Aidana Bazarkhankyzy

Background/Objectives: For the first time, water-soluble encapsulated forms of 20-hydroxyecdysone were synthesized as clathrate complexes with β-cyclodextrin. The derivatives included a ketoxime form (20-NOH), obtained by selective oximation of the C-6 carbonyl, and a triacetate form (3Ac-20E), obtained by regioselective acetylation of the C-2, C-3, and C-22 hydroxyl groups. Methods: The chemical structures of the obtained compounds were confirmed using spectroscopic methods, including ¹H and ¹³C NMR. The Z-configuration of the oxime in 20-NOH was established by the diagnostic upfield shift in the C-5 resonance (δ 36.0 ppm) relative to the parent compound (δ 51.4 ppm). Results: The antioxidant activity was evaluated using FRAP and DPPH assays. The β-cyclodextrin complexes were shown to exhibit significantly higher radical scavenging activity, with IC₅₀ values of 10 mg/mL). Conclusions: The obtained results indicate that β-cyclodextrin complexes significantly enhance the biological activity of 20E and highlight the potential of these compounds for pharmaceutical applications.

Ubaev FA, Esimova AM, Aimenova ZE, Iskakova ZB, Kolpek A, Tekebayeva ZB, Bazarkhankyzy A, Askarova N. 2026. Distribution, morphology, phytochemical composition, and antioxidant activity of Mediasia macrophylla (Apiaceae) from the Western Tien Shan, Kazakhstan. Biodiversitas 27 (3): d270315. https://doi.org/10.13057/biodiv/d270315. Mediasia macrophylla (Apiaceae) is a perennial Central Asian species with reported medicinal relevance; however, integrated ecological, morphological, and phytochemical data for populations in Kazakhstan remain limited. The present study provides a preliminary, exploratory, site-based characterization of M. macrophylla from two natural populations within the Aksu-Zhabagly State Nature Reserve (Western Tien Shan, southern Kazakhstan). Habitat conditions, quantitative morphology, essential oil composition, and antioxidant activity of solvent extracts were assessed. Field surveys confirmed that the species occurs in restricted, localized populations associated with rocky limestone slopes and meadow-steppe habitats. Quantitative morphometric analysis of mature, flowering individuals (n = 20) showed moderate variation in vegetative traits and comparatively conservative reproductive and fruit morphology, consistent with stable diagnostic morphology at the local population level. Essential oil composition was determined by GC-MS using a single pooled sample, revealing 29 compounds accounting for 95.83% of the total oil. Antioxidant activity of pooled solvent extracts was evaluated using FRAP and DPPH assays with technical replication. Phytochemical and antioxidant data were obtained from pooled material and technical replicates only and are therefore interpreted descriptively. A clear solvent-dependent pattern was observed: the ethyl acetate extract showed the highest Ferric Reducing Capacity (FRAP absorbance 1.17 at 1.0 mg/mL), whereas the ethanol extract exhibited the strongest radical scavenging activity (80.62% DPPH inhibition at 1.0 mg/mL), approaching that of gallic acid (86.14%). The chloroform extract displayed consistently weak activity. Overall, the results provide descriptive, hypothesis-generating data on the ecological context, morphology, and phytochemical and antioxidant profiles of M. macrophylla within the Aksu-Zhabagly Reserve and highlight the need for replicated, multi-site, and multi-season studies to assess population-level variability and potential chemotypic patterns.

Photodynamic therapy (PDT) is an established light-based treatment modality that relies on the activation of photosensitizers to generate reactive oxygen species (ROS) and induce localized cytotoxicity. In recent years, microalgae have emerged as a promising and sustainable source of natural photosensitizers due to their ability to biosynthesize structurally diverse pigments with strong light-harvesting capacity. This review provides a comprehensive, application-oriented analysis of microalgae-derived photosensitizers, focusing on chlorophylls and their derivatives, carotenoids, and phycobiliproteins. Particular attention is given to analytical strategies for pigment extraction, purification, and characterization, as well as to photophysical properties, subcellular localization, and ROS-mediated mechanisms underlying photodynamic activity. Recent advances in the chemical modification of algal pigments, including chlorin-based derivatives and 5-aminolevulinic acid–related systems, are critically discussed in relation to structure–activity relationships and translational performance. The accumulated evidence demonstrates that microalgae-derived pigments and their synthetic analogues can achieve efficient singlet oxygen generation, organelle-specific phototoxicity, and favorable therapeutic selectivity. Taken together, these findings highlight microalgae as a renewable and versatile platform for developing next-generation photosensitizers with broad biomedical potential in oncology, dermatology, and antimicrobial photodynamic therapy.

The object of the study was water samples, cultures of green microalgae Parachlorella kessleri U1 and Chlorella vulgaris I2, Maybalyk Lake (Astana). The aim and objectives of the study were to study the bioremediation potential of a consortium of two strains of microalgae Parachlorella kessleri U1 + Chlorella vulgaris I2 (hereinafter U1+I2) through the algolization of Lake Maibalyk according to microbiological and hydrochemical indicators. This lake is a large lake in Astana with fishery importance. The state of the reservoir is reflected in the state of the capital's air basin. A study of the water quality of Lake Maibalyk was conducted on the main morphometric, hydrochemical and hydrobiological indicators in May and June of 2020. To study the effect and determine the efficiency of using microalgae, preliminary biomass production and algolization of the U1 + I2 consortium were carried out. The introduction of a consortium of microalgae showed an improvement in the sanitary and microbiological indicators of the reservoir after just one month, due to its high antimicrobial properties and a decrease in such groups of bacteria as ammonifiers, coliforms, heterotrophic bacteria, coli group bacteria, pseudomonas, wax bacilli, staphylococcus, enterococci, enterobacteria, salmonella, fungi and yeast. After algolization for 30 days by the consortium I2+U1, an improvement was recorded not only in the organoleptic characteristics of water, but also in a number of hydrochemical parameters, including a decrease in COD, suspended solids, iron, SSAA and phosphates. . An increase in transparency, a decrease in water color and the absence of a specific odor were also noted. It was found that, although the content of BOD5, nitrates, sulfates in the original sample did not exceed the MРC values, the introduction of microalgae had a positive effect on reducing the concentration of these substances, which significantly affected the quality of the water in the reservoir. The results obtained can serve as a basis for developing environmentally friendly biotechnologies to improve water quality. In the future, it is necessary to conduct studies in triplicate, which will increase the reliability and quality of the data obtained, which will allow more effective assessment of the state of the ecosystem of the reservoir and ensure the safety of water use.

The physicochemical and adsorption properties of granular sorbents based on natural bentonite and modified sorbents based on it have been studied. It was found that modification of natural bentonite with iron (III) polyhydroxocations (mod. 1_Fe_5 GA) and aluminum (III) (mod. 1_Al_5 GA) by the “co-precipitation” method leads to a change in their chemical composition, structure, and sorption properties. It is shown that modified sorbents based on natural bentonite are finely porous (nanostructured) objects with a predominance of pores measuring 1.5–8.0 nm, with a specific surface area of 55–65 m²/g. Modification of bentonite with iron (III) and aluminum compounds by the “co-precipitation” method also leads to an increase in the sorption capacity of the obtained sorbents with respect to bichromate and arsenate anions and nickel cations by 5-10 times compared with natural bentonite. The obtained sorption isotherms were classified as Langmuir type isotherms. Kinetic analysis showed that at the initial stage the sorption process is controlled by an external diffusion factor, i.e. refers to the diffusion of sorbent from solution into a liquid film on the surface of the sorbent. Then the sorption process begins to proceed in a mixed diffusion mode, when it limits both the external diffusion factor and the internal diffusion factor (the diffusion of the sorbent to the active centers through the system of pores and capillaries). To determine the contribution of the chemical stage to the rate of adsorption of bichromate and arsenate anions and nickel(II) cations with the studied granular sorbents, kinetic curves were processed using the equations of chemical kinetics (pseudo-second-order model). As a result, it was found that the adsorption of the studied anions by modified sorbents based on natural bentonite is best described by a pseudo-second-order kinetic model. It is shown that the use of natural bentonite for the development of technology for the production of granular sorbents based on it has an undeniable advantage, firstly, in terms of its chemical and structural properties, it is easily and effectively modified, and secondly, having astringent properties, granules are easily made on its basis, which turn into ceramics during high-temperature firing. The result is a granular sorbent with high physical and mechanical properties. Since bentonite is an environmentally friendly product, the technology of recycling spent sorbents is also greatly simplified.

Microalgae in planktonic communities are the main producers of biomass in lake ecosystems; however, their stability is influenced by many environmental factors. This study aims to assess the ecological state of Lake Maybalyk, located in Astana (Kazakhstan), based on the study of the taxonomic diversity and structure of phytoplankton, zooplankton, and the physico-chemical properties of the water. From 2019 to 2021, samples were taken for phytoplankton analysis, hydrochemical analysis of the water, zooplankton, and saprobiological analysis of the algocenosis. The study also investigated the main morphometric parameters of the lake, as well as the composition of hydrobionts, such as zooplankton, zoobenthos, and ichthyofauna. The analysis of phytoplankton revealed the presence of 97 species and intraspecific taxa of microalgae, with 71 types of microalgal indicators indicating water saprobity. The planktonic algoflora in Lake Maybalyk is predominantly composed of diatoms (Bacillariophyta) and green algae (Chlorophyta), which play a vital role in oxygen production and the food chain within the reservoir. Based on the Pantle–Buck saprobity index (2.15–2.5), the water quality in Lake Maybalyk is classified as moderately polluted. The assessment of the water quality, considering the number and composition of indicator phytoplankton species, places Lake Maybalyk in class III (β-mesosaprobic). The hydrochemical indicators align with the hydrobiological indicators, confirming the water quality as class III. The trophic status of the reservoir, during the study period, can be described as average. The obtained data on both the hydrobiological and hydrochemical indicators correlate, suggesting satisfactory water quality and the ability of the reservoir to purify itself. This study contributes to the sustainable management of water resources, by providing essential data on the ecological state of Lake Maybalyk. The results underscore the importance of continuous biomonitoring, with microalgae as indicators of water quality, which is crucial for developing effective ecosystem conservation strategies.

The increasing volume of wastewater discharged in urban areas poses a significant environmental challenge, particularly due to the potential for organic carbon overload in aquatic ecosystems. This study aimed to identify bacterial isolates with the potential to mitigate this burden by effectively...

The physicochemical properties of natural bentonite and its sorbents were studied. It has been established the modification of natural bentonites using polyhydroxoxides of iron (III) (mod.1_Fe_5-c) and aluminum (III) (mod.1_Al_5-c) by the “co-precipitation” method led to changes in their chemical composition, structure, and sorption properties. It was shown that modified sorbents based on natural bentonite are finely porous (nanostructured) objects with a predominance of pores of 1.5–8.0 nm in size. The modification of bentonite with iron (III) and aluminum compounds by the “co-precipitation” method also leads to an increase in the sorption capacity of the obtained sorbents with respect to bichromate and arsenate anions. A kinetic analysis showed that, at the initial stage, the sorption process was controlled by an external diffusion factor, that is, the diffusion of the sorbent from the solution to the liquid film on the surface of the sorbent. The sorption process then began to proceed in a mixed diffusion mode when it limited both the external diffusion factor and the intra-diffusion factor (diffusion of the sorbent to the active centers through the system of pores and capillaries). To clarify the contribution of the chemical stage to the rate of adsorption of bichromate and arsenate anions by the sorbents under study, kinetic curves were processed using equations of chemical kinetics (pseudo-first-order, pseudo-second-order, and Elovich models). It was found that the adsorption of the studied anions by the modified sorbents based on natural bentonite was best described by a pseudo-second-order kinetic model. The high value of the correlation coefficient for the Elovich model (R² > 0.9) allows us to conclude that there are structural disorders in the porous system of the studied sorbents, and their surfaces can be considered heterogeneous. Considering that heterogeneous processes occur on the surface of the sorbent, it is natural that all surface properties (structure, chemical composition of the surface layer, etc.) play an important role in anion adsorption.

The biological variety of aquatic ecosystems is significantly impacted by the chemical and microbiological composition of water bodies, and there is strong reciprocal feedback between these two factors, especially for reservoirs, which can and do have a significant impact on neighboring ecosystems. Today there is an acute need to identify the most effective and economically feasible methods for cleaning and restoring water bodies. Therefore, the aim of the study was to find strains of microorganisms which are capable of biodegrading such problematic pollutants as insoluble phosphates and excess nitrogenous compounds and at the same time, are capable of suppressing the bacterial composition in reservoir waters. In the course of the research, a number of the most active strains of microorganisms were isolated from lake water samples. Five isolates were obtained from salt water and the isolates were then identified using morphological, and biochemical techniques, as well as the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). In addition to the characterization and identification of the isolates, the species-specific levels of phosphate solubilizing, and nitrifying activities were also established. Thus, all isolated strains were studied and characterized, and their influence on the content of minerals such as phosphorus and nitrogen, which are important for living organisms in water, was studied. In summary, the Pseudomonas Extrem-Orientalis isolate was observed to be highly effective in solubilizing phosphates, nitrifying, and had the greatest antagonistic capacity among the investigated isolates. The information gleaned from the study’s findings helps raise more awareness in the field of microbiology and water treatment in general. The findings offer promise for the development of biopreparations with bioremediation capabilities for cleaning polluted water bodies of pollutants from various sources.

This paper presents studies on the possibility of utilization of technogenic waste from the metallurgical industry by the method of complex processing in order to reduce the anthropogenic load on the environment of the region with the example of the zinc silicate-magnetite-carbon system. The selected sample of clinker dump from welting was subjected to chemical and scanning electron microscopic analyses and thermodynamic modeling. Thermodynamic studies were carried out in the temperature range 1600–2200 K and pressure p = 0.1 MPa, modeling the process of electric melting of clinker from welting in an arc furnace using the software application Astra 4 developed at the Bauman Moscow State Technical University (Moscow, Russian Federation). As a result of the thermodynamic modeling, the optimal temperature range was established, which was 1800–1900 K. Thermodynamic studies established that it is possible to drive away zinc from the system under study by 99–100% in the entire temperature range under study. The maximum degree of silicon extraction (α_Si) in the alloy is up to 69.44% at T = 1900 K, and the degree of iron extraction (α_Fe) in the alloy is up to 99.996%. In particular, it was determined and proved that clinker waste from welting can act as a secondary technogenic raw material when it is processed as a mono mixture to produce iron silicides with a silicon content of 18 to 28%.