Investigation of the Variability of Alkaloids in Buxus sempervirens L. Using Multivariate Data Analysis of LC/MS Profiles

Buxus sempervirens L. is a common ornamental plant in southern and central Europe, and has been used ethopharmacologically against a wide variety of diseases due to it containing nor-triterpene alkaloids of the nor-cycloartane type. Recently, we demonstrated the interesting antiprotozoal potential of some of these compounds. To characterize the temporal variability in the alkaloid profile of two different varieties and their leaves and twigs, 30 different extracts of B. sempervirens were evaluated by Ultra High Performance Liquid Chromatography/positive Mode-Electrospray Ionization Quadrupole Time-of-Flight-Tandem Mass Spectrometry (UHPLC/+ESI-QqTOF-MS/MS). The analytical profiles were thoroughly investigated by various methods of multivariate data analysis (MVDA). A principal component analysis (PCA) model elucidates the seasonal variation in the phytochemical composition of B. sempervirens var. arborescens and suffruticosa along with differences between the varieties. Analysis of a volcano plot illustrated the differences between the two organs, the leaf and twig. Eighteen compounds were highlighted by the models as constituents of the plant characteristic for a season, variety or organ. These compounds were dereplicated based on their chromatographic and +ESI-QqTOF-MS and –MS/MS data. In addition, mass spectral fragmentation pathways for already known alkaloids as well as new natural products could be postulated for the first time. In conclusion, the MVDA models give detailed information on the temporal variability in the alkaloid profile of two different varieties and their organs (leaf vs. twig) of B. sempervirens. Thus, the results of this study allow, e.g., the identification of characteristic compounds for the different varieties, plant organs, seasons, and the optimal harvesting time for the isolation of particular Buxus-alkaloids of interest for subsequent studies.

Review and analysis of technologies for harvesting perennial grain crops

In agriculture, according to the data of the statistical collection, the production of grain crops occupies a large part. At the moment, much attention is paid to the study of perennial crops such as Thinopyrum intermedium and Trititrigia cziczinii Tsvelev. These crops help to: slow down soil erosion, protect water resources, and minimize the leaching of nutrients [1,2]. The non-cereal part of the crop is a significant reserve for strengthening the fodder base of animal husbandry, expanding the range of sources of raw materials for the microbiological industry in the production of fodder proteins. The article provides an overview of technologies and equipment for harvesting grain crops, on the basis of which one of the optimal harvesting method for perennial crops is distinguished - stripping. Based on the results of the literature review, the main technologies used for harvesting grain crops were identified: direct and indirect singlephase and two-phase combine harvesting technologies; one-, two- or three-phase non-combine harvesting technologies including the “neveika” method; standing stripping technology. The purpose of this article is to review existing harvesting technologies and equipment, selection of the optimal harvesting technology for perennial crops such as Trititrigia cziczinii Tsvelev and Thinopyrum intermedium.

The influence of the timing and methods of harvesting the seed grass of the eastern goat’s rue (Galega orientales Lam.) on the yield and sowing quality of seeds

Eastern goat’s rue (Galega orientales Lam.) possesses high fodder productivity and accumulates a large amount of vegetative mass with high humidity for harvesting for seeds. This greatly complicates the harvesting of grass stand for seeds. One of the ways to solve this problem is to carry out desiccation of the grass stand. A complicating factor in choosing the optimal harvesting period is the extended flowering and ripening period of goat’s rue beans, the duration of which reaches 25-35 days. The use of the drug Reglon Super based on diquat is a highly effective agrotechnical method that allows increasing the collection of seeds by 24%. The desiccation of the herbage contributes to the production of seeds with high sowing qualities. The seeds with the best sowing qualities are found in beans with yellow, brown, brown or dark brown color of the beans. In light green beans, the seeds are fully formed, but have a high moisture content. Goat’s rue beans do not crack or crumble at the onset of the full ripeness phase. This allows the seed to be harvested when most of the beans are ripe. A comparative assessment of the timing and method of harvesting the seed herbage of the goat’s rue showed that with a ripening of 39% and the presence of 47% of light green and yellow beans, the yield losses ranged from 26 to 56%. The highest seed yield in one confidence interval of 422-453 kg / ha and 444 kg / ha was obtained, respectively, by direct threshing with preliminary desiccation of the grass stand in the ripening phase of 74-97% of beans or by separate harvesting when mowing into swaths during ripening 74 % beans.

The Dynamics of Biological Models with Optimal Harvesting

This paper aims to introduce a concept of an equilibrium point of a dynamical system which will call it almost global asymptotically stable. We also propose and analyze a prey-predator model with a suggested function growth in prey species. Firstly the existence and local stability of all its equilibria are studied. After that the model is extended to an optimal control problem to obtain an optimal harvesting strategy. The discrete time version of Pontryagin's maximum principle is applied to solve the optimality problem. The characterization of the optimal harvesting variable and the adjoint variables are derived. Finally these theoretical results are demonstrated with numerical simulations.

Vaccinium vitis-idaea L. Fruits: Chromatographic Analysis of Seasonal and Geographical Variation in Bioactive Compounds

Vaccinium vitis-idaea L. (lingonberry) fruits are promising sources of bioactive components with high potential in biomedical applications. Selection in plant breeding, determination of perspective wild clones with optimal growing conditions, and appropriate harvesting time leading to standardized extracts are key factors for achieving phytochemical quality to meet consumer’s needs. In the present study, lingonberry fruits collected along different phenological stages and from different geographical locations were analyzed for the composition of 56 constituents using validated chromatographic techniques. Early stages of lingonberries vegetation were determined as the best stages for obtaining high levels of most phenolics and triterpenoids, while the end of berry vegetation could be chosen as the optimal harvesting time in terms of anthocyanins. Furthermore, intensified continuous biosynthesis of triterpenoids and phenolic acids precursors after vegetation season in the winter sample was observed. Chemodiversity of lingonberries was affected by geographical factors as well as climatic and edaphic conditions, indicating different favorable growing conditions for the accumulation of particular compounds. Present findings could serve for breeders to obtain the highest yields of desirable lingonberry constituents, relevant in food and pharmaceutical industries.