Metabolomic Comparison of Guava (Psidium guajava L.) Leaf Extracts Fermented by Limosilactobacillus fermentum and Lactiplantibacillus plantarum and Their Antioxidant and Antiglycation Activities.

Probiotic fermentation of plant-based materials can lead to the generation of various bioactive substances via bacterial metabolites and the biotransformation of phenolic compounds. We compared the metabolic differences between fermentation by Limosilactobacillus fermentum KCTC15072BP (LFG) and fermentation by Lactiplantibacillus plantarum KGMB00831 (LPG) in guava leaf extract (0%, 0.5%, and 2% (w/v))-supplemented medium via non-targeted metabolite profiling. By performing multivariate statistical analysis and comparing the different guava leaf extract groups, 21 guava-derived and 30 bacterial metabolites were identified. The contents of guava-derived glucogallin, gallic acid, and sugar alcohols were significantly higher in LFG than they were in LPG. Similarly, significantly higher contents of guava-derived pyrogallol, vanillic acid, naringenin, phloretin, and aromatic amino acid catabolites were obtained with LPG than with LFG. LFG led to significantly higher antioxidant activities than LPG, while LPG led to significantly higher antiglycation activity than LFG. Interestingly, the fermentation-induced increase in the guava-leaf-extract-supplemented group was significantly higher than that in the control group. Thus, the increased bioactivity induced by guava fermentation with the Lactobacillaceae strain may be influenced by the synergistic effects between microbial metabolites and plant-derived compounds. Overall, examining the metabolic changes in plant-based food fermentation by differentiating the origin of metabolites provides a better understanding of food fermentation.

α-Cyperone, isolated from the rhizomes of Cyperus rotundus, inhibits LPS-induced COX-2 expression and PGE2 production through the negative regulation of NFκB signalling in RAW 264.7 cells.

ETHNOPHARMACOLOGICAL RELEVANCE: The rhizomes of Cyperus rotundus (Cyperaceae) have been used in Asian traditional medicine for the treatment of several inflammatory diseases. However, the anti-inflammatory effects of α-cyperone, a major active compound of Cyperus rotundus, are poorly understood. MATERIALS AND METHODS: PGE2 and cytokines released from cells were measured using an EIA assay kit. The expression of iNOS, COX-2, TNF-α, and IL-6 was measured by real-time RT-PCR and/or Western blot analysis. A luciferase assay was performed to measure the effect of α-cyperone on NFκB activity. RESULTS: The n-hexane fraction of the 80% EtOH extract from the rhizomes of Cyperus rotundus was found to inhibit both NO and PGE2 production in RAW 264.7 cells. α-Cyperone isolated from the n-hexane fraction significantly inhibited PGE2 production by suppressing the LPS-induced expression of inducible COX-2 at both the mRNA and the protein levels. In contrast, α-cyperone had little effect on NO production and iNOS expression. Additionally, α-cyperone downregulated the production and mRNA expression of the inflammatory cytokine IL-6. Moreover, treatment with α-cyperone suppressed the transcriptional activity of NFκB and the nuclear translocation of the p65 NFκB subunit in LPS-induced RAW 264.7 cells. CONCLUSION: The anti-inflammatory activity of α-cyperone is associated with the down-regulation of COX-2 and IL-6 via the negative regulation of the NFκB pathway in LPS-stimulated RAW 264.7 cells.