Mônica Pereira Garcia

The twelve principles of green chemistry represents an actual concern in most nanotechnology developments, highlighting the less use of hazardous chemicals in synthesis. Therefore, this study investigates the green synthesis of silver nanoparticles (AgNPs) using ethanolic extracts of Capsicum chinense (Murupi pepper) and evaluates their antibacterial potential. Extracts from fresh and dried fruits, prepared with varying ethanol concentrations (46%, 70%, and 92.8%), were chemically characterized for phenolics, flavonoids, and antioxidant activity. LC-MS analysis identified capsaicin, dihydrocapsaicin, and various flavonoids and polyphenolic compounds, which act as crucial reducing and stabilizing agents during AgNPs formation. Stable, predominantly spherical nanoparticles with an average core size of 37 ± 17 nm, were produced using silver nitrate precursor at 3 mM of concentration from the 92% ethanolic extract and 300 𝜇L of volume, particularly from dried fruit extracts, showing zeta potentials close to − 30 mV and hydrodynamic diameters generally above 100 nm. The antibacterial activity against E. coli, was verified with the lowest MIC for AgNPs suspension at 92% and 3 mM of precursor in 0.50 mg/mL, whereas the best ethanolic extracts (70% and 92.8%) showed an MIC of 12.50 mg/mL, the antimicrobial activity is predominantly associated with the presence of the nanoparticles rather than the extract components or the solvent alone. These results highlight Capsicum chinense as a promising bioresource for the sustainable synthesis of nanomaterials and the development of environmentally friendly antimicrobial agents.

Consumer interest in natural antioxidants has risen because their intake is linked to the prevention of chronic diseases. Blueberries (Vaccinium spp.)—rich in flavonoids, vitamin C and other bioactive compounds—are therefore being cultivated beyond temperate regions. In tropical areas, however, the lack of chilling hours may alter fruit physiology, and little is known about how pruning practices modulate quality under these conditions. The objective of this study was to quantify the effects of pruning types and seasons on the antioxidant activity, physical and chemical characteristics (TSS, TTA, TSS/TTA), and ash, moisture, and fiber contents in blueberries of the cultivar Biloxi grown under tropical climate conditions (without chilling hours), in Brasilia, DF, Brazil. The trial followed a randomized-block design with three replications. Plants received either severe pruning removing lateral branches (SPRLB) or severe pruning maintaining lateral branches (SPMLB) in winter, spring, summer or autumn; fruit harvested over the subsequent four weeks was analysed for DPPH radical-scavenging capacity, total soluble solids (TSS), titratable acidity (TTA), TSS/TTA ratio, ash, moisture and fibre contents. Pruning season exerted the strongest effect. Autumn pruning—regardless of type—produced the highest antioxidant activity and elevated TSS. SPRLB increased TTA, whereas SPMLB enhanced the TSS/TTA ratio during warmer seasons. These findings demonstrate that pruning season plays a key role in enhancing blueberry fruit quality under tropical conditions.

Background/Objectives: The biogenic synthesis of silver nanoparticles (AgNPs) is a promising alternative method, driven by the presence of metabolites in plant matrices capable of acting as reducing and stabilizing agents. Seasonality is a key factor that influences the phytochemical composition of plants and can directly impact the yield, physicochemical characteristics, stability, and bioactivities of the obtained AgNPs. This study aimed to synthesize AgNPs using aqueous extracts from Paullinia cupana leaves collected during dry and rainy seasons, prepared by two different methods (agitation or infusion), to evaluate the impact of these variables on the biosynthesis and properties of the nanostructures. Methods: The extracts were characterized by UHPLC-HRMS/MS, and their total phenolic compound (TPC) content and antioxidant potential against DPPH and ABTS radicals were determined. The AgNPs were characterized by UV/Vis spectrophotometry, dynamic light scattering (DLS), zeta potential (ZP), nano-particle tracking analysis (NTA), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDX). Results: The metabolic profile results showed a predominance of alkaloids and flavonoids in all extracts, with greater phytochemical diversity in samples prepared by infusion. TPC indicated superior phenolic extraction in extracts prepared by infusion during the rainy season, correlating with greater antioxidant potential via the elimination of free radicals. The evolution of AgNP synthesis was accompanied by a gradual change in the color of the suspensions and the formation of plasmon bands between 410 and 430 nm, characteristic of spherical AgNPs. The nanostructures presented hydrodynamic diameters between 37.49 and 145.5 nm, PdI between 0.222 and 0.755, and Zeta potential between −11.3 and −39.9 mV, suggesting satisfactory colloidal stability. Morphological analyses revealed predominantly spherical particles with average diameters ranging from 33.61 to 48.86 nm and uniform distribution, while EDX spectra confirmed the presence of silver. Conclusions: Thus, our results demonstrate that both seasonality and the method of extract preparation influence the phytochemical composition and, consequently, the morphology, stability, and optical properties of AgNPs, with subtle emphasis on collections made during the rainy season and extracts prepared by infusion. Such knowledge contributes to the advancement of more reproducible and purpose-oriented syntheses in the field of green nanotechnology, enabling applications in various sectors.

Background: Paullinia cupana Kunth, popularly known as guarana, a native Amazonian shrub cultivated by the Sateré-Mawé ethnic group, has been used in traditional medicine for various purposes, including stimulant and therapeutic actions, due to its chemical composition, which is rich in bioactive compounds. This study explored the reductive potential of guarana with nanobiotechnology and aimed to synthesize silver nanoparticles (AgNPs) using the aqueous extract of leaves collected during the dry and rainy seasons, assessing their biological and catalytic activities. Methods: The AgNPs were synthesized in a water bath at 70 °C for three hours and then characterized using techniques such as UV-Vis spectroscopy, DLS, zeta potential, MET, NTA, and EDX and had their effects on various biological systems assessed in vitro, as well as in catalytic tests aimed at indicating the probable influence of the time when the plant material was collected on the properties of the nanostructures. Results: The AgNPs had an average diameter between 39.33 and 126.2 nm, spherical morphology, absorption bands between 410 and 450 nm, and high colloidal stability over two years. The biological results showed antibacterial activity against all the species tested, as well as remarkable antioxidant action against DPPH and ABTS free radicals, in the same way as the aqueous leaf extracts of P. cupana, in addition to cytotoxic properties against cancerous (A431 and A549) and non-cancerous (HaCaT and HNTMC) cells. The AgNPs were active against promastigote forms of Leishmania (Leishmania) amazonensis while not affecting the viability of macrophages, and from the LC₅₀ and LC₉₀ values, the AgNPs were more effective than the metal salt solution in controlling Aedes aegypti larvae and pupae. We also reported that the catalytic degradation of the organic dyes methylene blue (MB) and methyl orange (MO) by AgNPs was over 90% after 40 or 14 min, respectively. Conclusions: Thus, our results support the potential of seasonal extracts of guarana leaves to produce AgNPs with diverse application possibilities for the health, industrial, and environmental sectors.

The green synthesis of silver nanoparticles (AgNPs) can be developed using safe and environmentally friendly routes, can replace potentially toxic chemical methods, and can increase the scale of production. This study aimed to synthesize AgNPs from aqueous extracts of guarana (Paullinia cupana) leaves and flowers, collected in different seasons of the year, as a source of active biomolecules capable of reducing silver ions (Ag⁺) and promoting the stabilization of colloidal silver (Ag⁰). The plant aqueous extracts were characterized regarding their metabolic composition by liquid chromatography coupled to high-resolution mass spectrometry (UHPLC-HRMS/MS), phenolic compound content, and antioxidant potential against free radicals. The synthesized AgNPs were characterized by UV/Vis spectrophotometry, dynamic light scattering (DLS), nanoparticle tracking analysis (NTA), transmission electron microscopy (TEM), and scanning electron microscopy coupled to energy-dispersive X-ray spectrometry (EDX). The results demonstrated that the chemical characterization indicated the presence of secondary metabolites of many classes of compounds in the studied aqueous extracts studied, but alkaloids and flavonoids were predominant, which are widely recognized for their antioxidant capabilities. It was possible to notice subtle changes in the properties of the nanostructures depending on parameters such as seasonality and the part of the plant used, with the AgNPs showing surface plasmon resonance bands between 410 and 420 nm using the leaf extract and between 440 and 460 nm when prepared using the flower extract. Overall, the average hydrodynamic diameters of the AgNPs were similar among the samples (61.98 to 101.6 nm). Polydispersity index remained in the range of 0.2 to 0.4, indicating that colloidal stability did not change with storage time. Zeta potential was above −30 mV after one month of analysis, which is adequate for biological applications. TEM images showed AgNPs with diameters between 40.72 to 48.85 nm and particles of different morphologies. EDX indicated silver content by weight between 24.06 and 28.81%. The synthesized AgNPs exhibited antimicrobial efficacy against various pathogenic microorganisms of clinical and environmental interest, with MIC values between 2.12 and 21.25 µg/mL, which is close to those described for MBC values. Therefore, our results revealed the potential use of a native species of plant from Brazilian biodiversity combined with nanotechnology to produce antimicrobial agents.

Curcumin is a polyphenolic compound, derived from Curcuma longa, and it has several pharmacological effects such as antioxidant, anti-inflammatory, and antitumor. Although it is a pleiotropic molecule, curcumin’s free form, which is lipophilic, has low bioavailability and is rapidly metabolized, limiting its clinical use. With the advances in techniques for loading curcumin into nanostructures, it is possible to improve its bioavailability and extend its applications. In this review, we gather evidence about the comparison of the pharmacokinetics (biodistribution and bioavailability) between free curcumin (Cur) and nanostructured curcumin (Cur-NPs) and their respective relationships with antitumor efficacy. The search was performed in the following databases: Cochrane, LILACS, Embase, MEDLINE/Pubmed, Clinical Trials, BSV regional portal, ScienceDirect, Scopus, and Web of Science. The selected studies were based on studies that used High-Performance Liquid Chromatography (HPLC) as the pharmacokinetics evaluation method. Of the 345 studies initially pooled, 11 met the inclusion criteria and all included studies classified as high quality. In this search, a variety of nanoparticles used to deliver curcumin (polymeric, copolymeric, nanocrystals, nanovesicles, and nanosuspension) were found. Most Cur-NPs presented negative Zeta potential ranging from −25 mV to 12.7 mV, polydispersion index (PDI) ranging from 0.06 to 0.283, and hydrodynamic diameter ranging from 30.47 to 550.1 nm. Selected studies adopted mainly oral and intravenous administrations. In the pharmacokinetics analysis, samples of plasma, liver, tumor, lung, brain, kidney, and spleen were evaluated. The administration of curcumin, in nanoparticle systems, resulted in a higher level of curcumin in tumors compared to free curcumin, leading to an improved antitumor effect. Thus, the use of nanoparticles can be a promising alternative for curcumin delivery since this improves its bioavailability.

Nanoceria has a broad variety of industrial and pharmacological applications due to its antioxidant activity. Nanoceria can be modified by surface coating with polyelectrolyte brushes. Brushes can increase the surface charge of nanoceria, providing greater aqueous stability while reducing agglomeration. However, surface-coating also behaves as a barrier around nanoceria, affecting its redox equilibrium and, hence, its biological and toxicological properties. In the present study, we examined whether bare nanoceria (CeO₂; 80–150 nm) and nanoceria modified by surface polymer brush, using negatively charged polyacrylic acid (CeO₂@PAA) and positively charged poly (2-(methacryloyloxy)ethyl-trimethyl-ammonium chloride (CeO₂@PMETAC), could induce systemic toxicity. As CeO₂ has limited colloidal stability, which might result in vascular occlusion, intraperitoneal injection was used instead of intravenous administration. C57Bl/6 mice were four times injected with three different doses of each nanoceria-based sample (corresponding to 1.8, 5.3 and 16 mg Ce/kg BW/administration) for a total period of 14 days. CeO₂@PMETAC induced a significant dose-dependent neutrophilia. Histopathological evaluation showed inflammatory processes in the capsule of liver, kidney, and spleen of animals at all doses of CeO₂@PMETAC, and with the highest dose of CeO₂@PAA and CeO₂. However, none of the nanoceria-based samples tested increased the level of DNA damage or micronuclei in blood cells, even though Ce was detected by inductively coupled plasma mass spectrometry analyses in the bone marrow. Only CeO₂@PMETAC induced the presence of megakaryocytes in the spleen. A higher accumulation of Ce in mononuclear phagocyte system organs (liver, spleen and bone marrow) was observed after CeO₂@PMETAC treatment compared with CeO₂@PAA and CeO₂.

Leishmaniasis is a neglected disease threatening over 350 million people. Antimonials are first‐line drugs due to resistance and side effects there is a demand for alternative chemotherapy. Itraconazole (ITZ) is an antimycotic. It was encapsulated into poly(lactic‐co‐glycolic acid) (PLGA) nanoparticles (NPs) and covered with mannose. The NPs were 250 nm and −1.1 mV ± 0.7. PLGA‐ITZ‐mannose NPs presented a toxicity of 20.7% for J774 cells, and no toxicity for THP 1. The J774 cells were infected with three Leishmania promastigotes strains and treated with ITZ loaded PLGA NPs with/without mannose. The parasite percentage of L.(V.) panamensis intracellular amastigotes significantly (p < 0.01) decreased from 34.4% to 13.7% and 5.7% for PLGA‐ITZ‐mannose NPs and PLGA‐ITZ NPs, respectively. For L.(L.) infantum there was a reduction (p < 0.001) from 18.1% to 4.8% and 8.3% for PLGA‐ITZ‐mannose NPs and PLGA‐ITZ NPs, respectively. Further with L.(L.) braziliensis amastigotes there was a significant reduction (p < 0.001) from 54.9% to 28% and 21.1% for PLGA‐ITZ‐mannose NPs and PLGA‐ITZ NPs, respectively. Adding mannose increased the efficacy PLGA‐ITZ NPs against L.(L.) infantum, while it had no effect against L(V.) panamensis and L.(L.) braziliensis amastigotes. We recommend further investigation of PLGA‐ITZ‐mannose NPs in animal models to evaluate their potential. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 00B: 000–000, 2018. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 680–687, 2019.

This study reports on in vitro and in vivo tests that sought to assess the antifungal activity of a newly developed magnetic carrier system comprising amphotericin B loaded onto the surface of pre-coated (with a double-layer of lauric acid) magnetite nanoparticles. The in vitro tests compared two drugs; i.e., this newly developed form and free amphotericin B. We found that this nanocomplex exhibited antifungal activity without cytotoxicity to human urinary cells and with low cytotoxicity to peritoneal macrophages. We also evaluated the efficacy of the nanocomplex in experimental paracoccidioidomycosis. BALB/c mice were intratracheally infected with Paracoccidioides brasiliensis and treated with the compound for 30 or 60 days beginning the day after infection. The newly developed amphotericin B coupled with magnetic nanoparticles was effective against experimental paracoccidioidomycosis, and it did not induce clinical, biochemical or histopathological alterations. The nanocomplex also did not induce genotoxic effects in bone marrow cells. Therefore, it is reasonable to believe that amphotericin B coupled to magnetic nanoparticles and stabilized with bilayer lauric acid is a promising nanotool for the treatment of the experimental paracoccidioidomycosis because it exhibited antifungal activity that was similar to that of free amphotericin B, did not induce adverse effects in therapeutic doses and allowed for a reduction in the number of applications. Lung fungal infections are caused by pathogens inhaled as spores which convert into invasive yeast forms in the lungs. This type of infection can spread to other sites in the body through the blood and lymphatic systems, sometimes leading to ulcerations and skin lesions. The drug of choice for treatment is Amphotericin B (AmB). AmB is a typical polyene with broad-spectrum antifungal activity that encounters some use limitations because of its side effects. We developed a magnetic carrier nanocomplex comprising of amphotericin B loaded onto the surface of magnetite nanoparticles pre-coated with a double-layer of lauric acid. We evaluated this approach for its antifungal activity against Paracoccidioides brasiliensis (strain Pb18) and its cytotoxicity in mammalian cell culture. We found that this nanocomplex exhibited antifungal activity without cytotoxicity to human urinary cells and low cytotoxicity to peritoneal macrophages. In vivo, the nanocomplex did not induce genotoxic effects in bone marrow cells and was effective against experimental paracoccidioidomycosis without inducing clinical, biochemical or histopathological alterations.

Purpose/objective: The aim of this study was to develop and investigate the properties of a magnetic iron oxide nanoparticle–ethiodised oil formulation for image-guided thermal therapy of liver cancer. Materials and methods: The formulation comprises bionised nano-ferrite (BNF) nanoparticles suspended in ethiodised oil, emulsified with polysorbate 20 (BNF-lip). Nanoparticle size was measured via photon correlation spectroscopy and transmission electron microscopy. In vivo thermal therapy capability was tested in two groups of male Foxn1^nu mice bearing subcutaneous HepG2 xenograft tumours. Group I (n = 12) was used to screen conditions for group II (n = 48). In group II, mice received one of BNF-lip (n = 18), BNF alone (n = 16), or PBS (n = 14), followed by alternating magnetic field (AMF) hyperthermia, with either varied duration (15 or 20 min) or amplitude (0, 16, 20, or 24 kA/m). Image-guided fluoroscopic intra-arterial injection of BNF-lip was tested in New Zealand white rabbits (n = 10), bearing liver VX2 tumours. The animals were subsequently imaged with CT and 3 T MRI, up to 7 days post-injection. The tumours were histopathologically evaluated for distribution of BNF-lip. Results: The BNF showed larger aggregate diameters when suspended in BNF-lip, compared to clear solution. The BNF-lip formulation produced maximum tumour temperatures with AMF >20 kA/m and showed positive X-ray visibility and substantial shortening of T1 and T2 relaxation time, with sustained intratumoural retention up to 7 days post-injection. On pathology, intratumoural BNF-lip distribution correlated well with CT imaging of intratumoural BNF-lip distribution. Conclusion: The BNF-lip formulation has favourable thermal and dual imaging capabilities for image-guided thermal therapy of liver cancer, suggesting further exploration for clinical applications.