Enhancing anti-inflammatory activity of noni (Morinda citrifolia L.) juice using lactic acid fermentation by Leuconostoc lactis for developing fermented noni microcapsules as a novel nutraceutical supplement

Noni is a pantropical species with fruits containing bioactive compounds that exhibit significant anti-inflammatory effects, which could be beneficial in managing chronic inflammatory conditions. This study aimed to evaluate the effects of lactic acid fermentation by Leuconostoc lactis on the physicochemical properties, bioactive compounds, and potential anti-inflammatory effect of fruit juice and subsequent freeze-dried fruit juice powder of noni grown in Vietnam. Results showed that fermentation significantly reduced total phenolic content (1650.06–568.56 mg GAE/L) and flavonoid content (1016.06–210.96 mg QE/L) along with antioxidant activity (1035.24–1774.14 to 358.78–959.72 mg TE/L) of noni juice. Despite these reductions, fermented noni juice (FNJ) demonstrated enhanced anti-inflammatory properties, particularly in suppressing pro-inflammatory cytokines IL-6 (30.65–35.48 % reduction) and NO (29.67–31.00 % reduction). Interestingly, freeze-dried fermented noni powder (FNP) exhibited higher antioxidant activity than non-fermented samples, with DPPH, ABTS, and FRAP values higher by 6.4 %, 4.1 %, and 16.4 %, respectively. In vitro digestion studies revealed improved bioavailability of phenolics in FNP, with 10.55 % release in the intestinal phase compared to 7.96 % for non-fermented noni powder (NFNP). These results suggest that lactic acid bacteria fermentation can modulate bioactive compound profiles and potentially enhance the functional properties of noni-based products. It is worth noting that the freeze-drying resulted in the total loss of anti-inflammatory properties in unfermented noni extract powder, whereas fermentation partially retained the anti-inflammatory compounds, allowing fermented powder to maintain its anti-inflammatory effects. This study demonstrates that lactic acid fermentation significantly enhances the anti-inflammatory properties of noni extract, making it a promising candidate for functional supplement applications.