Studies on chemical constituents of Laurencia saitoi / 中国中药杂志

In order to search for bioactive natural products from marine algae, the chemical constituents of red alga Laurencia saitoi was separated by the combination of normal phase silica gel, Sephadex LH-20 column chromatography and recrystallization. Seven compounds: aplysistatin (1), 5-acetoxypalisadin B (2), palisadin B (3), palisadin A (4), pacifigorgiol (5), stigmast4-en-3alpha, 6beta-diol (6), 2, 3, 5, 6-Tetrabromoindole (7), were isolated and their structures were elucidated by spectroscopic methods including 1H-NMR, 13C-NMR and MS techniques. All compounds were isolated from L. saitoi for the first time. Cytotoxicities of purified compounds were evaluated by MTT method, however, all of them were found inactive (IC50 >10 mg x L(-1).

Synthesis of (2'-bromo-4', 5'-dimethoxy-phenyl)-(2,3-dibromo-4,5-dimethoxy-phenyl)-methane as PTP1B inhibitor / 中国中药杂志

<p><b>OBJECTIVE</b>To synthesize (2'-bromo-4',5'-dimethoxy-phenyl)-( 2,3- dibromo-4,5-dimethoxy-phenyl)-methane (6) as protein tyrosine phosphatase 1B (PTP1B) inhibitor.</p><p><b>METHOD</b>Compound 6 was synthesized by Friedel-Crafts reaction, bromination and decarbonylation and screened inhibitory activity against PTP1B by the colorimetric assay. The structure of synthetic intermediates and target product were identified on the basis of spectral analysis.</p><p><b>RESULT</b>Compound 6 was synthesized successfully in four steps and evaluated for its PTP1B inhibitory activity, the screening result shown that compound 6 displayed good inhibitory activity against PTP1B.</p><p><b>CONCLUSION</b>The target compound 6 was synthesized with the overall yield of 20%, which was a new compound and shown good inhibitory activity against PTP1B (inhibition 40.16% at 5 mg x L(-1)).</p>