Synthesis of Gold Nanoparticles using Bioreductants from the Aqueous Leaves Extract of Dillenia philippinensis Rolfe. (Katmon)

Background and Objectives@#Endemic plants are integral part of the ecosystem that provide innumerable benefits. Thus, emerging studies and applications using these endemic plants continue to increase globally. In this study, the preparation of gold nanoparticles (AuNPs) has been carried out by using the aqueous leaves extract of Dillenia philippinensis Rolfe. (Katmon) as the bioreductants. @*Methodology@#After the synthesis of AuNPs, the process was further subjected to optimization to assure the production of AuNPs with the best parameters. Synthesized and optimized AuNPs were characterized using FTIR, XRD, DLS, Zeta Potential, and TEM. @*Results@#Optimization results that provide the desired properties for AuNPs were a volume ratio of 1:2 (HAuCl₄: leaves extract), no significant difference (p>0.05) with the sequence of addition and reaction time, and acidic pH. The synthesized AuNPs' particles were found to contain hydroxyl and amine groups, had broad, amorphous, and spherical particles that have a mean diameter of 60.6nm, a PDI of 0.563, and a repulsion force of -13.720mV. The optimized and characterized AuNPs were then further used as a colorimetric sensing material, showing the potential applicability of AuNPs in the heavy metal analysis.@*Conclusion@#Gold nanoparticles were able to be synthesized with the use of bioreductants that are present in the aqueous leaves extract of Katmon. This concludes that endemic plants in the Philippines can be used for the synthesis of AuNPs and can be applied in the field of phytonanotechnology and other applied sciences.

Cr(VI) toxicity inhibits microbe enhanced plant growth promotion without affecting bioremediation potential

Hexavalent Chromium [Cr(VI)], a toxic inorganic pollutant of agriculture soil derived from variousanthropogenic industrial sources, disturbs vegetation and contaminates the food chain. Chromate microbialtoxicity was studied using plant growth-promoting chromate reducing Pseudomonas aeruginosa ATCCP15442 (P15). With a minimum inhibitory concentration of 1,250 µg/ml Cr(VI), the isolate is capable of 98%bioreduction of 100 µg/ml Cr(VI) in 24 hours and 83% of 500 µg/ml Cr(VI) in 72 hours. Additionally, P15shows tolerance to cross heavy metal pollutants (Cd, Pb, and Zn), halotolerance, and the production of plantgrowth-promoting substance, such as indole acetic acid (IAA), siderophore, and phosphate solubilization in thepresence and absence of Cr(VI). This study also reports that 100 and 250 µg/ml Cr(VI) decreases the productionof IAA, siderophore, and phosphate solubilization without affecting the growth or Cr(VI) bioreduction ability.In Vigna mungo seed bacterization assay, P15 is capable of enhancing root and shoot length in absence ofCr(VI) and reversing toxic effects of 100 µg/ml Cr(VI). No enhancement of plant parameters was observed athigher Cr(VI) concentrations, except reversal of Cr toxicity. These data are indication of the detrimental effectof Cr(VI) pollution on rhizospheric microbial flora associated with plant growth-promoting activities.

Asymmetric bioreduction of ketoesters derivatives by Kluyveromyces marxianus: influence of molecular structure on the conversion and enantiomeric excess

ABSTRACT This study presents the bioreduction of six β-ketoesters by whole cells of Kluyveromyces marxianus and molecular investigation of a series of 13 β-ketoesters by hologram quantitative structure-activity relationship (HQSAR) in order to relate with conversion and enantiomeric excess of β-stereogenic-hydroxyesters obtained by the same methodology. Four of these were obtained as (R)-configuration and two (S)-configuration, among them four compounds exhibited >99% enantiomeric excess. The β-ketoesters series LUMO maps showed that the β-carbon of the ketoester scaffold are exposed to undergo nucleophilic attack, suggesting a more favorable β-carbon side to enzymatic reduction based on adopted molecular conformation at the reaction moment. The HQSAR method was performed on the β-ketoesters derivatives separating them into those provided predominantly (R)- or (S)-β-hydroxyesters. The HQSAR models for both (R)- and (S)-configuration showed high predictive capacity. The HQSAR contribution maps suggest the importance of β-ketoesters scaffold as well as the substituents attached therein to asymmetric reduction, showing a possible influence of the ester group carbonyl position on the molecular conformation in the enzyme catalytic site, exposing a β-carbon side to the bioconversion to (S)- and (R)-enantiomers.

Biofabrication of Ag nanoparticles using Moringa oleifera leaf extract and their antimicrobial activity

To formulate a simple rapid procedure for bioreduction of silver nanoparticles using aqueous leaves extract of Moringa oleifera (M. oleifera). Methods: 10 mL of leaf extract was mixed to 90 mL of 1 mM aqueous of AgNO3 and was heated at 60 - 80 ℃ for 20 min. A change from brown to reddish color was observed. Characterization using UV-Vis spectrophotometry, Transmission Electron Microscopy (TEM) was performed. Results: TEM showed the formation of silver nanoparticles with an average size of 57 nm. Conclusions: M. oleifera demonstrates strong potential for synthesis of silver nanoparticles by rapid reduction of silver ions (Ag+ to Ag0). Biological methods are good competents for the chemical procedures, which are eco-friendly and convenient.

Role of CYP hypotype on the metabolism of 629 in human liver microsomes in vitro / 中国药理学通报

0.05). Conclusions In human liver microsome system in vitro,CYP1A2,2B6 and CYP2A6 contribute to the metabolism of 629.It is very important for bioreduction drugs design and development,and provide the basic experimental and theoretical profiles for extensive application in clinic.