Objective:To examine the role of carvacrol in modulating PI3K/AKT signaling involved in human breast cancer pathogenesis using in vitro experimental model MCF-7 cells.Methods:MTT and lactate dehydrogenase assays were performed with cells treated with different doses of carvacrol (0-250 μ mol/L) at different time points (24 and 48 h).The nuclear morphology was assessed in MCF-7 cells with propidium iodide(PI) and acridine orange/ethidium bromide (AO/EB) staining and analyzed by fluorescence microscopy.Events like cell cycle arrest and apoptosis were observed by flow cytometric analysis and expressions of p-Rb,cyclin D1,cyclin-dependent kinase 4 (CDK4),CDK6,Bax,Bcl-2,PI3K/p-AKT were analyzed by immunoblot.Results:Carvacrol significantly reduced cell viability with the half maximal inhibitory concentration value of 200 μ mol/L at 24 and 48 h (P＜0.05).importantly,there was a significant increase in the accumulation of the G0/G1 phase upon treatment with carvacrol in MCF-7 cells (P＜0.05 or P＜0.01).A remarkable decrease in protein expressions of p-Rb,cyclin D1,CDK4 and CDK6 denoted cell cycle arrest (P＜0.05 or P＜0.01).In addition,carvacrol treatment significantly inhibited PI3K/p-AKT protein expressions leading to induction of apoptosis mediated by decreased Bcl2 and increased Bax protein expressions.Further:Annexin V/PI staining by FACS analysis,dual staining by AO/EB and PI staining studies suggested induction of apoptosis by carvacrol through PI3K/Akt signaling pathway in MCF-7 cells.Conclusion:Carvacrol significantly inhibited the breast cancer MCF-7 cell proliferation and induced apoptosis via suppressing PI3/AKT signaling pathway.