Researchers found that administering higher doses of vanillin to mouse models of psoriasis for 1 week led to a significant reduction in skin inflammation, compared with psoriatic mice that did not receive the compound or had lower doses.
Study co-author Chien-Yun Hsiang, of China Medical University Hospital in Taichung, Taiwan, and colleagues recently reported their findings in the Journal of Agricultural and Food Chemistry.
Psoriasis is a chronic disease triggered by an overactive immune system, which accelerates the production of new skin cells and causes inflammation. This leads to red, itchy, and flaky skin, particularly on the elbows, knees, scalp, hands, and feet.
According to the American Academy of Dermatology, around 7.5 million people in the United States have psoriasis. Around 20 percent of these individuals have moderate to severe psoriasis, in which the condition covers at least 5 percent of their body.
Topical treatments may help to reduce skin inflammation for people with mild to moderate psoriasis. For individuals with a more severe form of the disease, a combination of topical and oral treatments may be required, as well as light therapy.
The new study from Hsiang and team suggests that vanillin may not only help to reduce symptoms of psoriasis, but it could also help to prevent them, by targeting the inflammatory proteins that trigger the condition.
Testing vanillin on psoriatic mice
Vanillin is an artificial compound based on the main component of vanilla bean extract. It is often used to flavor food products, particularly cakes and other baked goods.
Previous studies, however, have indicated that there is more to vanillin than meets the taste buds. Researchers have found that the compound can reduce the expression of cytokines called interleukins, which are known to promote inflammation.
Hsiang and colleagues note that interleukin-17 (IL-17) and interleukin-23 (IL-23) have been identified as key players in psoriasis. For their study, the team set out to investigate whether vanillin can target these cytokines and reduce skin inflammation.
The researchers induced psoriatic skin inflammation in mice by applying a compound called imiquimod (IMQ) to the skin of the rodents' backs. This led to an increase in the expression of IL-17 and IL-23.
Next, the team applied varying doses of vanillin to the backs of the mice once, daily, for a total of 7 days. The doses were 1, 5, 10, 50, or 100 milligrams per kilogram (mg/kg) of body weight.
Vanillin reduced skin inflammation
Skin inflammation of the vanillin-treated mice was compared with that of mice that were not treated with the compound.
The study revealed that the mice that received vanillin at doses of 50 mg/kg and 100 mg/kg displayed a reduction in skin inflammation, compared with mice that did not receive the compound or that received it in smaller doses.
Interestingly, all rodents that were treated with vanillin experienced reductions in levels of IL-17 and IL-23.
Taken together, the findings suggest that a compound used to flavor cakes could one day help to prevent or treat psoriasis.
The researchers write:
"[V]anillin significantly decreased both the amounts of IL-17A and IL-23 and the infiltration of immune cells in the skin tissues of IMQ-treated mice. In conclusion, our findings suggested that vanillin was an effective bioactive compound against psoriatic skin inflammation."