Absolute Configuration of Franganine

The absolute configuration of franganine (<b>1</b>), a cyclopeptide alkaloid isolated from the methanol root bark extract of <i>Discaria americana</i>, was established on the basis of detailed NMR spectroscopic data and X-ray diffraction analysis of its salt (<b>2</b>)

Cyclopeptide Alkaloids: Stereochemistry and Synthesis of the Precursors of Discarines C and D and Myrianthine A

The stereochemistry of discarines C (<b>1</b>) and D (<b>2</b>) and myrianthine A (<b>3</b>), three cyclopeptide alkaloids isolated from <i>Discaria febrifuga</i>, was determined by a combination of NMR studies of <b>1</b>–<b>3</b>, enantioselective gas chromatography, and comparison of NMR data with those of synthetic tripeptides. For the synthesis of peptides, the nonproteinogenic amino acid 3-phenylserine was also obtained in its four diastereoisomeric forms (l and d <i>threo</i>, obtained by recrystallization of the diastereoisomeric tripeptide, and l and d <i>erythro</i>, obtained by a Mitsunobu reaction with the <i>threo</i>-tripeptides). The general synthetic strategy described in this paper allows the tripeptide to be obtained with the free N-terminal extremity protected or dimethylated. This strategy also allows the synthesis of the corresponding peptide with an imidazolidinone ring

Chemical composition and evaluation of prolyl oligopeptidase and acetylcholinesterase inhibitory activities of <i>Leonurus Sibiricus</i> L. from Brazil

<p>Chemical investigation of the aerial parts of <i>Leonurus sibiricus</i> L. used in Brazilian folk medicine led to the identification of the following constituents: the labdane-type diterpenoid leojaponin, the phytosterols β-sitosterol and β-sitosterol glucoside and the alkaloid leonurine. The crude extracts obtained from methanol and methanol/1% HCl and pure compounds isolated from <i>L. sibirius</i> were investigated as acetylcholinesterase (AChE) and prolyl oligopeptidase (POP) inhibitors. Extracts obtained by maceration were active against POP (53–58%), but showed weak activity against AChE. The isolated leojaponin and leonurine were evaluated as POP inhibitors.</p

Reaction by obtention of 2,3-dihydroxy chelerythrine derivative (14) from Chelerythrine (10).

<p>Reaction by obtention of 2,3-dihydroxy chelerythrine derivative (14) from Chelerythrine (10).</p

Minimum amount required (in µg) for inhibition of microbial growth on TLC plates for extracts and isolated alkaloids of <i>Z. rhoifolium</i>.

<p>*(ATCC =  merican Type Culture Collection): Bacteria: Staphylococcus epidermidis-Se (ATCC 12228); Staphylococcus aureus-Sa (ATCC 6538); Bacillus subtilis-Bs (ATCC 6633); Klebsiella pneumoniae-Kp (ATCC 13883); Escherichia coli-Ec (ATCC 25922); Pseudomonas aeruginosa-Pa (ATCC 27853); <i>Shigella sonnei-Ss</i> (ATCC 25931); Yeasts: Candida albicans-Ca (ATCC 10231); Sacharomyces cerevisae-Sc (ATCC 2601); Cryptococcus neoformans-Cn (ATCC 28952). NT =  not tested; NA =  not active;</p>a<p>basic;</p>b<p>Chloramphenicol for bacteria and Nystatin for yeasts.</p

Figure illustrating the structure-activity relationship for the antimicrobial activity of benzophenanthridine alkaloids.

<p>Figure illustrating the structure-activity relationship for the antimicrobial activity of benzophenanthridine alkaloids.</p

Alkaloids isolated from stem bark of <i>Zanthoxylum rhoifolium</i>.

<p>Alkaloids isolated from stem bark of <i>Zanthoxylum rhoifolium</i>.</p

Antimicrobial activity (MIC/MBC and MFC in µg/mL) for extracts and isolated alkaloids of <i>Z. rhoifolium</i>.

<p>*(ATCC =  American Type Culture Collection): Bacteria: Staphylococcus epidermidis-Se (ATCC 12228); Staphylococcus aureus- Sa (ATCC 6538); Streptococcus pyogenes-Sp (ATCC 19615); Bacillus subtilis-Bs (ATCC 6633); Klebsiella pneumoniae-Kp (ATCC 13883); Escherichia coli-Ec (ATCC 25922); Yeasts: Candida albicans-Ca (ATCC 10231); Sacharomyces cerevisae-Sc (ATCC 2601); Cryptococcus neoformans-Cn (ATCC 28952). NT = not tested;</p>a<p>basic;</p>b<p>Chloramphenicol for bacteria and Nystatin for yeasts.</p

Chelerythrine (CHE) <i>in vitro</i> effect on human erythrocytes: (A) Erythrocytes count; (B) Hemolysis; (C) Lipoperoxidation evaluated by TBARS assay; (D) protein oxidation evaluated by Advanced Oxidative Protein Products (AOPP) assay.

<p>CHE treatments were compared to control group by one-way analysis of variance followed by Dunnet <i>post hoc</i> test. * = p<0.05; ** = p<0.01; *** = p<0.001.</p

Antimicrobial activity (MIC/MBC and MFC in µg/mL) for Chelerythrine (<b>10</b>) and 2,3-dihydroxy chelerythrine derivative (<b>14</b>).

<p>*(ATCC =  American Type Culture Collection): Bacteria: Staphylococcus aureus- Sa (ATCC 6538); Bacillus cereus-Bc (ATCC 33019); Bacillus subtilis-Bs (ATCC 6633); <i>Enterococcus spp.-Es</i> (ATCC 6589); <i>Enterobacter aerogenes-Ea</i> (ATCC 13048); Escherichia coli-Ec (ATCC 25922); Pseudomonas aeruginosa-Pa (ATCC 27853); Enterobacter cloacae-E.cloacae (ATCC 1304); <i>Shigella sonnei-Ss (ATCC 25931); Salmonella typhimurium-St (ATCC 14028); Burkholderia cepacia-B.cepacia</i> (ATCC 17759); <i>Morganella morganii-Mm</i> (ATCC 25829); Yeasts: Candida albicans-Ca (ATCC 10231); Candida tropicalis-Ct (ATCC 18803); Candida krusei-Ck (ATCC 6258); Candida parapslosis-Cp (ATCC 22018); Sacharomyces cerevisae-Sc (ATCC 2601); Cryptococcus neoformans-Cn (ATCC 28952); Cryptococcus gatti-Cg (ATCC 2601). NT =  not tested; Ampicillin and Azithromycin for bacteria and Nystatin for yeasts.</p