Antifungal polybrominated proxyphylline derivative induces Candida albicans calcineurin stress response in Galleria mellonella

Different essential oils can inhibit Candida albicans biofilm formation on acrylic resin by suppressing aspartic proteinase: In vitro and in silico approaches

INTRODUCTION

Cymbopogon martini, Syzygium aromaticum, and Cupressus sempervirens are used for antimicrobial purposes in the worldwide. Both their extracts and essential oil contents are rich in active ingredients.

OBJECTIVE

The aim of this study was to investigate the inhibitory effect of Cymbopogon martini essential oil (CMEO), Syzygium aromaticum essential oil (SAEO) and Cupressus sempervirens essential oil (CSEO) on Candida albicans biofilm formation on heat-polymerized polymethyl methacrylate (PMMA) samples in vitro and in silico.

MATERIALS AND METHODS

Essential oil contents with anticandidal potential were determined by Gas Chromatography-Mass Spectrometry. Following C. albicans adhesion, PMMA samples were treated independently with Corega® and each essential oil. The anticandidal activity of the essential oils was determined by spectrophotometric absorbance measurement at 600 nm, taking into account the cultures of each sample. The cytotoxicity evaluation of essential oils was performed by MTT Colorimetric assay. The software package AutoDockTools (1.5.6) was used for the in silico studies. The effect of essential oil content on the inhibition of Secreted aspartic proteinase (SAP2) was evaluated considering the Ligand@SAP2 complex formation.

RESULTS

2% of CMEO and 5% of SAEO exhibited higher anticandidal activity than Corega® (p < 0.05), whereas Corega® had higher anticandidal activity than 2% and 5% of CSEO (p < 0.05). The cytotoxicity of essential oils on NIH/3T3 cells after 24 h was found to be 2.41 for CSEO, 2.84 for CMEO, and 2.85 µg/mL for SAEO. The results of the in silico study showed that citronellol from CMEO, chavibetol (m-eugenol) from SAEO and β-pinene from CSEO each had the highest effect on the inhibition of SAP2. The highest binding affinity value was found for citronellol at -5.3 kcal/mol.

CONCLUSIONS

The biofilm formation of C. albicans onto acrylic resin was inhibited by CMEO, SAEO and CSEO at a concentration of 2% through in vitro assay. The most effective inhibition was determined to be due to citronellol in CMEO through in silico analysis.

Tenebrio molitor as a Simple and Cheap Preclinical Pharmacokinetic and Toxicity Model

The progression of drugs into clinical phases requires proper toxicity assessment in animals and the correct identification of possible metabolites. Accordingly, different animal models are used to preliminarily evaluate toxicity and biotransformations. Rodents are the most common models used to preliminarily evaluate the safety of drugs; however, their use is subject to ethical consideration and elevated costs, and strictly regulated by national legislations. Herein, we developed a novel, cheap and convenient toxicity model using Tenebrio molitor coleoptera (TMC). A panel of 15 drugs-including antivirals and antibacterials-with different therapeutic applications was administered to TMC and the LD50 was determined. The values are comparable with those already determined in mice and rats. In addition, a TMC model was used to determine the presence of the main metabolites and in vivo pharmacokinetics (PK), and results were compared with those available from in vitro assays and the literature. Taken together, our results demonstrate that TMC can be used as a novel and convenient preliminary toxicity model to preliminarily evaluate the safety of experimental compounds and the formation of main metabolites, and to reduce the costs and number of rodents, according to 3R principles.

The Composites of Polyamide 12 and Metal Oxides with High Antimicrobial Activity

The lack of resistance of plastic objects to various pathogens and their increasing activity in our daily life have made researchers develop polymeric materials with biocidal properties. Hence, this paper describes the thermoplastic composites of Polyamide 12 mixed with 1-5 wt % of the nanoparticles of zinc, copper, and titanium oxides prepared by a twin-screw extrusion process and injection moulding. A satisfactory biocidal activity of polyamide 12 nanocomposites was obtained thanks to homogenously dispersed metal oxides in the polymer matrix and the wettability of the metal oxides by PA12. At 4 wt % of the metal oxides, the contact angles were the lowest and it resulted in obtaining the highest reduction rate of the Escherichia coli (87%), Candida albicans (53%), and Herpes simplex 1 (90%). The interactions of the nanocomposites with the fibroblasts show early apoptosis (11.85-27.79%), late apoptosis (0.81-5.04%), and necrosis (0.18-0.31%), which confirms the lack of toxicity of used metal oxides. Moreover, the used oxides affect slightly the thermal and rheological properties of PA12, which was determined by oscillatory rheology, thermogravimetric analysis, and differential scanning calorimetry.