4-amino-2-phenyl-6-(p-fluorophenyl)-5-carbonitrile-pyrimidine-bis-substituted-loaded liposomes as promising system for cancer treatment.

The aim of the present study was to perform in vitro and in vivo assessments of the antineoplastic action of 4-amino-pyrimidine encapsulated in liposomes. Liposomes were prepared and characterized for particle size and drug encapsulation and submitted to long-term stability tests. Cytotoxicity assays were performed in HeLa cells. Antineoplastic activity was investigated using the experimental sarcoma 180 tumor in Swiss albino mice. Encapsulation efficiency was 82.93 ± 0.04% and no significant changes were found with respect to particle size or pH after centrifugation and mechanical agitation tests. The in vitro results at concentration of 20 µg/mL indicated a considerable reduction in cell viability after treatment with encapsulated pyrimidine (75.91%). The in vivo assays using the compounds in encapsulated and free forms and 5-fluorouracil achieved tumor inhibition rates of 66.47 ± 26.8%, 50.46 ± 16.24% and 14.47 ± 9.22%, respectively. Mitotic counts demonstrated a greater reduction in the number of mitoses in animals treated with liposomal pyrimidine (32.15%) compared to those treated with the pyrimidine free (87.69%) and 5-fluorouracil (71.39%). This study demonstrated that the development of liposome formulations containing 4-amino-pyrimidine is a promising alternative for overcoming limitations related to the toxicity of current cancer treatment, ensuring greater therapeutic efficacy.

Histological evaluation of the liver of mice with sarcoma-180 treated with salazinic acid.

Many of the drugs used to fight cancer cells induce various damage causing hepatotoxic effects which are characterized by tissue changes. The aim of the study is to know the possible effects of salazinic acid on livers of mice exposed to Sacoma-180. The tumor was grown in the animals in ascitic form and inoculated subcutaneously in the axillary region of the mouse developing the solid tumor. Treatment with salazinic acid (25 and 50 mg/kg) and 5-Fluorouracil (20 mg/kg) started 24-hours after inoculation and was performed for 7 days. To verify these effects, the qualitative method of histological criteria investigated in liver tissue was used. It was observed that all treated groups showed an increase of pyknotic nuclei in relation to the negative control. There was an increase in steatosis in all groups compared to the negative control but there was a decrease in the groups treated with salazinic acid in the 5-Fluorouracil. There was no necrosis in the salazinic acid treated groups. However, this effect was seen in 20% of the positive control group. Therefore, it can be concluded that salazinic acid did not show hepatoprotective action on mice but demonstrated a decrease in steatosis and absence of tissue necrosis.

Machaerium acutifolium compounds with larvicidal activity against Aedes aegypti.

BACKGROUND: Plant extracts and isolated compounds are known for their insecticidal activity. The Aedes aegypti mosquito has a significant medical impact as it transmits a number of arboviruses and is able to develop resistance to the commercially available insecticides. This study investigates larvicidal compounds isolated from Machaerium acutifolium, designated by the Brazilian Forest Service as a sustainable species. RESULTS: A M. acutifolium trunk ethyl acetate extract was fractionated using chromatographic methods with full structural elucidation by mass spectrometry (MS), nuclear magnetic resonance and specific rotation analyses revealing: one new 3-arylcoumarin derivative 1; two flavonoids 2 and 3; a trans-stilbene 4, and an unprecedented natural indene 5. The larvicidal activity against Ae. aegypti after 24 h exposure was: crude extract (median lethal dose, LC50 205 mg L-1 ), fraction C (LC50 27 mg L-1 ) and 5 (LC50 24 mg L-1 ). CONCLUSION: A M. acutifolium extract showed larvicidal activity, which increased with prolonged exposure, demonstrating LC50 75 mg L-1 after 72 h. Although the flavonoids 2 and 3 and trans-stilbene 4 were deemed inactive according to the adopted mortality limit, additional tests revealed their ability to cause 65% Ae. aegypti larvae mortality, suggesting they could contribute to the larvicidal activity. Compound 5, identified by liquid chromatography-MS, was over eight-fold more toxic to larvae than the crude extract after 24 h. Therefore, 5 constitutes a structural model for new prototypes to control Ae. aegypti. These data reinforce the potential of natural products as a source of commercial alternatives for vector control strategies, respecting both sustainability and eco-friendly principles. © 2020 Society of Chemical Industry.

Use of GC/MS to identify chemical constituents and cytotoxic activity of the leaves of Phoradendron mucronatum and Phoradendron microphyllum (Viscaceae).

Phoradendron mucronatum and P. microphyllum are plants that found in tropical and subtropical areas, used in traditional medicine and popularly known as mistle-thrush. The aim of this study was to identify the chemical constituents of different leaf extracts from P. mucronatum and P. microphyllum and assess cytotoxic activity against strains from a human tumour cells. Extracts obtained with hexane, dichloromethane, chloroform and ethyl acetate from the leaves were analysed by gas chromatography coupled with mass spectrometry (GC-MS) and the cytotoxicity was assessed by the MTT method (bromide (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide)). The tested human tumour cells were NCI-H292 (human pulmonar mucoepidermoid carcinoma), MCF-7 (human breast adenocarcinoma) and HEp-2 (epidermoid carcinoma of the larynx). Analysis by GC/MS of the extracts from leaves of P. microphyllum and P. mucronatum detected 51 different compounds, such as alkaloids, diterpenes, triterpenes, sterols, alcohols, aldehydes, fatty acids and hydrocarbons. In the cytotoxic evaluation, hexane and ethyl acetate extracts from the leaves P. microphyllum inhibited cell growth of NCI-H292 strains (72.97%) and HEp-2 (87.53%), respectively. The extracts of P. mucronatum species showed an inhibitory effect towards NCI-H292 (83.19%/hexane), MCF-7 (88.69%/dichloromethane) and HEp-2 (93.40%/hexane). The extracts showed cytotoxic activity against the tested strains, especially the P. mucronatum, which presented the highest percentages of inhibition of cell growth.

Synthesis and evaluation of arylamidine derivatives for new antimicrobial and cytotoxic activities.

A series of arylamidines 3a-j was designed, synthesized and investigated for antimicrobial activity. Structures of the compounds were confirmed by IR, 1H-NMR and 13C-NMR and a 2D spectroscopic study was performed. A preliminary screening of the antimicrobial tests clearly showed that three out of ten arylamidines, viz, 3f, 3g and 3i, were effective against all the gram-negative bacteria: Klebsiella pneumoniae, Pseudomonas aeruginosa and Salmonella enteric; and against the yeast, candida albicans. Further, the Minimum Inhibitory Concentrations (MIC) against the bacteria and yeast were determined. All compounds 3a-d, 3f, 3g, 3i and 3j were also investigated for their low cytotoxic effects on tested cell lines. Compounds 3d and 3f were the most effective derivatives against HL-60 and HEp-2 cells, respectively, with IC50 value (2µg/mL), and low normal cells toxicity.

Use of GC/MS to identify chemical constituents and cytotoxic activity of the leaves of Phoradendron mucronatum and Phoradendron microphyllum (Viscaceae)

ABSTRACT Phoradendron mucronatum and P. microphyllum are plants that found in tropical and subtropical areas, used in traditional medicine and popularly known as mistle-thrush. The aim of this study was to identify the chemical constituents of different leaf extracts from P. mucronatum and P. microphyllum and assess cytotoxic activity against strains from a human tumour cells. Extracts obtained with hexane, dichloromethane, chloroform and ethyl acetate from the leaves were analysed by gas chromatography coupled with mass spectrometry (GC-MS) and the cytotoxicity was assessed by the MTT method (bromide (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide)). The tested human tumour cells were NCI-H292 (human pulmonar mucoepidermoid carcinoma), MCF-7 (human breast adenocarcinoma) and HEp-2 (epidermoid carcinoma of the larynx). Analysis by GC/MS of the extracts from leaves of P. microphyllum and P. mucronatum detected 51 different compounds, such as alkaloids, diterpenes, triterpenes, sterols, alcohols, aldehydes, fatty acids and hydrocarbons. In the cytotoxic evaluation, hexane and ethyl acetate extracts from the leaves P. microphyllum inhibited cell growth of NCI-H292 strains (72.97%) and HEp-2 (87.53%), respectively. The extracts of P. mucronatum species showed an inhibitory effect towards NCI-H292 (83.19%/hexane), MCF-7 (88.69%/dichloromethane) and HEp-2 (93.40%/hexane). The extracts showed cytotoxic activity against the tested strains, especially the P. mucronatum, which presented the highest percentages of inhibition of cell growth.

Synthesis and evaluation of arylamidine derivatives for new antimicrobial and cytotoxic activities

ABSTRACT A series of arylamidines 3a-j was designed, synthesized and investigated for antimicrobial activity. Structures of the compounds were confirmed by IR, 1H-NMR and 13C-NMR and a 2D spectroscopic study was performed. A preliminary screening of the antimicrobial tests clearly showed that three out of ten arylamidines, viz, 3f, 3g and 3i, were effective against all the gram-negative bacteria: Klebsiella pneumoniae, Pseudomonas aeruginosa and Salmonella enteric; and against the yeast, candida albicans. Further, the Minimum Inhibitory Concentrations (MIC) against the bacteria and yeast were determined. All compounds 3a-d, 3f, 3g, 3i and 3j were also investigated for their low cytotoxic effects on tested cell lines. Compounds 3d and 3f were the most effective derivatives against HL-60 and HEp-2 cells, respectively, with IC50 value (2µg/mL), and low normal cells toxicity.

Pharmacological screening and acute toxicity of bark roots of Guettarda platypoda

Due to its folk use, scientific reports and phytochemical screening, the purpose of this work was to study the phytochemical and the biological properties of the methanol extract and to evaluate the anti-inflammatory activity as well as determine the acute toxicity, antitumor and cytotoxic activity of the root barks of Guettarda platypoda DC., Rubiaceae. In this analysis the presence of flavonoids and therpenoids were identified. These data and the ones in the literature indicated it as a potential antioxidant and motivated the cytotoxic analysis related with three tumoral cell strains as well as to evaluate its antitumoral activity (sarcoma 180 and Ehrlich carcinoma) in female mice. Due to the presence of esteroids and the previous study of the ethanolic extract, its anti-inflammatory activity and toxicity were also evaluated. Absence or low toxicity in 2000 mg/kg doses was verified and the attention to their phytochemical and pharmacological properties is constantly increasing.

Comparative computational studies of 3,4-dihydro-2,6-diaryl-4-oxo-pyrimidine-5-carbonitrile derivatives as potential antinociceptive agents.

In this study, the antinociceptive properties of 3,4-dihydro-2,6-diaryl-4-oxo-pyrimidine-5-carbonitrile derivatives 5a-i at doses of 25 and 50 mg/kg were evaluated in mice, using the abdominal constriction test. Molecular modeling studies were also performed using density functional theory calculations. These data provided information about the electrostatic and ionization potentials and were used to compare the antinociceptive activity of the title compounds. The most active compounds were 3,4-dihydro-2-(4-chlorophenyl)-6-(4-methoxyphenyl)-4-oxo-pyrimidine-5-carbonitrile (5b) and 3,4-dihydro-2,6-diphenyl-4-oxo-pyrimidine-5-carbonitrile (5i), which inhibited the number of abdominal constrictions, at 50 mg/kg dose, in 88.6% and 88% of the sample, respectively. A preliminary SAR study demonstrated that halogen replacement in the phenyl rings of the compounds under study reduces the antinociceptive activity. DFT calculations showed that there is a high correlation between the ionization potentials and the analgesic properties of the compounds. It was found that compounds with a positive ionization potential (compounds 5b and 5i) were found to be the best analgesic drugs in this series.

Synthesis and cytotoxic profile of glycosyl-triazole linked to 1,2,4-oxadiazole moiety at C-5 through a straight-chain carbon and oxygen atoms.

The convergent synthesis of an unusual (but simple) class of compounds 5a-g has been achieved by the copper-catalyzed [3+2] cycloaddition reaction of 2,3,4,6-tetra-O-acetyl-beta-D-glucopyranosyl azide 4 with propynyl 3-[3-(aryl)-1,2,4-oxadiazol-5-yl] propionates 3a-g. The formerly known azide 4 has been prepared according to the literature procedure; however, the synthesis of esters 3a-g is being reported for the first time. The infrared as well as (1)H NMR spectra of all new products are in agreement with their proposed structures. By carrying out the nOe experiment of one of the final compounds 5a, we have been able to establish that only the 1,4-regioisomers have been formed in the cycloaddition reaction. All final products presented weak cytotoxic activity, but 5e and 5g had somewhat better behaviour showing 22-25% cell growth inhibition against two cell strains: NCI-H(292) (lung carcinoma) and HEp-2 (larynx carcinoma).

Synthesis of glycosyl-triazole linked 1,2,4-oxadiazoles.

The synthesis of four different types of oxadiazoles containing a terminal acetylenic group is described. Reaction of these oxadiazoles with various azidoglycosides via a copper-catalyzed [3+2] cycloaddition ('click chemistry') afforded the corresponding glycosyl-triazole linked 1,2,4-oxadiazoles in good yields.

Synthesis and antiinflammatory activity of 4-amino-2-aryl-5-cyano-6-{3- and 4-(N-phthalimidophenyl)} pyrimidines.

Six new 4-amino-5-cyano-2,6-diarylpyrimidines 5a-h has been synthesized in a facile manner by reacting the appropriate arylamidines 4a-d with bisnitriles 3a-e. Reduction of the nitro group of 5a-e using Pd in ethyl acetate furnished 6a-e in good yields. Reaction of 6a-e individually with phthalic anhydride yielded 7a-e in good to excellent yields. The newly synthesized heterocycles were characterized by IR, (1)H-NMR and mass spectral data. Compounds 5f-h and 7a-e were also evaluated against inflammation. Pyrimidines 5g, h exhibited better antiinflammatory activity when compared with acetylsalicylic acid (ASA). Phthalimide derivatives 7a-e also presented antiinflammatory activity, and three of them, viz., 7a-c have been found to be twice more active than aspirin. Cytotoxical evaluations of compounds 7a-e using neoplastic cells (NCI-H(292) and Hep-2) presented 41% of growth inhibition of neoplastic cells NCI-H(292).