title: Promotion of HepG2 cell apoptosis by flower of Allium atroviolaceum and the mechanism of action.
abstract: BACKGROUND
  Liver cancer is a high incidence and fatal disease, the fifth most frequent cancer worldwide that is usually diagnosed at an advanced stage. The number of deaths from liver cancer has not declined even following various therapies. Plant secondary metabolites and their semi-synthetic derivatives play a principal role in anti-cancer drug therapy, since they are effective in the treatment of specific characteristics while also reducing side effects. Allium atroviolaceum, a plant of the genus Allium has been used in folk medicine to protect against several diseases. However, cytotoxicity and the anti-proliferative effect of Allium atroviolaceum remain unclear. This work aims to investigate the anticancer properties of Allium atroviolaceum and the mechanism of action.
  
  
  METHODS
  To evaluate the in vitro cytotoxicity of flower of Allium atroviolaceum, methanol extract at a dose range from 100 to 3.12 μg/ml was assessed against the HepG2 hepatocarcinoma cell line, and also on normal 3T3 cells, by monitoring proliferation using the MTT assay method. A microscopy study was undertaken to observe morphological changes of HepG2 cells after treatment and cell cycle arrest and apoptosis were studied using flow cytometry. The apoptosis mechanism of action was assessed by the level of caspase-3 activity and expression of apoptosis related genes, Bcl-2, Cdk1 and p53. The combination effect of the methanolic extract with doxorubicin was also investigated by determination of a combination index.
  
  
  RESULTS
  The results demonstrated growth inhibition of cells in both dose- and time-dependent manners, while no cytotoxic effect on normal cell 3T3 was found. The results revealed the occurrence of apoptosis, illustrated by sub-G0 cell cycle arrest, the change in morphological feature and annexin-V and propidium iodide staining, which is correlated with Bcl-2 downregulation and caspase-3 activity, but p53-independent. In addition, a combination of Allium atroviolaceum and doxorubicin led to a significant synergistic effect.
  
  
  CONCLUSIONS
  These findings suggest that Allium atroviolaceum flower extract has potential as a potent cytotoxic agent against HepG2 cell lines, as it has commendable anti-proliferative activities against human hepatocarcinoma and it can be considered as an effective adjuvant therapeutic agent after the clinical trials.
authors.affiliation: Department of Biomedical Science, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Selangor, 43400, Malaysia.
authors.forename: S
authors.initials: S
authors.lastname: Khazaei
authors.affiliation: Department of Biomedical Science, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Selangor, 43400, Malaysia.
authors.forename: R
authors.initials: R
authors.lastname: Abdul Hamid
authors.affiliation: Department of Nutrition and Dietetics, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Selangor, 43400, Malaysia.
authors.forename: N
authors.initials: N
authors.lastname: Mohd Esa
authors.affiliation: Malaysian Research Institute of Aging, Universiti Putra Malaysia, Serdang, Selangor, 43400, Malaysia.
authors.forename: V
authors.initials: V
authors.lastname: Ramachandran
authors.affiliation: Department of Biomedical Science, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Selangor, 43400, Malaysia.
authors.forename: Ghomi Tabatabaee F
authors.initials: GT
authors.lastname: Aalam
authors.affiliation: Department of Biomedical Science, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Selangor, 43400, Malaysia.
authors.forename: A
authors.initials: A
authors.lastname: Etemad
authors.affiliation: Department of Biomedical Science, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Selangor, 43400, Malaysia. patimahismail@gmail.com.
authors.forename: P
authors.initials: P
authors.lastname: Ismail
mesh_terms: D000490:Allium / Q000737:chemistry*; D017209:Apoptosis / Q000187:drug effects*; D059447:Cell Cycle Checkpoints / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D035264:Flowers / Q000737:chemistry*; D056945:Hep G2 Cells; D006801:Humans; D010936:Plant Extracts / Q000494:pharmacology*
chemical_list: D010936:Plant Extracts
keywords: Allium atroviolaceum; Apoptosis; HepG2