Five Different Artemisia L. Species Ethanol Extracts' Phytochemical Composition and Their Antimicrobial and Nematocide Activity.

Among the plants that exhibit significant or established pharmacological activity, the genus Artemisia L. deserves special attention. This genus comprises over 500 species belonging to the largest Asteraceae family. Our study aimed at providing a comprehensive evaluation of the phytochemical composition of the ethanol extracts of five different Artemisia L. species (collected from the southwest of the Russian Federation) and their antimicrobial and nematocide activity as follows: A. annua cv. Novichok., A. dracunculus cv. Smaragd, A. santonica cv. Citral, A. abrotanum cv. Euxin, and A. scoparia cv. Tavrida. The study of the ethanol extracts of the five different Artemisia L. species using the methods of gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (HPLC-MS/MS) allowed establishing their phytochemical profile. The obtained data on the of five different Artemisia L. species ethanol extracts' phytochemical composition were used to predict the antibacterial and antifungal activity against phytopathogenic microorganisms and nematocidal activity against the free-living soil nematode Caenorhabditis elegans. The major compounds found in the composition of the Artemisia L. ethanol extracts were monoterpenes, sesquiterpenes, flavonoids, flavonoid glycosides, coumarins, and phenolic acids. The antibacterial and antifungal activity of the extracts began to manifest at a concentration of 150 µg/mL. The A. dracunculus cv. Smaragd extract had a selective effect against Gram-positive R. iranicus and B. subtilis bacteria, whereas the A. scoparia cv. Tavrida extract had a selective effect against Gram-negative A. tumefaciens and X. arboricola bacteria and A. solani, R. solani and F. graminearum fungi. The A. annua cv. Novichok, A. dracunculus cv. Smaragd, and A. santonica cv. Citral extracts in the concentration range of 31.3-1000 µg/mL caused the death of nematodes. It was established that A. annua cv. Novichok affects the UNC-63 protein, the molecular target of which is the nicotine receptor of the N-subtype.

Effect of Foliar Sodium Selenate and Nano Selenium Supply on Biochemical Characteristics, Essential Oil Accumulation and Mineral Composition of Artemisia annua L.

Selenium (Se) biofortification of aromatic plants is a promising strategy to produce valuable functional food with high biological activity and enhanced essential oil yield. The experiment carried out in 2021 and 2022 on A. annua treated with sodium selenate or nano-Se sprayed on foliar apparatus demonstrated a significant increase in photosynthetic pigments, pectin, waxes, macro- and microelements and a decrease in malonic dialdehyde (MDA) accumulation. Contrary to literature reports, neither selenate nor nano-Se showed a beneficial effect on essential oil accumulation; the oil yield did not differ between the selenate treated and control plants but was halved by the nano-Se application. Extremely high variations in the number of essential oil components, as well as in the eucalyptol, artemisia ketone, camphor and germacrene D ratio in the 2021 and 2022 experiments were recorded. The analysis of the 2016-2022 data for oil yield and composition in the control plants revealed a direct correlation between the number of components and of solar flares, and a negative correlation between oil yield and the percentage of spotless days. Both control plants and plants fortified with selenium showed higher levels of germacrene D and lower levels of artemisia ketone in 2022, characterized by more remarkable solar activity compared to 2021. Nano-Se supply resulted in the highest percentage of germacrene D accumulation. The results of the present research highlight the importance of the solar activity effect on the essential oil yield and quality of aromatic plants.

Evaluation of Factors Affecting Tree and Shrub Bark's Antioxidant Status.

The importance of using the barks of trees and shrubs as powerful natural antioxidants suggests the necessity to evaluate the effect of different environmental factors on bark extracts' quality. The determination of total antioxidant activity (AOA) and polyphenol content (TP) in the bark of 58 tree and shrub species from 7 regions differing in mean annual temperature, insolation, humidity, salinity level, and altitude was performed. The above stress factors positively affected bark AOA but did not have a statistically significant effect on TP. The bark of trees grown in the seashore proximity was characterized by significantly higher AOA than samples gathered in other areas, similarly to the trees grown at high altitude. The bark antioxidant status of 18 species was described for the first time. New sources of powerful antioxidants were represented by the ornamental shrubs Cornus sanguinea and Cornus alba, which showed the highest AOA (169−171 mg GAE g−1 d.w.). Among the typical halophytes, Calligonum and Tamarix had high AOA (172 and 85 mg GAE g−1 d.w.), while in the bark of tamarisk, an Se accumulator, an Se concentration of about 900 µg kg−1 d.w. was recorded. A significant positive correlation was found between leaves and bark AOA in the Karadag Nature Reserve's deciduous trees (r = 0.898, p < 0.01). The relationship between bark AOA and TP was highly significant (r = 0.809; p < 0.001) for all samples except the mountainous ones. The results of the present research revealed new opportunities in successive bark utilization.

Yield, Essential Oil and Quality Performances of Artemisia dracunculus, Hyssopus officinalis and Lavandula angustifolia as Affected by Arbuscular Mycorrhizal Fungi under Organic Management.

Utilization of arbuscular mycorrhizal fungi (AMF) for enhancing growth and development as well as production of essential oil in aromatic plants has been increasingly drawing research interest. In order to assess the AMF effects on different aromatic species, an open-field experiment was carried out using Artemisia dracunculus (tarragon), Lavandula angustifolia (lavender) and Hyssopus officinalis (hyssop). AMF stimulated the growth of tarragon and lavender plants, whereas hyssop showed a slight developmental slowing; nonetheless, a significant increase in essential oil content in the three species was seen. AMF application increased the biomass of A. dracunculus and H. officinalis by 20-35%. No differences in antioxidant activity and phenolics content were recorded at harvest between the control and AMF-inoculated plants, but the latter showed a significant increase in antioxidant status upon storage at high temperature and humidity compared to the untreated control. The enhancement of abiotic stress resistance during storage in plants inoculated with AMF was the highest in A. dracunculus, and the lowest in H. officinalis, while the untreated control plants showed a significant decrease in phenolics, ascorbic acid and chlorophyll content, as well as antioxidant activity, upon the abiotic stress. AMF inoculation differentially affected the mineral composition, increasing the accumulation of Se, I and Zn in A. dracunculus, and decreasing the levels of heavy metals and Co, Fe, Li, Mn in H. officinalis. Based on the outcome of the present research, AMF inoculation resulted in a significant enhancement of the overall performances of A. dracunculus, L. angustifolia and H. officinalis, and also in the improvement of plant antioxidant status upon storage in stress conditions.