Study of native dendroflora of Khabarovsk city

The problem of studying the dendroflora of cities is relevant when conducting modern ecological andbotanical research. The article presents the results of an inventory of native dendroflora of the city of Khabarovsk. Anannotated list of 116 species from 27 families was compiled, which exceeds the corresponding figures for the dendrofloraof Vladivostok and Birobidzhan. At the same time, the dendroflora of Komsomolsk-on-Amur, Blagoveshchensk,Petropavlovsk-Kamchatsky is much richer in terms of plant composition. Taxonomic, general, and biomorphologicalanalyzes of the flora have been carried out. The leading botanic families have been identified: Rosaceae, Salicaceae,Betulaceae, Caprifoliaceae. Large species are: Salix, Acer, Betula, Lonicera, Ulmus, Picea, Populus, Ribes, Spiraea, Rosa,Euonymus. Among woody plants, East Asian species predominate, which corresponds to the position of the city ofKhabarovsk within the Manchurian region of the East Asian floristic region. The nemoral group is the richest in species,which is typical for broad-leaved and coniferous-broad-leaved forests of the temperate zone. Analysis of life forms andrhythms of annual development show the predominance of summer-green shrubs, evergreen and summer-green trees inthe flora of the city. There is a small number of lianas, dwarf shrubs. Dwarf forms in the dendroflora of the city are rare,they are found on the territory of the Far Eastern Forestry Research Institute‘s Arboretum. There is rare and protectedspices in the flora of the city – Taxus cuspidata.

Optimization of Cellulase Production by a Novel Endophytic Fungus Penicillium oxalicum R4 Isolated from Taxus cuspidata

Endophytic fungi inside a plant can degrade a portion of plant lignin and cellulose. Endophytic Penicillium is one of the industrial microorganisms with the advantage of producing enzymes with a complete enzyme system that can be secreted into the extracellular space. The natural evolution of ancient tree species from special natural geographic environments to screen out cellulase-producing strains with excellent characteristics provides a promising direction for future industrial enzymes. The present study successfully isolated and screened a novel fungal endophyte, Penicillium oxalicum R4, with higher cellulase activity from Taxus cuspidata. Under the optimized culture conditions obtained by a Box–Behnken design (BBD) and an artificial neural network–genetic algorithm (ANN–GA), yields of Filter Paperase (FPase), Carboxymethyl Cellulase (CMCase) and β-glucosidase (βGLase) produced by P. oxalicum R4 were 1.45, 5.27 and 6.35 U/mL, which were approximately 1.60-fold, 1.59-fold and 2.16-fold higher than those of the non-optimized culture, respectively. The discovery of cellulase-producing strains of endophytic fungi located in special natural geographic environments, such as Taxus cuspidata, which is known as a living plant fossil, provides new research directions for future industrial enzymes.

Extraction, purification, and biological activities of flavonoids from branches and leaves of Taxus cuspidata S. et Z.

The optimal operational and process parameters were determined for the enzymatic hydrolysis and ultrasound-assisted extraction (EHUE) method of flavonoids extracted from Taxus cuspidata branches and leaves (TCBL), and the biological activity of obtained flavonoids was evaluated. According to single factor and central composite design experiments, the optimum key experimental parameters for EHUE were that pectinase enzyme concentration was 0.10 mg·mL-1, enzymatic hydrolysis temperature was 48 °C, and enzymolysis time was 39 min. The yield of flavonoids from TCBL under the optimized conditions was 5.23% ± 0.18%. Four purified flavonoid compounds from TCBL extract were identified as 1) (E)-1-methoxy-2-O-(p-coumaroyl)-myo-inositol, 2) catechin, 3) epicatechin, and 4) quercetin-3-O-glucoside. Among the 4 compounds, compounds 2 and 3 showed higher antioxidant capacities, α-amylase, and α-glucosidase inhibitory activities. The statistical analysis showed that epicatechin and catechin were potent antioxidants and active agents for inhibiting type II diabetes. In addition, all 4 compounds exerted clear antitumor activity against MCF-7, Hela, and HepG2 cells. Especially, compound 4 had highest antitumor capacity against MCF-7 and Hela, while compound 1 was best at suppressing the proliferation of HepG2 cells.

Investigation of bioactivities of Taxus chinensis, Taxus cuspidata, and Taxus × media by gas chromatography-mass spectrometry

Taxus species have attracted much attention for their potency in cancer treatment. However, investigating the bioactivities of Taxus species is a complex task, due to their diversity, slow growth, and endangered state. The most important Taxus species in China are Taxus chinensis (T. chinensis), Taxus cuspidata (T. cuspidata), and Taxus × media (T. media), which mainly grow in the northeastern region. This article probes deep into the differences among the leaves of T. chinensis, T. cuspidata, and T. media, with the aid of gas chromatography-mass spectrometry (GC-MS). Through GC-MS, 162 compounds were detected in the samples and found to contain 35 bioactive metabolites. On this basis, 20 metabolites with significant bioactivities (antibiotic, antioxidant, anticancer, and antiaging effects) were identified via unsupervised learning of principal component analysis and supervised learning of partial least squares-discriminant analysis. The results show that T. media has the most prominent antibiotic, antioxidant, and anticancer effects, while T. cuspidata has the most diverse and abundant metabolites that slow down aging.