Inhibitory activity of 1,8-cineol (eucalyptol) on cytokine production in cultured human lymphocytes and monocytes.
BACKGROUND
The therapeutic value of secretolytic agents in COPD and asthma is still disputed. For this reason, in a preclinical study we aimed to test the potential anti-inflammatory efficacy of 1,8-cineol (eucalyptol) in inhibiting polyclonal stimulated cytokine production by human unselected lymphocytes and LPS-stimulated monocytes.


METHODS
Cytokine production was determined following 20 h of incubation cells with 1,8-cineol simultaneously with the stimuli in culture supernatants by enzyme immunoassay.


RESULTS
Therapeutic concentrations of 1,8-cineol (1.5 microg/ml=10(-5)M) inhibited significantly (n=13-19, p=0.0001) cytokine production in lymphocytes of TNF-alpha > IL-1beta> IL-4> IL-5 by 92, 84, 70, and 65%, respectively. Cytokine production in monocytes of TNF-alpha > IL-1beta> IL-6> IL-8 was also significantly (n=7-16, p<0.001) inhibited by 99, 84, 76, and 65%, respectively. In the presence of 1,8-cineol (0.15 microg/ml=10(-6)M) production of TNF-alpha>IL-1beta by monocytes and of IL-1beta> TNF-alpha by lymph-ocytes was significantly inhibited by 77, 61 and by 36, 16%, respectively. 1,8-cineol (10(-6)M) had a larger impact on TNF-alpha and IL-1beta-production in monocytes compared to lymphocytes (p<0.03) and similar effects (p>0.59) at therapeutically relevant concentrations of 1,8-Cineol (10(-5)M).


CONCLUSIONS
These results characterize 1,8-cineol as strong inhibitor of TNF-alpha and IL-1beta and suggest smaller effects on chemotactic cytokines. This is increasing evidence for the role of 1,8-cineol to control airway mucus hypersecretion by cytokine inhibition, suggesting long-term treatment to reduce exacerbations in asthma, sinusitis and COPD.
Department of Pneumology, Allergology and Sleep Medicine, Medical Outpatient Clinic, Bonn University Hospital, Wilhelmestrasse 35-37, Bonn D-53111, Germany. uewjuergens@t-online.de
Uwe R
UR
Juergens
Tanja
T
Engelen
Kurt
K
Racké
Meinolf
M
Stöber
Adrian
A
Gillissen
Hans
H
Vetter
D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D002478:Cells, Cultured; D003511:Cyclohexanols / Q000494:pharmacology*; D016207:Cytokines / Q000037:antagonists & inhibitors* / Q000096:biosynthesis; D004797:Enzyme-Linked Immunosorbent Assay; D000077591:Eucalyptol; D006801:Humans; D008214:Lymphocytes / Q000378:metabolism*; D009000:Monocytes / Q000378:metabolism*; D039821:Monoterpenes / Q000494:pharmacology*; D018417:Th1 Cells / Q000378:metabolism; D018418:Th2 Cells / Q000378:metabolism
D000893:Anti-Inflammatory Agents; D003511:Cyclohexanols; D016207:Cytokines; D039821:Monoterpenes; D000077591:Eucalyptol