Ambrosia artemisiifolia L. is an allergen species that belongs to the group of invasive weeds, and is very frequent and present in our region. The use of essential oils in the control of weeds attracts great attention of researchers. Many of them have already pointed out the ability of some oils and/or their individual components to delay seed germination of various weeds or completely inhibit it. In this paper, we present results of the efficacy of three essential oils on A. artemisiifolia seeds; the trials were carried out using two different in vitro methods, in which the percentage of seed germination was measured 7th day.  In testings with seeds soaked in essential oil solution, in Petri dishes (500 ml in 100 ml of distilled water), a significant inhibition of germination was observed in the case A. graveolens and S. officinalis oil (100 % and 97 % , respectively), while the oil of S. montana demonstrated slightly weaker inhibitory effect (86 %). When essential oils were applied in form of a vapour (an oil droplet of 25 ml applied on the inner side od Petri dish lids), A. graveolens and S. officinalis oils inhibited the seed germination 100 % and and 95 % , respectively , while the oil of S. montana again demonstrated the weakest inhibitory effect (52 %).

The aim of the presented research was to determine whether the application of the essential oils of A. graveolens, S. officinalis and S. montana in form of a solution or vapor, affects, and to what extent they are important for germination of seeds of the weed species A. artemisiifolia L.

Comparison between conventional and microwave-assisted hydrodistillation at different power levels has been applied for the extraction of essential oil from Zingiber officinale Rosc. rhizome. In addition to the collected essential oils, as the main products, hydrolats were also collected, as valuable by-products from both extraction techniques. A comparison of two applied techniques was done in terms of extraction time, extraction yield, the chemical composition of essential oils and hydrolats, and environmental impact. Microwave-assisted hydrodistillation achieved a higher extraction yield (1.70, 1.70, and 1.85 % for power levels of 180, 360, and 600 W, respectively) compared to hydrodistillation (1.50 %). Furthermore, distillation time related to the energy consumption has been reduced from 144 min and 1.44 kWh for conventional hydrodistillation to 37, 32, 27 min and 0.11, 0.19, 0.27 kWh for power levels of 180, 360, and 600 W, respectively. Content of α-zingiberene in essential oil and hydrolat obtained by hydrodistillation was 29.89 and 6.87 %, while content of α-zingiberene in essential oils and hydrolats obtained by microwave-assisted hydrodistillation was higher yielding the amounts of 34.12, 34.43, and 42.00 % and 18.70, 22.60, and 32.92 % for power levels of 180, 360, and 600 W, respectively. Microwave-assisted hydrodistillation has proven to be promising technique for the isolation of ginger’s essential oil regarding improved yield, reduced time and energy requirements, as well CO2 emissions while maintains oil quality.

Bear’s breech or mountain thistle (Acanthus montanus (Nees) T. Anderson) is a shrub belonging to Acanthaceae family. It is widespread in Africa, Romania, Greece, and Eastern Mediterranean. African people engage its medicinal use for the management of urethral pain, endometritis, urogenital infections, urinary disease, aches and pains. Fresh leaves of A. montanus were collected from Forestry Research Institute of Nigeria (FRIN) herbal garden and identified at the Forestry Herbarium, Ibadan. About 200 g of the powered sample was macerated in 400 mL each of three organic solvents such as ethyl acetate, acetone and methanol respectively, for 24 h. Each extracts were screened for phytochemicals such as flavonoids, saponins, phenols, terpenoids, phlobotannins, alkaloids, tannins, and cardiac glycosides. Estimation of total flavonol content, and antioxidant assays such as 2,2-diphenyl-1-picrylhydrazyl (DPPH) and nitric oxide radical scavenging activity were also carried out. The quantitative phytochemical test (flavonol content) revealed that Acanthus montanus methanol extract was the richest one among the solvent systems while acetone extract gave the best antioxidant activity. It was observed that the antioxidant activity could be attributed to moderately polar extracts. The study, therefore, provides evidence that various solvents used in extraction can result in differences in quantitative phytochemicals and antioxidant activity.