Synergistic Effect of Imperata cylindrica Root Extract and Erlotinib on A549 Lung Cancer Cell Viability

Background: Erlotinib is typically used to treat lung adenocarcinoma and Imperata cylindrica extract has been shown to exert anti-cancer effects in various human cancer cell lines. Therefore, this study evaluated the combined anticancer effects of Imperata cylindrica ethanol root extract and erlotinib on the A549 lung cancer cell line. Method: The A-549 lung cancer cell line was treated with various combinations of 1/2 IC50, 3/8 IC50, 1/4 IC50, and 1/8 IC50 of I.cylindrica root ethanol extract and erlotinib for 48 hours. Cell viability was assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, analyzed and interpreted using CompuSyn software and a normalized isobologram curve. Result: Of the sixteen combinations, eleven combinations acted synergistically, four were additive, and one was in the antagonist zone. Conclusion: The combination of I. cylindrica root ethanol extract and erlotinib act synergistically to decrease A549 lung cancer cell viability, therefore they are potential lung cancer therapeutics.