Synthesis of isoflavone aglycones and equol in soy milks fermented by food-related lactic acid bacteria and their effect on human intestinal Caco-2 cells.

One hundred and three strains of lactic acid bacteria, isolated from various food ecosystems, were assayed for ß-glucosidase activity toward p-nitrophenyl-ß-D-glucopyranoside substrate. Lactobacillus plantarum DPPMA24W and DPPMASL33, Lactobacillus fermentum DPPMA114, and Lactobacillus rhamnosus DPPMAAZ1 showed the highest activities and were selected as the mixed starter to ferment various soy milk preparations, which mainly differed for chemical composition, protein dispersibility index, and size dimension. The soy milk made with organically farmed soybeans (OFS) was selected as the best preparation. All selected strains grew well in OFS soy milk, reaching almost the same values of cell density (ca. 8.5 log cfu/mL). After 96 h of fermentation with the selected mixed starter, OFS soy milk contained 57.0 µM daidzein, 140.3 µM genistein, 20.4 µM glycitein, and 37.3 µM equol. Fermented and nonfermented OFS soy milks were used for the in vitro assays on intestinal human Caco-2/TC7 cells. Fermented OFS soy milk markedly inhibited the inflammatory status of Caco-2/TC7 cells as induced by treatment with interferon-γ (IFN-γ) (1000 U/mL) and lipopolysaccharide (LPS) (100 ng/mL), maintained the integrity of the tight junctions, even if subjected to negative stimulation by IFN-γ, and markedly inhibited the synthesis of IL-8, after treatment with interleukin-1ß (2 ng/mL). As shown by using chemical standards, these effects were due to the concomitant activities of isoflavone aglycones and, especially, equol, which were synthesized in the fermented OFS soy milk preparation.

Synthesis of gamma-aminobutyric acid (GABA) by Lactobacillus plantarum DSM19463: functional grape must beverage and dermatological applications.

Agriculture surplus were used as substrates to synthesize gamma-aminobutyric acid (GABA) by Lactobacillus plantarum DSM19463 for the manufacture of a functional beverage or as a novel application for dermatological purposes. Dilution of the grape must to 1 or 4% (w/v) of total carbohydrates favored higher cell yield and synthesis of GABA with respect to whey milk. Optimal conditions for synthesizing GABA in grape must were: initial pH 6.0, initial cell density of Log 7.0 cfu/mL, and addition of 18.4 mM L-glutamate. L. plantarum DSM19463 synthesized 4.83 mM of GABA during fermentation at 30 degrees C for 72 h. The fermented grape must also contain various levels of niacin, free minerals, and polyphenols, and Log 10.0 cfu/g of viable cells of L. plantarum DSM19463. Freeze dried preparation of grape must was applied to the SkinEthic(R) Reconstructed Human Epidermis or multi-layer human skin model (FT-skin tissue). The effect on transcriptional regulation of human beta-defensin-2 (HBD-2), hyaluronan synthase (HAS1), filaggrin (FGR), and involucrin genes was assayed through RT-PCR. Compared to GABA used as pure chemical compound, the up-regulation HBD-2 was similar while the effect on the expression of HAS1 and FGR genes was higher.