(1S,4R)-(-)-4-(Fmoc-amino)-2-cyclopentene-1-carboxylic acid

One new bithiophenes, 5-(but-3-yne-1,2-diol)-50-hydroxy-methyl-2,20-bithiophene (2), two new polyacetylenic glucosides, 3-O-b-D-glucopyranosyloxy-1-hydroxy-4E,6E-tetradecene-8,10,12-triyne (8), (5E)-trideca-1,5-dien-7,9,11-triyne-3,4-diol-4-O-b-D-glucopyranoside (9), six new terpenoid glycosides, rel-(1S,2S,3S,4R,6R)-1,6-epoxy-menthane-2,3-diol-3-O-b-D-glucopyranoside (10), rel-(1S,2S,3S,4R,6R)-3-O-(6-O-caffeoyl-b-D-glucopyranosyl)-1,6-epoxy menthane-2,3-diol (11), (2E,6E)-2,6,10-trimethyl-2,6,11-dodecatriene-1,10-diol-1-O-b-D-glucopyranoside (12), 3b,16b,29-trihydroxy oleanane-12-ene-3-O-b-D-glucopyranoside (13), 3,28-di-O-b-D-glucopyranosyl-3b,16b-dihydroxy oleanane-12-ene-28-oleanlic acid (14), 3-O-b-D-glucopyranosyl-(1?2)-b-D-glucopyranosyl oleanlic-18-ene acid-28-O-b-D-glucopyranoside (15), along with fifteen known compounds (1, 3–7, and 16–24), were isolated from the aerial parts of Eclipta prostrata. Their structures were established by analysis of the spectroscopic data.

The function and survival of normal and malignant plasma cells depends on the elaborately regulated ubiquitin proteasome system. Proteasome inhibitors such as bortezomib have proved to be highly effective in the treatment of multiple myeloma (MM), and their effects are related to normal protein homeostasis which is critical for plasma cell survival. Many ubiquitin ligases are regulated by conjugation with NEDD8. Therefore, neddylation may also impact survival and proliferation of malignant plasma cells. Here, we show that MLN4924, a potent NEDD8 activating enzyme (NAE) inhibitor, induced cytotoxicity in MM cell lines, and its antitumor effect is associated with suppression of the AKT and mammalian target of rapamycin (mTOR) signaling pathways through increased expression of REDD1. Combining MLN4924 with the proteasome inhibitor bortezomib induces synergistic apoptosis in MM cell lines which can overcome the prosurvival effects of growth factors such as interleukin-6 and insulin-like growth factor-1.

Two new phytotoxic sesquiterpenoid acids, named pyrenophoric acids B and C, were isolated together with the related pyrenophoric and abscisic acids from solid Bromus tectorum (cheatgrass) seed culture of the seed pathogen Pyrenophora semeniperda. This fungus has been proposed as a mycoherbicide for biocontrol of cheatgrass (Bromus tectorum), a Eurasian annual grass that has become invasive in rangelands and is also a serious agricultural weed in the western U.S. Pyrenophoric acids B and C were characterized by spectroscopic methods (NMR and HR ESIMS) as (2Z,4E)-5-[(1R*,4R*,6R*)-1,4-dihydroxy-2,2,6-trimethylcyclohexyl]-3-methylpenta-2,4-dienoic and (2Z,4E)-5-[(1S*,3S*,4R*,6S*)-3,4-dihydroxy-2,2,6-trimethylcyclohexyl]-3-methylpenta-2,4-dienoic acids, respectively. Cytochalasins A, B, F, and Z3, as well as deoxaphomin and pyrenophoric acid, all previously isolated from P. semeniperda grown on wheat seed, were also isolated from cheatgrass seed culture.

Herein, we report for the first time that nematic liquid-crystalline environments drive the reversible self-aggregation of an enantiopure β-pentapeptide into oligomers with a well-defined structure. The peptide contains four (1S,2S)-2-aminocyclopentane carboxylic acid (ACPC) residues and the paramagnetic β-amino acid (3R,4R)-4-amino-1-oxyl-2,2,5,5-tetramethylpyrrolidine-3-carboxylic acid (POAC). The structure of the oligomers was investigated by electron paramagnetic resonance (EPR) spectroscopy, which allowed us to obtain the intermonomer distance distribution in the aggregates as a function of peptide concentration in two nematic liquid crystals, E7 and ZLI-4792. The aggregates were modeled on the basis of the EPR data, and their orientation and order in the nematic phase were studied by the surface tensor method.