Turmeric (Curcumin) - a widely used curry ingredient - can contribute to oxidative stress in Asian patients with acute Vitiligo

KU Schallreuter and H Rokos  

Indian J Dermatol Venereol Leprol 72:57-59 (2006)

Summary

Our in vivo results show that curcumin can contribute to the oxidative stress in acute vitiligo and prevent repigmentation. Therefore, dermatologists and other doctors treating patients with this disease should be aware of this possible problem.

Vitiligo is an acquired skin disorder with the loss of native skin pigment, which affects about 0.5-1% of the world population. Increased H₂O₂ levels in the epidermis and in blood are one of many hallmarks of this disease. Elevated epidermal H₂O₂ levels in the mM range inactivate epidermal and systemic catalase. Restoration of the skin colour can be achieved after reduction of epidermal H₂O₂ levels using a topical applied pseudocatalase cream (PC-KUS). Recently it has been shown, that epidermal catalase as well as other affected enzymes recover after treatment with this modality.

However, to our surprise part of our Asian patient population showed only moderate improvement or no response at all. Since the Asian cuisine uses a big variety of spices in the daily nutrition, we asked the question whether turmeric (haldi), which is widely used in curries, could possibly contribute to the poor outcome of this treatment. Besides serving as spice, turmeric was and still is widely used for wound healing and skin lightening in Asia . Its major active yellow pigment is curcumin (diferuloyl methane). There is substantial literature on curcumin, describing anti-oxidant, anti-inflammatory as well as anti-carcinogenic properties. However, high concentrations can lead to reactive oxygen species (ROS) generation via semiquinone radicals.

ROS generation using in vivo FT-Raman spectroscopy

before ( --- ) and 20 minutes after ( --- ) topical curcumin application in the skin of a healthy control (A) and an Asian patient with acute vitiligo (B) - as one example (see arrows for H₂O₂ at 875 cm^-1 and peroxides at 890 cm^-1) Note: the amount of ROS formation in the skin of the patients was significantly higher compared to controls. This result can be explained due to low epidermal catalase levels in acute vitiligo as demonstrated earlier.

Response rate in facial repigmentation after topical application of low-dose UVB-activated pseudocatalase (PC-KUS) twice per day after

       6 months using turmeric       2 months off turmeric        6 months off turmeric         (arrows show acute vitiligo;  photos were taken under WOOD's light)

Based on the in vivo results, we evaluated 15 Asian patients with acute vitiligo, who consumed turmeric daily, and their response rate in facial repigmentation after topical application of low-dose UVB-activated pseudocatalase (PC-KUS) twice per day. After 6 months, none of them showed any significant repigmentation.

Therefore, we advised 8 patients to avoid this spice ingredient in their diet and continue the application of PC-KUS twice daily. There was a significant improvement of the response already after 2 months in these patients. After 6 months treatment, the facial repigmentation was nearly completed in 6 of the 8 patients, whereas only minor to moderate or no response was obtained in the 7 patients who continued using turmeric together with PC-KUS.