Essential oils are mixtures of potent compounds with biological effects, such as those with antioxidant, antimicrobial, antitumor and/or anti-inflammatory effects. In this paper, the antioxidant and antimicrobial activity of essential oils of different types of commercial pepper was tested. Essential oils are prepared by hydrodistillation. Polyphenol content, reduction potential and DPPH radical inhibition were analyzed. Antimicrobial activity was tested on reference strains using the diffusion technique. The analysis showed that the essential oil of black pepper has a significantly higher antioxidant potential compared to the essential oils of green and white pepper. High antimicrobial activity was also found for the black pepper essential oil sample, except in the case of Pseudomonas aeruginosa. 

Sustainable development is a big global challenge for the 21st century. In recent years, a class of emerging contaminants known as microplastics (MPs) has been identified as a significant pollutant with the potential to harm ecosystems. These small plastic particles have been found in every compartment of the planet, with aquatic habitats serving as the ultimate sink. The challenge to extract MPs from different environmental matrices is a tangible and imperative issue. One of the primary specialties of research in environmental chemistry is the development of simple, rapid, low-cost, sensitive, and selective analytical methods for the extraction and identification of MPs in the environment. The present review describes the developments in MP extraction methods from complex environmental matrices. All existing methodologies (new, old, and proof-of-concept) are discussed and evaluated for their potential usefulness to extract MPs from various biotic and abiotic matrices for the sake of progress and innovation. This study concludes by addressing the current challenges and outlining future research objectives aimed at combating MP pollution. Additionally, a set of recommendations is provided to assist researchers in selecting appropriate analytical techniques for obtaining accurate results. To facilitate this process, a proposed roadmap for MP extraction is presented, considering the specific environmental compartments under investigation. By following this roadmap, researchers can enhance their understanding of MP pollution and contribute to effective mitigation strategies.

In this research, the antioxidant activity and its correlation with the polyphenolic content in pumpkin leaf extracts (Cucurbita pepo L.) were examined. Dried and pulverized pumpkin leaves were used as extraction material. Various solvents (water, methanol, ethanol, acetone) and their mixtures, in a ratio of 50:50 (v/v) (water: methanol, water: ethanol, water: acetone) were used for extraction. The solid-to-solvent ratio was 1:10. The influence of solvents on phenolic extraction, as well as the effect of ultrasonic extraction was investigated. The samples were subjected to ultrasound for 15 minutes. The total phenolic content was determined by the Folin-Ciocalteu method and the antioxidant activity of the extracts by FRAP and DPPH methods. The obtained results indicate the importance of choosing an adequate extraction solvent for phenolic isolation from plant material. Mixtures of organic solvents and water, especially a mixture of water and acetone, are the most suitable for the extraction of phenolic compounds. At the same time, a positive correlation was established between the content of total phenols and the antioxidant activity of the extracts. This suggests that phenols contribute significantly to the antioxidant properties of pumpkin leaves. The results showed the potential medicinal properties of pumpkin leaves but further studies are needed to identify, characterize and isolate different bioactive components, which could be used as a basis for obtaining new drugs for the treatment of various diseases.

Pelotherapy is the application of thermal muds (peloids) for therapeutic purposes. Artificial peloids were prepared usingpyrophilite shale maturated in three different types of thermal water in terms of their pH values. The samples after 30and 60 days of maturation were examined by X-ray diffraction. No significant variations in the mineralogical compositionand diffractograms of pyrophillite peloids were detected after maturation. Only the influence of the maturation processof pyrophillite on the pH value of mineral water with high and low pH value is noticed.

Plastic fragments, weathered into or released in the form of micro- and nanoplastics, are persistent and widespread in the environment, and it is anticipated that they have negative environmental impacts. This necessitates immediate efforts for management strategies throughout the entire plastics lifecycle. This opinion paper was initiated by the EU COST Action CA20101 PRIORITY, which focuses on the need to develop an effective global networking platform dealing with research, implementation, and consolidation of ways to address the worldwide challenges associated with micro- and nanoplastics pollution in the environment.

In this study, the chemical profiles, antioxidant and antibacterial activity of Helivhrysum italicum essential oils from three plantation fields in Herzegovina were analysed. GC/MS analysis showed that all samples were rich in sesquiterpenes (45.19%-50.07%) and monoterpenes (21.15%-23.21%), followed by oxygenated monoterpenes (9.92%-14.03%). Diketones in the essential oil were detected in quantities ranging 5.72% to 6.67%. The main components in essential oils were γ-curcumene, α-pinene, β-selinene and neril-acetate. All tested essential oils exhibited relatively weak DPPH-scavenging capacity. The antimicrobial activity of the essential oil was assayed by using the disk diffusion method. E. coli was most resistant against all three tested H. italicum essential oils, while moderate inhibitory activity against S. aureus and C. albicans was detected. The L. monocytogenes was the most sensitive where all three tested samples showed inhibitory activity.

Deep eutectic solvents (DESs), as an alternative to ionic liquids, have greener credentials than ionic liquids and have attracted increasing attention in many applications. Choline chloride-based DESs in combination with different hydrogen bond donors (organic acid, sugars and urea), showed a high extraction efficiency. The aim of this study was to examine the possible effects of choline chloride-based eutectic solvents on the antioxidant and antimicrobial activity of lemon and mandarin orange seed extracts. Lactic acid, glucose, urea and water were used to prepare choline chloride-based Natural Deep Eutectic Solvents (NADESs). Ferric-Reducing Antioxidant Power (FRAP) Assay and 2,2-diphenyl-1-picryl-hydrazyl (DPPH) method were used to determine Original Research Article Kolarević et al.; IRJPAC, 21(23): 120-128, 2020; Article no.IRJPAC.63470 121 antioxidant activity. Antibacterial activity was investigated by diffusion method on reference bacterial strains E. coli, E. faecalis, S. aureus, B. subtilis and L. monocytogenes. The analysis revealed a significant reduction potential of the eutectic solvent based on lactic acid as well as significant antioxidant activity of lemon and mandarin seed extracts. In general, mandarin extracts showed better antioxidant capacity. In vitro antibacterial activity assays showed a complete absence of bacterial growth inhibition of the extracts. However, eutectic solvents with lactic acid have shown a significant antimicrobial effect.