Immunomodulatory effects of crude acetone and water leaf extracts from <i>Tulbaghia violacea</i> on RAW264.7 cells stimulated with lipopolysaccharide (LPS)

Introduction: Tulbaghia violacea is a medicinal plant used in traditional healing practices in South Africa. This study sought to investigate if water and acetone extracts from T. violacea impact immunomodulation by influencing the production of cytokines and nitric oxide (NO) in macrophages stimulated by lipopolysaccharide (LPS). Methods: The 3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide (MTT) assay was performed to examine the toxicity of acetone and aqueous extracts from T. violacea on RAW264.7 cells treated with LPS over 24 hours. The effect of NO production in treated cells was examined using a Greiss assay, while cytokine levels were determined using a Luminex assay. Results: The viability of RAW264.7 cells remained higher than 80% after exposure to 50 µg/mL or lower concentrations of both water and acetone extracts. The acetone extract showed potent inhibitory effects on NO production at 50 µg/mL and increased pro-inflammatory cytokines, including tumor necrosis factor-alpha (TNF-α), interleukin-1a (IL-1α), and interleukin-6 (IL-6) but did not significantly affect interleukin-1beta (IL-1β). The water extract significantly increased IL-4 levels (P&lt;0.05) at 48 hours. Both extracts increased granulocyte-colony stimulating factor (GCSF), granulocyte-macrophage colony-stimulating factor (GM-CSF), interferon-gamma-induced protein 10 (IP10), macrophage inflammatory protein-1 alpha and beta (MIP-1α and MIP-1β), monocyte chemoattractant protein-1 (MCP-1), macrophage inflammatory protein-2 (MIP-2), and regulated upon activation, normal T cell expressed and secreted RANTES levels to over 10 000 pg/mL. Conclusion: Both extracts from T. violacea possess immunomodulatory activities on LPS-stimulated RAW264.7 cells. Further studies should determine their toxicities and suitability as alternatives to synthetic counterparts.