Identification of 3, 4-disubstituted pyridine derivatives as novel CDK8 inhibitors.

Selective inhibition of cyclin-dependent kinase 8 (CDK8) has been recently regarded as a potential approach for cancer therapy. A series of novel CDK8 inhibitors with the pyridine core was identified via scaffold hopping from the known CDK8 inhibitor A-7. The new inhibitors were designed to improve the ligand efficiency so as to enhance drug-likeness. Most of the compounds showed significant inhibition against CDK8/cyclin C, and the most active compounds (5d, 5e and 7') displayed IC50 values of 2.4 nM, 5.0 nM and 7.7 nM, respectively. Preliminary kinase profiling of selected compounds against a panel of kinases from different families indicated that this compound class might selectively inhibit CDK8 as well as its paralog CDK19. Some compounds exhibited cellular activity in both MTT and SRB assays against a variety of tumor cells, including HCT-116, A549, MDA-MB-231, KB, KB-VIN and MCF-7. Further flow cytometry analysis revealed a dose-dependent G2/M phase arrest in MDA-MB-231 cells treated with compounds 6'a, 6'b, 6'j and 6'k. In addition, compound 6'k demonstrated moderate antitumor efficacy in HCT-116 mouse models, although unfavorable pharmacokinetic profiles were suggested by preliminary study in mice. The results provided a new structural prototype for the search of selective CDK8 inhibitors as antitumor agents.

A new indole alkaloid with anti-inflammatory from the branches of Nauclea officinalis.

A new indole alkaloid, 17-oxo-19-(Z)-naucline, and six known alkaloids 2-7 were isolated from the branches of Nauclea officinalis. The structure of the new compound 1 was characterised mainly by analysing its physical data including IR, 1 D, 2 D NMR, and HR-ESI-MS. Other compounds were identified by comparisons their data with those reported in the literature. Compound1, 4, 5, 6, 7 showed in vitro anti-inflammatory activity decrease the LPS-stimulated production of nitric oxide in RAW264.7 cell, while all compounds exhibited weak cytotoxicity against human tumour cell lines (LOVO, A549 and HepG2).

Liver dysfunction induced by Levothyroxine Sodium Tablets (Euthyrox®) in a hypothyroid patient with Hashimoto's thyroiditis: case report and literature review.

A 49-year-old woman with hypothyroidism developed liver dysfunction after increasing dose of levothyroxine (L-T4) (Euthyrox®) from 25 µg to 50 µg. Viral hepatitis, autoimmune hepatitis and non-alcoholic steatohepatitis (NASH) were ruled out with examinations. She had no concurrent medication and had no history of infectious, chronic or any other autoimmune diseases. After cessation of Levothyroxine Sodium Tablets (Euthyrox®), liver enzymes gradually returned to normal. She was diagnosed levothyroxine-induced liver injury, based on criteria proposed in "Diagnosis and treatment guideline on drug-induced liver injury" issued by the Chinese Medical Association (2015). As an alternative 25 µg qod of Levothyroxine Sodium Tablets (Letrox®) was tried and increased gradually up to 75 µg daily. Since then liver enzymes have remained within normal range. The main difference of additive for both tablets is whether it contains lactose or not: Euthyrox® contains lactose which caused no liver injury, thus excluding the possibility that an additive of Euthyrox® contributed to liver injury. The relatively quicker and larger replacement with synthetic T4 for hypothyroidism inducing transient thyrotoxicosis was suspected, although thyroid function was normal. Immune-mediated drug-induced liver injury (DILI) was also not excluded. This is a rare case of drug-induced liver injury due to levothyroxine tablets. It reminded us that when replacement with synthetic T4 for hypothyroidism is done, smaller-dose initiation and slower-speed increase may be useful for treatment of cases similar to genetically susceptible individuals.

Synthesis of gypsogenin derivatives with capabilities to arrest cell cycle and induce apoptosis in human cancer cells.

Thirty-two gypsogenin derivatives were synthesized and screened for their cytotoxic activities. Their structures were established using IR, 1H NMR, 13C NMR, and LC-MS spectroscopic data. In MTT assays nearly all the compounds displayed good cytotoxicity in the low µM range for several human tumour cell lines (A549, LOVO, SKOV3 and HepG2). Low IC50 values were obtained especially for the carboxamides 7a-7j, for an oxime derivative 3 and a (2,4-dinitrophenyl)hydrazono derivative 4. In particular, the IC50 values of compounds 4 (IC50 = 2.97 ± 1.13 µΜ) and 7 g (IC50 = 3.59 ± 2.04 µΜ) against LOVO cells were found to be much lower than those of the other derivatives and parent compound. These compounds were submitted to an extensive biological testing and proved compounds 4 and 7 g to act mainly by an arrest of the tumour cells in the S phase of the cell cycle. In addition, compounds 4 and 7 g triggered the apoptotic pathway in cancer cells, showing high apoptosis ratios.

Two new triterpenoids from Gypsophila oldhamiana.

Two new triterpenoids (1-2) were isolated and elucidated from the roots of Gypsophila oldhamiana, together with four known triterpenoids (3-6). Their structures were identified to be 3ß-hydroxyolean-13(18)-ene-23, 28-dioic acid (1), 3ß, 12α-dihydroxy-23-carboxyolean-28, 13ß-olide (2), 3ß, 16α-dihydroxy-23-oxoolean-13(18)-en-28-oic acid (3), gypsogenin (4), quillaic acid (5) and gypsogenic acid (6) by spectral methods. All compounds were tested for their cytotoxicities against human tumour cell lines (lung cancer H460 and gastric cancer SGC-7901) and for their antiangiogenic effects using a zebra fish model. All compounds showed interesting antiangiogenic activities and the significant cytotoxicities against H460.