Effect of Lactobacillus Fermentation on the Anti-Inflammatory Potential of Turmeric

Curcumin, the major bioactive constituent of turmeric, has been reported to have a wide range of pharmacological benefits; however, the low solubility in water has restricted its systemic bioavailability and therapeutic potential. Therefore, in the current study, we aimed to investigate the effect of turmeric fermentation on its curcumin content and anti-inflammatory activity by using several lactic acid bacteria. Fermentation with Lactobacillus fermentum significantly increased the curcumin content by 9.76% while showing no cytotoxicity in RAW 246.7 cells, as compared to the unfermented turmeric, regardless of the concentration of L. fermentum-fermented turmeric. The L. fermentum-fermented turmeric also promoted cells survival; a significantly higher number of viable cells in lipopolysaccharide (LPS)-induced RAW 264.7 cells were observed as compared to those treated with unfermented turmeric. It also displayed promising DPPH scavenging activity (7.88 ± 3.36%) and anti-inflammatory activity by significantly reducing the nitrite level and suppressing the expression of the pro-apoptotic tumor necrosis factor-alpha (TNF-α) and Toll-like receptor-4 (TLR4) in LPS-induced RAW 264.7 cells. Western blot analysis further revealed that the anti-inflammatory activity of the fermented turmeric was exerted through suppression of the c-Jun N-terminal kinase (JNK) signal pathway, but not in unfermented turmeric. Taken together, the results suggested that fermentation with lactic acid bacteria increases the curcumin content of turmeric without increasing its cytotoxicity, while strengthening the specific pharmacological activity, thus, highlighting its potential application as a functional food ingredient.