Abstract
Lipophilic extracts of Isatis tinctoria L. exhibit significant activity against several clinically relevant targets of inflammation.
The alkaloid tryptanthrin was identified as one of the active principles in woad and
characterised as a potent dual inhibitor of COX-2 and 5-LOX. Here, the anti-inflammatory
efficacy of topical application of three different Isatis extracts and tryptanthrin was investigated in human volunteers. Two different models
were used, namely the sodium lauryl sulphate (SLS)-induced irritant contact dermatitis
(ICD) and UVB-induced erythema. Twenty healthy volunteers without any skin disease
participated in the study. Cumulative irritant contact dermatitis was induced on test
fields on the volunteers’ backs by twice daily application of 0.5 % sodium lauryl
sulphate over a period of four days. Half of the test fields were treated with the
test substances during the eliciting phase, while the remaining test fields were treated
over a period of 4 days after induction of dermatitis. In the second model, a UVB
erythema on the volunteers’ lower backs was induced using the double minimal erythema
dose (MED). Twenty-four hours after irradiation the test fields were treated with
the test substances over a period of 3 days. All reactions were assessed visually
and by non-invasive bioengineering methods (evaporimetry and chromametry). Treatment
with extracts during the ICD eliciting phase led to a significantly smaller increase
of visual scores and transepidermal water loss compared to the untreated test field.
For tryptanthrin this benefit was also observed, but the improvement was not statistically
significant. When treatment was performed after completing the eliciting phase, accelerated
resolution of the irritant reaction could not be observed. In the UVB erythema model
anti-inflammatory effects of the test substances were not observed.
Key words
Anti-inflammatory agents - irritant contact dermatitis -
Isatis tinctoria
- woad - Brassicaceae - sodium lauryl sulphate - tryptanthrin - UVB erythema
References
Isatis tinctoria - from the rediscovery of an ancient medicinal plant towards a novel anti-inflammatory
phytopharmaceutical.
Phytochem Rev.
2002;
1
333-44
Isatis tinctoria
.
Planta Med.
2001;
67
411-6
Isatis tinctoria extract by subcutaneous microdialysis coupled with isotope dilution ESI-LC-MS.
Planta Med.
2003;
69
385-9
Isatis tinctoria by ESI-L-MS.
Planta Med.
2002;
68
152-7
N -acetyl-5-methoxytryptamine). Influence of the application time point.
Dermatology.
1997;
195
248-52
elsner@derma.uni-jena.de
