The RNA binding protein Larp1 regulates cell division,apoptosis and cell migration

The RNA binding protein Larp1 was originally shown to be involved in spermatogenesis, embryogenesis and cell-cycle progression in Drosophila. Our data show that mammalian Larp1 is found in a complex with poly A binding protein and eukaryote initiation factor 4E and is associated with 60S and 80S ribosomal subunits. A reduction in Larp1 expression by siRNA inhibits global protein synthesis rates and results in mitotic arrest and delayed cell migration. Consistent with these data we show that Larp1 protein is present at the leading edge of migrating cells and interacts directly with cytoskeletal components. Taken together, these data suggest a role for Larp1 in facilitating the synthesis of proteins required for cellular remodelling and migration.     

Cytotoxic properties of oligostilbenoids from the tree barks of Hopea dryobalanoides

A new modified stilbene dimer, diptoindonesin D (1), was isolated from the acetone extract of the tree bark of Hopea dryobalanoides, together with seven known compounds, parviflorol (2), (-)-balanocarpol (3), heimiol A (4), hopeafuran (5), (+)-alpha-viniferin (6), vaticanol B (7) and (-)-hopeaphenol (8). Cytotoxic properties of compounds 1-8 were evaluated against murine leukemia P-388 cells. Compound 8 was found to be the most active with IC50 of 5.7 microM.     

Chrotacumines E and F,Two New Chromone‐Alkaloid Analogs from Dysoxylum acutangulum (Meliaceae) Leaves

A chemical investigation of the alkaloidal fraction of Dysoxylum acutangulum leaves led to the isolation and characterization of two new chromone alkaloid analogs named chrotacumines E and F ( 1 and 2 , resp.). Structure elucidation of 1 and 2 was achieved by spectroscopic analyses, including 2D‐NMR. Both of these alkaloids exhibited modest activities as tyrosinase inhibitors with 29.2 and 25.8% inhibition at 100 μg/ml, respectively.     

Phenolic constituents from the wood of Morus australis with cytotoxic activity

A new methylated flavonol, 5,7,2',4'-tetrahydroxy-3-methoxyflavone (1), had been isolated from the methanol extract of the wood of Morus australis, along with nine known compounds, kuwanon C (2), morusin (3), morachalcone A (4), oxyresveratrol (5), 4'-(2-methyl-2-buten-4-yl)oxyresveratrol (6), moracins M (7) and C (8), alboctalol (9), and macrourin B (10). The structures of these compounds were determined based on spectral evidence, including UV, IR, NMR, and mass spectra. Cytotoxic properties of compounds 1-10 were evaluated against murine leukemia P-388 cells. The prenylated stilbene 6 and 2-arylbenzofuran 8, and morusin (3) were found to have strong cytotoxic effects with IC50 values of 6.9, 8.7, and 10.1 microM, respectively.