Na-TiNT Nanocrystals: Synthesis, Characterization, and Antibacterial Properties.

Titanium nanotubes have attractive morphological and physicochemical properties for several applications, such as high surface area, mesoporous structure, good stability, ion exchange capacity, and antibacterial property. Therefore, the field of nanotube applications is increasingly expanding, such as in solar cells sensitized by dye, photocatalysis, and antibacterial activity, among others. Therefore, a study of the antibacterial properties of sodium titanate nanotubes (Na-TiNTs) was carried out together with physicochemical characterizations, such as Raman spectroscopy which shows a peak characteristic of Na-O-Ti from nanotube-agglomerated regions. The XRD diffractogram confirmed the Raman spectra and evidenced the crystalline structure associated to Na-TiNT, which showed the characteristic peaks of the sodium trititanate crystal. SEM and TEM images showed the morphology of hollow nanotubes and forming semispherical particles. EDS shows the percentage values of each of the compounds in the Na-TiNT. The bacterial activity of the Na-TiNT was analyzed in Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. Na-TiNT modified the activity of the gentamicin and norfloxacin antibiotics against multiresistant strains. Synergistic effects against Gram-positive S. aureus 10 and Gram-negative P. aeruginosa 15 bacteria were observed when the Na-TiNT was associated with gentamicin, reducing the concentration of this antibiotic that is required to inhibit bacterial growth. Another synergic effect was observed for S. aureus 10 with norfloxacin.

Phytochemical characterization of the Ziziphus joazeiro Mart. metabolites by UPLC-QTOF and antifungal activity evaluation.

The aim of this study was to evaluate the antifungal and modulatory potential of the Ziziphus joazeiro bark and leaf extracts, both in isolation and in association with fluconazole, against resistant species from the Candida genus. Antifungal assays were used to determine the half maximal inhibitory concentration (IC50) of the extract in isolation and in combination with fluconazole using the broth microdilution method and spectrophotometric readings, followed by verification of the minimum fungicidal concentration by solid medium subculture. According to the cell viability curve, both extracts inhibited fungal growth in a concentration dependent manner, in addition to showing inhibitory concentrations similar to fluconazole. However, the extracts behaved in a fungistatic manner with minimum inhibitory concentration > 8.19 mg/mL and IC50 values ranging from 0.450 mg/mL to 9 mg/mL. The minimum inhibitory concentration for both extracts decreased when in combination with fluconazole, with the AEL standing out against Candida albicans URM 4387, displaying an IC50 equal to that of fluconazole (0.002 mg/mL). Nevertheless, fluconazole antagonism was observed against the tested strains. Overall, the evaluation of both extracts against Candida spp. presented inhibitory concentration values greater than fluconazole. Moreover, despite these being chemically complex crude extracts, they did demonstrate antifungal effects and properties that concur with their ethno-biological aspect.

Antiparasitic effect of the Psidium guajava L. (guava) and Psidium brownianum MART. EX DC. (araçá-de-veado) extracts.

In the search for new therapeutic agents against neglected diseases, both aqueous and hydroethanolic extracts from Psidium guajava L. and P. brownianum Mart ex DC leaves were investigated regarding their antiparasitic effect and cytotoxic potential. The extracts were tested at three concentrations (250, 500 and 1000 µg/mL) against Trypanosoma cruzi epimastigote forms (Chagas, 1909), Leishmania braziliensis (Vianna, 1911) and L. infantum promastigotes forms (Nicolle, 1908), as well as against fibroblasts. P. guajava showed no activity against T. cruzi forms, while the hydroethanolic (PBHE), aqueous by decoction (PBAED) and aqueous by infusion (PBAEI) P. browninaum extracts were responsible, respectively, for inhibiting 100, 100 and 92.68% of T. cruzi epimastigote growth at the 1000 µg/mL concentration. The P. brownianum hydroethanolic extract (PBHE) at the highest concentration caused 58.46% death in L. braziliensis, thus demonstrating moderate activity, however when tested against L. infantum, the PBHE inhibited their growth by 37.16%, revealing its low activity. As for the cytotoxicity assays, the P. brownianum aqueous extract by decoction (PBAED) obtained the highest death percentage when compared to the others, causing 90.85% fibroblast mortality at the 1000 µg/mL concentration.

Physico-chemical characterization and antibacterial activity of inclusion complexes of Hyptis martiusii Benth essential oil in ß-cyclodextrin.

Cyclodextrins (CDs) have been used as important pharmaceutical excipients for improve the physicochemical properties of the drugs of low solubility as the essential oil of Hyptis martiusii. This oil is important therapeutically, but the low solubility and bioavailability compromises your use. Therein, the aim of this study was to obtain and to characterize physico-chemically the samples obtained by physical mixture (PM), paste complexation (PC) and slurry complexation (SC) of the essential oil Hyptis martiusii (EOHM) in ß-CD, and to compare the antibacterial and modulatory-antibiotic activity of products obtained and oil free. The physicochemical characterization was performed by differential scanning calorimetry (DSC), thermogravimetry/derivative thermogravimetry (TG/DTG), scanning electron microscopy (SEM), X-ray diffraction (XRD) and Karl Fischer titration. Additionally, the antibacterial tests were performed by microdilution technique. Thus, it was observed that the PM method showed low complexing capacity, unlike PC and SC in which it was observed the formation of inclusion complexes. In addition, the second stage of the TG/DTG curves showed that SC was the best method inclusion with mass loss of 6.9% over the PC that was 6.0%. The XRD results corroborate with the results above suggesting the formation of new solid phase and the SEM photomicrographs showed the porous surface of the samples PC and SC. The essential oil alone demonstrated an antibacterial and modulatory effect against the S. aureus and the Gram negative strain, respectively. However, the ß-CD and the inclusion complex did not demonstrate any biological activity in the performed antibacterial assays.

Phenolic composition and medicinal usage of Psidium guajava Linn.: Antifungal activity or inhibition of virulence?

Psidium guajava is a Myrtaceae plant whose medicinal properties are recognized in several locations. The use of teas and tinctures prepared from their leaves has been used to combat infections caused by fungi of the genus Candida. In this study, aqueous extracts of leaves and hydroethanolic were tested to verify the antifungal potential and its chemical composition has been investigated. The microbiological assays were performed by broth microdilution to determine the minimum inhibitory concentration (MIC) and from these the minimum fungicidal concentration was performed (MFC) by subculturing on solid media. A cell viability curve was obtained for demonstration of inhibition of fungal growth of strains of Candida albicans and Candida tropicalis. Tests to check morphological changes by the action of the extracts were performed in microcultive cameras depleted environment at concentrations of MIC/2, MIC and MIC × 2. Extracts analyzed by high performance liquid chromatography demonstrated flavonoids and phenolic acids. The extracts showed fungistatic effect and no fungicide with MIC >8192 µg/mL, MFC above 8192 µg/mL. The IC50 was calculated ranging from 1803.02 to 5623.41 µg/mL. It has been found that the extracts affect the morphological transition capability, preventing the formation of pseudohyphae and hyphae. Teas and tinctures, therefore, have the potential antifungal, by direct contact, causing inhibition of fungal multiplication and its virulence factor, the cell dimorphism, preventing tissue invasion. Further studies are needed to elucidate the biochemical pathways and genes assets involved in these processes.