scholarly journals Glenthenamines A–F: Enamine pyranonaphthoquinones from the Australian pasture plant-derived Streptomyces sp. CMB-PB042

2021 ◽  
Author(s):  
Taizong Wu ◽  
Angela Salim ◽  
Hui Cui ◽  
Zeinab Khalil ◽  
Paul Bernhardt ◽  
...  
Keyword(s):  
Spectroscopic Analysis ◽  
Scientific Literature ◽  
Solid Phase ◽  
Carcinoma Cells ◽  
Streptomyces Sp ◽  
Doxorubicin Resistance ◽  
X Ray ◽  
Colon Carcinoma Cells ◽  
Australian Sheep ◽  
Pasture Plant

Chemical investigations into solid phase cultivations of an Australian sheep station pasture plant-derived Streptomyces sp. CMB-PB042, yielded the rare enamine naphthopyranoquinones BE-54238A (1) and BE-54238B (2), together with four new analogues, glenthenamines B–D (4–6) and F (8), and two handling artifacts, glenthenamines A (3) and E (7). Single crystal X-ray analyses of 1–2 resolved configurational ambiguities in the scientific literature, while detailed spectroscopic analysis and biosynthetic considerations assigned structures inclusive of absolute configuration to 3–8. We propose a plausible sequence of biosynthetic transformations linking structural and configurational features of 1–8, and apply a novel Schiff base "fishing" approach to detect a key deoxyaminosugar precursor. These enamine naphthopyranoquinone disclose a new P-gp inhibitory pharmacophore capable of reversing doxorubicin resistance in P-gp overexpressing colon carcinoma cells.

scholarly journals Alkaloids from an Endophytic Streptomyces sp. YIM66017

2013 ◽  
Vol 8 (10) ◽  
pp. 1934578X1300801 ◽  
Author(s):  
Hao Zhou ◽  
Yabin Yang ◽  
Jucheng Zhang ◽  
Tianfeng Peng ◽  
Lixing Zhao ◽  
...  
Keyword(s):  
Culture Filtrate ◽  
Spectroscopic Analysis ◽  
Crystallographic Analysis ◽  
Natural Source ◽  
Streptomyces Sp ◽  
X Ray ◽  
Alpinia Oxyphylla ◽  
Endophytic Streptomyces ◽  
First Time ◽  
Mcf 7

Three alkaloids, flavensomycinoic acid (1), a linear polyketide, alpiniamide (2), and cyclo (L-Trp-L-Ala) (3), were isolated from the culture filtrate of endophytic Streptomyces sp. YIM66017 from Alpinia oxyphylla. Their structures were elucidated by spectroscopic analysis and the structure of 1 was confirmed by X-ray crystallographic analysis. Compound 1 was isolated from a natural source for the first time, and compound 2 is a new compound. Compound 1 showed cytotoxicity to MCF-7 with an IC 50 value of 17.0 μM.

scholarly journals Novel Macrolactams from a Deep-Sea-Derived Streptomyces Species

Marine Drugs ◽  
2020 ◽  
Vol 19 (1) ◽  
pp. 13
Author(s):  
Pei Wang ◽  
Dongyang Wang ◽  
Rongxin Zhang ◽  
Yi Wang ◽  
Fandong Kong ◽  
...  
Keyword(s):  
Deep Sea ◽  
Spectroscopic Analysis ◽  
Fermentation Broth ◽  
Light Conditions ◽  
X Ray Diffraction ◽  
Chemical Methods ◽  
Streptomyces Species ◽  
Deep Sea Sediment ◽  
Streptomyces Sp ◽  
X Ray

Four polyene macrolactams including the previously reported niizalactam C (4), and three new ones, streptolactams A–C (1–3) with a 26-membered monocyclic, [4,6,20]-fused tricyclic and 11,23-oxygen bridged [14,16]-bicyclic skeletons, respectively, were isolated from the fermentation broth of the deep-sea sediment-derived Streptomyces sp. OUCMDZ-3159. Their structures were determined based on spectroscopic analysis, X-ray diffraction analysis, and chemical methods. The abiotic formation of compounds 2 and 4 from compound 1 were confirmed by a series of chemical reactions under heat and light conditions. Compounds 1 and 3 showed a selective antifungal activity against Candida albicans ATCC 10231.

Reversal of doxorubicin resistance by the amiloride analogue EIPA in multidrug resistant human colon carcinoma cells

1996 ◽  
Vol 14 (1) ◽  
pp. 11-18 ◽  
Author(s):  
Antonella Pannocchia ◽  
Silvia Revelli ◽  
Giacomo Tamponi ◽  
Angelica Giorgianni ◽  
Roberta Todde ◽  
...  
Keyword(s):  
Colon Carcinoma ◽  
Human Colon ◽  
Multidrug Resistant ◽  
Carcinoma Cells ◽  
Doxorubicin Resistance ◽  
Colon Carcinoma Cells ◽  
Human Colon Carcinoma

The influence of extracts from Rubus caesius leaves on human colon carcinoma cells cultured in vitro

Planta Medica ◽  
2014 ◽  
Vol 80 (16) ◽  
Author(s):  
R Paduch ◽  
M Tomczyk ◽  
A Wiater ◽  
A Dudek ◽  
M Pleszczynska ◽  
...  
Keyword(s):  
Colon Carcinoma ◽  
Human Colon ◽  
Carcinoma Cells ◽  
Colon Carcinoma Cells ◽  
Human Colon Carcinoma ◽  
Cells Cultured

Impact of Rutile Fraction on TiO2 Visible-Light Absorption and Visible-Light-Induced Photocatalytic Activity

2018 ◽  
Author(s):  
David Maria Tobaldi ◽  
Luc Lajaunie ◽  
ana caetano ◽  
nejc rozman ◽  
Maria Paula Seabra ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Light Absorption ◽  
Solid Phase ◽  
Diffraction Method ◽  
Band Alignment ◽  
Quantitative Phase Analysis ◽  
Transmission Microscopy ◽  
Visible Light Absorption ◽  
X Ray

<div>Titanium dioxide is by far the most utilised semiconductor material for photocatalytic applications. Still, it is transparent to visible-light. Recently, it has been proved that a type-II band alignment for the rutile−anatase mixture would improve its visible-light absorption.</div><div>In this research paper we thoroughly characterised the real crystalline and amorphous phases of synthesised titanias – thermally treated at different temperatures to get distinct ratios of anatase-rutile-amorphous fraction – as well as that of three commercially available photocatalytic nano-TiO2. </div><div>The structural characterisation was done via advanced X-ray diffraction method, namely the Rietveld-RIR method, to attain a full quantitative phase analysis of the specimens. The microstructure was also investigated via an advanced X-ray method, the whole powder pattern modelling. These methods were validated combining advanced aberration-corrected scanning transmission microscopy and high-resolution electron energy-loss spectroscopy. The photocatalytic activity was assessed in the liquid- and gas-solid phase (employing rhodamine B and 4-chlorophenol, and isopropanol, respectively, as the organic substances to degrade) using a light source irradiating exclusively in the visible-range.</div><div>Optical spectroscopy showed that even a small fraction of rutile (2 wt%) is able to shift to lower energies the apparent optical band gap of an anatase-rutile mixed phase. But is this enough to attain a real photocatalytic activity promoted by merely visible-light?</div><div>We tried to give a reply to that question.</div><div>Photocatalytic activity results in the liquid-solid phase showed that a high surface hydroxylation led to specimen with superior visible light-induced catalytic activity (i.e. dye and ligand-to-metal charge transfer complexes sensitisation effects). That is: not photocatalysis <i>sensu-strictu</i>.</div><div>On the other hand, the gas-solid phase results showed that a higher amount of the rutile fraction (around 10 wt%), together with less recombination of the charge carriers, were more effective for an actual photocatalytic oxidation of isopropanol.</div>

Sign in / Sign up

Export Citation Format

Share Document