Rongcai Yue

Construction of 2-substituted-3-functionalized benzofurans via intramolecular Heck coupling: application to enantioselective total synthesis of daphnodorin B.

A novel approach was developed for the synthesis of 2-substituted-3-functionalized benzofurans, using an intramolecular Heck reaction which was further applied in the first enantioselective total synthesis of Daphnodorin B.

Metabolomic Study of Collagen-Induced Arthritis in Rats and the Interventional Effects of Huang-Lian-Jie-Du-Tang, a Traditional Chinese Medicine

Huang-Lian-Jie-Du-Tang (HLJDT) is a traditional Chinese medicine (TCM) with anti-inflammatory activity. The present study used a metabolomic approach based on LC-Q-TOF-MS to profile rheumatoid-arthritis- (RA-) related metabolic changes and to investigate the interventional mechanisms of HLJDT in collagen-induced arthritis rats. Forty male Wistar rats were randomly divided into five groups: (1) a model group, (2) a normal control group, (3) a dexamethasone group, (4) a HLJDT group, and (5) a group that received 13 components of HLJDT. Plasma samples were collected 8, 15, and 22 days after the rats were injected with bovine type II collagen. By combining variable importance in the projection values with partial least squares discriminant analysis, 18 potential biomarkers were identified in the plasma samples. The biomarkers were primarily involved in glycerophospholipid metabolism, fatty acid metabolism, tryptophan metabolism, linoleic acid metabolism, phenylalanine metabolism, purine metabolism, arachidonic acid metabolism, and bile acid biosynthesis. Using the potential biomarkers as a screening index, the results suggest that HLJDT can potentially reverse the process of RA by partially regulating fatty acid oxidation and arachidonic acid metabolism. This study demonstrates that a metabolomic strategy is useful for identifying potential RA biomarkers and investigating the underlying mechanisms of a TCM in RA treatment.

Neuroprotective effects of bacopaside I in ischemic brain injury

PURPOSE Bacopa monnieri (L.) WETTST. is extensively used in traditional Indian medicine as a nerve tonic. The neuropharmacological properties of bacopaside I, an important component from B. monnieri, have not been studied so far. The present study investigated the effects and possible mechanisms of bacopaside I in a rat model of transient focal ischemia induced by middle cerebral artery occlusion (MCAO). METHODS Adult male Sprague-Dawley rats were divided into five groups: sham-operated group, ischemia group, and three bacopaside I-treated groups (3, 10 and 30 mg/kg) respectively. Bacopaside I or vehicle (0.5% CMC-Na) was administered orally once a day for 6 days. On the third day, the rats were subjected to 2 h right MCAO via the intraluminal filament technique and 70 h reperfusion. Assessment of behavioral deficits both at 22 and 70 h, and measurement of cerebral infarct volume, edema, cerebral energy metabolism, relative enzyme activities, malondialdehyde (MDA) content, nitric oxide (NO) level, and antioxidant enzyme activities at 70 h, performed after MCAO reperfusion. RESULTS Bacopaside I (10 and 30 mg/kg) treatment produced significant reduction in neurological deficits at 22 and 70 h, and significantly reduced cerebral infarct volume and edema at 70 h, when compared with the ischemia group. Animal, that were orally treated with bacopaside I (3, 10 and 30 mg/kg) showed increased the brain ATP content, energy charge (EC), total adenine nucleotides (TAN), nitric oxide (NO) level, Na+K+ATPase and Ca2+Mg2+ATPase activity. Bacopaside I (3, 10 and 30 mg/kg) treatment also improved antioxidant enzyme activities including brain superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), in varying degrees, compared with the ischemia group. In addition, three doses of bacopaside I (3, 10 and 30 mg/kg) markedly inhibited the increase in MDA content of the brain. CONCLUSIONS These findings indicated that bacopaside I possess a neuroprotective effect against injury caused by cerebral ischemia. The protective mechanism might be related to improving cerebral energy metabolism and increasing antioxidant levels.

The antidepressant-like effect of bacopaside I: possible involvement of the oxidative stress system and the noradrenergic system.

In the present study, the antidepressant-like effect of bacopaside I, a saponin compound present in the Bacopa monniera plant, was evaluated by behavioral and neurochemical methods. Bacopaside I (50, 15 and 5 mg/kg) was given to mice via oral gavage for 7 successive days. The treatment significantly decreased the immobility time in mouse models of despair tests, but it did not influence locomotor activity. Neurochemical assays suggested that treatment by bacopaside I (50, 15 and 5 mg/kg) improved brain antioxidant activity to varying degrees after the behavioral despair test. Bacopaside I (15 and 5 mg/kg) significantly reversed reserpine-induced depressive-like behaviors, including low temperature and ptosis. Conversely, bacopaside I did not affect either brain MAO-A or MAO-B activity after the behavioral despair test in mice. Additionally, 5-hydroxytryptophan (a precursor of 5-serotonin) was not involved in the antidepressant-like effect of bacopaside I. These findings indicated that the antidepressant-like effect of bacopaside I might be related to both antioxidant activation and noradrenergic activation, although the exact mechanism remains to be further elucidated.

Cynandione A mitigates ischemic injuries in rats with cerebral ischemia.

J. Neurochem. (2012) 121, 451–464.

(−) and (+)-Merrilliaquinone, a pair of new quinone enantiomers from Illicium merrillianum and their distinctive effect on human hepatoma and hepatic cells

Merrilliaquinone (1), a new racemic quinone was isolated from the branches and leaves of Illicium merrillianum. Chiral separation of 1 gave two enantiomers (−)-merrilliaquinone (1a) and (+)-merrilliaquinone (1b). The structure of 1 was established by comprehensive spectroscopic analysis, and the absolute configurations of 1a and 1b were determined by quantum mechanical calculation of ECD spectra. It is very interesting that 1b had a selective cytotoxicity against human hepatoma cell lines SMMC7721 and HuH7 with IC50 values of 0.91 μM and 1.29 μM, while its IC50 values on normal human hepatic cells QSG7701 and LO2 were 47.79 μM and 36.71 μM, respectively. Moreover, 1a and racemate 1 only exhibited very weak cytotoxicity against SMMC7721 and HuH7 cells with IC50 values of 27.01–37.82 μM. These results implied that the absolute configurations of 1a and 1b possess remarkable influences on their cytotoxicities. Further mechanism studies indicated that 1b dose-dependently induced SMMC7721 cell apoptosis and reduction of mitochondrial membrane potential (MMP) at 1–10 μM. Flow cytometry analysis showed that the 1b-induced SMMC7721 cell apoptosis was associated with cell cycle arrest during the G0/G1 phase.

Jacarelhyperol A induced apoptosis in leukaemia cancer cell through inhibition the activity of Bcl-2 proteins

BackgroundHypericum japonicum Thunb. ex Murray is widely used as an herbal medicine for the treatment of hepatitis and tumours in China. However, the molecular mechanisms of its effects are unclear. Our previous research showed that extracts of H. japonicum can induce apoptosis in leukaemia cells. We also previously systematically analysed and isolated the chemical composition of H. japonicum.MethodsThe fluorescence polarisation experiment was used to screen for inhibitors of Bcl-2 proteins which are proved as key proteins in apoptosis. The binding mode was modelled by molecular docking. We investigated the proliferation attenuating and apoptosis inducing effects of active compound on cancer cells by MTT assay and flow cytometry analysis. Activation of caspases were tested by Western blot. A broad-spectrum caspase inhibitor Z-VAD-FMK was used to investigate the caspases-dependence. In addition, co-immunoprecipitation was performed to analyse the inhibition of heterodimerization between anti-apoptotic Bcl-2 proteins with pro-apoptotic proteins. Moreover, in vivo activity was tested in a mouse xenograph tumour model.ResultJacarelhyperol A (Jac-A), a characteristic constituent of H. japonicum, was identified as a potential Bcl-2 inhibitor. Jac-A showed binding affinities to Bcl-xL, Bcl-2, and Mcl-1 with Ki values of 0.46 μM, 0.43 μM, and 1.69 μM, respectively. This is consistent with computational modelling results, which show that Jac-A presents a favorable binding mode with Bcl-xL in the BH3-binding pocket. In addition, Jac-A showed potential growth inhibitory activity in leukaemia cells with IC50 values from 1.52 to 6.92 μM and significantly induced apoptosis of K562 cells by promoting release of cytochrome c and activating the caspases. Jac-A also been proved that its effect is partly caspases-dependent and can disrupt the heterodimerization between anti-apoptotic Bcl-2 proteins with pro-apoptotic proteins. Moreover, Jac-A dose-dependently inhibited human K562 cell growth in a mouse xenograph tumour model with low toxicity.ConclusionIn this study, a characteristic constituent of H. japonicum, Jac-A, was shown to induce apoptosis in leukaemia cells by mediating the Bcl-2 proteins. Therefore, we propose a new lead compound for cancer therapy with a low toxicity, and have provided evidence for using H. japonicum as an anti-cancer herb.

Evaluation of novel saponins from Psammosilene tunicoides and their analogs as immunomodulators.

Two original oleanane-type triterpenoid saponins, tunicosaponin A (TSA) and tunicosaponin E (TSE) were isolated from the roots of Psammosilene tunicoides. Four semi-synthetic saponin derivatives, TSA1, TSA2, TSA3, and TSA4, were synthesized from TSA; two derivatives TSE1 and TSE2 were prepared from TSE. Through comparing their hemolytic activity and effects on ovalbumin (OVA)-induced IgG response with those of Quil A, TSA2 was selected as a lead candidate to evaluate acute and hepatotoxic toxicities and adjuvant potentials on the cellular and humoral immune responses of ICR mice against OVA. TSA2 had lower hemolytic activity than Quil A and TSA (P<0.001). Furthermore, TSA2 did not cause any mortality and side effects when mice were administered subcutaneously at a dose up to 1.6 mg. Moreover, no significant hepatotoxic effect was observed in TSA2 groups in doses ranging from 0.05 mg to 0.8 mg. The Con A-, LPS-, and OVA-induced splenocyte proliferation, OVA-specific antibody levels (IgG, IgG1, IgG2a and IgG2b) and IFN-γ, TNF-α, IL-2, IL-4 and IL-5 in serum were significantly enhanced by TSA2 (25 μg/mouse). The present study of structure-activity relationship indicates that the hydrophobicity of the ester/amide chains bonds to the carboxyl group of the glucuronic acid residue at position C-3 of the triterpene aglycone and the type of sugar chain at C-28 position of saponin could affect the potential of toxicity and adjuvant. Our findings demonstrate that TSA2 possesses higher adjuvant activities with less adverse effects and should be further explored as an immunomodulator for immune responses.

Pseudolaridimers A and B, Hetero-Cycloartane–Labdane Diels–Alder Adducts from the Cone of Pseudolarix amabilis

Pseudolaridimers A (1) and B (2), two unprecedented heterodimers formed via a [4 + 2] Diels-Alder cycloaddition between a cycloartane triterpenoid unit and a labdane diterpenoid unit, were isolated from the cones of Pseudolarix amabilis. Their structures were established by extensive analysis of HRESIMS and NMR spectra. The absolute configuration of 1 was determined by single crystal X-ray diffraction (CuK(α)) of its methyl esterified derivative. Pseudolaridimer A (1) showed strong cytotoxicity against HCT116, ZR-75-30, and HL-60 human tumor cell lines, with IC(50) values 9.62, 7.84, 8.29 μg/mL, respectively. Pseudolaridimer B (2) only exhibited potent inhibition against the HL-60 cell line with an IC(50) value of 7.50 μg/mL.

Synthesis and biological evaluation of phenyl substituted polyoxygenated xanthone derivatives as anti-hepatoma agents

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.