Synthesis and Evaluation of Pyrimidine Steroids as Antiproliferative Agents

Design, synthesis and molecular docking of novel D-ring substituted steroidal 4,5-dihydropyrazole thiazole derivatives that act as iNOS/COX-2 inhibitors with potent anti-inflammatory activity against LPS-induced RAW264.7 macrophage cells

Inflammation, an important biological protective response to tissue damage or microbial invasion, is considered to be an alarming signal for the progress of varied biological complications. Based on the previous reports in the literature that proved the noticeable efficacy of pyrazole and thiazole scaffold as well as nitrogen heterocyclic based compounds against acute and chronic inflammatory disease, a new set of novel D-ring substituted steroidal 4,5-dihydropyrazole thiazole derivatives were synthesized and evaluated their anti-inflammatory activities in vitro. Preliminary structure-activity relationship (SAR) analysis was conducted by their inhibitory activities against nitric oxide (NO) release in lipopolysaccharide (LPS)-induced RAW 264.7 cells, and the optimal compound 12b [3β-hydroxy-pregn-5-en-17β-yl-5'- (o- chlorophenyl)- 1'-(4''- phenyl -[1'', 3'']- thiazol-2''- yl) - 4',5'-dihydro - 1'H-pyrazol - 3'- yl] exhibited more potent anti-inflammatory activity than the positive control treatment methylprednisolone (MPS), with an IC50 value of 2.59 μM on NO production and low cytotoxicity against RAW 264.7 cells. In further mechanism study, our results showed that compound 12b significantly suppressed the production of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and inhibited the expressions of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) through blocking NF-κB p65 nuclear translocation and phosphorylation of IκBα. Compound 12b also attenuated LPS-induced activation of c-Jun amino-terminal kinase (JNK) and p38 phosphorylation in RAW 264.7 cells. Molecular docking study revealed the strong binding affinity of compound 12b to the active site of the COX-2 proteins, which confirmed that compound 12b acted as an anti-inflammatory mediator. These results indicate that steroidal derivatives bearing 4,5-dihydropyrazole thiazole structure might be considered for further research and scaffold optimization in designing anti-inflammatory drugs and compound 12b might be a promising therapeutic anti-inflammatory drug candidate.

Developments in the Antitumor Activity, Mechanisms of Action, Structural Modifications, and Structure-Activity Relationships of Steroidal Saponins

Steroidal saponins, a class of natural products formed by the combination of spirosteranes with sugars, are widely distributed in plants and have various biological activities, such as anti-tumor, anti-inflammatory, anti-bacterial, anti-Alzheimer's, anti-oxidation, etc. Particularly, extensive researches on the antitumor property of steroidal saponins have been received. Steroidal sapogenins, the aglycones of steroidal saponins, also have attracted much attention due to a vast range of pharmacological activities similar to steroidal saponins. In the past few years, structural modifications on the aglycones and sugar chains of steroidal saponins have been carried out and some achievements have been made. In this mini-review, the antitumor activity, action mechanisms, and structural modifications along with the structure-activity relationships of steroidal saponins and their derivatives are summarized.

Synthesis, pharmacological evaluation and Molecular modelling studies of pregnenolone derivatives as inhibitors of human dihydrofolate reductase

In current study, we synthesized chalcone derivatives (13a-c) via base-catalyzed Claisen-Schmidt condensation reaction. We further treated diamino compounds with synthesized chalcones to produce 3,4-dihydropyrimidin-2(1H)-one (18a-c), 3,4-dihydropyrimidin-2(1H)-thione (19a-c) and 2-aminopyrimidine (20a-c) derivatives of pregnenolone by cyclization reaction. Cell viability test of synthesized steroidal chalcones and their pyrimidine and thiopyrimidine derivatives against human breast (MCF-7), human lung (A549) and human prostate (PC-3) cancer cell lines was performed using (4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), assay. Compounds were further evaluated for their inhibition potential against recombinant human DHFR (rhDHFR). All compounds showed activity from low micromolar to submicromolar range. Compound 20b with IC₅₀ value of 180 nM emerged as most potent compound against rhDHFR. Interaction of the newly synthesized pregnenolone derivatives with hDHFR and estrogen receptor alpha (ERα) were also explored via docking simulations. The overall results of hDHFR inhibition have shown that these analogues can be further optimized and developed as potent anticancer agents.

Synthesis of Novel 2-(Pyridin-2-yl) Pyrimidine Derivatives and Study of Their Anti-Fibrosis Activity

A pyrimidine moiety exhibiting a wide range of pharmacological activities has been employed in the design of privileged structures in medicinal chemistry. To prepare libraries of novel heterocyclic compounds with potential biological activities, a series of novel 2-(pyridin-2-yl) pyrimidine derivatives were designed, synthesized and their biological activities were evaluated against immortalized rat hepatic stellate cells (HSC-T6). Fourteen compounds were found to present better anti-fibrotic activities than Pirfenidone and Bipy55'DC. Among them, compounds ethyl 6-(5-(p-tolylcarbamoyl)pyrimidin-2-yl)nicotinate (12m) and ethyl 6-(5-((3,4-difluorophenyl)carbamoyl)pyrimidin-2-yl)nicotinate (12q) show the best activities with IC₅₀ values of 45.69 μM and 45.81 μM, respectively. Furthermore, the study of anti-fibrosis activity was evaluated by Picro-Sirius red staining, hydroxyproline assay and ELISA detection of Collagen type I alpha 1 (COL1A1) protein expression. Our study showed that compounds 12m and 12q effectively inhibited the expression of collagen, and the content of hydroxyproline in cell culture medium in vitro, indicating that compounds 12m and 12q might be developed the novel anti-fibrotic drugs.