Design, synthesis and evaluation of biological activities of some novel anti-TB agents with bio-reducible functional group

Challenging the Biginelli scaffold to surpass the first line antitubercular drugs: Mycobacterium tuberculosis thymidine monophosphate kinase (TMPKmt) inhibition activity and molecular modelling studies

New Biginelli adducts were rationalised, via the introduction of selected anti-tubercular (TB) pharmacophores into the dihydropyrimidine (DHPM) ring of deoxythymidine monophosphate (dTMP), the natural substrate of Mycobacterium tuberculosis thymidine monophosphate kinase (TMPKmt). Repurposing was one of the design rationale strategies for some selected mimics of the designed compounds. The anti-TB activity was screened against the Mtb H37Rv strain where 11a was superior to ethambutol (EMB), and was 9-fold more potent than pyrazinamide (PZA). Additionally, compounds 11b, 4a, 4b, 13a, 13b and 14a elicited higher anti-TB activity than PZA, showing better safety profiles than EMB against RAW 264.7 cells' growth. The in vitro TMPKmt inhibition assay released compounds 11a, 11b and 13b as the most potent inhibitors. Docking studies presumed the binding modes and molecular dynamics (MD) simulation revealed the dynamic stability of 11a-TMPKmt complex over 100 ns. In silico prediction of the chemo-informatics properties of the most active compounds was conducted.

An Active Compound from the Pyrazine Family Induces Apoptosis by Targeting the Bax/Bcl2 and Survivin Expression in Chronic Myeloid Leukemia K562 Cells

BACKGROUND

It has been established that pyrazine derivatives, which have widespread bioactivities, can effectively treat cancer.

OBJECTIVES

In this study, we investigated the effects of 2-methoxy-5-(oxiran-2-ylmethyl) phenyl pyrazine-2- carboxylate (2-mOPP), a new pyrazine derivative, on proliferation, viability, and apoptosis induction in human leukemia K562 cells.

METHODS

For this purpose, the K562 cells were treated with various concentrations (20-120 μM) of the 2-mOPP for 24-72 hours. Cell viability was determined by MTT growth inhibition assay. Apoptotic activity of 2-mOPP was investigated morphologically by Hoechst staining, cell surface expression assay of phosphatidylserine by Annexin-V/PI technique, as well as DNA fragmentation assay. The effect of 2-mOPP on the K562 cell cycle was studied by flow cytometry. To determine the impact of 2-mOPP on the expression of intrinsic apoptosis-related genes, Bcl2 (anti-apoptotic), Bax (pro-apoptotic), and Survivin genes expression levels were evaluated before and after treatment with 2-mOPP through Real-Time PCR analysis.

RESULTS

The results revealed that 2-mOPP inhibited viability with IC50 of 25μM in 72 h. Morphological changes assessment by fluorescence microscopy, Annexin V/PI double staining by flow cytometry, and DNA ladders formation upon cell treatment with the 2-mOPP showed that this compound induces apoptosis at IC50 value. Cell cycle arrest was observed in the G0/G1 phase, and the sub-G1 cell population (the sign of apoptosis) increased in a time-dependent manner. Low expression levels of Bcl2 and Survivin in K562 cells were observed 24-72 h after treatment. Along with the down-regulation of Survivin and Bcl2, the expression of Bax was increased after treatment with 2-mOPP.

CONCLUSION

These findings demonstrate that the new pyrazine derivative plays a crucial role in blocking the proliferation of the leukemic cells by inducing cell cycle arrest and apoptosis.