Vol 43, No 7 (2017)

Biologically active substances and antioxidant activity of extracts from leaves and inflorescences of nine representatives of the genus Spiraea L. growing on the territory of the Far East of Russia were investigated. Widespread species of the genus Spiraea (S. salicifolia, S. media var. media, S. betulifolia and S. ussuriensis subsp. ussuriensis) have the highest levels of biologically active substances. The inflorescences of spiraeas there contain more flavonols (up to 3.9%), oxycinnamic acids (up to 1.2%), catechins (up to 5.7%) and saponins (up to 5.1%) compared to their leaves, and there are more tannins (up to 11.6%) in the leaves. Among the Far Eastern representatives of the genus Spiraea, S. betulifolia and S. beauverdiana (section Calospira), S. humilis and S. salicifolia (section Spiraria), S. pubescens and S. media var. media (section Chamaedryon) are promising antioxidants. Plants of the genus Spiraea probably contain water-soluble antioxidant compounds of phenolic type, because the antioxidant activity of aqueous extracts in the leaves and inflorescences of spiraeas is higher (0.16–2.79 mg/g) than that of water-alcoholic compounds (0.06–2.54 mg/g). The antioxidant activity in the leaves of spiraeas is generally higher than that in the inflorescence. A reliable positive correlation is observed between the antioxidant activity of aqueous extracts from the organs of spiraeas and a content of oxycinnamic acids.

The composition of terpen lactones and flavonol glycosides of commercial preparation series based on Ginkgo biloba extracts was investigated by ¹H NMR spectroscopy. The content of individual terpen lactones was determined using DMSO-d₆ and acetone-d₆ solvents. The effect of the structure of flavonol glycosides on the signal of the hydroxyl proton at a position 5 of the ring A was examined. A new approach was proposed for semiquantitative determination of the total amount of flavonol glycosides by the integral intensity of this signal, which is a superposition of the singlets in the region of 12.5–12.65 ppm of individual flavonoids in DMSO-d₆. Since the corresponding signals of aglycones (quercetin, kaempferol, isorhamnetin), which are minor components of the Ginkgo biloba extracts, appear separately in a slightly different region (12.45–12.48 ppm), the proposed method can also be used for detecting adulteration of Ginkgo biloba extracts by means of the addition into them of relatively cheap aglycones or rutin as well as for assessment of the content of flavonoids of similar structure in some types of plant raw materials.

We characterized polysaccharide complexes from Centaurea scabiosa L. and Centaurea pseudomaculosа Dobrocz. We proposed the technique of sequential selection of water-soluble polysaccharides and pectin substances from the aerial parts of studied objects. We have discovered that the content of water-soluble polysaccharides in the aerial parts of C. scabiosa was 2.8 times higher (2.7 ± 0.3%, n = 3) than in C. pseudomaculosа (0.97 ± 0.50%, n = 3). The content of pectin substances in the aerial parts of C. scabiosa was 2 times higher (7.6 ± 0.4%, n = 3) than in C. pseudomaculosа (3.9 ± 0.3%, n = 3). The residues of D-galacturonic acid, L-rhamnose, D-xylose, D-mannose, D-glucose, and D-galactose are the monomeric units of polysaccharide complexes from C. scabiosa and C. pseudomaculosa. Using ion-exchange chromatography, three polysaccharide fractions (molecular weights 667, 722, and 1027 kDa), whose monomer units are D-galacturonic acid, L-rhamnose, D-galactose, D-xylose, and D-glucose were isolated from the water-soluble polysaccharides of C. scabiosa.

Potentilla alba L. is used as a medicinal plant that contains a variety of biologically active substances. Natural resources are not meeting the needs of the pharmaceutical industry. We obtained the first biomass of P. alba plant-regenerants using hydroponics technique with clonal micropropagation. We have conducted a comprehensive study of the chemical composition of a vegetable raw materials P. alba, obtained in the Biotechnology Department (plant-regenerants) in comparison with raw material obtained from plants grown under field conditions (intact plants). We have established the quantitative content of the structural components in the samples: cellulose in roots and rhizomes of intact plants, 15.4%, in the roots of plant-regenerants, 4.3%, in the leaves of plant-regenerants, 2.5%; lignin in roots and rhizomes of intact plants, 40.7%, in the roots of plant-regenerants, 37.0%, and in the leaves of plant-regenerants, 36.8%. We determined the content of extractives in P. alba samples, recovered by sequential treatment with hexane, 96% and 40% ethanol solution, water and 1% aqueous sodium hydroxide solution. We identified the total content of extractives in the roots and rhizomes of intact plants at 15.3%, in the roots of plants-regenerants, 11.2%, and in the leaves of plant-regenerants, 5.1%. We characterized the chemical composition of extractives by UV-spectroscopy. Phenolic substances (λ = 279.5–280.0 nm) were dominant in the composition of the extracts. We have established the authenticity of the samples by the TLC chromatography based on the presence of flavonoids and tannins. We showed the identity of the phytochemical composition of vegetable raw materials produced by micropropagation and grown hydroponically for two months.

The antioxidant activity of dihydroquercetin (DHQ) complexes with zinc, copper(II) and calcium was studied in vitro in blood plasma of healthy donors. The state of lipid peroxidation (LPO) in blood plasma was assessed by the content of malondialdehyde (MDA), diene (DC) and triene (TC) conjugates. The effect of DHQ and the complexes on the activity of the catalase enzyme in blood plasma was determined. It was found that DHQ complex with zinc ion reduces the MDA content in blood plasma by 14.9% compared with the control, which is twice as high as for DHQ (7.5%). The corresponding parameters of DHQ complexes with copper(II) and calcium ions were 11.2 and 3.7%, respectively. The effect of the complexes on the decrease in the DC and TC content in blood plasma compared with the control is comparable with the corresponding parameters for DHQ. The DHQ complex with zinc ion increases the catalase activity by 1.5% compared with DHQ. The complexes containing copper(II) and calcium ions increase the catalase activity no more than DHQ.

The consumption rate of chlorine dioxide in the reaction with the residual lignin was studied using measurements of the potential of a redox couple ClO₂/ClO₂⁻ in an aqueous suspension of lignocellulose powder material. The methodology was developed for the study of reaction kinetics of chlorine dioxide with the residual lignin using the first order reaction model with the initial lignin concentration in the reaction medium varying in the range of (1–17) × 10^–4 М at the initial chlorine dioxide concentration of 4.48 × 10^–4 М. The monochronic rate constant of the second order reaction of chlorine dioxide with the residual lignin was calculated by the dependence k_eff(I) = k_eff(II)[L]₀ under the lignin excess conditions, it was 1462 ± 108 М^–1 s^–1. Considering the initial concentrations of reagents, it was found that, with increasing the degree of lignin conversion Θ from ≈0.27 to 0.54, its reactivity in the interaction with the chlorine dioxide is reduced, and the value of k_eff(II) decreased from ≈1280 to 900 М^–1 s^–1, which according to the theory of polychronic kinetics was a manifestation of the kinetic nonequivalence of the various ensembles of macromolecules of the residual lignin. Thus, it was experimentally shown for the first time that residual lignin of lignocellulose powder material had a kinetic nonequivalence in the interaction with chlorine dioxide.

Synthesis of water-soluble copper-containing sulfates of arabinogalactan was carried out for the first time by the ion exchange method. Their composition and structure were studied by the methods of elemental and chemical analysis, X-ray spectral microanalysis, atomic force microscopy (AFM), infrared spectroscopy (FTIR), and electron paramagnetic resonance (EPR). According to the AFM data, the surface of copper-containing polymer films does not have inclusions and consists of homogeneous crystallites of a spherical and slightly elongated shape and transverse dimensions of about 100 nm. The composition of copper- containing polymers was studied by the chemical method and X-ray spectral microanalysis. The absence of nitrogen in the obtained polymer indicates the complete replacement of ammonium cations in the ammonium salt of AG sulfate with the copper cations. The IR spectrum of copper-containing AG sulfate is similar to that of the sodium salt of sulfated arabinogalactan. Superposition of two signals was observed in the EPR spectrum of copper-containing AG sulfate. One of them belongs to isolated Cu²⁺ ions; another, to associated Cu²⁺ ions in the salt-like compounds. The integral intensity of isolated Cu²⁺ ion signals (anisotropic signal) and associated ions (isotropic signal) depends on the copper content in the polymer. Water-soluble coppercontaining polymers of AG sulfates have prospects for their use in medicine.

New water-soluble derivatives of starch, pectin, and Na-CMC containing the sulfamic groups have been obtained by the reaction of sulfamic acid with dialdehyde polysaccharide derivatives. The structure and composition of the resulting compounds have been studied by IR spectroscopy, elemental (nitrogen and sulfur) analysis, and X-ray diffraction. The sulfamic derivatives of starch, pectin, and Na-CMC with a different content of the sulfamic groups have been obtained by varying the ratio of sulfamic acid to the dialdehyde polysaccharide derivatives. The optimal–СНО: NH₂SO₃H ratio was found to be 1: 2.5. The interaction rate of sulfamic acid with the dialdehyde derivatives of starch, pectin, and Na-CMC has been evaluated. The antibacterial and antifungal effects of sodium salts of the sulfamic starch, pectin, and Na-CMC derivatives against Gram-positive and Gram-negative bacteria and fungi have been studied at different concentrations (10, 25, 50 mg/mL) by the disk diffusion method. The synthesized compounds have not been found to exhibit antifungal activity against Candida albicans. Nevertheless, they have been shown to have the antibacterial activity against Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Proteus vulgaris, Streptococcus faecalis, Streptococcus pyogenes, and Streptococcus faecalis at the concentration of 50 mg/mL. The concentration dependence of antibacterial action of sodium salts of the starch, pectin, and Na-CMC sulfamic derivatives has been demonstrated. The antibacterial activity of the drugs has been found to directly depend on the content of the sulfamic groups in polysaccharides. The results on the acute toxicity of the sulfamic polysaccharide derivatives have shown that these compounds can be attributed to low-toxicity substances of Class V.

The review presents the results of scientometric analysis of data on the level of study and chemical diversity of flavonoids of the Scutellaria L. genus species of the world’s flora. Flavonoid composition in 63 species of skullcap is reported, together with the data on distribution in plants, structure, and sources of 301 flavonoids belonging to the groups of flavones, flavanones, flavanonols, flavonols, chalcones, isoflavones, flavolignans, and bioflavonoids. The greatest number of flavonoids was shown to be isolated from plants of S. indica, S. baicalensis, S. barbata, S. amoena, S. prostrata, S. galericulata, S. discolor, S. ramosissima, and S. supina. Scientometric studies indicate the constantly growing interest in the study of species of the Scutellaria L. genus by scientists of various branches of science, including phytochemists, biologists, and pharmacologists. Information provided in the review can be used to address issues of chemosystematics of plants of the Scutellaria L. genus.