Bioassay-Guided Fractionation and In Vitro Antiproliferative Effects of Fractions of Artemisia nilagirica on THP-1 cell line

ABSTACT

Artemisia nilagirica (Clarke) is a widely used medicinal herb in Indian traditional system of medicine. Therefore, the present study was designed to evaluate the effects of A. nilagirica extracts/fractions on inhibition of proliferation and apoptosis in a human monocytic leukemia (THP-1) cell line. The crude extracts (A. nilagirica ethyl acetate extract [ANE] and A. nilagirica methanolic extract [ANA]) showed cytotoxic activity toward THP-1 cells with the IC₅₀ values of 38.21 ± 7.37 and 132.41 ± 7.19 µg/ml, respectively. However, the cytotoxic activity of active fractions (ANE-B and ANM-9) obtained after column chromatography was found to be much more pronounced than their parent extracts. The IC₅₀ values of ANE-B and ANM-9 were found to be 27.04 ± 2.54 µg/ml and 12.70 ± 4.79 µg/ml, respectively, suggesting greater susceptibility of the malignant cells. Cell cycle analysis and terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end-labeling (TUNEL) assay revealed that inhibition of cell growth by A. nilagirica fractions on THP-1 cells was mediated by apoptosis. Active fractions of A. nilagirica increased the expression levels of caspase-3, −7, and poly-ADP-ribose polymerase (PARP), a critical member of the apoptotic pathway. These results suggested that active fractions of A. nilagirica may play a promising role in growth suppression by inducing apoptosis in human monocytic leukemic cells via mitochondria-dependent and death receptor-dependent apoptotic pathways.

Acknowledgments

This work was supported by grants from the University of Hyderabad-UPE Phase-2. We thank CRIUM, Hyderabad, Telangana for providing the plant material. The authors MZG, SC, and MYB acknowledge the financial support in the form of Senior Research Fellowship from Council of Scientific and Industrial Research and University Grants Commission (UGC), New Delhi, India respectively. MK acknowledges the financial support from Department of Science and Technology (DST), Govt. of India, in the form DST-WOSA Scientist program. The authors would also like to thank D. Prasanth, Technical Assistant, Metabolomics facility for his assistance in LC-MS analysis. The authors are also thankful to UoH—Metabolomics facility funded by DBT-CREBB, Flow Cytometry facility of Animal Biology, UoH, DBT-CREBB, DST-FIST level-II support, and UGC-SAP-CAS, UGC-XI plan seed money for supporting infrastructural facilities of Department of Plant Sciences and School of Life Sciences, University of Hyderabad.