Antineoplastic Agents, Phytogenic/pharmacology; Apoptosis/immunology; CD4-Positive T-Lymphocytes/drug effects; Sesquiterpenes/pharmacology; Antigens, CD/drug effects; Antigens, CD/immunology; Antigens, CD/metabolism; Apoptosis/drug effects; Apoptosis Inducing Factor/immunology; Apoptosis Inducing Factor/metabolism; CD4-Positive T-Lymphocytes/immunology; Cell Cycle Proteins/drug effects; Cell Cycle Proteins/immunology; Cell Cycle Proteins/metabolism; Cell Proliferation/drug effects; Humans; Interferon-gamma/immunology; Interferon-gamma/metabolism; Interleukin-2/antagonists & inhibitors; Interleukin-2/immunology; Interleukin-2/metabolism; Jurkat Cells; Lymphocyte Activation/immunology; Membrane Potential, Mitochondrial/drug effects; Membrane Potential, Mitochondrial/physiology; NF-kappa B/antagonists & inhibitors; NF-kappa B/immunology; NF-kappa B/metabolism; NFATC Transcription Factors/drug effects; NFATC Transcription Factors/immunology; NFATC Transcription Factors/metabolism; Proteasome Endopeptidase Complex/immunology; Proteasome Endopeptidase Complex/metabolism; Proto-Oncogene Proteins c-bcl-2/genetics; Proto-Oncogene Proteins c-bcl-2/immunology; Proto-Oncogene Proteins c-bcl-2/metabolism; Reactive Oxygen Species/immunology; Reactive Oxygen Species/metabolism; Sesquiterpenes, Guaiane; Tumor Suppressor Protein p53/immunology; Tumor Suppressor Protein p53/metabolism