of CMI (0.01 mg/kg) was blocked when mice were pretreated with the antagonists: SCH23390 [D1‐receptor antagonist, 0.05 mg/kg, intraperitoneally (i.p.)], WAY100635 (5‐HT1A‐receptor antagonist, 0.7 mg/kg, i.p.), ondansetron (5‐HT3‐receptor antagonist, 0.5 mg/kg, i.p.), ketanserin (5‐HT2A/2C‐receptor antagonist, 0.3 mg/kg, i.p.), naloxone (non‐selective antagonist 1 mg/kg, i.p.), caffeine (non‐selective antagonist, 3 mg/kg, i.p.) and prazosin (&agr;1‐receptor antagonist, 0.15 mg/kg, i.p). These results demonstrate that the antinociceptive effect of CMI is mediated by monaminergic, opioidergic and adenosinergic modulations and can be a promising molecule capable of modulating different pathways for the treatment of pain and inflammation. Graphical abstract Figure. No Caption available.

Óleos Essenciais como Matéria-Prima Sustentável para o Preparo de Produtos com Maior Valor Agregado

The use of renewable feedstocks, which may substitute those derived from petroleum, is currently a great challenge in the chemical and pharmaceutical industries. However, plant essential oils (EOs) that have been studied for their biological activities, such as antioxidant, antimicrobial, antifungal and antinociceptive are generally regarded as safe additives maintaining the microbiological stability of foods. EOs are a mixture of natural volatile compounds, that are predominantly formed during the secondary metabolism in plants and commonly concentrated in the leaves, bark or fruits of aromatic plants. They are complex mixtures composed mainly of terpenes (hydrocarbons or oxygenated compounds) and phenylpropanoids, which can be used as a source of raw materials for fine chemicals industry. In recent years, researchers and industries have been focusing on the major compounds of EOs in order to use them as solvents or as bio-based building blocks adding value to this material derived from biomass.