Phytochemical analysis and anti-lung cancer effects in vitro and in vivo of Eomecon chionantha root.

Background: Eomecon chionantha, a traditional Chinese medicine, is a perennial herb widely cultivated for its medical properties and has been used to treat cancer. However, there are few studies on its anticancer properties.

Objective: This work aimed to identify the chemical composition of E. chionantha root and firstly assess its anti-lung cancer effects in vitro and in vivo.

Methods: E. chionantha root was extracted by reflux using different solvents in sequence to prepare petroleum ether extract (PEE), ethyl acetate extract (EAE), n-butanol extract (NBE), and water extract (WE). Phytoconstituent analysis of E. chionantha root WE was performed by UHPLC-Q-Orbitrap-MS. In in vitro assays, cytotoxicity of four samples from E. chionantha root on non-cancerous MRC-5 cell line and A549 lung cancer cell line was done by MTT. The impact of E. chionantha root WE on A549 cell proliferation was tested by colony formation assay, and flow cytometry with PI staining was utilized for evaluating its influence on the cell cycle. We performed morphological observations, AO/EB staining, Hoechst 33258 staining, and Annexin V-FITC/PI staining assays to investigate the capacity of E. chionantha root WE to induce A549 cell apoptosis. Wound healing and transwell invasion tests assessed its potential to inhibit A549 cell migratory and invasive abilities. Western blot was used to determine its effect on protein levels associated with proliferation, apoptosis, and metastasis in A549 cells. To further validate its in vivo anticancer efficiency, we established an A549 cell xenograft tumor nude mouse model, recorded tumor volume and weight, and conducted histopathological changes using H&E staining and TUNEL assay.

Results: Sixty-one constituents were identified from E. chionantha root WE. For in vitro anticancer properties, E. chionantha root WE displayed selective cytotoxicity against A549 cells (IC50 = 5.39 ± 0.18 μg/mL) and lower toxicity to MRC-5 cells (IC50 = 11.75 ± 1.10 μg/mL). E. chionantha root WE triggered G1 phase arrest via up-regulating p21 levels and down-regulating CDK4, CDK6, and cyclin D3 levels, which markedly suppressed A549 cell proliferation. It induced A549 cell apoptosis via a mitochondria-mediated pathway, leading to Bax up-regulation, ΔΨm down-regulation, Cyt C release, activation of caspase 9 and caspase 3, and PARP cleavage. In addition, it repressed the migratory and invasive abilities of A549 cells through lowering MMP-2 and N-cadherin levels. Regarding in vivo antitumor activity, E. chionantha root WE effectively inhibited A549 xenograft tumor growth and induced cell apoptosis in nude mice. Hence, E. chionantha root WE repressed A549 cell proliferation, induced apoptosis, and inhibited the migratory and invasive abilities in vitro and suppressed tumor growth by inducing apoptosis in vivo.

Conclusions: E. chionantha root WE exhibited pronounced anti-lung cancer efficiency in vivo and in vitro and can be considered a novel source of anticancer agents with great value for development in the pharmaceutical industry.