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. 

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.

Hibiscus is a widely used plant, which has been proven to have numerous positive effects on human health, such as lowering blood pressure, maintaining optimal blood cholesterol levels, liver protection, prevention of oxidative stress, etc. In this study, the content of polyphenols, flavonoids and antioxidant capacity of aqueous, ethanolic and hydroethanolic (50/50 v/v) hibiscus extracts, prepared by maceration and ultrasonic extraction, was analyzed. Analysis of antioxidant activity was performed in vitro, using FRAP and DPPH methods. The results showed that the mixture of water and ethanol had a significantly higher effect of extraction of bioactive components from hibiscus than the remaining two solvents. The lowest content of polyphenols and flavonoids, and thus the weakest antioxidant activity was recorded in extracts prepared in absolute ethanol. By comparing the efficiency of the techniques used, maceration proved to be slightly more efficient in the case of aqueous and hydroethanol extracts, while higher polyphenol content and higher antioxidant activity were observed in ethanolic extracts prepared by ultrasonic extraction.

Extracts obtained from plant material have widely applied in the chemical and pharmaceutical industries because they contain significant concentrations of biologically active substances. Commercial daisy extract (Bellis perennis) was used in this paper for in vitro testing of tyrosinase enzyme inhibition, and antioxidant and antimicrobial activity. Inhibition of the tyrosinase enzyme was determined by monitoring dopachrome formation at a wavelength of 492 nm. Antioxidant activity was tested using FRAP and DPPH methods, while antibacterial activity was tested by diffusion technique on reference strains from the ATCC collection. The results showed that daisy extract inhibits tyrosinase enzyme in a dose-dependent manner. The extract effectively neutralized DPPH radicals and also showed good reducing ability. Bacterial strains used for in vitro antimicrobial activity testing did not show sensitivity to the extract concentrations used in this study.

Copper (II) complexes with commercial antibiotics, amoxicillin (AMX), azithromycin (AZT) and ciprofloxacin (CFL) were synthesized and isolated as solids. Structures of the isolated products were determined by FTIR spectroscopy. Antibacterial activities were determined on reference bacterial strains from the ATCC collection by diffusion technique. The results show that AMX and CFL coordinate Cu (II) ion as bidentate O-donor ligand. AZT coordinates metal center as bidentate NO-donor ligand. A difference in the morphology of antibiotic crystals and the synthesized complexes was found. Complex of Cu (AMX)2 show complete absence of antibacterial activity, while the other com-plexes show the same or even lower activity than the parent ligands.  

The samples of stinging nettle were collected during June in the Tuzla region. Aqueous extracts were prepared from fresh and dried leaves in order to determinate and compare content of bioactive components and antioxidant potential. Conventional soxhlet, ultrasound assisted extraction and traditional maceration extraction were used as extraction methods. Quantitative determination of phenols and flavonoids was carried out using spectrophotometric methods. Antioxidant activity of nettle aqueous extracts was determined using ferric reducing antioxidant power and DPPH free radical scavenging activity. Extracts obtained by Soxhlet extraction showed the highest total phenolic and flavonoid content and expected the highest antioxidant capacity, while extracts obtained by maceration gave the lowest results. KEYWORDS:stinging nettle extract;bioactive components;extraction;antioxidant

Metal complexes due to their antibacterial, antifungal, antitumor and antioxidant properties have been extremely studied today. A large number of metal complexes have the ability to neutralize free radicals, which most often occur as a result of metabolic processes in the body, smoking, exposure to radiation and chemical substances. Testing the antioxidant capacity of metal complexes can be tested by various methods in vitro and in vivo. This paper will present the efficiency of neutralization of free radicals by metal complexes synthesized in the past few years using different ligands, as well as the most commonly used methods for testing the antioxidant capacity of this group of compounds. 

Pepper is one of the most famous and widespread spices in the world. This commercial plant belongs to the Piperaceae family. Depending on the treatment to which the pepper fruit is exposed, we distinguish between black, white and green pepper. In this research, methanolic extracts of different types of pepper (Piper nigrum) and pink pepper (Schinus terebinthifolius Raddi) were prepared. Maceration and ultrasonic extraction were used to extract bioactive components from pepper samples. The reduction potential of the extracts was tested using the FRAP method. The efficiency of free radical inhibition was determined by the DPPH method. Pink pepper extract showed the highest antioxidant activity in in vitro conditions. High antioxidant activity was also recorded in green pepper extracts. In general, the extracts showed high potency in neutralizing free radicals.

Aims: The aims of the study were to analyse the polyphenols of Pulicaria dysenterica (L.) Bernh. methanolic extracts from aerial and underground parts, assessment of antioxidant activity and to evaluate their cytotoxicity on HeLa cells of cervical cancer. Methodology: The total phenolic content (TPC) of extracts was determined by the Folin-Ciocalteu spectrophotometric method. The qualitative and quantitative analysis of individual polyphenolic compounds were performed by the reverse phase HPLC method. The antioxidant capacity was evaluated by both, 2,2-diphenyl1-picrylhydrazyl radical and FRAP assay, while cytotoxicity of the extracts was assessed by MTT assay. Results: TPC of the samples were 127.62±2.22 and 244.12±8.84 mg gallic acid equivalent/g extract. In the extracts chlorogenic acid in amount of 10.06±0.96 and 11.32±0.28 mg/g, flavonoid rutin in amount of 5.68±0.13 mg/g and three caffeic acid derivatives were recorded. Extract from underground parts achieved better antioxidant activity with IC50 value 55.36±0.75 µg/mL and FRAP value 2411.12±37.22 µmol Fe2+g-1 compared to the one from aerial parts. Extract from aerial parts achieved better cytotoxic activity with 50% inhibition of viability (IC50) at concentration of 0.389±0.07 mg/mL, against HeLa cells, compared to the extract from underground parts. Conclusion: Analyzed Pulicaria dysenterica extracts contained phenolic acids and flavonoids. The extracts showed good antioxidant activity and cytotoxic properties against HeLa cells in vitro.

Origanum compactum, an endemic Moroccan medicinal herb, possesses many different activities such as antibacterial, antifungal, antioxidant and anticancer. The aim of this study was to investigate the stability and antifungal activity of liposomal dispersion with this essential oil. Liposomal dispersion stability was evaluated by testing the vesicle size, polydispersity index and zeta potential. It was also examined the in vitro release of thymol and carvacrol from liposomal dispersion. The major components of this essential oil were carvacrol (58.4%), thymol (12.5%) and γ-terpinene (10.7%). Origanum compactum essential oil showed a strong antifungal activity, and the inhibition zones ranged from 24 to 45 mm. After 210 minutes, 80.88% thymol and 16.67% carvacrol were released. Stability assessment was performed for three months and the liposomal dispersion showed a good stability.

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.

In this study, metal complex of Copper(II) with a Schiff base derived from 2,2-dihydroxyindane-1,3-dione and 2-aminoethanoic acid were synthesized. The product are characterized by spectral methods. The antimicrobial activity was tested on reference bacterial strains and the antioxidant capacity was analyzed by using the DPPH and FRAP methods. The spectral data indicates that the Schiff base coordinates the Copper(II) as a tridentate ONO donor ligand. The compounds showed weaker antimicrobial activity on certain tested microorganisms. In vitro testing of antioxidant activity showed a significant reducing ability of the complex, as well as inhibitory activity against DPPH radicals.

In this paper, the polyphenol content and antioxidant activity of fig leaf extracts were analyzed. Extraction was performed with methanol, ethanol, acetone and their aqueous mixtures (50:50 v/v). Extractions were performed with stirring at 300 rpm on a vibromix and ultrasonic bath for 15 minutes. The polyphenol content was determined spectrophotometrically using the Folin-Ciocalteu test. Antioxidant capacity was tested using the FRAP and DPPH methods. The results showed a significant effect of extraction of bioactive components using an organic solvent:water mixture in relation to the organic solvent itself. Ultrasonic extraction proved to be a more efficient technique compared to mixing at 300 rpm.