Anti-inflammatory Effects of a Crude Hydroethanolic Sideritis cilicica Extract on LPS-Induced Gene Expression in RAW 264.7 Macrophages

Background Medicinal plants belonging to the genus Sideritis are widely consumed as herbal teas in Türkiye and the Mediterranean region [1]. Although several Sideritis species have been associated with antioxidant [2], antimicrobial [3], and anti-inflammatory properties [4], the transcript-level effects of endemic Turkish Sideritis extracts on macrophage inflammatory activation remain insufficiently characterised. This study investigated whether a crude hydroethanolic extract prepared from an endemic Turkish Sideritis species could attenuate LPS-induced pro-inflammatory gene expression in macrophages. Methods Aerial parts of Sideritis cilicica were extracted using 70% ethanol by simple maceration [5]. RAW 264.7 macrophages were treated with non-cytotoxic concentrations of the extract, followed by LPS stimulation [6]. Cell viability was assessed using MTT assay [7]. Transcript levels of pro-inflammatory markers, including Il6 [8], Tnf [9], Cox2 [10], and Nos2 [11], were examined by conventional reverse transcription PCR [12]and visualised using agarose gel electrophoresis [13]. Band intensities were quantified by densitometric analysis and normalised to Actb [14]. Results Densitometric analysis showed that LPS markedly increased Il6, Tnf, Cox2, and Nos2 expression compared with untreated control cells [15]. Pre-treatment with 50 and 100 µg/mL Sideritis cilicica extract reduced the LPS-induced transcript levels, with the stronger effect observed at 100 µg/mL. The extract did not show significant cytotoxicity at the concentrations selected for gene-expression analysis. Conclusion These findings suggest that the endemic Turkish Sideritis extract suppresses early macrophage inflammatory activation at the transcript level. The study provides a simple molecular basis for the traditional anti-inflammatory use of Sideritis species and supports further phytochemical and mechanistic investigation.