Development and Characterization of Hydroxyethyl Cellulose-Based Gels Containing Lactobacilli Strains: Evaluation of Antimicrobial Effects in In Vitro and Ex Vivo Models.

This study aimed to develop a hydroxyethyl cellulose-based topical formulation containing probiotics and to evaluate its antimicrobial action using in vivo and ex vivo models. Initially, the antagonistic effects of Lacticaseibacillus rhamnosus ATCC 10863, Limosilactobacillus fermentum ATCC 23271, Lactiplantibacillus plantarum ATCC 8014 and Lactiplantibacillus plantarum LP-G18-A11 were analyzed against Enterococcus faecalis ATCC 29212, Klebsiella pneumoniae ATCC 700603, Staphylococcus aureus ATCC 27853 and Pseudomonas aeruginosa ATCC 2785. The best action was seen for L. plantarum LP-G18-A11, which presented high inhibition against S. aureus and P. aeruginosa. Then, lactobacilli strains were incorporated into hydroxyethyl cellulose-based gels (natrosol); however, only the LP-G18-A11-incorporated gels (5% and 3%) showed antimicrobial effects. The LP-G18-A11 gel (5%) maintained its antimicrobial effects and viability up to 14 and 90 days at 25 °C and 4 °C, respectively. In the ex vivo assay using porcine skin, the LP-G18-A11 gel (5%) significantly reduced the skin loads of S. aureus and P. aeruginosa after 24 h, while only P. aeruginosa was reduced after 72 h. Moreover, the LP-G18-A11 gel (5%) showed stability in the preliminary and accelerated assays. Taken together, the results show the antimicrobial potential of L. plantarum LP-G18-A11, which may be applied in the development of new dressings for the treatment of infected wounds.

Chemical Characterization and Leishmanicidal Activity In Vitro and In Silico of Natural Products Obtained from Leaves of Vernonanthura brasiliana (L.) H. Rob (Asteraceae).

Vernonanthura brasiliana (L.) H. Rob is a medicinal plant used for the treatment of several infections. This study aimed to evaluate the antileishmanial activity of V. brasiliana leaves using in vitro and in silico approaches. The chemical composition of V. brasiliana leaf extract was determined through liquid chromatography-mass spectrometry (LC-MS). The inhibitory activity against Leishmania amazonensis promastigote was evaluated by the MTT method. In silico analysis was performed using Lanosterol 14alpha-demethylase (CYP51) as the target. The toxicity analysis was performed in RAW 264.7 cells and Tenebrio molitor larvae. LC-MS revealed the presence of 14 compounds in V. brasiliana crude extract, including flavonoids, flavones, sesquiterpene lactones, and quinic acids. Eriodictol (ΔGbind = -9.0), luteolin (ΔGbind = -8.7), and apigenin (ΔGbind = -8.6) obtained greater strength of molecular interaction with lanosterol demethylase in the molecular docking study. The hexane fraction of V. brasiliana showed the best leishmanicidal activity against L. amazonensis in vitro (IC50 12.44 ± 0.875 µg·mL-1) and low cytotoxicity in RAW 264.7 cells (CC50 314.89 µg·mL-1, SI = 25.30) and T. molitor larvae. However, the hexane fraction and Amphotericin-B had antagonistic interaction (FICI index ≥ 4.0). This study revealed that V. brasiliana and its metabolites are potential sources of lead compounds for drugs for leishmaniasis treatment.

Schinus terebinthifolius Leaf Lectin (SteLL) Reduces the Bacterial and Inflammatory Burden of Wounds Infected by Staphylococcus aureus Promoting Skin Repair.

Staphylococcus aureus is commonly found in wound infections where this pathogen impairs skin repair. The lectin isolated from leaves of Schinus terebinthifolius (named SteLL) has antimicrobial and antivirulence action against S. aureus. This study evaluated the effects of topical administration of SteLL on mice wounds infected by S. aureus. Seventy-two C57/BL6 mice (6−8 weeks old) were allocated into four groups: (i) uninfected wounds; (ii) infected wounds, (iii) infected wounds treated with 32 µg/mL SteLL solution; (iv) infected wounds treated with 64 µg/mL SteLL solution. The excisional wounds (64 mm2) were induced on the dorsum and infected by S. aureus 432170 (4.0 × 106 CFU/wound). The daily treatment started 1-day post-infection (dpi). The topical application of both SteLL concentrations significantly accelerated the healing of S. aureus-infected wounds until the 7th dpi, when compared to untreated infected lesions (reductions of 1.95−4.55-fold and 1.79−2.90-fold for SteLL at 32 µg/mL and 64 µg/mL, respectively). The SteLL-based treatment also amended the severity of wound infection and reduced the bacterial load (12-fold to 72-fold for 32 µg/mL, and 14-fold to 282-fold for 64 µg/mL). SteLL-treated wounds show higher collagen deposition and restoration of skin structure than other groups. The bacterial load and the levels of inflammatory markers (IL-6, MCP-1, TNF-α, and VEGF) were also reduced by both SteLL concentrations. These results corroborate the reported anti-infective properties of SteLL, making this lectin a lead candidate for developing alternative agents for the treatment of S. aureus-infected skin lesions.