RESUMO
Resveratrol (RSV), a phytoalexin from grapes and peanuts, has been reported to exhibit antiproliferative effects on various cancer cell lines. In breast cancer, RSV has been demonstrated to exert an antiproliferative effect on both hormone-dependent and hormone-independent breast cancer cell lines. However, RSV is a lipophilic drug, and its therapeutic effect could be improved through nanoencapsulation. Functionalizing polymeric nanoparticles based on polycaprolactone (PCL) with polyethylene glycol 1000 tocopheryl succinate (TPGS) has been reported to prolong drug circulation and reduce drug resistance. However, the effect of TPGS on the physicochemical properties and biological effects of breast cancer cells remains unclear. Therefore, this study aimed to develop RSV-loaded PCL nanoparticles using nanoprecipitation and investigate the effect of TPGS on the nanoparticles' physicochemical characteristics (particle size, zeta potential, encapsulation efficiency, morphology, and release rate) and biological effects on the 4T1 breast cancer cell line (cytotoxicity and cell uptake), in vitro and in vivo. The optimized nanoparticles without TPGS had a size of 138.1 ± 1.8 nm, a polydispersity index (PDI) of 0.182 ± 0.01, a zeta potential of -2.42 ± 0.56 mV, and an encapsulation efficiency of 98.2 ± 0.87%, while nanoparticles with TPGS had a size of 127.5 ± 3.11 nm, PDI of 0.186 ± 0.01, zeta potential of -2.91 ± 0.90 mV, and an encapsulation efficiency of 98.40 ± 0.004%. Scanning electron microscopy revealed spherical nanoparticles with low aggregation tendency. Differential Scanning Calorimetry (DSC) and Fourier Transform Infrared Spectroscopy (FTIR) identified the constituents of the nanoparticles and the presence of drug encapsulation in an amorphous state. In vitro release studies showed that both formulations followed the same dissolution profiles, with no statistical differences. In cytotoxicity tests, IC50 values of 0.12 µM, 0.73 µM, and 4.06 µM were found for the formulation without TPGS, with TPGS, and pure drug, respectively, indicating the potentiation of the cytotoxic effect of resveratrol when encapsulated. Flow cytometry and confocal microscopy tests indicated excellent cellular uptake dependent on the concentration of nanoparticles, with a significant difference between the two formulations, suggesting that TPGS may pose a problem in the endocytosis of nanoparticles. The in vivo study evaluating the antitumor activity of the nanoparticles confirmed the data obtained in the in vitro tests, demonstrating that the nanoparticle without TPGS significantly reduced tumor volume, tumor mass, maintained body weight, and improved survival in mice. Moreover, the biochemical evaluation evidenced possible hepatotoxicity for formulation with TPGS.
RESUMO
Latex, a milky fluid found in several plants, is widely used for many purposes, and its proteins have been investigated by researchers. Many studies have shown that latex produced by some plant species is a natural source of biologically active compounds, and many of the hydrolytic enzymes are related to health benefits. Research on the characterization and industrial and pharmaceutical utility of latex has progressed in recent years. Latex proteins are associated with plants' defense mechanisms, against attacks by fungi. In this respect, there are several biotechnological applications of antifungal proteins. Some findings reveal that antifungal proteins inhibit fungi by interrupting the synthesis of fungal cell walls or rupturing the membrane. Moreover, both phytopathogenic and clinical fungal strains are susceptible to latex proteins. The present review describes some important features of proteins isolated from plant latex which presented in vitro antifungal activities: protein classification, function, molecular weight, isoelectric point, as well as the fungal species that are inhibited by them. We also discuss their mechanisms of action.