Phytochemical Profiles and In Vitro Immunomodulatory Activities of Extracts Obtained from Limonium gmelinii Using Different Extraction Methods.

Limonium (L.) gmelinii is a valuable pharmacopoeial Kazakhstani plant. Several studies have reported on the various biological activities of the plant. The purpose of our research was to study and compare the extraction yields, immunomodulatory activities, and chemical compositions of extracts from the above-ground parts of L. gmelinii obtained via conventional extraction (CE; Extract 1) and ultrasound-assisted extraction (UAE; Extract 2). The extracts were characterized by a considerable number of polyphenols and flavonoids: 378.1 ± 4.5 and 382.2 ± 3.3 GAE mg/g, and 90.22 ± 2.8 and 94.61 ± 1.9 QE mg/g in Extract 1 and Extract 2, respectively. Extract 2 had a slightly higher extraction yield (33.5 ± 2.4%) than Extract 1 (30.2 ± 1.6%). Liquid Chromatography-Diode-Array Detection-Electrospray Ionization-Quadrupole Time-of-Flight Mass Spectrometry (LC-QToF-MS) revealed the presence of 54 biologically active compounds in both extracts. It was shown that the studied extracts stimulate the secretion of TNF-α and IL-6 by intact mouse peritoneal macrophages and splenic lymphocytes, whilst they have an inhibitory effect on the secretion of these cytokines by activated immune cells. Both extracts demonstrated similar patterns of stimulation and inhibition in a splenocyte proliferation assay. Altogether, the L. gmelinii extracts obtained via CE and UAE might be suggested as effective immunomodulatory agents. The application of UAE for this purpose seems to be more efficient with a view of obtaining of a highly potent extract in a much shorter time.

Plant Extract of Limonium gmelinii Attenuates Oxidative Responses in Neurons, Astrocytes, and Cerebral Endothelial Cells In Vitro and Improves Motor Functions of Rats after Middle Cerebral Artery Occlusion.

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.