Background:
Microtubules are considered to be an important therapeutic target for most of the anticancer drugs. These are
highly dynamic structures comprising of α-tubulin and β-tubulin which are usually heterodimers and found to be involved in cell movement,
intracellular trafficking, and mitosis inhibition of which might kill the tumour cells or inhibit the abnormal proliferation of cells. Most of
the tubulin polymerization inhibitors such as Vinca alkaloids consist of Indole as main scaffold. The literature, also suggests the use of
triazole moiety in the chemical entities, potentiate the inhibitory activity against cell proliferation. So, in our study, we used indole triazole
scaffolds to synthesize the derivatives against tubulin polymerization.
Objective:
The main objective of this study to synthesize indole triazole conjugates by using environmentally friendly solvents (green
chemistry) and click chemistry. To carry out the MTT assay and tubulin polymerization assay for the synthesized indole triazole conjugates.
Methods:
All the synthesized molecules were subjected to molecular docking studies using Schrodinger suite and the structural
confirmation was performed by Mass, proton-NMR and carbon-NMR, documented in DMSO and CDCL3. Biological studies were
performed using DU145 (prostate cancer), A-549 (lung cancer) and, MCF-7 (breast cancer), cell lines obtained from ATCC were
maintained as a continuous culture. MTT assay was performed for the analogues using standard protocol. Cell cycle analysis was carried
out using flow cytometry.
Results:
The Indole triazole scaffolds were synthesized using the principles of Green chemistry. The triazole formation is mainly achieved
by using the Click chemistry approach. Structural elucidation of synthesized compounds was performed using Mass spectroscopy (HRMS), Proton-Nuclear Magnetic Spectroscopy (1H-NMR) and Carbon-Nuclear Magnetic Spectroscopy (13C-NMR). The XP-docked poses
and free energy binding calculations revealed that 2c and 2g molecules exhibited highest docking affinity against tubulin-colchicine domain
(PDB:1SA0). Invitro cytotoxic assessment revealed that 2c and 2g displayed promising cytotoxicity in MTT assay (with CTC50 values
3.52 μM and 2.37 μM) which are in good agreement with the computational results. 2c and 2g also arrested 63 and 66% of cells in the
G2/M phase, respectively, in comparison to control cells (10%) and tubulin polymerization inhibition assay revealed that 2c and 2g
exhibited significant inhibition of tubulin polymerization with IC50 values of 2.31µM, and 2.62 µM, respectively in comparison to
Nocodazole, a positive control, resulted in an IC50 value of 2.51 µM.
Conclusion:
Indole triazole hybrids were synthesized by using click chemistry, and docking studies were carried out using Schrodinger for
the designed molecules. Process Optimization has been done for both the schemes. Twelve compounds (2a-2l) have been successfully
synthesized and analytical evaluation was performed using NMR and HR-MS. In vitro evaluation was for the synthesized molecules to check tubulin polymerization inhibition for antiproliferative action. Among the synthesized compounds, 2c and 2g have potent anticancer
activities by inhibiting tubulin polymerization.
Triterpenoids with Cytotoxic Potential from the Leaves of Tridax procumbens L.
