Julianna Ferreira Cavalcanti de Albuquerque

Discovery of new inhibitors of Schistosoma mansoni PNP by pharmacophore-based virtual screening.

Schistosomiasis is considered the second most important tropical parasitic disease, with severe socioeconomic consequences for millions of people worldwide. Schistosoma mansoni , one of the causative agents of human schistosomiasis, is unable to synthesize purine nucleotides de novo, which makes the enzymes of the purine salvage pathway important targets for antischistosomal drug development. In the present work, we describe the development of a pharmacophore model for ligands of S. mansoni purine nucleoside phosphorylase (SmPNP) as well as a pharmacophore-based virtual screening approach, which resulted in the identification of three thioxothiazolidinones (1-3) with substantial in vitro inhibitory activity against SmPNP. Synthesis, biochemical evaluation, and structure-activity relationship investigations led to the successful development of a small set of thioxothiazolidinone derivatives harboring a novel chemical scaffold as new competitive inhibitors of SmPNP at the low-micromolar range. Seven compounds were identified with IC(50) values below 100 μM. The most potent inhibitors 7, 10, and 17 with IC(50) of 2, 18, and 38 μM, respectively, could represent new potential lead compounds for further development of the therapy of schistosomiasis.

Synthesis, antimicrobial and cytotoxic activities of some 5-arylidene-4-thioxo-thiazolidine-2-ones

Several 5-arylidene-4-thioxo-thiazolidine-2-ones (3a-n) were synthesized and evaluated as antimicrobial agents against representative strains, including multidrug-resistant strains of clinical isolates. Also, the antiproliferative activity was evaluated against two human carcinoma cell lines (NCI-H292 and HEp-2). The compounds containing the 5-arylidene subunit presented greater antimicrobial activities against Gram positive bacteria, including the multidrug-resistant clinical isolates, than the 4-thioxo-thiazolidine-2-one. Important SAR information was also gathered, such as the contribution of thiocarbonyl attached at 4-position on the thiazolidine heterocyclic for antimicrobial properties. None of the derivatives exhibited significant antiproliferative activity against the human carcinoma cell lines.

Central Antinociceptive Effects of Cissus sicyoides. on Mice

Abstract The acute and chronic treatment of mice with a hydroalcohol extract from the leaves of Cissus sicyoides. L. (Vitaceae) (CS) at doses of 300, 600, and 1000 mg/kg, by intraperitoneal administration, produced a significant central antinociceptive effect on the hot plate, tail immersion, and acetic acid–induced writhing, tests, and the effect was inhibited by naloxone. CS was given to mice daily for 30 days at a dose of 600 mg/kg, causing an effect similar to that of drugs with typical action on opioid receptors. The effective dose (ED50) was approximately 600 mg/kg in mice.

Antinociceptive Effect of the Essential Oil Obtained from the Leaves of Croton cordiifolius Baill. (Euphorbiaceae) in Mice

Croton cordiifolius Baill. is a shrub known as “quebra-faca” and is used to treat inflammation, pain, wounds, and gastrointestinal disturbances in the semiarid region in the northeast of Brazil. In an ethnobotanical survey in the state of Pernambuco, “quebra-faca” use was cited in 33% of the interviews. Thus, we decided to evaluate the antinociceptive effects of the essential oil from C. cordiifolius (CcEO). Chemical analysis by gas chromatography-mass spectrometry revealed 1,8-cineole (25.09%) and α-phellandrene (15.43%) as major constituents. Antinociceptive activity was evaluated using murine models of chemically induced pain (writhing induced by acetic acid, formalin, capsaicin, and glutamate tests). Opioid and central nervous systems (CNS) involvement were also investigated. Regarding antinociceptive activity, CcEO (50 and 100 mg/kg) reduced the number of writhing responses induced by acetic acid and decreased the licking times in both phases of the formalin test. CcEO also was evaluated in capsaicin- and glutamate-induced nociception. While no effect was observed in the capsaicin test, CcEO (100 mg/kg) was effective in the glutamate test. Naloxone, an opioid antagonist, did not affect the antinociceptive activity of CcEO in writhing test. In conclusion, the antinociceptive effect of CcEO could be explained, at least in part, by inhibition of the glutamatergic system.

Chemical composition, antioxidant and topical anti-inflammatory activities of Croton cordiifolius Baill. (Euphorbiaceae)

Croton cordiifolius is widely used in Brazilian Caatinga folk medicine to treat general inflammation, pain, and gastrointestinal disturbances. Currently, its medicinal properties are not well understood, owing to the absence of chemical and pharmacological studies. The aims of this work were to analyze the chemical composition of C. cordiifolius stem bark and evaluate its in vitro antioxidant and in vivo anti-inflammatory activities. C. cordiifolius ethanolic extract (CcEE) was obtained by maceration, while essential oil (CcEO) was extracted by hydrodistillation in a Clevenger-type apparatus. The chemical composition was evaluated by thin-layer chromatography and GCMS. Total phenolics, flavonoids, and antioxidant activity were quantitated by spectrophotometry. Topical anti-inflammatory activity was evaluated by different ear edema models in mice. The major compounds in CcEO were α-pinene (51.76%) and β-pinene (19.08%). CcEE analysis indicated the presence of alkaloids, mono- and sesquiterpenes, flavonoids, phenylpropanoids, triterpenes, steroids, and coumarins. CcEE showed antioxidant activity in vitro. In a topical anti-inflammatory assay, CcEO showed no activity. On the contrary, CcEE inhibited ear edema induced by phorbol 12-myristate 13-acetate (PMA), arachidonic acid (AA), ethyl phenylpropriolate (EPP), and phenol. Probable mechanisms include inhibition of AA metabolite biosynthesis, vasoactive amine activity, and cytokine release/activity. These results corroborate the popular reputation of C. cordiifolius as an anti-inflammatory remedy. Key words: Croton cordiifolius, Euphorbiaceae, caatinga, topical anti-inflammatory activity, ear edema.

Synthesis and antimicrobial activities of 5-Arylidene-thiazolidine-2,4-dione derivatives.

Antibiotic resistance is considered one of the worlds major public health concerns. The main cause of bacterial resistance is the improper and repeated use of antibiotics. To alleviate this problem, new chemical substances against microorganisms are being synthesized and tested. Thiazolidines are compounds having many pharmacological activities including antimicrobial activities. For this purpose some thiazolidine derivatives substituted at position 5 in the thiazolidine nucleus were synthesized and tested against several microorganisms. Using a disc diffusion method, antimicrobial activity was verified against Gram-positive, Gram-negative, and alcohol acid resistant bacteria and yeast. The minimum inhibition concentrations (MIC) and minimum bactericidal concentrations (MBC) were determined. All derivatives showed antimicrobial activity mainly against Gram-positive bacteria, with MIC values ranging from 2 to 16 µg/mL.

Antitumor Activity of Leaves from Hyptis mutabilis (A. Rich.) Briq. (Lamiaceae) in Mice Bearing Tumor

The Hyptis genus has more than 400 species, many of them being used in folk medicine to treat several conditions. Some anticancer compounds have been isolated from plants of this genus, and for that reason we decided to investigate the potential in vivo antitumor activity of extracts of leaves of Hyptis mutabilis with different polarities (hexane, methanol, water, and hot water) against two mice tumors: sarcoma 180 and Ehrlich solid tumor. Phytochemical analysis revealed strong presence of steroids, saponins, flavonoids (mainly dihydroflavanols), and catechins. Acute toxicity was perfomed according to the up-and-down method showing LD50 values ranging from 100 up to 2500 mg/kg. Antitumor activity was investigated using 10% of the LD50 for each extract. Methotrexate was used as positive control. Both aqueous extracts showed strong inhibition of tumor growth with values up to 70% of inhibition growth for sarcoma 180. Ehrlich solid tumor was only slight inhibited by hexane extract (38.6%). In conclusion, the aqueous extracts of H. mutabilis showed promising results against sarcoma 180 mice tumor.

Selective cytotoxic and genotoxic activities of 5-(2-bromo-5-methoxybenzylidene)-thiazolidine-2,4-dione against NCI-H292 human lung carcinoma cells

BACKGROUND Thiazolidine-2,4-dione ring system is used as a pharmacophore to build various heterocyclic compounds aimed to interact with biological targets. In the present study, benzylidene-2,4-thiazolidinedione derivatives (compounds 2-5) were synthesized and screened against cancer cell lines and the genotoxicity and cytotoxicity of the most active compound (5) was investigated on normal and lung cancer cell line. METHODS For in vitro cytotoxic screening, the MTT assay was used for HL60 and K562 (leukemia), MCF-7 (breast adenocarcinoma), HT29 (colon adenocarcinoma), HEp-2 (cervix carcinoma) and NCI-H292 (lung carcinoma) tumor cell lines and Alamar-blue assay was used for non-tumor cells (PBMC, human peripheral blood mononuclear cells) were used. Cell morphology was visualized after Giemsa-May-Grunwald staining. DNA content, phosphatidylserine externalization and mitochondrial depolarization were measured by flow cytometry. Genotoxicity was assessed by Comet assay. RESULTS 5-(2-Bromo-5-methoxybenzylidene)-thiazolidine-2,4-dione (5) presented the most potent cytotoxicity, especially against NCI-H292 lung cancer cell line, with IC50 value of 1.26μg/mL after 72h incubation. None of the compounds were cytotoxic to PBMC. After 48h incubation, externalization of phosphatidylserine, mitochondrial depolarization, internucleosomal DNA fragmentation and morphological alterations consistent with apoptosis were observed in NCI-H292 cells treated with compound (5). In addition, compound (5) also induced genotoxicity in NCI-H292 cells (2.8-fold increase in damage index compared to the negative control), but not in PBMC. CONCLUSION Compound 5 presented selective cytotoxic and genotoxic activity against pulmonary carcinoma (NCI-H292 cells).