Immunmodulatory and Photosensitisating Effects of Hypericum
by Dr. Christoph Schempp, Hautklinik, Universität Freiburg
01/98 - 06/98
Hypericum oil or cream may be very helpful in healing cutaneous diseases, however it is suspected that hypericum ingredients can lead to photosensitisation. Focussing on the aspect of photosensitisating, the pilot study uses artificial solar radiation: a sun simulator and a source of light with an absorption maximum of hypericin (550 - 700 nm). The threshold value of the skin for radiation in each wave length area is determined and also the pigmentation of the skin as a reaction to radiation.
24 healthy male and female subjects aged between 18 and 59 were included and randomly assigned to three groups. Two groups were treated with a special hypericum cream; the third group was administered a hypericum oil.
Methods
Forearms were treated with hypericum cream (concentration of hypericin 30 g/ml) or oil (concentration of oily hypericin 110 g/ml) and then irradiated (sunsimulator light source). All three groups were examined directly after beeing exposed to radiation, and again after 24 hours and 48 hours. Using a standardised visual scale and an additional photometrical analysis (mexameter) the intensity of erythema and pigmentation was registered.
Results
After treatment with hypericum cream and both forms of radiation, pigmentation and erythema do not show a statistical difference between treated and untreated skin. The intensity of radiation is not an important factor. The findings of hypericum oil are different. Skin pigmentation does not differ between oiled und unoiled skin. Whereas the erythema differs significantly according to the results of the mexameter. It must be noted that the results of the visual scale do not correspond with those of the mexameter. The effect is therefore not relevant for clinical practice. The pilot study indicates that there is no effect of photosensitisation during radiation treatment using hypericum oil or cream.
2. Immunomodulatory Effects of Hypericum
The sescon question of the study was to find out whether the application of hypericum oil or cream influences the in vivo function of Langerhans cells. Langerhans cells serve as a test system where the imunologic effect is determined by the antigen presenting function of these cells. A proliferation of Langerhans cells is the indicator for an increase in immunologic effect.
12 healthy volunteers were randomly assigned to two groups. Group A was treated with cream, group B with oil. A sunsimulator was used to find out whether light is an immunmodulating factor. Cream and oil were tested on the forearms of the volunteers. Two testfields were marked on each forearm. One field was treated with hypericum cream or oil and then irradiated with a certain dose of the sunsimulator. The other three served as controls: a) irradiated b) treated with cream or oil c) untreated.
A control group (four volunteers) was set up afterwards. Here, the influence of the base of cream or oil itself on the proliferation of Langerhans cells was to be tested. The volunteers were either treated with cream-base or oil-base or remained untreated. After treatment the epidermis of the testfields was dissected and analysed for the proliferation of Langerhans cells by MECLR (mixed epidermal cell leukocyte reaction).
Results
Using hypericum cream an inhibiting effect on proliferation was noted. This significant effect was not influenced by additional light treatment. Therefore the inhibition was presumably due to a characteristic essence of hypericum (e.g. hyperforine, highly concentrated in the cream). On the contrary, using hypericum oil there was an increase of cell proliferation. This increase was also not influenced by additional light treatment. It is not yet clear which ingredients of hypericum are responsible for the increase. It should be noted that hypericum cream and oil have a pharmacological effect on the skin.
Schempp
CM, Winghofer B, Lüdtke R, Simon JC, Schöpf E
Photosensibilisierende und immunmodulierende Eigenschaften von Johanniskrautcreme
und Johanniskrautöl
In: Albrecht H, Frühwald M, eds. Jahrbuch der Karl und Veronica Carstens-Stiftung,
Band 5 (1998). Essen: KVC; 1999: 113-151.
Schempp CM , Lüdtke
R, Winghofer B, Simon JC
Effect of topical application of Hypericum perforatum extract (St. John's
wort) on skin sensitivity to solar simulated radiation, Photodermatol
Photoimmunol Photomed 16, 2000, S. 125-128
Schempp CM, Winghofer B, Lüdtke R, Simon-Haarhaus B, Schöpf
E, Simon JC
Topical application of St John's wort (Hypericum perforatum L.) and of
its metabolite hyperforin inhibits the allostimulatory capacity of epidermal
cells, Brit J Dermatol 142, 2000: 979-984.
Universitäts-Hautklinik
Dr. C.M. Schempp
Hauptstr. 7
D-79104 Freiburg
Germany
schempp@haut.ukl.uni-freiburg.de