Figure 1. (A) Morphological features of TS plant samples at different phenological stages and structures of main components of the essential oil detected by GC/MS and FTIR. (B) Percentage of cancer cell viability after treatment with various concentrations of Thymus hirtus Ssp. algeriensis (TS) for different time points (0, 24, 48 and 72 hrs); * = statistical significance; P˂0.05. (C) TS sensitizes TRAIL-induced cytotoxicity. Briefly, HCT116 cells (5 × 103 cells/well) were seeded in triplicate in 96-well plates. The cells were exposed to different concentrations of thyme volatile oil (0, 0.01 or 0.05 μl/ml) for 12 h, the medium was removed, and tumor cells were then incubated with 25 ng/ml TRAIL for additional 24 h. Cell viability was then determined by the MTT assay. (D) Effect of TS on RAW cell viability. RAW 264.7 cells, seeded in triplicate in 96-well plates, were exposed to different concentrations of TS (0, 0.001, 0.005, 0.01 or 0.05 μl/mL) and incubated for 24 h, 48 h and 72 h. Cell viability was analyzed with the MTT assay.