Antiproliferative activity, cell-cycle arrest, apoptotic induction and LC-HRMS/MS analyses of extracts from two Linum species.

CONTEXT: Linum is the largest genus of the Linaceae family; the species of this genus are known to have anticancer activity. OBJECTIVE: In this study, ethyl acetate extracts of L. numidicum Murb. (EAELN) and L. trigynum L. (EAELT) were examined, for the first time, for their anticancer capacity. The secondary metabolites compositions were analysed by LC-HRMS/MS. MATERIALS AND METHODS: The antiproliferative effect of EAELN and EAELT (0-10.000 µg/mL) against PC3 and MDA-MB-231 cell lines were evaluated by the MTT assay after 72 h of treatment. Flow cytometer analysis of apoptosis (Annexin V-FITC/PI) and cell cycle (PI/RNase) was also performed after treatment with EAELN and EAELT at 250, 500, and 1000 µg/mL, for 24 h. RESULTS: EAELN had the highest antiproliferative activity against PC3 (IC50 133.2 ± 5.73 µg/mL) and MDA-MB-231 (IC50 156.9 ± 2.83 µg/mL) lines, EAELN had also shown better apoptotic activity with 19 ± 2.47% (250 µg/mL), 87.5 ± 0.21% (500 µg/mL), and 92 ± 0.07% (1000 µg/mL), respectively, causing cell cycle arrest of PC3 cells in G2/M phase, whereas arrest in G0/G1 and G2/M phases was observed after treatment with EAELT. LC-HRMS/MS profiling of the extracts revealed the presence of known compounds that might be responsible for the observed anticancer activity such as chicoric acid, vicenin-2, vitexin and podophyllotoxin-ß-d-glucoside. DISCUSSION AND CONCLUSIONS: We have shown, for the first time, that EAELN and EAELT exert anticancer activity through cell cycle arrest and induction of apoptosis. EAELN can be considered as a source to treat cancer. Further studies will be required to evaluate the effect of the active compounds, once identified, on other cancer cell lines.