The Influence of Solvent, Host, and Phenological Stage on the Yield, Chemical Composition, and Antidiabetic and Antioxidant Properties of Phragmanthera capitata (Sprengel) S. Balle

Phragmanthera capitata was reported to possess many biological properties making it a good candidate for the formulation of a phytomedicine with multiple effects. In this work, we studied some factors likely to modify these therapeutic properties with the aim to contribute to its standardization as an improved traditional medicine. P. capitata parasitizing Persea americana, Psidium guajava, and Podocarpus mannii were harvested at three phenological stages (vegetative, flowering, and fruiting stages). The extracts were prepared by maceration in n-hexane, ethyl acetate, ethanol, methanol, and distilled water. The total phenolic, flavonoid, flavonol, and tannin contents were measured using appropriate methods. The antioxidant potential of extracts was investigated using TAC, DPPH scavenging, and FRAP methods. The α-amylase and α-glucosidase inhibitory activities of extracts were determined using enzymatic methods. The ethyl acetate extracts with the best phenolic content were subjected to HPLC analysis. The extraction yields were higher with methanol. The ethyl acetate extract of P. capitata harvested from P. guajava showed a stable HPLC profile during the development of the plant, while extracts from the plant collected from P. americana and P. mannii showed both qualitative and quantitative variations according to phonological stages of the plant. The inhibition of α-amylase was more pronounced for P. capitata harvested from P. guajava, decreasing during flowering and fruiting, while inhibition of α-glucosidase was not influenced by the phenological stage and the host of the plant. The α-amylase inhibitors were better extracted by ethyl acetate and those of α-glucosidase by ethanol or methanol. The phenolic contents and antioxidant properties of the extracts were influenced by the phenological stage of P. capitata and its hosts. These results suggest that it is preferable to harvest P. capitata during flowering or during fruiting stages on any host. None of the used solvents permitted an optimal extraction of active principles form P. capitata, suggesting that the mixture of solvents must be considered in further studies

Enhanced poly(3-hydroxypropionate) production via β-alanine pathway in recombinant <i>Escherichia coli</i>

<div><p>Poly(3-hydroxypropionate) (P3HP) is a thermoplastic with great compostability and biocompatibility, and can be produced through several biosynthetic pathways, in which the glycerol pathway achieved the highest P3HP production. However, exogenous supply of vitamin B₁₂ was required to maintain the activity of glycerol dehydratase, resulting in high production cost. To avoid the addition of VB₁₂, we have previously constructed a P3HP biosynthetic route with β-alanine as intermediate, and the present study aimed to improve the P3HP production of this pathway. L-aspartate decarboxylase PanD was found to be the rate-limiting enzyme in the β-alanine pathway firstly. To improve the pathway efficiency, PanD was screened from four different sources (<i>Escherichia coli</i>, <i>Bacillus subtilis</i>, <i>Pseudomonas fluorescens</i>, and <i>Corynebacterium glutamicum</i>). And PanD from <i>C</i>. <i>glutamicum</i> was found to have the highest activity, the P3HP production was improved in flask cultivation with this enzyme. To further improve the production, the host strain was screened and the culture condition was optimized. Under optimal conditions, production and content of P3HP reached to 10.2 g/L and 39.1% (wt/wt [cell dry weight]) in an aerobic fed-batch fermentation. To date, this is the highest P3HP production without VB₁₂.</p></div

Effect of the host strain on P3HP production.

<p>Different host strains carrying plasmids pHP302 and pFS03 were grown in minimal medium, and the P3HP production (white), CDW (light grey), and P3HP content (heavy grey) were presented. The experiments were perfomed in triplicate in shake-flask cultures.</p

Electrochemical behavior and in-vitro antimicrobial screening of some thienylazoaryls dyes

Abstract Background A series of recently reported phenolic azo dyes 7a–e were prepared by coupling the thienyl diazonium sulfate of 3-Amino-4H-benzo[f]thieno[3,4-c](2H)chromen-4-one with selected diversely substituted phenolic and naphtholic derivatives. These compounds were evaluated for their antibacterial and antifungal activities. Furthermore their voltammetric behavior was compared at a glassy carbon electrode. Results The voltammetric behavior of the five recently reported azo dyes has been compared at a glassy carbon electrode. It is shown that the azo dyes 7a–e with a hydroxyl group in the ortho position with respect to the azo bridge give rise to well defined, irreversible peaks for the oxidation and reduction process within a pH range of 2–7. The mechanisms of electrochemical oxidation of compound 7a–c and 7e are proposed. For the hydroxyl-substituted dyes, re-oxidation peaks were obtained in the subsequent scan. The antimicrobial activities of the reported compounds 7a–e along with the entire precursors 1–4 and 6a–e were performed against selected bacterial and fungal species and their activities compared to those of nystatin, griseofulvin and ciprofloxacin used as reference drugs. Conclusions The present study showed significant antimicrobial activity of compounds 6d, 7a and 7c,e against the tested microorganisms; this result confirms the antimicrobial potency of azo compounds and some of their precursors

Time profiles for CDW, P3HP production and substrate consumption during an aerobic fed-batch fermentation of <i>E</i>. <i>coli</i> JM109(DE3)/pHP302/pFS03.

<p>The content of P3HP was calculated using the ratio of P3HP weight to cell dry weight.</p

Effect of β-alanine and L-aspartate on the P3HP production.

<p>The strain Q2153 was grown in minimal medium with supplement of 5 g/L β-alanine (β-Ala) or L-aspartate (L-Asp), cultivation without amino acid was used as the control (CK), and the P3HP production (white), CDW (light grey), and P3HP content (heavy grey) were presented. The experiment was carried out in shaking flask in triplicate. All shake-flask experiments were incubated for 48 h after induction.</p

Bacterial strains, plasmids, and primers used in this study.

<p>Bacterial strains, plasmids, and primers used in this study.</p

Effect of IPTG on the biomass and P3HP production.

<p>Effect of IPTG on the biomass and P3HP production.</p

β-Alanine pathway used in this study.

<p>Four L-aspartate decarboxylases (PanD) from <i>E</i>. <i>coli</i>, <i>B</i>. <i>subtilis</i>, P. <i>fluorescens</i>, and <i>C</i>. <i>glutamicum</i> were tested. PP0596, β-alanine-pyruvate transaminase from <i>Pseudomonas putida</i>; YdfG, 3-hydroxyacid dehydrogenase from <i>E</i>. <i>coli</i>; PrpE, propionyl-CoA synthase rom <i>E</i>. <i>coli</i>; PhaC1, polyhydroxyalkanoate synthase from <i>Cupriavidus necator</i>.</p