Chemical composition and cytotoxic properties of <i>Clinacanthus nutans</i> root extracts

<p><b>Context:</b><i>Clinacanthus nutans</i> Lindau (Acanthaceae) is a medicinal plant that has been reported to have anti-inflammatory, antiviral, antimicrobial and antivenom activities. In Malaysia, it has been widely claimed to be effective in various cancer treatments but scientific evidence is lacking.</p> <p><b>Objective:</b> This study investigates the chemical constituents, anti-proliferative, and apoptotic properties of <i>C. nutans</i> root extracts.</p> <p><b>Materials and methods:</b> 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.</p> <p><b>Results:</b> 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 <i>BCL2</i> and unaltered expression of <i>BAX</i>. 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.</p> <p><b>Discussion and conclusions:</b> The results demonstrated that root extracts promote apoptosis by suppressing <i>BCL2</i> 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.</p