Clinacanthus Nutans hexane extracts induce apoptosis through a caspase-dependent pathway in human cancer cell lines

Pei Ying Ng, Soi Moi Chye, Chew Hee Ng, Rhun Yian Koh, Yee Lian Tiong, Liew Phing Pui, Yong Hui Tan, Crystale Siew Ying Lim, Khuen Yen Ng

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    Abstract

    Background: Clinacanthus nutans (C.nutans) is a plant consumed as a cancer treatment in tropical Asia. Despite the availability of numerous anecdotal reports, evaluation of active anticancer effects has remained elusive. Therefore we here examined antiproliferative, reactive oxygen species (ROS)-inducing and apoptosis mechanisms of whole plant extracts in different cancer cell lines. Methods: Antiproliferative actions of five solvent extracts (hexane, chloroform, ethyl acetate, methanol and water) of C.nutans were tested on non-small cell lung cancer (A549), nasopharygeal cancer (CNE1) and liver cancer (HepG2) cells using MTT assay. The most potent anticancer extract was then assessed by flow cytometry to study cell cycle changes . Intracellular levels of ROS were quantified by DCFH-DA assay. Involvement of the caspase pathway in induction of apoptosis was assessed using caspase assay kits. GC-MS analysis was performed to identify phytoconstituents in the extracts. Results: Hexane and chloroform extracts were antiproliferative against all three cell lines, while the ethyl acetate extract, at 300 μg/mL, was antiproliferative in the CNE1 but not A549 and HepG2 cases. Methanol and water extracts did not inhibit cancer cell proliferation. The most potent anticancer hexane extract was selected for further testing. It induced apoptosis in all three cell lines as shown by an increase in the percentage of cell in sub-G1 phase. Dose-dependent increase in ROS levels in all three cell lines indicated apoptosis to be possibly modulated by oxidative stress. At high concentrations (>100 μg/mL), hexane extracts upregulated caspases 8, 9 and 3/7 across all three cell lines. GC-MS analysis of the hexane extract revealed abundance of 31 compounds. Conclusion: Among the five extracts of C.nutans, that with hexane extract demonstrated the highest antiproliferative activity against all three cancer cell lines tested. Action appeared to be via ion of intracellular ROS, and induction of apoptosis via intrinsic and extrinsic caspase pathways.

    Original languageEnglish
    Pages (from-to)917-926
    Number of pages10
    JournalAsian Pacific Journal of Cancer Prevention
    Volume18
    Issue number4
    DOIs
    Publication statusPublished - Apr 2017

    Keywords

    • Apoptosis
    • Cancer
    • Caspase
    • Clinacanthus nutans
    • Reactive oxygen species

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