Gynura procumbens ethanol extract and its fractions inhibit macrophage derived foam cell formation

ETHNOPHARMACOLOGY RELEVANCE: Gynura procumbens (Lour.) Merr. displayed cardio-protective effect that may prevent atherogenesis. The primary underlying pathological process of cardiovascular disease is atherosclerosis. Atherosclerotic lesion composed of macrophages, T cells and other immune cells which incorporated with cholesterol that infiltrates from the blood.

AIM OF THE STUDY: The present study was performed to determine underlying mechanism of G. procumbens ethanol extract and its fractions such as aqueous, chloroform, ethyl acetate and hexane affect macrophage derived foam cell formation.

MATERIALS AND METHODS: Lipid droplets accumulation in treated macrophages were visualized by Oil Red O staining while the total cholesterol present in the treated macrophages were measured using Cholestryl Ester quantification assay kit. Enzyme-Linked Immunosorbent Assay (ELISA) were used to detect TNF-α and IL-1β secretion in the supernatant of treated macrophages. Gene expression of Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) and ATP-binding cassette transporter A-1 (ABCA-1) in treated macrophages were analyzed using Real-Time Quantitative Polymerase Chain Reaction (RT-qPCR).

RESULTS: G. procumbens ethanol extract and its fractions reduced lipid droplet accumulation and total cholesterol in oxLDL-treated macrophages together with significantly reduction of TNF-α and IL-1β secretions in supernatant oxLDL-treated macrophages. LOX-1 gene expression was significantly reduced when G. procumbens ethanol extract and its fractions were added in oxDL-treated macrophages. In contrast, G. procumbens ethanol extract and its fractions significantly increased the expression of ABCA-1 gene in oxLDL-treated macrophages.

CONCLUSION: In conclusion, G. procumbens ethanol extract and its fractions inhibit the formation of macrophage derived foam cell by reducing TNF-α and IL-1β expression, which usually highly expressed in atherosclerotic plaques, suppressing scavenger receptor LOX-1 gene that binds oxLDL but induced ABCA-1 gene that mediate lipid efflux from macrophages.