title: In vitro inhibitory effects of thymol and carvacrol on dendritic cell activation and function.
abstract: BACKGROUND
  Thyme has been used in traditional medicine for medicinal purposes since ancient times.
  
  
  OBJECTIVE
  The objective of this study was to investigate the effects of thymol and carvacrol as two major constituents of thyme on dendritic cells (DCs) maturation and T cell activation.
  
  
  METHODS
  Splenic DCs were treated with non-cytotoxic concentrations of the components and then analyzed for MHC II, CD86, and CD40 expression by flow cytometry. The effects of compounds on mitogenic, as well as allogenic T cell responses in mixed lymphocyte culture (MLR) and the release of cytokines were investigated.
  
  
  RESULTS
  At 0.1 µg/ml, reduced mean fluorescent intensity (MFI) of CD86 for thymol (80.3 ± 0.2% of untreated control) and CD40 for carvacrol (79.5 ± 0.14%) was observed (p < 0.001). Decreased mitogenic T cell proliferation by thymol [proliferation index (PI) from 0.93 ± 0.11 at 1 µg/ml to 0.42 ± 0.16 at 100 µg/ml (p < 0.01)] and carvacrol [PI from 1.08 ± 0.3 at 1 µg/ml to 0.28 ± 0.1 at 100 µg/ml (p < 0.001)] was seen. Ten micrograms/ml thymol (PI, 0.85 ± 0.04) and carvacrol (PI, 0.89 ± 0.03) inhibited allogenic T cell response (p < 0.05). Decreased IFN-γ level in MLR supernatant from 1441 ± 27.7 pg/ml in untreated cells to 944 ± 32.1 at 10 µg/ml of thymol and of carvacrol (886 ± 31.7 pg/ml) (p < 0.01) was found. IL-4 levels were decreased in the presence of both compounds (p < 0.01).
  
  
  CONCLUSIONS
  These data showed the suppressive effects of thymol and carvacrol on DCs maturation and function, as well as T cell responses.
authors.affiliation: a Department of Immunology , Shiraz University of Medical Sciences , Shiraz , Iran .|b Autoimmune Diseases Research Center and Medicinal Natural Products Chemistry Research Center, Shiraz University of Medical Sciences , Shiraz , Iran .
authors.forename: Zahra
authors.initials: Z
authors.lastname: Amirghofran
authors.affiliation: a Department of Immunology , Shiraz University of Medical Sciences , Shiraz , Iran .|c Department of Immunology , School of Public Health, Tehran University of Medical Sciences , Tehran , Iran , and.
authors.forename: Hossein
authors.initials: H
authors.lastname: Ahmadi
authors.affiliation: d Transplant Research Center, Shiraz University of Medical Sciences , Shiraz , Iran.
authors.forename: Mohammad Hossein
authors.initials: MH
authors.lastname: Karimi
authors.affiliation: a Department of Immunology , Shiraz University of Medical Sciences , Shiraz , Iran .
authors.forename: Fathollah
authors.initials: F
authors.lastname: Kalantar
authors.affiliation: a Department of Immunology , Shiraz University of Medical Sciences , Shiraz , Iran .
authors.forename: Nasser
authors.initials: N
authors.lastname: Gholijani
authors.affiliation: a Department of Immunology , Shiraz University of Medical Sciences , Shiraz , Iran .
authors.forename: Zahra
authors.initials: Z
authors.lastname: Malek-Hosseini
mesh_terms: D000818:Animals; D051940:B7-2 Antigen / Q000276:immunology / Q000378:metabolism; D019013:CD40 Antigens / Q000276:immunology / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D018920:Coculture Techniques; D000081007:Cymenes; D016207:Cytokines / Q000276:immunology / Q000378:metabolism; D003713:Dendritic Cells / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D000949:Histocompatibility Antigens Class II / Q000276:immunology / Q000378:metabolism; D007166:Immunosuppressive Agents / Q000302:isolation & purification / Q000494:pharmacology*; D008213:Lymphocyte Activation / Q000187:drug effects; D008297:Male; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D039821:Monoterpenes / Q000302:isolation & purification / Q000494:pharmacology*; D010641:Phenotype; D008517:Phytotherapy; D010946:Plants, Medicinal; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D013943:Thymol / Q000302:isolation & purification / Q000494:pharmacology*; D046930:Thymus Plant / Q000737:chemistry
chemical_list: D051940:B7-2 Antigen; D019013:CD40 Antigens; C497965:Cd86 protein, mouse; D000081007:Cymenes; D016207:Cytokines; D000949:Histocompatibility Antigens Class II; D007166:Immunosuppressive Agents; D039821:Monoterpenes; D013943:Thymol; C073316:carvacrol
keywords: CD40; CD86; immunomodulation; interferon-γ; interleukin-4; lymphocyte proliferation; medicinal plants; mixed lymphocyte culture