BSc - MSc(Int.)

The study entitled “Antiproliferative and apoptotic activities of black turmeric
(Curcuma caesia Roxb)” was carried out at the Department of Plant Biotechnology,
College of Agriculture, Vellayani, in the year 2021-2022 to evaluate the
antiproliferative and cytotoxic properties of methanolic extract of Curcuma caesia
rhizome in cancer cell lines and to elucidate its action on the apoptotic pathway.
The dried rhizome of Curcuma caesia was extracted with methanol using the soxhlet
apparatus and yielded 250mg of crude extract from 5g. The evaluation of the
antiproliferative and cytotoxic activity of the extract was performed in lung (A549) and
breast cancer (MDA-MB-231) cell lines and normal (HEK-293) cell line cultured in
DMEM medium.
3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay was
performed in the cell lines treated with different concentrations of the extract for 48h,
by keeping absolute ethanol as vehicle control and the standard chemotherapeutic drug,
5-Fluorouracil as the positive control. The extract showed cytotoxicity to the cancer
cells with IC50 values of 100.54 µg/mL and 166.51 µg/mL in the lung and breast cancer
cell lines respectively without any cytotoxicity to the normal cell line up to 200 µg/ml.
In the clonogenic assay which assesses the proliferative and colony forming ability of
the cells, the crude extract at IC50 showed 80.2% inhibition of colony formation in A549
cells and 100% in MDA-MB-231 cells.
The DNA isolated from treated cell lines was assessed for fragmentation to determine
the effect of Curcuma caesia rhizome extract on apoptosis. There was no visible
shearing or fragmentation observed on 1.8% agarose gel. Gene expression profiles of
five apoptotic genes with Β ACTIN as a reference gene were analysed using Real-time
PCR. The ratio of expression of the apoptotic marker genes, BAX and BCL-2 were 10
and 1.9 in the lung and breast cancer cell line, respectively, indicating the chances of
activation of the apoptotic pathway. But these genes were found downregulated in
A549 and MDA-MB-231 treated with the extract compared to the untreated control. In
A549 cells, CASPASE 9, CASPASE 3 and PARP1 genes were downregulated. In MDAMB-231, CASPASE 9 was upregulated, while CASPASE 3 and PARP1 were
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downregulated. The exact mechanism of action of C. caesia rhizome is not understood
completely and more studies are required.
The study concludes that methanolic rhizome extract of C.caesia possesses cytotoxic
and antiproliferative effects in the breast and lung cancer cell lines without affecting
normal cell lines, indicating its promising anticancer potential which can be explored
by further studies.