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.

Herein, we have reviewed the comparative analysis relating pharmacognostic and chemical approaches in the investigation of the chosen plants from Montenegrin flora known for the constituents recognized as carriers of different biological activities. In addition, some of the mentioned extensively studied plants were with uncertain status in the systematics, as not being recognized as new species. The results of pharmacognostic studies with the thorough chemical analyses addressing the problem in positioning some of the investigated plants from Swertia, Gentiana and Gentianella genera belonging to family Gentianaceae in systematics, performed within the collaboration of two research groups from Institute for Medicinal Plants Research “Dr. Josif Pančić” and Faculty of Chemistry, the University of Belgrade under the leadership of Dr. Nebojša Menković and Prof. Dr. Slobodan Milosavljević were summarized. In addition, the complete chemical structure elucidation of sesquiterpene lactones present in Anthemis sp. as potential anti-inflammatory agents, applying the sophisticated 2D NMR techniques was reviewed. Further, the parthenolide content determination in Tanacetum larvatum revealed the possibility of the successful application of 1H NMR techniques in quantification studies. The findings presented in the published literature stressed the importance of a combined chemical and pharmacognostic approach in the investigation of natural products originating from plants.

This study investigated solvent effects on the phytochemical composition of Quassia undulata leaves a medicinal plant used in treating arrays of diseases including fever and cough. The leaves were collected, washed, air-dried, pulverized and evaluated for some inherent phytochemicals using four different solvent systems based on their polarities. The solvents are methanol, acetone, ethyl acetate and chloroform. The methanol extract was found to have the highest number of secondary metabolites (saponins, tannins, flavonoids, steroids, coumarins, anthraquinones, alkaloids and phenols). None of the extracts tested positive for the presence of phlobatannins, terpenoids and emodins. The methanol extract was further analyzed quantitatively for some of the determined phytochemicals. Tannins had a concentration of 3.131 mg of catechin equivalents per 100 mg sample (mg CE/100g), alkaloids - 5.200 %, total phenolics - 11.828 mg of gallic acid equivalents per gram of extract (mg GAE/g), flavonoids - 8.074 mg of quercetin equivalents per gram of extract (mg QE/g) while 0.673 % saponins were detected. The presence of these secondary metabolites might justify the ethnomedicinal uses of Quassia undulata leaves as their bioactivity has been found to be dependent on the solvent used for extraction.