Total synthesis of the indole alkaloids henrycinol A and B

The total synthesis of new indole alkaloids henrycinol A and B were accomplished starting from L-tryptophan methyl ester. The key step is a stereochemically flexible Pictet-Spengler reaction governed by the presence or absence of an N-allyl group in the tryptophan precursor. The natural products henrycinol A and B were synthesized in good overall yield in eight and nine steps, respectively. (C) 2014 Elsevier Ltd. All rights reserved.

2-(4-Chlorobenzyl)-6-arylimidazo2,1-b]1,3,4]thiadiazoles: Synthesis, cytotoxic activity and mechanism of action

The cytotoxic activity of a new series of 2-(4'-chlorobenzyl)-5,6-disubstituted imidazo2,1-b]1,3,4]wthiadiazoles against different human and murine cancer cell lines is reported. Among the tested compounds, two derivatives namely 2-(4-chlorobenzyl)-6-(2-oxo-2H-chromen-3-yl)imidazo2,1-1)]1,3,4]th iadiazole-5-carbaldehyde 4i and 2-(4-chlorobenzyl)-6-(2-oxo-2H-chromen-3-ypimidazo2,1-1)]1,3,4]thi adiazol-5-yl thiocyanate 5i emerged as the most potent against all the cell lines. To investigate the mechanism of action, we selected compounds 4i for cell cycle study, analysis of mitochondrial membrane potential and Annexin V-FITC flow cytometric analysis and DNA fragmentation assay. Results showed that 4i induced cytotoxicity by inducing apoptosis without arresting the cell cycle. (C) 2014 Elsevier Masson SAS. All rights reserved.

Synthesis, antioxidant, and cytotoxic activities of bis(oxazolyl/thiazolyl/imidazolyl)amidomethanesulfonyl Acetamides

A new class of bis(oxazolyl/thiazolyl/imidazolyl)amidomethanesulfonyl acetamides was prepared from the respective (oxazolyl/thiazolyl/imidazolyl)carbamoyl-methylthio acetic acid and studied their antioxidant activity and cytotoxic activitity against A549 lung adenocarcinoma cells. The methyl-substituted sulfonyl bisoxazoles exhibited excellent radical scavenging activity. On the other hand, the chloro-substituted sulfonyl bisthiazoles (IC50 = 49 A mu M) and sulfonyl bisimidazoles (IC50 = 24 A mu M) showed noticeable cytotoxic activity on A549 cells.

Development of Asymmetric Protonation Reactions for the Synthesis of Indoline Alkaloids

Nitrogen-containing heterocycles, such as indolines and pyrroloindolines, are prevalent in a variety of diverse natural products, many of which exhibit remarkable biological activities. These frameworks have inspired innovative research aimed at discovering novel methods for their stereoselective preparation.

We have developed an enantioselective synthesis of pyrroloindolines based on a formal (3 + 2) cycloaddition of indoles and 2-amidoacrylates. This reaction is promoted by (R)-BINOL•SnCl₄; this complex is a Lewis acid-assisted Brønsted acid that effects a highly face-selective catalyst-controlled protonation of an enolate. Mechanistic studies also determined that the initial product of this reaction is an indolinium ion, which upon aqueous workup undergoes cyclization to the pyrroloindoline.

Based on this result, we investigated alternative nucleophiles to trap the indolinium ion. First, addition of sodium borohydride to the optimized reaction conditions yields indoline-containing amino acid derivatives.

Next, carbon nucleophiles were explored. Indole substrates incorporating a tethered alkene were exposed to the conditions for the formal (3 + 2) cycloaddition, resulting in a conjugate addition/asymmetric protonation/Prins cyclization cascade. In this transformation, the indolinium ion is attacked by the olefin, and the resulting carbocation is quenched by a chloride ion. Zirconium tetrachloride was found to be the optimal Lewis acid. Stoichiometric proton and chloride sources were also found to be crucial for reactivity.

Immnunomodulatory and cytotoxic effects of aqueous leaf extracts of certain plants on common carp, Cyprinus carpio

Effect of aqueous leaf extracts of Catheranthus roseus, Calotropis gigantium and Datura stromoneum on common carp, Cyprinus carpio were investigated. C. carpio were separately fed with 1 and 2% aqueous extracts of these three plant leaves for a period of seven days. In 1% Catheranthus roseus of leaf extract fed group no significant tissue level changes were recorded. One and 2% of other two species fed treated group showed mild to severe necrotic and cellular changes in liver, kidney and spleen. Immunologically, significant rise in antibody titre and respiratory burst activity was recorded for 1% Catheranthus roseusfed group.

Periglaucines A-D, anti-HBV and -HIV-1 alkaloids from Pericampylus glaucus

Four new hasubanane-type alkaloids, periglaucines A-D (1-4), and three known alkaloids, norruffscine (5), (-)-8-oxotetrahydropalmatine (6), and (-)-8-oxocanadine (7), were isolated from the aerial parts of Pericampylus glaucus. Their structures were eluci

Isolatin [sic] the bacteria produced biactive [sic] metabolits [sic] cytotoxic compound in order to prduction [sic] anticancer substance in the coral regin [sic] the Persian Gulf (Larak Island)

In the present investigation the marine bacteria isolated from corals, sponges sea water and sediments of coral regions in the larak Island located in the Persian Gulf and were examined for ability to produce cytotoxic metabolits in order to use as an anticancer compounds. Cytotoxic effect were isolated bacteria from different samples and were examined by Artemia Cytotoxic Bioassay test, in which 4.5 percent of sea waters, 12 percent of sediments and 28 percent of marine invertebrat showed cytotoxic activity, using Brine Shrimp Bioassay test. Streptomyces S-2004 isolated from soft coral specified as Sinularia erecta had LC50=0.5mg/m1 in Brine Shrimp Bioaassay test. The streptomyces S-2004 produced cytotoxic metabolits in low nutrient condition and sea water medium after 7 days on 250 rpm shaken in vitro condition. The extract partially were semipurified. Then ethyl acetate extraction from aceton extracted of bacterial plate had cytotoxic effect (LC50=4.19ktg/m1) in Human epidermoid carcinoma of mouth cells (KB) by using neutral red assay. Morphological effects of this extract on KB cells showed turgescence, cellular blebs and apoptosis which was a proof for anticancer compounds of the extract. It is seems that streptomyces S-2004 is a new strain and could be introduced as a talented bacteria, which produced cytotoxic metabolits.

Short-term cytotoxic and inflammatory responses of human monocytes to stainless steel fibre networks

The aim of the current work was to examine the human monocyte response to 444 ferritic stainless steel fibre networks. 316L austenitic fibre networks, of the same fibre volume fraction, were used as control surfaces. Fluorescence and scanning electron microscopies suggest that the cells exhibited a good degree of attachment and penetration throughout both networks. Lactate Dehydrogenase (LDH) and TNF-α releases were used as indicators of cytotoxicity and inflammatory responses respectively. LDH release indicated similar levels of monocyte viability when in contact with the 444 and 316L fibre networks. Both networks elicited a low level secretion of TNF-α, which was significantly lower than that of the positive control wells containing zymosan. Collectively, the results suggest that 444 ferritic and 316L austenitic networks induced similar cytotoxic and inflammatory responses from human monocytes. © 2012 Materials Research Society.

Indole Alkaloids from the Leaves of Anthocephalus chinensis

Anthocephalusine A (1) and 3 beta-isodihydrocadambine 4-oxide (2) were isolated from the leaves of Anthocephalus chinensis (Rubiaceac), together with five known compounds. The structures were established by spectroscopic methods including 2D-NMR analyses.

Analysis of quinolizidine alkaloids in Sophora flavescens Ait. by capillary electrophoresis with tris(2,2 '-bipyridyl) ruthenium (II)-based electrochemiluminescence detection

A capillary electrophoresis method coupled with electrochemiluminescence detection for the analysis of quinolizidine alkaloids was established, especially, oxymatrine (OMT) which could not be measured by previous electrochemiluminescence methods was detected sensitively herein. Complete separation of sophoridine (SR), matrine (MT) and OMT was achieved within 13 min using a background electrolyte of 50mM phosphate buffer at pH 8.4 and a separation voltage of 15 kV. The calibration curves showed a linear range from 2.8 x 10(-8) to 4.4 x 10(-7) M for SR, 2.7 x 10(-8) to 4.4 x 10(-7) M for MT.