Synthesis, biological evaluation and preliminary mechanisms of 6-amino substituted harmine derivatives as potential antitumor agents.

To explore the effect of the introduction of the amino and substituted amino groups on the antitumor activity of harmine, twenty-five novel 6-amino substituted harmine derivatives (3a-3j and 5a-5o) were synthesized and evaluated for anti-proliferative activity on a panel of cancer cell lines. Compounds 3i and 5n exhibited the most potent antiproliferative activity with IC50 values lower than 2.2 µM. Especially, compound 5n possessed extremely potent antitumor activity with IC50 values of 0.34 µM and 0.65 µM against HL-60 and A549 cell lines, respectively. Further, the preliminary studies of mechanisms showed that compound 5n could significantly induce cell apoptosis in a dose-dependent manner, cause cell cycle arrest at the G2/M phase and intercalate into ct-DNA via the competition with EB, while displaying very weak topoisomerase I (Topo I) inhibition activity. More importantly, 5n showed mild cytotoxicity against human normal lung epithelial cells BEAS-2B. Based on these considerations, 5n may be a good antitumor candidate compound for further exploration.

[Four new cis-phenylethanoid glycosides from stems of Cistanche deserticola cultured in Tarim desert].

In order to clarify the chemical constituents of Cistanche deserticola cultured in Tarim desert, a systematically phytochemical investigation was carried out. The chemical constituents were isolated by column chromatography, such as silica gel, Sephadex LH-20, MCI gel, ODS and semi-preparative HPLC, and their structures were determined on the basis of MS, NMR spectroscopic analysis, and comparison with literature data. Four compounds were isolated from the 85% ethanol extract of the stems of C. cultured in Tarim desert. Their structures were identified as cis-tubuloside (1), cis-cistanoside (2), cis-cistanoside J (3), and cis-isocistanoside C(4). Compounds 1-4 were four new cis-phenylethanoid glycosides. Herein, we firstly report the ¹H, ¹³C-NMR data of the new compounds(1-4) for the first time. This study will provide the scientific evidence for comprehensively analyzing the chemical constituents of C. deserticola cultured in Tarim desert.

Cucumis sativus L. WAX2 Plays a Pivotal Role in Wax Biosynthesis, Influencing Pollen Fertility and Plant Biotic and Abiotic Stress Responses.

Cuticular waxes play an important part in protecting plant aerial organs from biotic and abiotic stresses. In previous studies, the biosynthetic pathway of cuticular waxes and relative functional genes has been researched and understood; however, little is known in cucumber (Cucumis sativus L.). In this study, we cloned and characterized an AtWAX2 homolog, CsWAX2, in cucumber and found that it is highly expressed in the epidermis, where waxes are synthesized, while subcellular localization showed that CsWAX2 protein is localized to the endoplasmic reticulum (ER). The transcriptional expression of CsWAX2 was found to be induced by low temperature, drought, salt stress and ABA, while the ectopic expression of CsWAX2 in an Arabidopsis wax2 mutant could partially complement the glossy stem phenotype. Abnormal expression of CsWAX2 in transgenic cucumbers specifically affected both very long chain (VLC) alkanes and cutin biosynthesis. Furthermore, transgenic cucumber plants of CsWAX2 showed significant changes in pollen viability and fruit resistance to water loss and pathogens compared with the wild type. Collectively, these results indicated that CsWAX2 plays a pivotal role in wax biosynthesis, influencing pollen fertility and the plant's response to biotic and abiotic stresses.