Biosynthesis of novel daidzein derivatives using Bacillus amyloliquefaciens whole cells

Changes in Isoflavone Profile from Soybean Seeds during Cheonggukjang Fermentation Based on High-Resolution UPLC-DAD-QToF/MS: New Succinylated and Phosphorylated Conjugates

In this study, thirty-eight isoflavone derivatives were comprehensively identified and quantified from the raw, steamed and fermented seeds of four selected soybean cultivars based on UPLC-DAD-QToF/MS results with reference to the previously reported LC-MS library and flavonoid database, and summarized by acylated group including glucosides (Glu), malonyl-glucosides (Mal-Glu), acetyl-glucosides (Ac-Glu), succinyl-glucosides (Suc-Glu) and phosphorylated conjugates (Phos) in addition to aglycones. Among them, Suc-Glu and Phos derivatives were newly generated due to fermentation by B. subtilis AFY-2 (cheonggukjang). In particular, Phos were characterized for the first time in fermented soy products using Bacillus species. From a proposed roadmap on isoflavone-based biotransformation, predominant Mal-Glu (77.5-84.2%, raw) decreased rapidly by decarboxylation and deesterification into Ac-Glu and Glu (3.5-8.1% and 50.0-72.2%) during steaming, respectively. As fermentation continued, the increased Glu were mainly succinylated and phosphorylated as well as gradually hydrolyzed into their corresponding aglycones. Thus, Suc-Glu and Phos (17.3-22.4% and 1.5-5.4%, 36 h) determined depending on cultivar type and incubation time, and can be considered as important biomarkers generated during cheonggukjang fermentation. Additionally, the changes of isoflavone profile can be used as a fundamental report in applied microbial science as well as bioavailability research from fermented soy foods.

Prunetin 4'-O-Phosphate, a Novel Compound, in RAW 264.7 Macrophages Exerts Anti-Inflammatory Activity via Suppression of MAP Kinases and the NFκB Pathway

Biorenovation, a microbial enzyme-assisted degradation process of precursor compounds, is an effective approach to unraveling the potential bioactive properties of the derived compounds. In this study, we obtained a new compound, prunetin 4′-O-phosphate (P4P), through the biorenovation of prunetin (PRN), and investigated its anti-inflammatory effects in lipopolysaccharide (LPS)-treated RAW 264.7 macrophage cells. The anti-inflammatory effect of P4P was evaluated by measuring the production of prostaglandin-E₂ (PGE₂), nitric oxide (NO), which is an inflammation-inducing factor, and related cytokines such as tumor necrosis factor-α (TNFα), interleukin-1β (IL1β), and interleukin-6 (IL6). The findings demonstrated that P4P was non-toxic to cells, and its inhibition of the secretion of NO—as well as pro-inflammatory cytokines—was concentration-dependent. A simultaneous reduction in the protein expression level of pro-inflammatory proteins such as cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) was observed. Moreover, the phosphorylation of mitogen-activated protein kinases (MAPKs) such as extracellular signal-regulated kinases (ERKs), c-Jun N-terminal kinase (JNK), p38 MAPK (p38), and nuclear factor kappa B (NFκB) was downregulated. To conclude, we report that biorenovation-based phosphorylation of PRN improved its anti-inflammatory activity. Cell-based in vitro assays further confirmed that P4P could be applied in the development of anti-inflammatory therapeutics.

Recent Advances in Heterologous Synthesis Paving Way for Future Green-Modular Bioindustries: A Review With Special Reference to Isoflavonoids

Isoflavonoids are well-known plant secondary metabolites that have gained importance in recent time due to their multiple nutraceutical and pharmaceutical applications. In plants, isoflavonoids play a role in plant defense and can confer the host plant a competitive advantage to survive and flourish under environmental challenges. In animals, isoflavonoids have been found to interact with multiple signaling pathways and have demonstrated estrogenic, antioxidant and anti-oncologic activities in vivo. The activity of isoflavonoids in the estrogen pathways is such that the class has also been collectively called phytoestrogens. Over 2,400 isoflavonoids, predominantly from legumes, have been identified so far. The biosynthetic pathways of several key isoflavonoids have been established, and the genes and regulatory components involved in the biosynthesis have been characterized. The biosynthesis and accumulation of isoflavonoids in plants are regulated by multiple complex environmental and genetic factors and interactions. Due to this complexity of secondary metabolism regulation, the export and engineering of isoflavonoid biosynthetic pathways into non-endogenous plants are difficult, and instead, the microorganisms Saccharomyces cerevisiae and Escherichia coli have been adapted and engineered for heterologous isoflavonoid synthesis. However, the current ex-planta production approaches have been limited due to slow enzyme kinetics and traditionally laborious genetic engineering methods and require further optimization and development to address the required titers, reaction rates and yield for commercial application. With recent progress in metabolic engineering and the availability of advanced synthetic biology tools, it is envisaged that highly efficient heterologous hosts will soon be engineered to fulfill the growing market demand.

Anti-Inflammatory Effects of Formononetin 7-O-phosphate, a Novel Biorenovation Product, on LPS-Stimulated RAW 264.7 Macrophage Cells

Biorenovation is a microbial enzyme-catalyzed structural modification of organic compounds with the potential benefits of reduced toxicity and improved biological properties relative to their precursor compounds. In this study, we synthesized a novel compound verified as formononetin 7-O-phosphate (FMP) from formononetin (FM) using microbial biotransformation. We further compared the anti-inflammatory properties of FMP to FM in lipopolysaccharide (LPS)-treated RAW264.7 macrophage cells. We observed that cell viabilities and inhibitory effects on LPS-induced nitric oxide (NO) production were greater in FMP-treated RAW 264.7 cells than in their FM-treated counterparts. In addition, FMP treatment suppressed the production of proinflammatory cytokines such as prostaglandin-E₂ (PGE₂), interleukin-6 (IL-6), and interleukin-1β (IL-1β) in a dose-dependent manner and concomitantly decreased the mRNA expression of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2). We also found that FMP exerted its anti-inflammatory effects through the downregulation of the extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and nuclear factor kappa B (NF-κB) signaling pathways. In conclusion, we generated a novel anti-inflammatory compound using biorenovation and demonstrated its efficacy in cell-based in vitro assays.

Biotransformation of Naringenin by Bacillus amyloliquefaciens Into Three Naringenin Derivatives

In this study, a whole-cell biotransformation by Bacillus amyloliquefaciens Korean Collection for Type Culture 13588 was carried out to acquire naringenin derivatives. High-performance liquid chromatography analysis of the reaction metabolites showed the presence of 3 different products. The structure of the metabolites was confirmed through high-resolution quadrupole-time-of-flight electrospray-ionization mass spectrometry and nuclear magnetic resonance analysis. The result revealed that B. amyloliquefaciens catalyzes naringenin into 3 derivatives, naringenin 7- O-phosphate, naringenin 7- O-glucoside (prunin), and 6''- O-succinylprunin. To our knowledge, this is the first report of the production of 3 different derivatives when naringenin was used as a substrate. Furthermore, our study also revealed that the product naringenin 7- O-phosphate has approximately 45-fold higher water solubility than that of naringenin. Our finding suggests that biotransformation might solve the low bioavailability of flavonoids.

'Structural constraints in cyanobacteria-mediated whole-cell biotransformation of methoxylated and methylated derivatives of 2'-hydroxychalcone

Halophilic and freshwater strains of cyanobacteria representing the Oscillatoriales, Nostocales, Chroococcales, and Synechococcales orders of Cyanophyta were examined to determine (i) the resistance of their cultures when suppressed by the presence of exogenous methoxylated and methylated derivatives of 2'-hydroxychalcone, (ii) morphological changes in cells treated with the tested chalcones and, most importantly, (iii) whether these photoautotrophic microorganisms transform chalcone derivatives in a structure- or strain-dependent manner. The growth of cyanobacterial cultures depended on chalcone derivatives and the strain; nevertheless, trends for correlations between these parameters are difficult to determine. The exposure of cyanobacteria to the tested chalcones revealed severe membrane damage that was consistent with the disruption of membrane integrity. All examined blue-green algae transformed methoxy derivatives of 2'-hydroxychalcone via hydrogenative bio-reduction and formed the corresponding hydroxydihydro derivatives with various efficiencies (≤1 - 70%), depending more on the structure than on the strain. We observed dependency of the routes and efficiency of biohydrogenation of tested chalcones on the location of the methoxyl substituent and, to a lesser extent, on cyanobacterial strains. 2'-hydroxy-4″-methylchalcone was also converted by cyanobacteria to various products, amongst which the most interesting were 2'-ethoxy derivatives. The final products of biocatalytic transformation were extracted from the cyanobacterial media, separated by high performance thin-layer chromatography (HPTLC) and identified by a combination of liquid chromatography-tandem mass spectrometry (LC-MS/MS technique) and one-dimensional (1D ¹H and ¹³C) and two-dimensional (2D HSQC and COSY) nuclear magnetic resonance (NMR) spectroscopy.