Polyoxovanadates (POV) are a subgroup of polyoxometalates (POM), which are nanosized clusters with reported biological activities. This manuscript describes the first toxicity evaluation of a mixed-valence polyoxovanadate, pentadecavanadate, (Me₄N)₆[V₁₅O₃₆Cl], abbreviated as V₁₅. Cytotoxicity experiments using peripheral blood mononuclear cells (PBMC), larvae of Artemia salina Leach, and in vivo oral acute and repeated 28-day doses in mice was carried out. The LC₅₀ values in PBMC cells and A. salina were 17.5 ± 5.8 μmol L⁻¹, and 17.9 µg L⁻¹, respectively, which indicates high cytotoxic activity. The toxicity in mice was not observed upon acute exposure in a single dose, however, the V₁₅ repeated 28-day oral administration demonstrated high toxicity using 25 mg/kg, 50 mg/kg and, 300 mg/kg doses. The biochemical and hematological analyses during the 28-day administration of V₁₅ showed significant alteration of the metabolic parameters related to the kidney and liver, suggesting moderate toxicity. The V₁₅ toxicity was attributed to the oxidative stress and lipid peroxidation, once thiobarbituric acid (TBAR) levels significantly increased in both males and females treated with high doses of the POV and also in males treated with a lower dose of the POV. This is the first study reporting a treatment-related mortality in animals acutely administrated with a mixed-valence POV, contrasting with the well-known, less toxic decavanadate. These results document the toxicity of this mixed-valence POV, which may not be suitable for biomedical applications.

Polyphenolics from Rhizophora mangle (R. mangle) have shown wound healing and anti- inflammatory effects that may be potentiated by being associated with ascorbic acid, an important substance for collagen and elastin synthesis that plays a role in tissue repair. In our study, we aimed to formulate an association of R. mangle and ascorbic acid in hydrogels and evaluate the association’s cytotoxic and immunomodulatory effects. In a pre-formulation study, three gelling polymers (i.e.xanthan gum, poloxamer and hydroxyethyl cellulose) were tested. The selected polymer (i.e. xanthan gum) was used to evaluate cytotoxic and immunomodulatory effects using flow cytometry. Xanthan gum (1.5%) had a homogeneous appearance, an orange colour, a smooth surface, intense brightness and the typical odour, as well as non-Newtonian pseudoplastic behaviour. With a pH of 5.0-5.3 and a non-cytotoxic profile, xanthan gum induced the proliferation and activation of CD4 +, CD8+ and NK T lymphocytes and the production of IL- 2, IL-4, IL-10, IL-17 and TNF-α cytokines in stimulated splenocytes. The results suggest that the association of R. mangle and ascorbic acid in 1.5% xanthan gum hydrogel may be promising in preparations for wound-healing processes.

The introduction of optimized nanoheaters, which function as theranostic agents integrating both diagnostic and therapeutic processes, holds significant promise in the medical field. Therefore, developing strategies for selecting and utilizing optimized plasmonic nanoheaters is crucial for the effective use of nanostructured biomedical agents. This work elucidates the use of the Joule number ($J_o$) as a figure of merit to identify high-performance plasmonic theranostic agents. A framework for optimizing metallic nanoparticles for heat generation was established, uncovering the size dependence of plasmonic nanoparticles optical heating. Gold nanospheres (AuNSs) with a diameter of 50 nm and gold nanorods (AuNRs) with dimensions of $41\times 10$ nm were identified as effective nanoheaters for visible (530 nm) and infrared (808 nm) excitation. Notably, AuNRs achieve higher $J_o$ values than AuNSs, even when accounting for the possible orientations of the nanorods. Theoretical results estimate that $41\times 10$ nm gold nanorods have an average Joule number of 80, which is significantly higher compared to larger rods. The photothermal performance of optimal and suboptimal nanostructures was evaluated using photoacoustic imaging and photothermal therapy procedures. The photoacoustic images indicate that, despite having larger absorption cross-sections, the large nanoparticle volume of bigger particles leads to less efficient conversion of light into heat, which suggests that the use of optimized nanoparticles promotes higher contrast, benefiting photoacoustic-based procedures in diagnostic applications. The photothermal therapy procedure was performed on S180-bearing mice inoculated with $41\times 10$ nm and $90\times 25$ nm PEGylated AuNRs. Five minutes of laser irradiation of tumor tissue with $41\times 10$ nm produced an approximately 9.5% greater temperature rise than using $90\times 25$ AuNRs in the therapy trials. Optimizing metallic nanoparticles for heat generation may reduce the concentration of the nanoheaters used or decrease the light fluence for bioscience applications, paving the way for the development of more economical theranostic agents.

Plants used in traditional medicine offer an affordable new alternative in tissue repair therapy. This study aimed to evaluate the effectiveness of the 5% Rhizophora mangle cream compared to the 5% dexpanthenol cream in healing open surgical wounds on the upper eyelid. A total of 18 patients were submitted to the experiment and divided into 2 groups with 9 patients each who used topically and daily 5% dexpanthenol cream (control group) or 5% R.mangle cream (intervention group) for 7 days. Clinical, morphometric and histomorphometric analyses of wounds and surgical procedures for skin removal were performed. In the morphometric analysis, all wounds treated with R.mangle and dexpanthenol creams showed complete macroscopic scars, without inflammatory signs and infection free. The skin hydration values in pre and post application periods of the cream were 43.82 ± 43.93 and 62.12 ± 67.40 respectively. The histomorphometric study showed lower values of epithelium distance in R. mangle group and higher in dexpanthenol group with significant difference between groups (p < 0.05). The R.mangle 5% cream proved to be effective in healing wounds of human upper eyelid skin with a significant improvement in epithelization compared to dexpanthenol 5% cream.

Conocarpus erectus, popularly known as button mangrove, is one of the most common species found in mangroves and it is widely used in folk medicine for anemia, phlegm and diabetes prevention. The present study aimed to evaluate the methanolic extract of leaves of Conocarpus erectus (MELCe) to unravel its phytochemical constituents. The botanical material was collected in Itamaracá,PE, Brazil, mangrove. The extract was obtained by infusion with methanol and characterized by high-performance liquid chromatography (HPLC) and high-performance thin layer chromatography (HPTLC). Analysis on HPTLC showed the presence of phenolic compounds, mainly ellagic acid and p-coumaric acid. In addition, to analyze and to quantify the phenolic compounds, it was performed a flavonoid quantification at concentrations of 1000, 500, and 250 μg/ml. HPLC confirmed the presence of ellagic acid and a quercetin-type compound. Flavonoid quantification assays shows 72.52 ± 5.12, 36.54 ± 1.13, and 17.29 ± 1.45 μg/ml, respectively, obtained as quercetin equivalent. Leaves of C. erectus contain phenolic compounds, and the presence of the flavonoid quercetin is suggested.