Chlorogenic Acid Potentiates the Anti-Inflammatory Activity of Curcumin in LPS-Stimulated THP-1 Cells

The anti-inflammatory effects of curcumin are well documented. However, the bioavailability of curcumin is a major barrier to its biological efficacy. Low-dose combination of complimentary bioactives appears to be an attractive strategy for limiting barriers to efficacy of bioactive compounds. In this study, the anti-inflammatory potential of curcumin in combination with chlorogenic acid (CGA), was investigated using human THP-1 macrophages stimulated with lipopolysaccharide (LPS). Curcumin alone suppressed TNF-alpha production in a dose-dependent manner with a decrease in cell viability at higher doses. Although treatment with CGA alone had no effect on TNF-alpha production, it however enhanced cell viability and co-administration with curcumin at a 1:1 ratio caused a synergistic reduction in TNF-alpha production with no impact on cell viability. Furthermore, an qRT-PCR analysis of NF-kappa B pathway components and inflammatory biomarkers indicated that CGA alone was not effective in reducing the mRNA expression of any of the tested inflammatory marker genes, except TLR-4. However, co-administration of CGA with curcumin, potentiated the anti-inflammatory effects of curcumin. Curcumin and CGA together reduced the mRNA expression of pro-inflammatory cytokines [TNF-alpha (similar to 88%) and IL-6 (similar to 99%)], and COX-2 (similar to 92%), possibly by suppression of NF-kappa B (similar to 78%), I kappa B-beta-kinase (similar to 60%) and TLR-4 receptor (similar to 72%) at the mRNA level. Overall, co-administration with CGA improved the inflammation-lowering effects of curcumin in THP-1 cells.