Curcumin (1,7-bis-(4-hydroxy-3-methoxyphenyl)-hepta-1,6-diene-3,5-dione) is a natural lipophilic polyphenol that exhibits significant pharmacological effects in vitro and in vivo through various mechanisms of action. Numerous studies have identified and characterised the pharmacokinetic, pharmacodynamic, and clinical properties of curcumin. Curcumin has an anti-inflammatory, antioxidative, antinociceptive, antiparasitic, antimalarial effect, and it is used as a wound-healing agent. However, poor curcumin absorption in the small intestine, fast metabolism, and fast systemic elimination cause poor bioavailability of curcumin in human beings. In order to overcome these problems, a number of curcumin formulations have been developed. The aim of this paper is to provide an overview of recent research in biological and pharmaceutical aspects of curcumin, methods of sample preparation for its isolation (Soxhlet extraction, ultrasound extraction, pressurised fluid extraction, microwave extraction, enzyme-assisted aided extraction), analytical methods (FTIR, NIR, FT-Raman, UV-VIS, NMR, XRD, DSC, TLC, HPLC, HPTLC, LC-MS, UPLC/Q-TOF-MS) for identification and quantification of curcumin in different matrices, and different techniques for developing formulations. The optimal sample preparation and use of an appropriate analytical method will significantly improve the evaluation of formulations and the biological activity of curcumin.

Sulfonamides are the first successfully synthesized antimicrobial drugs. The mechanism of sulfonamides antimicrobial action involves competitive inhibition of folic acid synthesis which prevents the growth and reproduction of microorganisms. Due to this mechanism of action, sulfonamides belong to the group of bacteriostatic agents. Although they have been applied in therapy for more than 70 years, sulfonamides are still the drugs of choice for the treatment of several conditions and diseases. A wider sulfonamides application in the therapy is limited by bacterial resistance and sulfonamides side effects. Antimicrobial sulfonamides and their metabolites are classified as persistent organic pollutants. For sulfonamides degradation and removal from the environment, various techniques can be applied such as different oxidation techniques, including chlorination and advanced oxidation processes, adsorption processes, membrane processes and combined processes.

This work aimed to isolate the essential oil from the nutmeg (Myristica fragrans Houtt.) seed, to determine the qualitative and quantitative chemical composition of the obtained essential oil, as well as to examine its antioxidant and antimicrobial activity. The essential oil was obtained by Clevenger-type hydrodistillation from the disintegrated nutmeg seed (hydromodulus 1:15 m/V, extraction time 180 minutes). The qualitative and quantitative chemical composition of the nutmeg essential oil was determined by GC/MS and GC/FID analysis. Twenty-five compounds were identified in the nutmeg essential oil and the most abundant was monoterpene hydrocarbon sabinene (42.3 %). The antioxidant activity was spectrophotometrically examined by using DPPH assay. The nutmeg essential oil showed a good antioxidant activity after incubation (EC₅₀ = 1.35 ± 0.003 mg/ml). The antimicrobial activity of the nutmeg essential oil was examined by using a disc diffusion method on Gram-positive bacteria (Staphylococcus aureus, Bacillus cereus, B. luteus, Listeria monocytogenes), Gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus vulgaris) and fungus (Candida albicans). The essential oil showed good antifungal and antibacterial activity. The anticandidal activity of the essential oil (28 mm) was comparable to the activity of conventional antifungal drug nystatin (17 mm). Of the tested Gram-positive bacteria, the most sensitive was B. luteus with the inhibition zone diameter of 23 mm, while the tested Gram-negative bacteria showed lower sensitivity. The isolated nutmeg essential oil has the potential for use in the pharmaceutical, chemical and food industry as a natural antioxidant and an antimicrobial agent.

Phytoestrogens represent polyphenolic and non-steroid compounds that have a similar structure and biological activity as human estrogens. They are the plant secondary metabolites and widespread in over 300 various plant species. The phytoestrogens are divided into two main subgroups, isoflavonoids and lignans. The isoflavonoids are divided into isoflavones and coumestans. Isoflavones are most present in soybean and red clover. A great number of isoflavones has been identified in the plants in the form of non-active glycosides (daidzein and genistein) and in the form of 4’-methylated derivatives (formononetin and biochanin A). Coumestans can also be found in red clover and legumes, while lignans are most present in the flax seed. Coumestans have the most pronounced estrogenic effect of all phytoestrogens. The most famous representative of this subgroup of compounds is coumestrol. Lignans include matairesinol, secoisolariciresinol, lariciresinol, pinoresinol and their metabolites, enterodiol, enterolactone and equol. Numerous studies in animals and humans have shown that phytoestrogens can have protective effects in the estrogen-dependent conditions and estrogen-dependent diseases. It was also shown that the use of phytoestrogens can have a positive effect on insomnia and cognitive functions, i.e. neural disorders, such as Alzheimer’s disease. They can express the antioxidant activity in two ways, as the scavengers of free radicals or by the formation of chelating complexes with metal ions. Free metal ions increase the amount of reactive oxygen species by reduction of hydrogen peroxide resulting in a very reactive hydroxyl radical.

The surface quality of denture base resins allows for easy colonization by microorganisms including Candida albicans and Staphylococcus aureus, which cause major diseases of the oral cavity such as denture stomatitis. The widespread use of silver nanoparticles (AgNPs) in various fields of medicine has led to research of their possible application in dentistry, mostly in the prevention of bacterial adhesion, proliferation, and biofilm formation. The aim of the study was to synthesize cold and heat-curing denture base resins modified with AgNPs and AgCl, and evaluate the potential of the modified resins to reduce the growth of C. albicans and S.aureus. The produced material was characterized by Fourier transform infrared spectroscopy (FTIR). The antimicrobial potential of the modified material was demonstrated by the disc-diffusion method, microdilution method, and a modified microdilution method (i.e., disk-diffusion method in broth with viable counting). Spectroscopy confirmed the incorporation of biocidal materials into the structure of the denture base resins. The AgCl and AgNPs modified resins showed an antimicrobial effect. The significance of the study is in the potential therapeutic effects of the modified materials for prevention and threating staphylococci and candida in elderly patients, who are in most cases denture wearers and have a greater susceptibility to develop opportunistic infections. Modified denture base resins can significantly reduce the presence of infection at the point of contact between the denture and the mucous membrane of the prosthetic restoration. Biological tests of modified denture base resins will follow.

The main goal of this study was to develop a liposome formulation with sulfanilamide and to investigate the liposomes impact on its release and stability to the UV-A/UV-B and UV-C irradiation. Liposome dispersions with incorporated sulfanilamide were prepared by thin-film hydration method and liposomes role to the sulfanilamide release was investigated by using a dialysis method. Comparatively, sulfanilamide in phosphate buffer solution was subject to release study as well to the UV irradiation providing for the possibilities of kinetics analysis. In vitro drug release study demonstrated that 20% of sulfanilamide was released from liposomes within 1 h that is approximately twice as slower as in the case of dissolved sulfanilamide in phosphate buffer solution. The kinetic release process can be described by Korsmeyer-Peppas model and according to the value of diffusion release exponent it can be concluded that drug release mechanism is based on the phenomenon of diffusion. The sulfanilamide degradation in phosphate buffer solution and liposomes is related to the formation of UV-induced degradation products that are identified by UHPLC/MS analysis as: sulfanilic acid, aniline and benzidine. The UV-induced sulfanilamide degradation in the phosphate buffer solution and liposome vesicles fits the first- order kinetic model. The degradation rate constants are dependent on the involved UV photons energy input as well as sulfanilamide microenvironment. Liposome microenvironment provides better irradiation sulfanilamide stability. The obtained results suggest that liposomes might be promising carriers for delayed sulfanilamide delivery and may serve as a basis for further research.