Variability of Lactic Acid Bacteria in Curcumin Metabolism and Its Biological Implications

The interaction between lactic acid bacteria (LAB) and curcumin can influence curcumin bioactivity; however, the strain-specific metabolic transformations of curcumin by LAB remain unclear. In our study, two LAB exhibiting distinct metabolic activities on curcumin were selected: Lactobacillus gasseri ATCC 33323 (LM) could metabolize curcumin, while Limosilactobacillus reuteri ATCC 23272 (LUM) could not. Liquid chromatography-mass spectrometry (LC-MS) analysis showed that LUM preserved curcumin's native form, whereas LM metabolized it completely. Time-course studies indicated that LM metabolized curcumin via hydrogenation and demethylation, producing over 70% tetrahydrocurcumin. Additionally, LUM fermentation exhibited superior anti-inflammatory effects than LM in LPS-induced RAW264.7 macrophages. Conversely, LM broth demonstrated higher antioxidant activity than LUM. These findings indicate that different LAB strains interact with curcumin in ways that significantly alter its bioactivities. This research enhances our understanding of the biological effects of curcumin under the influence of LAB strains.