OBJECTIVE: This study investigates the chemical constituents, anti-proliferative, and apoptotic properties of C. nutans root extracts.
MATERIALS AND METHODS: The roots were subjected to solvent extraction using methanol and ethyl acetate. The anti-proliferative effects of root extracts were tested at the concentrations of 10 to 50 μg/mL on MCF-7 and HeLa by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay for 72 h. Morphological changes were observed under light microscope. Pro-apoptotic effects of root extracts were examined using flow cytometric analysis and RT-PCR. The chemical compositions of root extracts were detected using GC-MS.
RESULTS: The proliferation of MCF-7 cells was inhibited with the IC50 values of 35 and 30 μg/mL, respectively, for methanol and ethyl acetate root extracts. The average inhibition of HeLa cells was ∼25%. Induction of apoptosis in MCF-7 was supported by chromatin condensation, down-regulation of BCL2 and unaltered expression of BAX. However, only ethyl acetate extract caused the loss of mitochondrial membrane potential. GC-MS analysis revealed the roots extracts were rich with terpenoids and phytosterols.
DISCUSSION AND CONCLUSIONS: The results demonstrated that root extracts promote apoptosis by suppressing BCL2 via mitochondria-dependent or independent manner. The identified compounds might work solely or cooperatively in regulating apoptosis. However, further studies are required to address this.
METHODS AND RESULTS: The leaves extracts were analysed for its antiproliferative effect on breast cancer (MCF7) cells and normal epithelial breast (MCF 10A) cells using Sulforhodamine B (SRB) assay. The selective extract was evaluated for its ability to induce apoptosis using Annexin V-FITC apoptosis staining and the expression of molecular genes using qualitative reverse transcription-polymerase chain reaction (RT-PCR) against MCF7 cells. Gas chromatography-mass spectrometry (GC-MS) was used to identify the compounds from the selective extract. The findings showed that dichloromethane fraction (CV-Dcm) extract had high antiproliferative effect against MCF7 cells (IC50 = 24 µg/mL, selective index (SI) = 8.17). The percentages of apoptosis cells in CV-Dcm-treated MCF7 cells was 58.8%. The CV-Dcm extract induced downregulation of PCNA level. The apoptotic genes were also triggered in both extrinsic and intrinsic signaling pathways, affecting a 1.5-fold increase in BAX, 1.4-fold increase in cytochrome c, 1.3-fold increase in caspase-8, 1.7-fold increase in caspase-3 and 0.5-fold-decrease in BCL-2. Treated MCF7 cells also activated P53-dependent apoptotic death pathway.
CONCLUSIONS: The present work strongly suggests that high efficacy of CV-Dcm extract was attributed to its antiproliferative and apoptosis-inducing activation in MCF7 cells, most likely due to its favourable compounds.
METHODOLOGY/PRINCIPAL FINDINGS: The hexane extract of C. cassia demonstrated high anti-proliferative activity against MCF-7 and MDA-MB-231 cells (IC50, 34 ± 3.52 and 32.42 ± 0.37 μg/ml, respectively). Oxidative stress due to disruption of antioxidant enzyme (SOD, GPx and CAT) activity is suggested as the probable cause for apoptosis initiation. Though the main apoptosis pathway in both cell lines was found to be through caspase-8 activation, caspase-9 was also activated in MDA-MB-231 cells but suppressed in MCF-7 cells. Gene expression studies revealed that AKT1, the caspase-9 suppressor, was up-regulated in MCF-7 cells while down-regulated in MDA-MB-231 cells. Although, AKT1 protein expression in both cell lines was down-regulated, a steady increase in MCF-7 cells was observed after a sharp decrease of suppression of AKT1. Trans-cinnamaldehyde and coumarin were isolated and identified and found to be mainly responsible for the observed anti-proliferative activity of CE (Cinnamomum cassia).
CONCLUSION: Activation of caspase-8 is reported for the first time to be involved as the main apoptosis pathway in breast cancer cell lines upon treatment with C. cassia. The double effects of C. cassia on AKT1 gene expression in MCF-7 cells is reported for the first time in this study.