The present study describes DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity and antimutagenic properties of the essential oil of myrtle (Myrtus communis L.). Plant samples were collected from the two distant localities (southernmost and northern point) of the Montenegro coastline. Chemical profiles of the two samples were evaluated by GC-MS. In both of the samples monoterpenes were found to be the predominant compounds. Among them a-pinene, linalool, 1,8-cineole, and myrtenyl acetate were the major compounds. Significant differences between the samples were found in the ranges of a-pinene (14.7%–35.9%) and myrtenyl acetate (5.4%–21.6%). Both oils exhibited moderate DPPH scavenging activity, with IC₅₀ values of 6.24 mg/mL and 5.99 mg/mL. The antimutagenic properties were assayed against spontaneous and t-BOOH-induced mutagenesis in Escherichia coli oxyR mutant IC202, a bacterial strain deficient in removing ROS. Reduction of the spontaneous mutagenesis in presence of myrtle EO was only slight, up to 13% at the highest concentration tested. When the oxidative mutagen was used, EO expressed higher reduction of mutagenesis, in a concentration dependent manner, with statistical significance for effect at the highest concentration tested (28%). Suppression of t-BOOH induced mutagenesis was correlated with the observed scavenging activity.

The St John's Wort (Hypericum perforatum; Clusiaceae) has been used in traditional and modern medicine for a long time due to its high content of biologically active phenolics. The purpose of this work was to develop a method for their fractionation and identification, and to determine the most active antioxidant compounds in plant extract.

The present study describes radical scavenging capacity (RSC), antimutagenic and antibacterial properties of the essential oil (EO) of the leaves of Eucalyptus gunnii Hook. (Southern Montenegro). Chemical composition was evaluated by gas chromatography-mass spectrometry (GC-MS). In oil, 1,8-cineole (67.8%) and α-pinene (14.12%) were the major compounds comprising almost 82% of total EO. EO exhibited moderate DPPH (2,2-diphenyl-1-picrylhydrazyl) scavenging activity, with IC₅₀ value of 7.19 µL/mL. The antimutagenic properties were assayed against the spontaneous and t-BOOH-induced mutagenesis in Escherichia coli IC202 oxyR mutant strain, deficient in removing radical oxygen species (ROS). Reduction of the spontaneous mutagenesis in the presence of E. gunnii EO was only slight, up to 12% at the highest concentration tested. However, when the oxidative mutagen was used, EO displayed more significant reduction of mutagenesis (maximum 23%) in a concentration dependent manner. Antibacterial activity was tested against the selected strains from ATTC and NCIB collections: Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, Escherichia coli, Bacillus subtilis, Micrococcus flavus, Klebsiella pneumoniae, and the two Escherichia coli strains from our laboratory collection (SY252 and IB112) using both the disk-diffusion and MIC assays. The greatest sensitivity was shown by M. flavus, K. pneumoniae and E. coli lpcA (MIC = 0.83 mg/mL), while the highest resistance was shown by E. coli (ATTC 25922) and S. epidermidis. This study represents the first report on chemical composition and biological activity of the Eucalyptus gunnii in the South Balkan region and beyond.

Herb-drug interactions are an important safety concern and this study was conducted regarding the interaction between the natural top-selling antidepressant remedy Hypericum perforatum (Hypericaceae) and conventional drugs. This study examined the influence of acute pretreatment with different extracts of Hypericum perforatum from Serbia on pentobarbital-induced sleeping time, impairment of motor coordination caused by diazepam and paracetamol pharmacokinetics in mice. Ethanolic extract, aqueous extract, infusion, tablet and capsule of Hypericum perforatum were used in this experiment. The profile of Hypericum perforatum extracts as well as paracetamol plasma concentration was determined using RP-HPLC analysis. By quantitative HPLC analysis of active principles, it has been proven that Hypericum perforatum ethanolic extract has the largest content of naphtodianthrones: hypericin (57.77 µg/mL) and pseudohypericin (155.38 µg/mL). Pretreatment with ethanolic extract of Hypericum perforatum potentiated the hypnotic effect of pentobarbital and impairment of motor coordination caused by diazepam to the greatest extent and also increased paracetamol plasma concentration in comparison to the control group. These results were in correlation with naphtodianthrone concentrations. The obtained results have shown a considerable influence of Hypericum perforatum on pentobarbital and diazepam pharmacodynamics and paracetamol pharmacokinetics.