Effects of dihydromyricetin on biological properties of Bloom syndrome helicase / 中国药理学通报

; Aim To explore the anti-tumor mechanism of dihydromyricetin (DMY), a kind of flavonoid compound with anti-inflammatory and anti-tumor effects, via studying the effect of DMY on biological activities of Bloom helicase. Methods The effect of DMY on the biological activities of BLM helicase was studied by ultraviolet spectrum (UV), circular dichroism (CD), fluorescence polarization and free phosphorus detection. Results The results of CD and UV showed that DMY could bind to a site of the BLM helicase. In the concentration of DMY in 0 ~ 25 μmol . L 1 range, DMY showed a positive correlation with the interference ability of BLM helicase secondary structure with the increase of concentration, while in the concentration of DMY in 25 ~ 75 μmol . L 1 range, DMY showed a negative correlation. Fluorescence polarization and free phosphorus detection experiments showed that DMY could bind to BLM helicase, thus inhibiting the helicase activity of BLM helicase. Conclusions DMY can competitively bind to the DNA binding site of BLM helicase and change the spatial structure of BLM helicase, inhibiting the binding of BLM helicase to DNA and the biological activity of BLM helicase accordingly.

Two new cyclic bisbibenzyl derivatives from Hebertus dicranus / 中国天然药物

In the present study, two new cyclic bisbibenzyls (1, 2) co-occuring with a known compound, isoplagiochins C (3) were isolated from Hebertus dicranus. The structures were determined mainly by extensive 1D and 2D NMR experiments, and the absolute configurations of 1 and 2 were established by the circular dichroism spectrum. Furthermore, all these three rare compounds were tested in vitro for inhibitory activity against the growth of human cancer cell lines (A549, HCT116, MDA-MB-231, and BEL7404) by the MTT assay, and compound 2 exhibited moderately inhibitory activity with IC50 values ranging from 13.89 to 31.62 μmol·L(-1). In conclusion, our results provided a basis for future development and modification of these compounds for cancer therapy.

Absolute determination of stereochemical configuration of some marine natural products / 国际药学研究杂志

The determination of stereochemical absolute structure is an important issue in structural elucidation of natural products. The absolute configuration of natural compounds with a chiral α, β -unsaturated ketone chromorphore can be determined by the Cotton effect in 320-350 nm (n→π,* transition) and 220-260 nm (π→π,* transition) regions of the circular dichroism (CD) spectrum. This paper reviews the absolute stereochemical asignment of some α, β-unsaturated ketone compounds as well as some of the longer fatty chain derived compounds.