The plants in the Sideritis genus are postulated to exhibit several important medicinal properties due to their unique chemical composition. To isolate the targeted phytochemical compounds, the selection of a suitable extraction method is of primary importance. In this work, a comparative study on the phytochemical profiles of various Sideritis raeseri and Sideritis scardica extracts has been carried out. An untargeted metabolomics approach based on ultra-high performance liquid chromatography coupled with high-resolution mass spectrometry was applied to investigate the metabolic differences between extracts obtained by conventional extraction and extractions assisted by microwaves, ultrasounds and high pressure. Additionally, the influence of extraction solvents on HPLC antioxidant profiles obtained following the derivatization of analytes with ABTS reagent was evaluated. A total of 102 metabolites have been putatively identified. The major secondary metabolites groups were classified as flavonoids, terpenoids, phenylethanoid glycosides and phenolic acids. The main antioxidants in the extracts were isoscutellarein and hypolaetin derivatives as well as verbascoside and chlorogenic acid. The results showed that 70% ethanol was the most effective extractant for different classes of phytochemicals including antioxidants. In addition, extraction supported with microwaves, ultrasounds or high pressure improved the overall recovery of metabolites by about 3 times compared to the conventional extraction method.

Drying is an inseparable part of industrial microalgae production. In this work, the impacts of eight different drying methods on the metabolome and lipidome of Arthrospira platensis were investigated. The studied drying methods were freeze drying (FD), sun drying (SD), air drying at 40 and 75 °C (AD′ and AD″), infrared drying at 40 and 75 °C (IRD′ and IRD″), and vacuum drying at 40 and 75 °C (VD′ and VD″). Results gathered by reversed-phase liquid chromatography separation coupled with high-resolution tandem mass spectrometry with electrospray ionization (RP-LC-ESI-Orbitrap HRMS/MS) analysis allowed researchers to identify a total of 316 metabolites (including lipids) in aqueous and ethanolic extracts. The compounds identified in ethanolic extracts were mainly lipids, such as neutral and polar lipids, chlorophylls and carotenoids, while the compounds identified in the aqueous extracts were mainly amino acids and dipeptides. Among the identified compounds, products of enzymatic and chemical degradation, such as pyropheophytins, monoacylglycerols and lysophosphatidylcholines were also identified and their amounts depended on the drying method. The results showed that except for FD method, recognized as a control, the most protective method was AD′. Contrary to this, VD′ and VD″, under the conditions used, promoted the most intense degradation of valuable metabolites.

This study focuses on the investigation of the antioxidant and anti-inflammatory activities of alcohol extracts from Ribes nigrum leaves on murine BV-2 microglial Wt and Acyl-CoA oxidase 1 deficient (Acox1−/−) cell line models, useful for the investigation of some neurodegenerative disorders. The extract chemical composition was analyzed via LC-Q-Orbitrap HRMS. Various assays, including DPPH, MTT, and H2DCFDA, were used to assess the extract’s antioxidant capacity, cell viability, and reactive oxygen species (ROS) production. Immunoblotting and RT-qPCR techniques were employed to measure protein expression and gene transcription in treated cells. Statistical analysis was conducted using GraphPad Prism, with significance determined at p < 0.05. Investigations showed the presence of phenolic compounds in this extract, among which flavan-3-ols, flavonols, furanocoumarins, hydroxycinnamates were major components, which are known for their biological activity in various test systems. The MTT test revealed a concentration of 0.125 mg/mL of R. nigrum extract as the highest non-toxic. The investigated extract showed high antioxidant activity in chemical-based tests. The antioxidant potential of the R. nigrum leaf extract was furtherly explored using the BV-2 microglial cell line models. Moreover, the extract was found to alter the activity of the main antioxidant enzyme, catalase and fatty acid oxidation enzyme, Acyl-CoA oxidase 1 (ACOX1) as well as the expression of appropriate genes in Wt and Acox1−/− BV-2 microglial cells such as Cat, iNos, Il-1β, Tnf-α, and Abcd1. In Wt cells, after the 24-hour treatment with R. nigrum leaf extract, ACOX1 activity was downregulated, meanwhile the catalase activity remains unchanged. Further treatment led to the downregulation of catalase and the upregulation of ACOX1 activity. However, in Acox1−/− cells, which represent a model of oxidative stress, an increase in catalase activity was observed only after 48 h of treatment. It was also observed the reduced ROS and NO formation in cells, showing the pronounced antioxidant capacity of R. nigrum extract in the investigated cell-models. Our study demonstrated the protective effects of R. nigrum leaf extracts on BV-2 microglial cells by reducing oxidative and nitrosative stress, decreasing pro-inflammatory gene expression, and normalizing peroxisomal function, highlighting the potential of these extracts as therapeutic agents for managing oxidative stress and inflammation.

High-performance liquid chromatography (HPLC) and high-performance thin-layer chromatography (HPTLC) coupled with radical scavenging assays, such as 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) can be both used for the detection of the antioxidants in plant extracts. In this study, the ethanolic (70% v/v) extracts from different morphological parts of Ligustrum vulgare collected at different stages of maturity were used as the source of antioxidants. The final identification of antioxidants was performed using high-resolution mass spectroscopy (HRMS). As a result, 19 compounds with antioxidant properties detected with HPLC-ABTS assay and 10 compounds detected with HPTLC-DPPH/ABTS assay were identified, mostly from the group of iridoids, phenylethanoids, and flavonoids. When comparing different L. vulgare samples, it was found that the extracts obtained from leaves contained the greatest number of antioxidants. The results of this study suggest that HPTLC-DPPH/ABTS as well as HPLC-ABTS derivatization coupled with the HRMS can be successfully used for profiling and identification of antioxidants from natural sources. Planar chromatography is more suitable for screening multiple samples because of its simplicity, whereas more challenging liquid chromatography provides more detailed information and is therefore better for a selected set of samples.

Bee bread (BB) is a natural apicultural product that exerts a broad spectrum of biological activities, including antimicrobial properties. The identification of novel antiviral agents is of considerable importance in light of the ongoing global impact of viral pathogens, particularly the...