Researchers are looking for the most effective ways to extract the bioactive substances of Juniperus communis L. berries, which are capable of displaying the greatest range of biological activity, namely antimicrobial potential “against phytopathogens”, antioxidant activity and nematocidal activity. This study provides detailed information on the chemical activity, group composition and biological activity of the extracts of juniper berries of 1- and 2-year maturity (JB1 and JB2), which were obtained by using different solvents (pentane, chloroform, acetone, methanol and 70% ethanol) under various extraction conditions (maceration and ultrasound-assisted maceration (US)). Seventy percent ethanol and acetone extracts of juniper berries were analyzed via gas chromatography–mass spectrometry, and they contained monoterpenes, sesquiterpenes, polysaccharides, steroids, fatty acid esters and bicyclic monoterpenes. The antimicrobial activity was higher in the berries of 1-year maturity, while the acetone extract obtained via ultrasound-assisted maceration was the most bioactive in relation to the phytopathogens. Depending on the extraction method and the choice of solvent, the antioxidant activity with the use of US decreased by 1.5–1.9 times compared to the extracts obtained via maceration. An analysis of the nematocidal activity showed that the sensitivity to the action of extracts in Caenorhabditis elegans was significantly higher than in Caenorhabditis briggsae, particularly for the acetone extract obtained from the juniper berries of 1-year maturity.

This study evaluates the antibacterial and antifungal effects of ethanol extracts from Gnaphalium uliginosum L. derived from freshly harvested plant biomass, including stems, leaves, flowers, and roots. The extract was analyzed using gas chromatography-mass spectrometry (GC-MS) to determine its antimicrobial activity against phytopathogenic bacteria and fungi. Two methods were used in the experiments: agar well diffusion and double serial dilution. Extraction was carried out using the maceration method with different temperature regimes (25 °C, 45 °C, and 75 °C) and the ultrasonic method at various powers (63–352 W) for different durations (5 and 10 min). It was found that the 70% ethanol extract obtained through the ultrasonic experiment at 189 W power for 10 min and at 252 W power for 5 min had the highest antimicrobial activity compared to the maceration method. The most sensitive components of the extracts were the Gram-positive phytopathogenic bacteria Clavibacter michiganensis and the Gram-negative phytopathogenic bacteria Erwinia carotovora spp., with MIC values of 156 μg/mL. Among the fungi, the most sensitive were Rhizoctonia solani and Alternaria solani (MIC values in the range of 78–156 µg/mL). The evaluation of the antimicrobial activity of extracts using the diffusion method established the presence of a growth suppression zone in the case of C. michiganensis (15–17 mm for flowers, leaves, and total biomass), which corresponds to the average level of antimicrobial activity. These findings suggest that G. uliginosum has potential as a source of biologically active compounds for agricultural use, particularly for developing novel biopesticides.

The search for new classes of agrochemicals is a key task of modern agrochemistry due to the growing resistance of phytopathogens and stricter environmental requirements for pesticides. In this work, the antimicrobial activity of a number of synthesized α,β-bis(diphenylphosphinoxide)ethanes against economically significant phytopathogens was investigated. Antimicrobial activity was assessed by serial micro-dilution in broth to determine the minimum inhibitory (MIC) and fungicidal/bactericidal (MFC/MBC) concentrations. To assess the effect of solubility on biological activity, studies were conducted in two solvent systems: 5 and 50% aqueous ethanol. In a system with 5% ethanol, most compounds showed no activity against Fusarium graminearum and Alternaria alternata fungi. However, with an increase in ethanol concentration to 50%, compounds [1-(2-fluorophenyl)ethane-1,2-diyl]bis(diphenylphosphine oxide) and (1-phenylhexane-1,2-diyl)bis(diphenylphosphine oxide) demonstrated pronounced fungicidal activity against F. graminearum (MIC = 312 μg/mL). The highest antibacterial activity was recorded for (1-phenylhexane-1,2-diyl)bis(diphenylphosphine oxide), especially against the gram-negative bacterium Erwinia carotovora (MIC = 19 μg/mL), which significantly exceeds the performance of the reference drug chloramphenicol (MIC = 312 μg/mL). Thus, the compounds studied, especially bisphosphine oxide with a long alkyl substituent, have demonstrated high potential as antibacterial agents. The dependence of their fungicidal activity on solubility was revealed. [1-(2-Fluorophenyl)ethane-1,2-diyl]bis(diphenylphosphine oxide) is a promising leader structure for the further development of new plant protection products.