There are numerous publications demonstrating that plant polyphenols can reduce oxidative stress and inflammatory processes in the brain. In the present study we have investigated the neuroprotective effect of plant extract isolated from the roots of L. gmelinii since it contains a rich source of polyphenols and other biologically active compounds. We have applied an oxidative and inflammatory model induced by NMDA, H₂O₂, and TNF-α in human primary neurons and astrocytes, and mouse cerebral endothelial cell (CECs) line in vitro. The levels of ROS generation, NADPH oxidase activation, P-selectin expression, and activity of ERK1/2 were evaluated by quantitative immunofluorescence analysis, confocal microscopy, and MAPK assay. In vivo, sensorimotor functions in rats with middle cerebral artery occlusion (MCAO) were assessed. In neurons NMDA induced overproduction of ROS, in astrocytes TNF-α initiated ROS generation, NADPH oxidase activation, and phosphorylation of ERK1/2. In CECs, the exposure by TNF-α induced oxidative stress and triggered the accumulation of P-selectin on the surface of the cells. In turn, pre-treatment of the cells with the extract of L. gmelinii suppressed oxidative stress in all cell types and pro-inflammatory responses in astrocytes and CECs. In vivo, the treatment with L. gmelinii extract improved motor activity in rats with MCAO.

Limonium gmelini (Willd.) Kuntze, a plant widely used in traditional medicine, has garnered increasing attention for its diverse pharmacological activities, including anti-inflammatory, hepatoprotective, antioxidant, and antimicrobial effects. This study aimed to explore the chemical composition and biological activities of polysaccharides and polyphenolic compounds extracted from both the roots and aboveground parts of Limonium gmelini. Several methods of extraction, including ultrasound-assisted extraction (UAE), conventional maceration (CM), and supercritical fluid extraction (SFE), were employed to obtain bioactive fractions. Chemical profiling, primarily represented by monosaccharides and polyphenolic compounds, was characterized and analyzed using proton nuclear magnetic resonance spectroscopy (¹H-NMR) and gas chromatography-mass spectrometry (GC-MS) techniques. While polyphenol-rich fractions exhibited significant antibacterial activity, particularly against Staphylococcus epidermidis, polysaccharide-rich aqueous fractions showed minimal antibacterial activity. Among the methods, CM and UAE yielded higher polyphenol content, whereas SFE provided more selective extractions. Notably, methanolic SPE fractions derived from the roots were especially enriched in active polyphenols such as gallic acid, myricetin, and naringenin, and they exhibited the highest antibacterial activity against Staphylococcus epidermidis. In contrast, extracts from the aboveground parts showed more moderate activity and a partially different chemical profile. These findings underscore the importance of plant part selection and support the targeted use of root-derived polyphenol-enriched fractions from L. gmelini as promising candidates for the development of natural antibacterial agents. Further investigation is needed to isolate and validate the most active constituents for potential therapeutic applications.

Limonium is a genus of plants that includes more than 300 different species worldwide, out of which in Kazakhstan, the most industrially significant and productive is Limonium (L.) gmelinii (Willd.). Major part of previous research was conducted on roots, from which four drugs were obtained, included at the National drugs register issued by the Ministry of Health Care. Underestimated aerial part might have some practical advantages, in particular large mass and less damage to the plant population along with novel biological activities. The object of the current research is plant material, harvested in Almaty region in 2018, dried, milled and assessed for its good quality in accordance with the requirements of the State Pharmacopeia. Preliminary phytochemical study revealed presence of the following groups of biologically active compounds: tannins (4.17 %), flavonoids (6.84 %), organic acids (4.07 %), and carbohydrates (3.89 %). In lipophilic fraction, tricosane was dominating (47.44 %). High content of phytol acetate (12.88 %) related to derivatives of acyclic diterpene alcohols was established. In addition, the 3,7,11,15-tetramethyl-2-hexadecan-1-ol, detected in the amount of 5.17%, was identified. After extraction with 50% ethanol in 1:5 ratio, with ultrasonic intensification of the extraction process at a frequency of 37 kHz and a temperature of 40°C, the resulting extract was dried under vacuum to completely remove the solvent. As a result, the degree of extraction was 53.55% of the weight of processed raw material, with increased amount of tannins (24.05 %), flavonoids (10.17 %), organic acids (5.84 %), and carbohydrates (4.13 %). Comparative analysis of biological activities is underway.