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A series of new α-methylene-γ-lactone carbamates were synthesized by an asymmetric synthetic route. The activities on inhibiting nitric oxide (NO) release of these compounds were evaluated in lipopolysaccharide (LPS)-induced RAW 264.7 macrophages. The results indicated that most of the compounds except one exhibited potent NO inhibitory effect with IC50 value more than 2 μΜ. The cytotoxicities of these compounds were estimated via MTT assays. The results suggested that six compounds were accompanied by low cytotoxicity. The structure–activity relationships were also discussed. The S configuration of C3 on lactones ring would be more helpful to NO inhibitory effect.

A guaiane framework was scaffolded by photochemical rearrangement reactions using α-santonin 1 as a starting material. Then, using a series of reactions, we synthesized the guaiane-type sesquiterpene lactone 5 in high yield. The inhibitory activities of compound 5 and of a series of derivatives on nitric oxide (NO) release were evaluated in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. Compounds 6g, 7h, 7i, 7k and 8g, exhibited significant inhibitory effects on NO production, with IC50 values of 14.8, 22.3, 18.3, 17.4 and 7.0 μM, respectively. Their cytotoxicities were also estimated using an MTT assay. The structure–activity relationships of these compounds were also discussed.

A series of novel derivatives of phenyl substituted tetramethoxy xanthone were synthesized and evaluated for their in vitro cytotoxicity against human hepatocellular carcinoma (HCC) and non-tumor hepatic cells. Among these derivatives, compound 6 was more potent than positive control 5-fluorouracil (5-Fu) on QGY-7703 and SMMC-7721 cells with IC50 values of 6.27 μM, 7.50 μM and 15.56 μM, 14.55 μM, respectively. Furthermore, compounds 6, 14, 16, and 29 exhibited much better selectivity toward the normal hepatic cell line QSG-7701 than 5-Fu. Additionally, compound 6 significantly induced cell apoptosis in QGY-7703 cells. Our findings suggested that these phenylxanthone derivatives may hold promise as chemotherapeutic agents for the treatment of human HCC.

The eight novel ivangustin enantiomer analogues possessing α-methylene-γ-butyrolactone moiety have been synthesized using (4S6R, 4S6S)-4-tert-butyldimethylsilyloxy-6-methylcyclohex-2-en-1-one (1) as starting material. These transformations were mainly carried out by aldol condensation reaction and one-pot annelation procedure. The stereochemistry of these synthesized analogues was determined by NOE analysis. Their cytoxicity was evaluated against the human cancer cell lines HCT-116 (colon), HL-60 (leukemia), QGY-7701 (liver), SMMC-7721 (liver), A549 (lung), MCF-7 (breast). The results showed that these analogues were more selective against the cell lines HL-60 and QGY-7701. Analogue 17 exhibited potent cytotoxicity and high selectivity toward HL-60 cell line with IC50 value of 1.02 μM, which suggested that it might be a promising anti-cancer lead compound. The inhibitory activities against NO production and the cytotoxicities in RAW 264.7 macrophages were determined at the same time. All of the analogues significantly inhibited the NO production with IC50 value in the range of 3.44-6.99 μM. Analogues 17, 22, 23 and 7 showed higher cytotoxicities, indicated their inhibitory activities against NO production may be influenced by the cytotoxicities.

(E)-2-(1-hydroxyl-4-oxocyclohexyl) ethyl caffeine (HOEC), a naturally caffeic ester isolated from Incarvillea mairei, has been reported to possess anti-inflammatory activity by targeting 5-lipoxygenase. However, its other potential activities have yet to be explored. In this study, we measured antioxidant activity of HOEC using the DPPH free radical-scavenging assay. Then, we exposed rat pheochromocytoma (PC12) cells to hydrogen peroxide (H2O2)-induced damage and investigated the antioxidant activity of HOEC. Cell viability, lactate dehydrogenase (LDH) release, cellular morphology, Hoechst 33342 fluorescent staining, and apoptosis of the PC12 cells were assessed after treatment with 0.3-10 μM HOEC for 2 h and exposure to 600 μM H2O2. Additionally, glutathione reductase (GR), superoxide dismutase (SOD), lipid peroxidation malondialdehyde (MDA), and intracellular reactive oxygen species (ROS) accumulation were assayed after the PC12 cells were exposed to H2O2. To investigate mechanism, apoptosis-related protein were evaluated, including cleaved caspase 3/7, cleaved PARP, Bcl-2, Bcl-XL, and cytochrome c. The results showed that HOEC possessed potent antioxidant activity and pre-treatment with HOEC prior to H2O2 exposure significantly increased cell viability, reduced the release of LDH, ameliorated changes in cell morphology, and inhibited apoptosis. Further, HOEC did the following: reduced intracellular accumulation of ROS and MDA; rescued loss of SOD and GR activities; inhibited activated caspase-3 and caspase-7, cleaved PARP, and cytochrome c release; up-regulated the antiapoptosis-related protein Bcl-2 and Bcl-XL; and down-regulated the apoptosis-related proteins Bax and Bad. These findings suggested that HOEC may be a therapeutic agent for treating oxidative stress-derived neurodegenerative disorders.

Valeneomerins A-D [(I)-(III)] are isolated and screened for their neuroprotective activities on hydrogen peroxide-induced apoptosis in human neuroblastoma SH-SY5Y cell lines.