M. S. Chinese Chemical Letters 2009

A unusual flavone glycoside named Shamimarin (1) and a new compound Acetoxy-8-methyl-chromen-2H-one (2) were isolated from aerial parts of Rhododendron lepidotum L. along with four known coumarins daphnin (3), daphnetin 8-O-b-D-glucopyranoside (4), daphnetin (5) and umbelliferone (6). The structural elucidations were based on analyses of chemical and spectroscopic data by including ID and 2D NMR analyses. Rhododendron spp. (Ericaceae) has long been used traditional medicine for medicinal purposes [1,2]. Maximum concentration of these species occurs in Eastern and Western Himalayas, China and Japan, few species occur in Arctic region. Phytochemical analysis of Rhododendron species showed that these species contain phenolic glycosides [3], triterpene flavanone glycosides [4], flavonoid glycosides [5], anti-HIV chromanic acids [6], dihydroflavanol glycoside [7], phloroacetophenone glucoside [8], quercetin 5,4 0 -dimethyl ether [9], terpenoids [10], b-diketones [11], steryl acetates [12], phenolics [13], diterpenes [14], noreugenin [15], cyaniding glycosides [16], friedoolean oxide [17], germacrone sesquiterpene [18], polyphenols, flavonoids, methyl ethers . Our previous work on this particular species leads to the isolation of new coumarin glycosides . Taking into consideration the biological activity of phenolics we further investigated the methanolic extract of Rhododendron lepidotum L. which leads to the isolation two new compounds (1-2) along with four known constituents (3-6) which forms the first report of occurrence in Rhododendron spp.

A convenient and efficient phosphine-free procedure for the one-pot conversion of primary, secondary and tertiary alcohols into the corresponding alkyl thiocyanates or alkyl isothiocyanates is described using trichloroisocyanuric acid/NH 4 SCN.

We synthesized thirty-six novel pyrazole derivatives and studied their antiproliferative activity in human ovarian adenocarcinoma A2780 cells, human lung carcinoma A549 cells, and murine P388 leukemia cells. Four of these substances were selected because of their higher antiproliferative activity and further analyses showed that they were all able to induce apoptosis, although to a different extent. The expression of p53 and p21(waf1), which induce apoptosis and cell cycle arrest, was evaluated by western blot analysis in cells treated with compound 12d. The analysis of the cell cycle showed that all the selected compounds cause a partial G2/M block and the formation of polyploid cells. Furthermore, the four selected compounds were tested for their interaction with the microtubular cytoskeletal system by docking analysis, tubulin polymerization assay and immunofluorescence staining, demonstrating that the compound 12d, unlike the other active derivatives, was able to significantly b...