Alam P, Tyagi R, Farah MA, Rehman MT, Hussain A, AlAjmi MF, Siddiqui NA, Al-Anazi KM, Amin S, Mujeeb M, Mir SR. Cytotoxicity and molecular docking analysis of racemolactone I, a new sesquiterpene lactone isolated from
Inula racemosa.
PHARMACEUTICAL BIOLOGY 2021;
59:941-952. [PMID:
35294328 PMCID:
PMC8274518 DOI:
10.1080/13880209.2021.1946090]
[Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 03/15/2021] [Accepted: 06/16/2021] [Indexed: 06/13/2023]
Abstract
CONTEXT
Traditionally, Inula racemosa Hook. f. (Asteraceae) has been reported to be effective in cancer treatment which motivated the authors to explore the plant for novel anticancer compounds.
OBJECTIVE
To isolate and characterize new cytotoxic phytoconstituents from I. racemosa roots.
MATERIALS AND METHODS
The column chromatography of I. racemosa ethyl acetate extract furnished a novel sesquiterpene lactone whose structure was established by NMR (1D/2D), ES-MS and its cytotoxic properties were assessed on HeLa, MDAMB-231, and A549 cell lines using MTT and LDH (lactate dehydrogenase) assays. Further, morphological changes were analyzed by flow cytometry, mitochondrial membrane potential, AO-EtBr dual staining, and comet assay. Molecular docking and simulation were performed using Glide and Desmond softwares, respectively, to validate the mechanism of action.
RESULTS
The isolated compound was identified as racemolactone I (compound 1). Amongst the cell lines tested, considerable changes were observed in HeLa cells. Compound 1 (IC50 = 0.9 µg/mL) significantly decreased cell viability (82%) concomitantly with high LDH release (76%) at 15 µg/mL. Diverse morphological alterations along with significant increase (9.23%) in apoptotic cells and decrease in viable cells were observed. AO-EtBr dual staining also confirmed the presence of 20% apoptotic cells. A gradual decrease in mitochondrial membrane potential was observed. HeLa cells showed significantly increased comet tail length (48.4 µm), indicating broken DNA strands. In silico studies exhibited that compound 1 binds to the active site of Polo-like kinase-1 and forms a stable complex.
CONCLUSIONS
Racemolactone I was identified as potential anticancer agent, which can further be confirmed by in vivo investigations.
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