Pollyanna Francielli de Oliveira

Preparation and characterization of a bacterial cellulose/silk fibroin sponge scaffold for tissue regeneration

Bacterial cellulose (BC) and silk fibroin (SF) are natural biopolymers successfully applied in tissue engineering and biomedical fields. In this work nanocomposites based on BC and SF were prepared and characterized by scanning electron microscopy (SEM), infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). In addition, the investigation of cytocompatibility was done by MTT, XTT and Trypan Blue dye technique. Cellular adhesion and proliferation were detected additionally. The evaluation of genotoxicity was realized by micronucleus assay. In vitro tests showed that the material is non-cytotoxic or genotoxic. SEM images revealed a greater number of cells attached at the BC/SF:50% scaffold surface than the pure BC one, suggesting that the presence of fibroin improved cell attachment. This could be related to the SF amino acid sequence that acts as cell receptors facilitating cell adhesion and growth. Consequently, BC/SF:50% scaffolds configured an excellent option in bioengineering depicting its potential for tissue regeneration and cultivation of cells on nanocomposites.

Chemical Composition and in vitro Schistosomicidal Activity of the Essential Oil of Plectranthus neochilus Grown in Southeast Brazil

The chemical composition and the in vitro schistosomicidal effects of the essential oil of Plectranthus neochilus (PN‐EO) grown in Southeast Brazil was studied. β‐Caryophyllene (1; 28.23%), α‐thujene (2; 12.22%), α‐pinene (3; 12.63%), β‐pinene (4; 6.19%), germacrene D (5; 5.36%), and caryophyllene oxide (6; 5.37%) were the major essential oil constituents. This chemical composition differed from that previously reported for specimens harvested in Africa. Concerning the in vitro schistosomicidal activity against adult Schistosoma mansoni worms, PN‐EO was considered to be active, but less effective than the positive control praziquantel (PZQ) in terms of separation of coupled pairs, mortality, decrease in the motor activity, and tegumental alterations. However, PN‐EO caused an interesting dose‐dependent reduction in the number and the percentage of developed S. mansoni eggs. These results suggest that PN‐EO might be very promising for the development of new schistosomicidal agents.

Assessment of the genotoxicity and antigenotoxicity of (+)-usnic acid in V79 cells and Swiss mice by the micronucleus and comet assays

Usnic acid is one of the most common and abundant metabolites found in various lichen genera, which are important sources of biologically active compounds. The aim of this study was to evaluate the genotoxic and antigenotoxic potential of (+)-usnic acid (UA) by the micronucleus and comet assays in V79 cell cultures and Swiss mice. For assessment of genotoxicity, V79 cells were treated with 15, 30, 60, and 120μg/mL UA, established based on clonogenic efficiency cytotoxic assay. Swiss mice were treated with UA doses of 25, 50, 100, and 200mg/kg body weight. The same concentrations of UA were combined with methyl methanesulfonate (MMS) for evaluation of antigenotoxicity. The in vitro results demonstrated that UA induced DNA damage at concentrations of 60 and 120μg/mL in the comet assay. However, no genotoxic effect was observed in the micronucleus test using V79 cells at the concentrations tested. No genotoxic effects were observed for the different UA treatments in in vivo test system. Combined administration of UA and MMS significantly reduced the frequencies of micronuclei and DNA damage in vitro and in vivo when compared to treatment with MMS alone. Although the mechanisms underlying the protective effect of UA are not completely understood, the antioxidant activity of this metabolite may explain its protective effect against MMS-induced genotoxicity.

Differential effect of manool - A diterpene from Salvia officinalis, on genotoxicity induced by methyl methanesulfonate in V79 and HepG2 cells

Salvia officinalis (sage) is a perennial woody subshrub native to the Mediterranean region that is commonly used as a condiment and as an anti-inflammatory, antioxidant and antimicrobial agent due to its biological activities. Manool is the most abundant micro-metabolite found in Salvia officinalis essential oils and extracts. We therefore decided to evaluate the cytotoxic, genotoxic and antigenotoxic potential of manool in Chinese hamster lung fibroblasts (V79) and human hepatoma cells (HepG2). Cytotoxicity was assessed by the colony-forming assay in V79 cells and toxic effects were observed at concentrations of up to 8.0 μg/mL. The micronucleus test was used to evaluate the genotoxicity and antigenotoxicity of manool in V79 and HepG2 cells at concentrations of 0.5-6.0 μg/mL and 0.5-8.0 μg/mL, respectively. For evaluation of antigenotoxicity, the concentrations of manool were combined with methyl methanesulfonate (MMS, 44 μg/mL). The results showed a significant increase in the frequency of micronuclei in cultures of both cell lines treated with the highest concentration tested, demonstrating a genotoxic effect. On the other hand, manool exhibited a protective effect against chromosome damage induced by MMS in HepG2 cells, but not in V79 cells. These data suggest that some manool metabolite may be responsible for the antigenotoxic effect observed in HepG2 cells.

In Vivo Assessment of Genotoxic, Antigenotoxic and Anticarcinogenic Activities of Solanum lycocarpum Fruits Glycoalkaloidic Extract

The fruits of Solanum lycocarpum, known as wolf-fruit, are used in folk medicine, and because of that we have evaluated both the genotoxic potential of its glycoalkaloidic extract (SL) and its influence on the genotoxicity induced by methyl methanesulfonate. Furthermore, the potential blocking effect of SL intake in the initial stage of colon carcinogenesis in Wistar rats was investigated in a short-term (4-week) bioassay using aberrant crypt foci (ACF) as biomarker. The genotoxic potential was evaluated using the Swiss mice peripheral blood micronucleus test. The animals were treated with different doses of SL (15, 30 and 60 mg/kg b.w.) for 14 days, and the peripheral blood samples were collected at 48 h, 7 days and 14 days after starting the treatment. For antigenotoxicity assessment, MMS was administered on the 14th day, and after 24 h the harvesting of bone marrow and liver cells was performed, for the micronucleus and comet assays, respectively. In the ACF assay, male Wistar rats were given four subcutaneous injections of the carcinogen 1,2-dimethylhydrazine (DMH, 40 mg/kg b.w.), twice a week, during two weeks to induce ACF. The treatment with SL (15, 30 and 60 mg/kg b.w.) was given for four weeks during and after carcinogen treatment to investigate the potential beneficial effects of SL on DMH-induced ACF. The results demonstrated that SL was not genotoxic in the mouse micronucleus test. In animals treated with SL and MMS, the frequencies of micronucleus and extensions of DNA damage were significantly reduced in comparison with the animals receiving only MMS. Regarding the ACF assay, SL significantly reduced the frequency of ACF induced by DMH.

A comparative study of the modulatory effects of (−)-cubebin on the mutagenicity/recombinogenicity induced by different chemical agents

(-)-Cubebin (CUB) is a lignan isolated from dry seeds of Piper cubeba. We aimed to assess its genotoxic potential and influence on chromosomal damage (frequency of micronuclei - MN) induced by doxorubicin (DXR) in V79 cells and by urethane (URE) in somatic Drosophila melanogaster cells. Our findings indicate an absence of a CUB-mediated genotoxic effect at the concentrations tested. The results also revealed that CUB significantly reduced the frequency of MN induced by DXR, with a mean reduction of 63.88%. In a previous study, our research group demonstrated an absence of CUB-mediated mutagenic effects through the wing Somatic Mutation and Recombination Test (SMART) in Drosophila. In the present study, we used the standard and high bioactivation versions of the SMART to estimate the antigenotoxic effects of CUB associated with URE. At lower concentrations, the recombination level decreased, but at the highest concentration, the recombination level increased. Our data and previous studies suggest that CUB may act as a free radical scavenger at low concentrations, a pro-oxidant at higher concentrations when it interacts with the enzymatic system that catalyzes the metabolic detoxification of DXR or URE, and/or an inducer of recombinational DNA repair.

Anthelmintic Effects of the Essential Oil of Fennel (Foeniculum vulgare Mill., Apiaceae) against Schistosoma mansoni

Foeniculum vulgare Mill. (Apiaceae), known as fennel, is a widespread aromatic herbaceous plant, and its essential oil is used as additive in the food, pharmaceutical, cosmetic, and perfume industries. The in vitro antischistosomal activity and cytotoxic effects against V79 cells of the essential oil of F. vulgare cultivated in southeastern Brazil (FV‐EO) was investigated. The FV‐EO was obtained by hydrodistillation and characterized by GC‐FID and GC/MS analyses. (E)‐Anethole (69.8%) and limonene (22.5%) were identified as the major constituents. Its anthelmintic activity against Schistosoma mansoni was evaluated at concentrations of 10, 50, and 100 μg/ml, and it was found to be active against adult S. mansoni worms, although it was less effective than the positive control praziquantel (PZQ) in terms of separation of the coupled pairs, mortality, and decreased motor activity. However, FV‐EO elicited an interesting dose‐dependent reduction in the number of S. mansoni eggs. On their own, (E)‐anethole and the limonene enantiomers were much less effective than FV‐EO and PZQ. An XTT‐cytotoxicity‐based assay evidenced no FV‐EO cytotoxicity against V79 cells. In summary, FV‐EO displayed moderate in vitro schistosomicidal activity against adult S. mansoni worms, exerted remarkable inhibitory effects on the egg development, and was of low toxicity.

Evaluation of a Propolis Water Extract Using a Reliable RP-HPLC Methodology and In Vitro and In Vivo Efficacy and Safety Characterisation

Since the beginning of propolis research, several groups have studied its antibacterial, antifungal, and antiviral properties. However, most of these studies have only employed propolis ethanolic extract (PEE) leading to little knowledge about the biological activities of propolis water extract (PWE). Based on this, in a previous study, we demonstrated the anti-inflammatory and immunomodulatory activities of PWE. In order to better understand the equilibrium between effectiveness and toxicity, which is essential for a new medicine, the characteristics of PWE were analyzed. We developed and validated an RP-HPLC method to chemically characterize PWE and PEE and evaluated the in vitro antioxidant/antimicrobial activity for both extracts and the safety of PWE via determining genotoxic potential using in vitro and in vivo mammalian micronucleus assays. We have concluded that the proposed analytical methodology was reliable, and both extracts showed similar chemical composition. The extracts presented antioxidant and antimicrobial effects, while PWE demonstrated higher antioxidant activity and more efficacious for the most of the microorganisms tested than PEE. Finally, PWE was shown to be safe using micronucleus assays.

Ruthenium(II) Complexes Containing Anti-Inflammatory Drugs as Ligands: Synthesis, Characterization and in vitro Cytotoxicity Activities on Cancer Cell Lines

The synthesis, characterization and cytotoxic activity of cis-[Ru(dicl)(dppm)2]PF6 and cis-[Ru(ibu)(dppm)2]PF6, (dppm = 1,1-bis(diphenylphosphine)methane; dicl = diclofenac anion and ibu = ibuprofen anion), are described in this work. Complexes were characterized by elemental analysis, Fourier transform infrared spectroscopy (FTIR), UV-Vis, 31P{1H} nuclear magnetic resonance (NMR) and high-resolution mass spectrometry (HRESIMS). X-ray structure of cis-[Ru(ibu)(dppm)2]PF6 is also described. Preliminary calf thymus DNA (ct-DNA) binding studies were carried out by UV-Vis and viscosity experiments, with results suggesting the existence of electrostatic interactions between ruthenium complexes and ct-DNA. Cytotoxicity assays were carried out on a panel of human cancer cell lines and a human normal cell line. Complexes displayed a high to moderate cytotoxicity with IC50 ranging from 5 to 47 µmol L-1. cis-[Ru(ibu) (dppm)2]PF6 was found to be the most active, with IC50 values lower than cisplatin. The degree of cytotoxicity was maintained for the normal cell line, although cis-[Ru(ibu)(dppm)2]PF6 exhibited a similar selectivity to that of cisplatin but with a higher activity for at least two tumor cell lines which evidences a promising anticancer candidate and selects this complex for further experiments.

Comparative Evaluation of Antiproliferative Effects of Brazilian Green Propolis, Its Main Source Baccharis dracunculifolia, and Their Major Constituents Artepillin C and Baccharin

This study evaluated the antiproliferative activity of the Brazilian green propolis and Baccharis dracunculifolia extracts and their major compounds artepillin C and baccharin in different tumor cell lines. The lowest IC50 values observed for Brazilian green propolis and B. dracunculifolia extracts were 41.0 ± 4.5 µg/mL for U343 and 44.9 ± 7.1 µg/mL for HepG2, respectively. Regarding artepillin C and baccharin, the lowest IC50 values were 20.1 ± 2.9 for U343 and 13.0 ± 1.5 µg/mL for B16F10, respectively. For the association of artepillin C plus baccharin, the lowest IC50 result was 35.2 ± 0.5 µg/mL for B16F10. Artepillin C and baccharin were more cytotoxic than both Brazilian green propolis and B. dracunculifolia extracts. No additive or synergistic effect was observed for the association of artepillin C plus baccharin.