Evaluation of the antibiofilm and antimicrobial activities of Glycyrrhiza glabra and Viola odorata in poly herbal formulations

Exploring essential oil-based bio-composites: molecular docking and in vitro analysis for oral bacterial biofilm inhibition

Oral bacterial biofilms are the main reason for the progression of resistance to antimicrobial agents that may lead to severe conditions, including periodontitis and gingivitis. Essential oil-based nanocomposites can be a promising treatment option. We investigated cardamom, cinnamon, and clove essential oils for their potential in the treatment of oral bacterial infections using in vitro and computational tools. A detailed analysis of the drug-likeness and physicochemical properties of all constituents was performed. Molecular docking studies revealed that the binding free energy of a Carbopol 940 and eugenol complex was -2.0 kcal/mol, of a Carbopol 940-anisaldehyde complex was -1.9 kcal/mol, and a Carbapol 940-eugenol-anisaldehyde complex was -3.4 kcal/mol. Molecular docking was performed against transcriptional regulator genes 2XCT, 1JIJ, 2Q0P, 4M81, and 3QPI. Eugenol cinnamaldehyde and cineol presented strong interaction with targets. The essential oils were analyzed against Staphylococcus aureus and Staphylococcus epidermidis isolated from the oral cavity of diabetic patients. The cinnamon and clove essential oil combination presented significant minimum inhibitory concentrations (MICs) (0.0625/0.0312 mg/mL) against S. epidermidis and S. aureus (0.0156/0.0078 mg/mL). In the anti-quorum sensing activity, the cinnamon and clove oil combination presented moderate inhibition (8 mm) against Chromobacterium voilaceum with substantial violacein inhibition (58% ± 1.2%). Likewise, a significant biofilm inhibition was recorded in the case of S. aureus (82.1% ± 0.21%) and S. epidermidis (84.2% ± 1.3%) in combination. It was concluded that a clove and cinnamon essential oil-based formulation could be employed to prepare a stable nanocomposite, and Carbapol 940 could be used as a compatible biopolymer.

Development of Chitosan-Based Nanoemulsion Gel Containing Microbial Secondary Metabolite with Effective Antifungal Activity: In vitro and in vivo Characterizations

Purpose

Microbial resistance to antibiotics is one of the most important public health concerns of the 21^st century. We isolated, purified, and structurally elucidated antifungal secondary metabolites from red soil microbes and encapsulated them into chitosan (CS)-based nanoemulsion (NE) gel (NEG).

Methods

Three compounds were isolated and purified of which only one compound (Pure 2) showed potent antifungal activity (MFC: 8–132 µg/mL), which was also significantly (P<0.05) more efficient than fluconazole (MFC: 32–132 µg/mL). Pure 2 was structurally elucidated using 1D- and 2D-NMR before its incorporation into NEG. The formulations were prepared by high-speed homogenization technique. Physicochemical and pharmacological characterizations of formulations (ie, droplet size, PDI, zeta potential, drug content, viscosity, SEM, FTIR, spreadability, in vitro drug release, ex vivo permeation, in vitro antifungal and in vivo antifungal activities) were assessed.

Results

NMR analyses identified the compound as a derivative of phthalic acid ester (PAE). The optimized formulations displayed a droplet size <100 nm, -ve zeta potential, and PDI <0.45. The drug content was within the official limit of pharmacopeia (ie, 100±10%). Insignificant changes (P>0.05) in the viscosity of the formulations stored were observed. The morphology of the formulations indicated mesh-like structure. The FTIR study indicated that there were no interactions between the drug and other ingredients of the formulations. Optimum spreadability was observed in all formulations. NEG released 75.3±1.12% of Pure 2 after 12 hrs while NE released 85.33±1.88% of the compound. The skin permeation of F2 (71.15±1.28%) was significantly different (P<0.05) from F3 (81.80±1.91%) in rabbits. Complete and apparently safe recovery from the fungal infection was achieved in rabbits treated topically with Pure 2-loaded NEGs.

Conclusion

Hence, the NEG-loaded PAE isolated from Pseudomonas fluorescens represents a possible alternative for the treatment of fungal infections as compared to available therapies.