Sofia A. Costa Lima

Biodegradation of p-nitrophenol by microalgae

A study was made on the use of a mixed microalgal consortium to degrade p-nitrophenol. The consortium was obtained from a microbial community in a waste container fed with the remains and by-products of medium culture containing substituted aromatic pollutants (nitrophenols, chlorophenols, fluorobenzene). After selective enrichment with p-nitrophenol (p-NP), followed by an antibiotic treatment, an axenic microalgal consortium was recovered, which was able to degrade p-nitrophenol. At a concentration of 50 mg L−1, total degradation occurred within 5 days. Two species, Chlorella vulgaris var. vulgaris f. minuscula and Coenochloris pyrenoidosa, were isolated from the microalgal consortium. The species were able to accomplish p-NP biodegradation when cultured separately, although Coenochloris pyrenoidosa was more efficient, achieving the same degradation rate as the original axenic microalgal consortium. When Coenochloris pyrenoidosa was associated with Chlorella vulgaris in a 3:1 ratio, complete removal of the nitro-aromatic compound occurred within three days. This is apparently the first report on the degradation of a nitro-aromatic compound by microalgae.

A new topical formulation for psoriasis: development of methotrexate-loaded nanostructured lipid carriers.

The aim of the present work was to develop and assess the potential of nanostructured lipid carriers (NLCs) loaded with methotrexate as a new approach for topical therapy of psoriasis. Methotrexate-loaded NLCs were prepared via a modified hot homogenization combined with ultrasonication techniques using either polysorbate 60 (P60) or 80 (P80) as surfactants. The produced NLCs were within the nanosized range (274-298 nm) with relatively low polydispersity index (<0.25) and zeta potential values around -40 mV. NLCs demonstrated storage stability at 25°C up to 28 days. The entrapment efficiency of methotrexate in NLC-P60 and -P80 was ∼65%. Cryo-SEM images showed the spherical shape of the empty and methotrexate-loaded NLCs. FT-IR confirmed methotrexate presence within the NLCs. The in vitro release of methotrexate from the NLCs followed a fast release pattern reaching ∼70% in 2h. In vitro skin penetration study demonstrated that methotrexate-loaded NLCs-P60 had higher skin penetration when compared to free methotrexate, suggesting a significant role of drug-nanocarriers on topical administration. Methotrexate-loaded NLC-P60 provided drug fluxes of 0.88 μg/cm(2)/h, higher (P<0.001) than with the free drug (control, 0.59 μg/cm(2)/h). The results indicate the potential of NLCs for the delivery of methotrexate to topical therapy of psoriasis.

Cellular uptake and transcytosis of lipid-based nanoparticles across the intestinal barrier: Relevance for oral drug delivery.

Oral administration is the preferred route for drug delivery and nanosystems represent a promising tool for protection and transport of hardly soluble, chemically unstable and poorly permeable drugs through the intestinal barrier. In the present work, we have studied lipid nanoparticles cellular uptake, internalization pathways and transcytosis routes through Caco-2 cell monolayers. Both lipid nanosystems presented similar size (∼180nm) and surface charge (-30mV). Nanostructured lipid carriers showed a higher cellular uptake and permeability across the barrier, but solid lipid nanoparticles could enter cells faster than the former. The internalization of lipid nanoparticles occurs mainly through a clathrin-mediated endocytosis mechanism, although caveolae-mediated endocytosis is also involved in the uptake. Both lipid nanoparticles were able to cross the intestinal barrier by a preferential transcellular route. This work contributed to a better knowledge of the developed nanosystems for the oral delivery of a wide spectrum of drugs.

Optimization of nanostructured lipid carriers loaded with methotrexate: A tool for inflammatory and cancer therapy.

The aim of this study was to optimize and assess the potential of nanostructured lipid carriers (NLC), prepared by the hot ultrasonication method, as carrier for methotrexate (MTX), highlighting the application of factorial design. Preliminary screening drug/lipid solubility, allowed us to select Witepsol(®) E85 as the solid lipid and Mygliol(®) 812 as liquid lipid for the NLC loaded with MTX. Then, a 3-level, 3-factor Box-Behnken design and validated by ANOVA analysis; the correspondence between the predicted values and those measured experimentally confirmed the robustness of the design. Properties of optimized MTX-loaded NLCs such as morphology, size, zeta potential, entrapment efficiency, storage stability, in vitro drug release and cytotoxicity were investigated. NLCs loaded with MTX exhibited spherical shape with 252-nm, a polydispersity of 0.06±0.02, zeta potential of -14 mV and an entrapment efficiency of 87%. In vitro release studies revealed a fast initial release followed by a prolonged release of MTX from the NLC up to 24-h. The release kinetics of the optimized NLC best fitted the Peppas-Korsmeyer model for physiological and inflammatory environments and the Hixson-Crowell model skin simulation conditions. No toxicity was observed in fibroblasts. Thus, the optimized MTX-loaded NLC have the potential to be exploited as delivery system.

P-glycoprotein activity in human Caucasian male lymphocytes does not follow its increased expression during aging.

P‐glycoprotein (P‐gp) is a transmembrane protein that mediates the efflux of innumerous structurally unrelated compounds. It was initially found over‐expressed in tumor cells, associated to a multidrug resistance phenotype (MDR). Then, P‐gp was found constitutively expressed in excretory cells/tissues and in circulating cells, such as lymphocytes. Considering the importance of this transporter in the establishment of therapeutic protocols and the existence of contradictory results, this study aimed at evaluating the influence of aging in the expression and function of P‐gp in human lymphocytes, comparing two different methodologies to assess both parameters. P‐gp activity and expression were evaluated in lymphocytes isolated from whole blood samples of 65 healthy caucasian male donors, divided into two groups according to age (group 1: under 30‐years old; group 2: above 60‐years old). P‐gp expression was assessed using the anti‐P‐gp monoclonal antibody, UIC2, in the presence and in absence of vinblastine (Vbl). P‐gp activity was evaluated measuring the efflux rate of the fluorescent P‐gp substrate rhodamine 123 (Rho 123) and also using UIC2 shift assay. Flow cytometric analysis was performed to assess all the proceedings. Furthermore, P‐gp expression and each of the P‐gp activity determination methods were compared, through correlation analysis and linear regression models. We observed a significant age‐dependent increase in mean P‐gp expression (p = 0.029), which was not reflected in the transporters activity (p > 0.050). Statistical analysis allowed selection of UIC2 shift assay over Rho 123 efflux assay as a more selective method to assess P‐gp activity. Despite the significant correlation between P‐gp expression and P‐gp activity found in lymphocytes (Gp1(group 1)—r = 0.609, p < 0.001; Gp2—r = 0.461, p = 0.012), using UIC2 shift assay, these data reinforce the need for P‐gp activity assessment, rather than P‐gp expression determination alone, when starting new therapeutic regimens with P‐gp substrates, especially in men older than 60 years of age.

Synthesis and anti-parasitic activity of a novel quinolinone-chalcone series

A series of novel quinolinone-chalcone hybrids and analogues were designed, synthesized and their biological activity against the mammalian stages of Trypanosoma brucei and Leishmania infantum evaluated. Promising molecular scaffolds with significant microbicidal activity and low cytotoxicity were identified. Quinolinone-chalcone 10 exhibited anti-parasitic properties against both organisms, being the most potent anti-L. infantum agent of the entire series (IC50 value of 1.3±0.1 μM). Compounds 4 and 11 showed potency toward the intracellular, amastigote stage of L. infantum (IC50 values of 2.1±0.6 and 3.1±1.05 μM, respectively). Promising trypanocidal compounds include 5 and 10 (IC50 values of 2.6±0.1 and 3.3±0.1 μM, respectively) as well as 6 and 9 (both having IC50 values of <5 μM). Chemical modifications on the quinolinone-chalcone scaffold were performed on selected compounds in order to investigate the influence of these structural features on antiparasitic activity.

Temperature-responsive polymeric nanospheres containing methotrexate and gold nanoparticles: A multi-drug system for theranostic in rheumatoid arthritis.

Inflammation plays a crucial role in rheumatoid arthritis progress. In the present work, a novel stealth polymeric nanospheres platform able to carry anti-inflammatory drugs and an imaging agent was developed. Incorporation of gold nanoparticles will allow photoacoustic imaging and near infra-red photothermal application. Through emulsion-diffusion evaporation technique methotrexate and gold nanoparticles were incorporated in the pegylated-poly(DL-lactic-co-glycolic acid) nanospheres. In vitro drug release assays revealed pH and temperature-dependence on gold nanoparticles. Blank nanospheres exhibited negligible in vitro cytotoxicity, while methotrexate-loaded nanospheres hampered monocytes and macrophages viability at a higher level than free methotrexate. Confocal fluorescent microscopy and flow cytometry revealed effective nanospheres internalization, and that their cellular uptake was energy dependent mediated by caveolae and clathrin-endocytosis mechanism. Finally, MTX-loaded multifunctional nanospheres containing gold lead to a significant reduction of IL-1β, IL-6 and TNF-α inflammatory cytokines produced by monocytes and macrophages upon in vitro inflammatory stimulation, suggesting a favorable anti-inflammatory activity. These results confirm that the multifunctional nanospheres represent a promising theranostic platform for RA diagnosis and intracellular treatment, by combining methotrexate and gold nanoparticles for a highly effective targeted chemo-photothermal therapy.

Characterization and evaluation of BNIPDaoct- loaded PLGA nanoparticles for visceral leishmaniasis: in vitro and in vivo studies

OBJECTIVE To overcome the limitation of bisnaphthalimidopropyldiaaminooctane (BNIPDaoct) low physiological solubility and potentially increase its efficiency against visceral leishmaniasis (VL), a delivery system based on poly(d,l-lactide-co-glycolide) (PLGA) nanoparticles was developed. MATERIALS & METHODS BNIPDaoct-PLGA nanoparticles were prepared by nanoprecipitation and characterized. Anti-Leishmania activity was evaluated using in vitro and in vivo VL infection models. RESULTS BNIPDaoct-PLGA nanoparticles were successfully produced and were sized at 156.0 ± 2.8 nm with an encapsulation efficiency of approximately 85%. The PLGA nanoparticles reduced BNIPDaoct cellular toxicity, retained its in vitro anti-leishmanial activity and led to a significant reduction (∼80%) in the parasite burden in the infected mice spleen when compared with the free drug or amphotericin B. In the liver the effect was less pronounced, with a 30-50% reduction observed between the nanoformulation and the BNIPDaoct per se or the amphotericin B, respectively. CONCLUSION PLGA nanoparticles provide controlled and effective delivery of BNIPDaoct for treatment of VL.

In vitro evaluation of bisnaphthalimidopropyl derivatives loaded into pegylated nanoparticles against Leishmania infantum protozoa.

Bisnaphthalimidopropyl (BNIP) derivatives have recently been shown to have potential as antileishmanial agents. However, these compounds have some drawbacks, including their low aqueous solubility and some toxic effects. In this study, we designed a drug delivery system for enhanced delivery of BNIP derivative compounds whilst reducing adverse toxic effects, and hence increasing their biological efficacy. A coated drug delivery system based on polymeric nanoparticles of pegylated poly(lactic acid) (PLA), a biodegradable polymer, was successfully achieved. The pegylated PLA nanoformulations loaded with BNIP derivatives were evaluated in an in vitro model of intracellular amastigotes in murine J774 and human THP-1 cells for visceral leishmaniasis using luciferase-expressing Leishmania infantum parasites. Pegylation of PLA nanoparticles significantly reduced the capacity of empty nanoparticles in inhibiting intracellular parasite growth. The BNIP derivatives BNIPDadec and BNIPDaoct exhibited EC(50) values (concentration of compound necessary to decrease cell viability to 50% of the untreated control) of ca. 4.5 μM for THP-1 and J774 cells and ca. 9.0 μM for mouse bone marrow-derived macrophages. Nanoparticle encapsulation of the BNIP derivative compounds decreased their toxicity towards macrophages by ≥10-fold as evaluated by the MTT assay. The antileishmanial activity of free BNIPDadec was 1.02±0.41 μM and 0.73±0.06 μM for THP-1 and J774 macrophages, respectively. Pegylation of PLA nanoparticles loaded with BNIPDadec resulted in EC(50) values of 1.43±0.63 μM and 1.79±0.77 μM for THP-1 and J774 macrophages, respectively. A similar trend was observed for free BNIPDaoct and pegylated BNIPDaoct PLA nanoparticles (2.43±0.19 μM and 1.23±0.40 μM for THP-1 macrophages and 1.36±0.17 μM and 1.52±0.57 μM for J774 macrophages). The nanoformulations were more efficient in reducing parasitic growth inside human macrophages than in murine cells, suggesting host cell-dependent metabolism.

Aurones: A Promising Heterocyclic Scaffold for the Development of Potent Antileishmanial Agents

A series of (Z)-2-benzylidenebenzofuran-3-(2H)-ones (aurones) bearing a variety of substituents on rings A and B were synthesized and evaluated for their antiparasitic activity against the intracellular amastigote form of Leishmania infantum and their cytotoxicity against human THP1-differentiated macrophages. In general, aurones bearing no substituents on ring A (compounds 4a–4f) exhibit higher toxicity than aurones with 4,6-dimethoxy substitution (compounds 4g–4l). Among the latter, two aurones possessing a 2′-methoxy or a 2′-methyl group (compounds 4i and 4j) exhibit potent antileishmanial activity (IC50 = 1.3 ± 0.1 μM and IC50 = 1.6 ± 0.2 μM, resp.), comparable to the activity of the reference drug Amphotericin B, whereas they present significantly lower cytotoxicity than Amphotericin B as deduced by the higher selectivity index.