HPLC-ESI/MS-MS characterization of compounds in Dolomiaea costus extract and evaluation of cytotoxic and antiviral properties: molecular mechanisms underlying apoptosis-inducing effect on breast cancer.

BACKGROUND: Dolomiaea costus (syn: Saussurea costus; Family Asteraceae) occupies an important place in the traditional Chinese medicinal plants and is prescribed for a wide range of disorders. The current study aimed to tentatively identify the phytoconstituents of D. costus extract and to explore antiproliferative activity against human breast cancer cells and its possible apoptotic mechanism along with antiviral activity against human adenovirus 5 (Adv-5). METHODS: The phytoconstituents of 70% ethanol extract of D. costus were assessed using HPLC/ESI-MS/MS technique. The cell viability was investigated against breast cancer cell line (MCF-7) via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Mechanistically, the apoptotic effects on the Bax, Bcl2 and Caspase 3 were determined via quantitative reverse transcriptase-polymerase chain reaction (RT-qPCR). Further, the antiviral activity was assessed against Adv-5 based on virucidal and adsorption mechanisms. RESULTS: The HPLC/MS analysis of the extract revealed tentative identification of twenty compounds of polyphenolic nature, mainly flavonoids, lignans, coumarins, and anthocyanidins. The plant extract showed a cytotoxic effect against MCF-7 and Vero cells with IC50 values of 15.50 and 44 µg/ml, respectively, indicating its aggressiveness against the proliferation of breast cancer cells as confirmed by apoptotic genes expression which revealed upregulation of Bax and Caspase 3 but further insight analysis is needed to explore exact mechanistic pathway. Antiviral activity against Adv-5 was observed at a non-toxic concentration of the tested extract. CONCLUSIONS: Such observations against human breast cancer and viral replication supported further studies for nanoformulations in drug delivery systems as targeting therapy and in vivo studies before biomedical applications.

IR-enhanced photothermal therapeutic effect of graphene magnetite nanocomposite on human liver cancer HepG2 cell model.

Background: Graphene magnetite nanocomposites (G/Fe3O4) exhibit light photothermal conversion upon enhancement by 808 nm IR laser excitation. We evaluated the cytotoxic and photothermal effects of G/Fe3O4 on a HepG2 human liver cancer cell model. Methods: Graphene nanosheets (rGO), magnetite nanoparticles (Fe3O4), and G/Fe3O4 were prepared by chemical methods and characterized using transmission electron microscopy, Raman spectroscopy, zeta analysis, and vibrating sample magnemeter. Dark and light cytotoxicity were screened with colorimetric Sulforhodamine B cell viability assay after 24 and 48 hours. DNA fragmentation and some apoptotic genes on a transcriptional RNA level expression were performed. All prepared nanomaterials were evaluated for their photothermal effect at concentrations of 10 and 50 µg/mL. The power density incident on the cells by 300 mW 808 IR diode laser was 0.597 W/cm2. Results: Treatment of HepG2 with 400 µg/mL of rGO, Fe3O4, and G/Fe3O4 showed alteration in cell morphology after 24 hours of cell treatment and revealed toxic effects on cellular DNA. Evaluation of the cytotoxic effects showed messenger RNA (mRNA) in ß-actin and Bax apoptotic genes, but no expression of mRNA of caspase-3 after 24 hours of cell exposure, suggesting the involvement of an intrinsic apoptotic caspase-independent pathway. A photothermal effect was observed for G/Fe3O4 after irradiation of the HepG2 cells. A marked decrease was found in cell viability when treated with 10 and 50 µg/mL G/Fe3O4 from 40% to 5% after 48 hours of cell treatment. Conclusion: Results indicate that G/Fe3O4 nanocomposite was effective at transformation of light into heat and is a promising candidate for cancer therapy.