Genome-enabled discovery of anthraquinone biosynthesis in Senna tora.

Senna tora is a widely used medicinal plant. Its health benefits have been attributed to the large quantity of anthraquinones, but how they are made in plants remains a mystery. To identify the genes responsible for plant anthraquinone biosynthesis, we reveal the genome sequence of S. tora at the chromosome level with 526 Mb (96%) assembled into 13 chromosomes. Comparison among related plant species shows that a chalcone synthase-like (CHS-L) gene family has lineage-specifically and rapidly expanded in S. tora. Combining genomics, transcriptomics, metabolomics, and biochemistry, we identify a CHS-L gene contributing to the biosynthesis of anthraquinones. The S. tora reference genome will accelerate the discovery of biologically active anthraquinone biosynthesis pathways in medicinal plants.

Quercetin 3-O-xyloside ameliorates acute pancreatitis in vitro via the reduction of ER stress and enhancement of apoptosis.

BACKGROUND AND PURPOSE: Glycosylation of phenolic compounds has been reported to increase water-solubility, reduce toxicity, and sometimes give improved or novel pharmacological activities. Present study was aimed to evaluate and compare the beneficial effects of quercetin aglycone (Quer) and its glycosylated derivative, quercetin 3-O-xyloside (Quer-Xyl), against acute pancreatitis (AP). METHODS: The cellular acute pancreatitis model was established by treating the rat pancreatic acinar cells (AR42J) with lipopolysaccharide (10 µg/ml) and cerulein (10-7 M). The cytotoxicity of Quer or Quer-Xyl on AR42J cells was assessed by MTT assay. Calcium and ROS levels were fluorometrically determined. The ER stress levels (PERK, GRP78), expression levels of amylase and lipase, and apoptotic markers (caspase-3 and -9) were measured by RT-PCR, western blotting, or fluorometric assay. RESULTS: While Quer increased the mRNA expressions of AP marker enzymes, amylase and lipase, Quer-Xyl dose-dependently reversed their expressions. Quer-Xyl suppressed intracellular ROS production and both mRNA and protein levels of GRP78 and PERK, which were significantly elevated in cerulein and LPS-treated AR42J cells. Further, RT-PCR and fluorescence assay revealed that Quer-Xyl dose-dependently augmented the mRNA expressions and activities of caspase-3 and -9. CONCLUSION: These results showed that Quer-Xyl, but not Quer, has a significant anti-pancreatitis activity through attenuating intracellular ROS production and ER stress response and enhancing apoptotic cell death, suggesting that it might be useful as a potent functional ingredient in health-beneficial foods or as a therapeutic agent to prevent or treat AP.

Sparassis crispa exerts anti-inflammatory activity via suppression of TLR-mediated NF-κB and MAPK signaling pathways in LPS-induced RAW264.7 macrophage cells.

ETHNOPHARMACOLOGY RELEVANCE: Sparassis crispa, also known as cauliflower mushroom, has been used historically in traditional Asian medicine. It possesses various biological activities, such as immunopotentiation, anti-diabetes, anti-cancer, and anti-inflammatory effects. Recently, we isolated the non-aqueous fraction from methanol extract of S. crispa (SCF4) by using water-organic solvent mixtures and high-performance liquid chromatography (HPLC). In the present study, we identified the anti-inflammatory activity and action mechanism of SCF4 in lipopolysaccharide (LPS)-stimulated RAW264.7 murine macrophage cells. MATERIALS AND METHODS: The chloroform layer isolated from S. crispa methanol extract was separated into seven fractions using preparative HPLC. The fractions were then applied to NO assay to identify the fraction with the best anti-inflammatory activity. The inflammation inhibitory effect and underlying mechanism of SCF4 in LPS-stimulated RAW264.7 cells were assessed using WST-1 assay, enzyme-linked immunosorbent assay (ELISA), ROS assay, and Western blot analysis. RESULTS: SCF4 significantly suppressed LPS-induced production of pro-inflammatory mediators, such as nitric oxide (NO) and prostaglandin E2 (PGE2), and pro-inflammatory cytokines, including tumor necrosis factor (TNF)-α, interleukin (IL)- 6, and IL-1ß, without cytotoxicity. In addition, SCF4 downregulated not only the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), but also the activation of nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinases (MAPKs) stimulated by LPS. SCF4 also blocked the nuclear translocation of NF-κB via reduction of inhibitor of κB alpha (IκBα) degradation. Furthermore, SCF4 inhibited the phosphorylation of transforming growth factor beta-activated kinase 1 (TAK1), an important upstream factor of NF-κB and MAPK signaling mediated through toll-like receptor (TLR). CONCLUSIONS: These findings demonstrate for the first time the correlation between the anti-inflammatory activity of SCF4 and TLR-mediated NF-κB and MAPK signaling pathways in LPS-stimulated RAW264.7 macrophage cells, suggesting that the non-aqueous extract of S. crispa could be applied as a promising natural product for the prevention and treatment of inflammatory diseases.

Apigenin Inhibits Cancer Stem Cell-Like Phenotypes in Human Glioblastoma Cells via Suppression of c-Met Signaling.

Glioblastoma (GBM) is a highly malignant human brain tumor with limited treatment choices. The extremely aggressive characteristics of GBM result from GBM stem cells (GSCs), a subpopulation in tumor having self-renewal potential and resistance to chemotherapy and radiotherapy. Therefore, eliminating GSCs is an effective strategy to treat this fatal disease. In this study, we investigated the therapeutic effects of dietary flavonoids, including apigenin, quercetin, and naringenin, against cancer stem cell-like phenotypes of human GBM cell lines U87MG and U373MG. Among flavonoids studied, apigenin and quercetin significantly suppressed not only the self-renewal capacity such as cell growth and clonogenicity, but also the invasiveness of GBM stem-like cells. Notably, apigenin blocked the phosphorylation of c-Met and its downstream effectors, transducer and activator of transcription 3, AKT (Protein kinase B), and mitogen-activated protein kinase in the GSCs, thereby reducing the expression levels of GSC markers such as CD133, Nanog, and Sox2. These results suggest that the GSC inhibition effect of apigenin may be caused by downregulation of c-Met signaling pathway.

Enzymatic synthesis of novel isobavachalcone glucosides via a UDP-glycosyltransferase.

Glycosylation is often used to improve a natural product's properties such as water solubility, chemical stability, pharmacological potency, and structure diversification. In this study, we studied the enzymatic synthesis of novel isobavachalcone glucosides using a UDP-glycosyltransferase (YjiC) from Bacillus licheniformis DSM-13. The chemical structures of compounds 1 and 2 were elucidated by spectroscopic techniques, including LC-MS, MS, and NMR. Meanwhile, the parameters of glycosylation reaction such as incubation time, UDP-glucose concentration, and pH of buffer were also optimized during this study. Furthermore, the compounds 1 and 2 exhibited weak anti-proliferative activities against five human cancer cell lines, with IC50 values ranging from 58.6 to 86.6 µM.

Glycosylation and subsequent malonylation of isoflavonoids in E. coli: strain development, production and insights into future metabolic perspectives.

Genistin and daidzein exhibit a protective effect on DNA damage and inhibit cell proliferation. Glycosylation and malonylation of the compounds increase water solubility and stability. Constructed pET15b-GmIF7GT and pET28a-GmIF7MAT were used for the transformation of Escherichia coli and bioconversion of genistein and daidzein. To increase the availability of malonyl-CoA, a critical precursor of GmIF7MAT, genes for the acyl-CoA carboxylase α and ß subunits (nfa9890 and nfa9940), biotin ligase (nfa9950), and acetyl-CoA synthetase (nfa3550) from Nocardia farcinia were also introduced. Thus, the isoflavonoids were glycosylated at position 7 by 7-O-glycosyltranferase and were further malonylated at position 6(″) of glucose by malonyl-CoA: isoflavone 7-O-glucoside-6(″)-O-malonyltransferase both from Glycine max. Engineered E. coli produced 175.7 µM (75.90 mg/L) of genistin and 14.2 µM (7.37 mg/L) genistin 6''-O-malonate. Similar conditions produced 162.2 µM (67.65 mg/L) daidzin and 12.4 µM (6.23 mg/L) daidzin 6''-O-malonate when 200 µM of each substrate was supplemented in the culture. Based on our findings, we speculate that isoflavonoids and their glycosides may prove useful as anticancer drugs with added advantage of increased solubility, stability and bioavailability.

A neutral lipase applicable in biodiesel production from a newly isolated Streptomyces sp. CS326.

In an attempt to isolate a biocatalyst able to catalyze biodiesel production from microbial source, Streptomyces sp. CS326 was screened from hundreds of soil isolates collected from various parts of Korea. In 16S rRNA sequence analysis, the strain showed high degree of similarity with Streptomyces xanthocidicus (99.79%); therefore, it is classified as Streptomyces sp. CS326. An extracellular lipase produced by the strain (LP326) was purified using a single step gel permeation chromatography on Sepharose CL-6B. Molecular weight of LP326 was estimated to be 17,000 Da by SDS-PAGE. The activity was optimum at 40 °C and pH 7.0 and was stable at pH 5.0-8.0 and below 50 °C. It preferred p-nitrophenyl palmitate (C16), a long chain substrate; and K (m) and V (max) for the substrate were determined to be 0.24 mM and 4.6 mM/min mg, respectively. First 10 N-terminal amino acid sequences were APDLVALQSE, which are different from so far reported lipases. LP326 catalyzed biodiesel production using methanol and various oils; therefore, the enzyme can be applicable in the field of biofuel.