Xanthine oxidase (XO) is an important enzyme catalyzing the hydroxylation of hypoxanthine to xanthine and xanthine to uric acid which is excreted by kidneys. Excessive production and/or inadequate excretion of uric acid results in hyperuricemia. This paper presents a detailed review of methods of isolation, determination of xanthine oxidase activity, and the effect of plant extracts and their constituents on it. Determining the content and activities of XO can be used for diagnostic purposes. Testing inhibition of XO is important for detection of potentially effective compounds or extracts that can be used to treat diseases that are caused by increased activity of XO. In vitro bioassays are used to examine test material for XO inhibition, as inhibitors of XO may be potentially useful for the treatment of gout or other XO induced diseases. Several authors reported on the XO inhibitory potential of traditionally used medicinal plants.

Vanillic acid is used in the food industry and perfumery, and the optimization of its extraction process from the natural source is important for saving time and money. The presence of vanillic acid in pumpkin seeds was proven using HPLC analysis. Computational optimization of the extraction shows that for the concentration of ethanol 40% and solmodul: V/m=20, the optimum condition for the extraction of vanillic acid from pumpkin seeds was 100 min and 450C. The estimation of fitting for each kinetic model to the experimental kinetic data was performed using the root mean square, standard deviation, and the correlation coefficient. Ponomarev model was shown as the most suitable with the highest accuracy among the six considered kinetic models. The enthalpy and entropy changes were positive, while the Gibbs free energy was negative and decreased when temperature increased during the thermodynamic analysis. Therefore, the extraction of vanillic acid from pumpkin seeds was endothermic, spontaneous, and irreversible.

Headspace volatiles (HS) and hydrodistilled essential oils (EO) of fresh aerial parts of Artemisia annua L. and A. scoparia Waldst. et Kit., were analyzed by GC?MS/FID. Artemisia ketone was found to be the most abundant component among the EO volatiles (55.8 %), as well as among HS (52.1 %) of A. annua. Additionally, in both A. annua samples, EO and HS, ?-pinene (12.7 and 24.2 %, respectively) was found in high percentage. On the other hand, it has been determined that the dominant components of A. scoparia EO and HS were different; in the essential oil capillene (63.8 %) was found as the main constituent, while ?-pinene (26.1 %), (Z)-?-ocimene (23.8 %) and limonene (10.7 %) were the major components among the HS. This is the first report on the composition of HS volatiles of the A. annua and A. scoparia obtained by direct static headspace.

Volatiles of diethyl ether extract (DE), ethyl acetate extract (EE), and hexane extract (HE) of Artemisia scoparia Waldst. et Kit. were analyzed by gas chromatography with flame ionization detector and gas chromatography-mass spectrometry. In both DE and EE, the main compound was scoparone (24.0% and 86.1%, respectively) while in the HE, alkanes were dominant with nonacosane as the most represented (19.4%). Antimicrobial activity was tested against 4 bacterial strains and 1 fungal strain using disc-diffusion method. Tested samples were inactive against Gram-negative bacteria and they exhibited activity against Gram-positive bacteria and yeast Candida albicans. This is the first report on the chemical composition of volatile components and antimicrobial activity of DE, EE, and HE of A. scoparia Waldst. et Kit.

Chemical composition of the headspace volatiles and essential oils isolated from different parts of Ferulago sylvatica was determined by GC and GC/MS analyses. The results showed that headspace volatiles obtained from the aerial parts and roots were similar regarding the number of identified compounds and main components. However, essential oils obtained from different plant organs showed significant differences in chemical composition. Myrcene was the most abundant component of the inflorescences and shoots volatiles, while α-pinene make up over 50% of the root volatiles. Only three components were identified in the root essential oil with 2,3,6-trimethyl benzaldehyde (92.7%) as the main component. In the shoots sample the terpenoid fractions represented 56% of the oil, unevenly distributed between monoterpenoids and sesquiterpenoids with germacrene D (32.5%) recognized as the main constituent. On the other hand, more than 94% of the inflorescences oils were monoterpenoids with myrcene as the most abundant contributor (29.2%). Graphical Abstract

Essential oils (EOs) derived from evergreen conifer trees are recognized as complex sources of agents with various biological activities. In this study, the biological activities of the EOs derived from Chamaecyparis lawsoniana (A.Murray bis) Parl. (CLEO) and Thuja plicata Donn ex D.Don (TPEO) were investigated. The third instar larvae of the fruit fly Drosophila melanogaster were used as a model organism to determine the in vivo toxicity, genotoxicity, and antigenotoxicity of five different concentrations of CLEO and TPEO, ranging from 0.19% to 3%. Artemia salina was used for acute toxicity assessment and determination of LC₅₀ after 24 h and 48 h. The antimicrobial activity of the CLEO and TPEO was tested against fourteen bacterial and two fungal strains using the microdilution method. The larvicidal activity and developmental time of D. melanogaster increased as the concentrations of the EOs rose. CLEO and TPEO produced a dose-dependent increase in DNA damage compared with the negative control. Both oils, at concentrations up to 1.5%, demonstrated the ability to reduce the genotoxic effect induced by ethyl methanesulfonate, with a reduction rate exceeding 60%. CLEO and TPEO were highly toxic against Artemia salina nauplii. The results indicate that the tested EOs act as antimicrobial agents against some pathogenic bacteria and fungi. CLEO and TPEO show promising potential as a source of antimicrobial and antigenotoxic agents and as potential biocides against pest insects and arthropods.