Microbial synthesis of plant polyphenols / 生物工程学报

Plant polyphenols are phenylpropanoid derivatives including phenolic acids, stilbenes, curcumins and flavonoids. These compounds display a variety of biological and pharmacological activities such as antioxidation, vasorelaxation, anti-coagulation, anti-inflammation, anti-tumor and anti-virus, conferring a huge application potential in the sectors of drugs, foods, cosmetics, and chemicals. Microorganisms have become important hosts for heterologous synthesis of natural products due to the advantages of fast growth, easiness of culture and industrial operation. In recent years, the development of synthetic biology has boosted the microbial synthesis of plant natural products, achieving substantial progress. In this review, we summarize the synthesis of plant polyphenols in engineered Escherichia coli, Saccharomyces cerevisiae and other microorganisms equipped with the designed biosynthetic pathways of polyphenols. We also discuss the optimization strategies such as precursor engineering, dynamic regulation, and co-cultivation to improve the production of polyphenols and propose future prospects for polyphenol pathway engineering.

Isolation and identification of chemical constituents from extract of salvia polyphenolic acids / 中草药

Objective To investigate the chemical constituents from salvia polyphenolic acids. Methods Various column chromatographic techniques were used to separate and purify the chemical constituents and their structures were identified by spectral analysis. Results Seven compounds were isolated and obtained from salvia polyphenolic acids, which were identified as (2R)-2-[(3-(7-hydroxy-2-oxo-2,3-dihydrobenzofuran-4-yl)-(2E)-acryloyl) oxy]-3-(3,4-dihydroxyphenyl)-propanoic acid (1), salvianolic acid D (2), protocatechuic aldehyde (3), rosmarinic acid (4), lithospermic acid (5), salvianolic acid B (6), and salvianolic acid Y (7). Conclusion Compound 1 is a new compound, which is named as salvianolic acid D lactone.

Inhibitory potentials of phenolic-rich extracts from Bridelia ferruginea on two key carbohydrate-metabolizing enzymes and Fe-induced pancreatic oxidative stress / 中西医结合学报

<p><b>OBJECTIVE</b>The current study was designed to evaluate the various antioxidant potentials and inhibitory effects of phenolic-rich leaf extracts of Bridelia ferruginea (BF) on the in vitro activities of some key enzymes involved in the metabolism of carbohydrates.</p><p><b>METHODS</b>In this study, BF leaf free and bound phenolic-rich extracts were used. We quantified total phenolic and flavonoid contents, and evaluated several antioxidant activities using assays for ferric reducing antioxidant power, total antioxidant activity (phosphomolybdenum reducing ability), 1,1-diphenyl-2-picrylhydrazyl and thiobarbituric acid reactive species. Also, extracts were tested for their ability to inhibit α-amylase and α-glucosidase activity.</p><p><b>RESULTS</b>The total phenolic and total flavonoid contents in the free phenolic extract of BF were significantly greater than in the bound phenolic extract. Also, all the antioxidant activities considered were significantly greater in the free phenolic extract than in the bound phenolic extract. In the same vein, the free phenolic-rich extract had a significantly higher percentage inhibition against α-glucosidase activity (IC = 28.5 µg/mL) than the bound phenolic extract (IC = 340.0 µg/mL). On the contrary, the free phenolic extract (IC = 210.0 µg/mL) had significantly lower inhibition against α-amylase than the bound phenolic-rich extract (IC = 190.0 µg/mL).</p><p><b>CONCLUSION</b>The phenolic-rich extracts of BF leaves showed antioxidant potentials and inhibited two key carbohydrate-metabolizing enzymes in vitro.</p>