Efficient biosynthesis of resveratrol via combining phenylalanine and tyrosine pathways in Saccharomyces cerevisiae.

BACKGROUND: Resveratrol is a commercially available stilbenoid widely used as dietary supplements, functional food ingredients, and cosmetic ingredients due to its diverse physiological activities. The production of resveratrol in microorganisms provides an ideal source that reduces the cost of resveratrol, but the titer in Saccharomyces cerevisiae was still much lower than that in other hosts. RESULTS: To achieve enhanced production of resveratrol in S. cerevisiae, we constructed a biosynthetic pathway via combining phenylalanine and tyrosine pathways by introducing a bi-functional phenylalanine/tyrosine ammonia lyase from Rhodotorula toruloides. The combination of phenylalanine pathway with tyrosine pathway led to a 462% improvement of resveratrol production in yeast extract peptone dextrose (YPD) medium with 4% glucose, suggesting an alternative strategy for producing p-coumaric acid-derived compounds. Then the strains were further modified by integrating multi-copy biosynthetic pathway genes, improving metabolic flux to aromatic amino acids and malonyl-CoA, and deleting by-pathway genes, which resulted in 1155.0 mg/L resveratrol in shake flasks when cultured in YPD medium. Finally, a non-auxotrophic strain was tailored for resveratrol production in minimal medium without exogenous amino acid addition, and the highest resveratrol titer (4.1 g/L) ever reported was achieved in S. cerevisiae to our knowledge. CONCLUSIONS: This study demonstrates the advantage of employing a bi-functional phenylalanine/tyrosine ammonia lyase in the biosynthetic pathway of resveratrol, suggesting an effective alternative in the production of p-coumaric acid-derived compounds. Moreover, the enhanced production of resveratrol in S. cerevisiae lays a foundation for constructing cell factories for various stilbenoids.

New iridoids from Patrinia scabiosaefolia and their hypoglycemic effects by activating PI3K/Akt signaling pathway.

Growing in regions of Asia and North America, Patrinia scabiosaefolia is a wild vegetable and herb that has demonstrated health-promoting properties. Iridoids are one of the most bioactive phytochemicals in P. scabiosaefolia but the in-depth study is scarce. Herein we reported the separation and characterization of nine iridoids (compounds 1-9) from P. scabiosaefolia, and two compounds (2 and 6) were new. All the structures of the nine iridoids were characterized and confirmed with NMR (1D & 2D), HRMS, IR and UV. Compound 2 is a five-member ring iridoid, reminiscent of a broken C-1 and C-2 bond. Compound 6 has a typical monoene valerian iridoid, but the 5-deoxyglucose moiety at C-11 position is uncommon in this genus. The anti-diabetic evaluation of the isolated compounds revealed that compounds 1, 2, and 9 significantly increased the glucose absorption in 3 T3-L1 cells (P < 0.01). Further mechanism investigations have demonstrated that compound 1 promoted glucose uptake in dexamethasone-treated 3 T3-L1 adipocytes by activating PI3K/Akt signaling pathway. The expression of GLUT4 mRNA and protein was also upregulated. These results provide scientific references for the potential use of P. scabiosaefolia as a functional food to manage hyperglycemia.

Recent Progress on Chemical Constituents and Pharmacological Effects of the Genus Nigella.

Seeds of the genus Nigella plants as folk medicine are often used to prevent and treat asthma, diarrhea, dyslipidemia, and other diseases around the world. Pharmacological researches showed that seed extract and seed oil have antibacterial, antioxidant, hypoglycemic, and hepatoprotective effects which attributed to their bioactive constituents such as alkaloids, saponins, flavones, and phenols. This paper has covered recent progresses on chemical and pharmacological researches on these plants, including their compounds and pharmacological effects. It was found that the chemical component researches were focused on the seed oil. Therefore, more attention should be paid to the profile of the whole constituents in the seeds.

Antiviral activity of a polysaccharide from Radix Isatidis (Isatis indigotica Fortune) against hepatitis B virus (HBV) in vitro via activation of JAK/STAT signal pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Hepatitis B virus (HBV) infection frequently results in both acute and chronic hepatitis and poses serious threats to human health worldwide. Despite the availability of effective HBV vaccine and anti-HBV drugs, apparently inevitable side effects and resistance have limited its efficiency, thus prompt the search for new anti-HBV agents. The traditional Chinese medicine Radix Isatidis has been used for thousands of years, mainly for the treatment of viral and bacterial infection diseases including hepatitis. AIM OF THE STUDY: In this study, antiviral activities of a Radix Isatidis (Isatis indigotica Fortune) polysaccharide (RIP) were evaluated in vitro model using the HepG2.2.15 cell line and the underlying mechanism was elucidated with the aim of developing a novel anti-HBV therapeutic agent. MATERIALS AND METHODS: Structure features of the purified polysaccharide RIP were investigated by a combination of chemical and instrumental analysis. Drug cytotoxicity was assessed using the MTT assay. The contents of HBsAg, HBeAg, intracellular and extracellular IFN-α level were measured using respective commercially available ELISA kit. The HBV DNA expression was evaluated by real-time quantitative polymerase chain reaction (PCR) and the relevant proteins involved in TFN/JAK/STAT signaling pathways were examined by western blot assay. RESULTS: MTT assay showed that RIP had no toxicity on HepG2.2.15 cell line below the concentration 400 µg/ml at Day 3, 6 and 9. Furthermore, RIP at the concentration of 50, 100 and 200 µg/ml significantly reduced extracellular and intracellular level of HBsAg, HBeAg and HBV DNA in HepG2.2.15 cells in a time and dose-dependent manner. Moreover, RIP also enhanced the production of IFN-α in HepG2.2.15 cell via activation of JAK/STAT signal pathway and induction of antiviral proteins, as evidenced by the increased protein expression of p-STAT-1, p-STAT-2, p-JAK1, p-TYK2, OAS1, and Mx in HepG2.2.15 cells. In addition, the over expression of SOCS-1 and SOCS-3 was significantly abolished under same conditions. CONCLUSIONS: These results suggested that the HBV inhibitory effect of RIP was possibly due to the activation of IFN-α-dependent JAK/STAT signal pathway and induction of the anti-HBV protein expression.