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A new bis-γ-pyrone polypropionate compound onchidione II (1), together with three known compounds, was isolated from a marine pulmonate mollusc Onchidium struma, collected at Hainan Island of China. The structure of new compound was determined by extensive spectroscopic analyses including IR, 1D and 2D NMR techniques, and chemical methods. Compounds 1–4 were evaluated for their cytotoxicity against human tumor cell lines HepG-2, A549, and MCF-2. The results showed that compounds 1 and 2 were moderate cytotoxic against HepG-2, A549, and MCF-2 cell lines, with IC50 values from 13.2 to 22.4 μM. [ABSTRACT FROM AUTHOR]

Plant-derived natural products have been the highly significant sources of novel antitumor agents. The cassane-type diterpenes of genusCaesalpiniahave been reported to bear antiproliferative activities toward different types of cancer cells. In this study, we evaluated the antineoplasmic activities of 16 natural origin cassane-type diterpenes isolated from the CHCl3extract of the seeds ofC. minaxin pituitary adenomas cells and identified caesalpin G (CAG) showed the strongest cytotoxicity. Moreover, we further investigated the structure–activity relationship and molecular mechanism of these derivatives systematically. The results confirmed the unsaturated lactone-type ring, hydroxyl at C-7, and alkenyl at C-11 or C-14 functionality as critical for anticancer activity in this family of natural products. In addition, the mechanism experiments also demonstrated unfolded protein response and ER stress and Wnt/β-catenin pathway were involved in the CAG-induced apoptosis. [ABSTRACT FROM PUBLISHER]

Five diarylpentanol derivatives including two new compounds stellerasme A (1), stellerasme B (2) were isolated from the aerial parts ofStelleropsis tianschanica. Their structures were elucidated by various spectroscopic techniques (UV, IR, MS, CD, 1D and 2D NMR). All compounds were evaluated for their cytotoxicity activity against HeLa and KB cell lines, and compound1showed selective activities against HeLa cell line with an IC50value of 7.4 μM. [ABSTRACT FROM PUBLISHER]

A new ursane-type triterpene, cymosic acid (1) together with two known compounds, 3β,19α-dihydroxy-2-oxo-12-ursen-28-oic acid (2) and 2α,19α-dihydroxy-3-oxo-12-ursen-28-oic acid (3), were isolated from Rosa cymosa Tratt. The structure of compound 1 was elucidated by analyzing its 1H and 13C NMR, 1H–1H COSY, HSQC, HMBC, NOESY, and HR-ESI-MS values. The three compounds were found to display moderate inhibitory activities against nitric oxide production in lipopolysaccharide-activated macrophage cell lines, RAW 264.7 cells. [ABSTRACT FROM AUTHOR]

Two new cassane-type diterpenes, neocaesalpin MR (1) and minaxin C (2), were isolated from Caesalpinia minax HANCE. The structures of these compounds were elucidated by means of spectroscopic analysis. Among these isolated compounds, neocaesalpin MR showed mild activities toward HeLa and colon cancer (HCT-8) human cancer cell lines. [ABSTRACT FROM PUBLISHER]