Cytotoxicity and apoptogenic properties of the standardized extract of Portulaca oleracea on glioblastoma multiforme cancer cell line (U-87): a mechanistic study

The traditional uses of Portulaca oleracea L. (PO) with anti-inflammatory and anti-cancer activity as well as antioxidants properties were expressed previously. Glioma is considered the most common primary brain tumor and its malignant form is the most lethal adult brain tumor, that glioblastoma covers about 50 % of glioma tumors. The present study was aimed to evaluate the cytotoxicity and apoptogenic effects of the hydro-ethanolic extract of PO on human glioblastoma cancer cell line (U-87) and the role of NF-κB. Cytotoxicity of the extract in the presence or absence of Vitamin C was evaluated using MTT assay, and the following hypotonic PI and SubG1 peak were performed. Moreover, the reactive oxygen species (ROS), the level of NF-κB protein and nitric oxide (NO) production were investigated. The extract had cytotoxicity and apoptogenic effects on U-87 cells in both the concentration and time-dependent manners. The mechanism of cytotoxicity and apoptosis induction of the extract at the first hours of incubation and low concentrations were dependent on ROS. However, the toxicity was replaced with NO pathway with time-lapse and higher concentrations. Results also indicated that the extract acts as an NF-κB inhibitor with concentration and time-dependent manners. The present study may suggest the anti-NF-κB activity of PO along with two upstream ROS and NO mechanisms. Furthermore, the extract as ethnobotanical may be used as adjunctive anti-cancer therapy against glioblastoma multiforme.