In vitro Study of Cnidoscolus aconitifolius Leaf Extracts on Foam Cells and their Antioxidant

Background: Internalization of oxidized low-density lipoprotein (oxLDL) by macrophages results in lipid-laden foam cell transformation and pro-inflammatory cytokine releasing leading to atherosclerosis which is one of chronic inflammatory diseases. Leaf extracts from Chaya or Cnidoscolus aconitifolius (Mill.) I. M. Johnst. were reported to show a potential effect on levels of lipids and lipoproteins in in vivo. Objectives: This study was to determine the biological activities of crude ethanolic extracts from Chaya leaves on foam cell formation and inflammation. Materials and Methods: Extracts of age different leaves were screened the contents of phenolics and flavonoids, antioxidant, cytotoxicity and nitric oxide production by using macrophages (RAW264.7). The effective extract was selected to study on the formation of foam cells, protein production and TNF-α gene expression. Results: All extracts showed antioxidative activity and less cytotoxicity to the cells. A mature leaf extract (Ma-CAE) significantly reduced nitric oxide production (IC50 of 235.23 ± 21.29 μg/mL). For foam cell formation, Ma-CAE slightly reduced oxLDL-induced foam cell formation. Co-treatment of oxLDL, LPS and Ma-CAE decreased the level of TNF-α production. In addition, co-treatment of 800 μg/mL Ma-CAE and oxLDL as well as co-treatment of 800 μg/mL Ma-CAE, oxLDL and LPS, significantly decreased mRNA levels of TNF-α genes. Conclusion: These results indicated that Chaya leaf extracts could slightly decrease foam cell formation and also reduce pro-inflammatory mediators which may further decrease foam cell formation.

Key words: Cnidoscolus aconitifolius, Anti-inflammation, OxLDL, TNF-α, Foam cells.