2. Mie Prefecture Agricultural Research Institute, Matsuzaka, Mie, Japan.
3. Research and Development Department, Fundamental Research Division, Mikimoto Pharmaceutical & CO. Ltd., Ise, Mie, Japan.
Background: Corchorus olitorius leaves are rich in antioxidants, fatty acids, minerals, vitamins and mucilaginous polysaccharides, and have been used as traditional folk medicine. In a previous study, we found that Corchorus olitorius extract reduced transepidermal water loss, and increased skin hydration in atopic dermatitis (AD)-like lesions in NC/Nga mice. The aim of this study was to investigate the effects of topical application of Corchorus olitorius leaf Extract Excluding the high molecular weight compounds (COEE), on atopic dermatitis (AD), and to elucidate the mechanism underlying the ameliorating effect of COEE on AD-like skin lesions.
Methods: NC/Nga mice housed under specific pathogen-free (SPF) and conventional conditions were each divided into three groups (control, COEE, base cream). At the start of the experiment, the AD scores on the rostral skin of SPF mice and conventional mice were 0 and 8, respectively. We prepared the COEE cream, and applied it on the rostral skin in NC/Nga mice, and then performed a macroscopic evaluation, an enzyme-linked immunosorbent assay to analyze the plasma levels of immunoglobulin E (IgE) and histamine and immunohistochemical staining for tryptase, matrix metalloproteinase-9 (MMP-9) and collagen type IV.
Results: After 14 days of treatment with the COEE cream under conventional conditions, the AD scores and plasma IgE concentrations in the COEE group were significantly lower than those in the other groups. Compared to the control and BC groups, the expression levels of tryptase and MMP-9 were lower, and the degradation of collagen type IV at the basement membrane area was not observed in the COEE group by immunohistochemistry. The mice housed under the SPF conditions were not affected by the test creams.
Conclusions: Our results indicate that COEE may therefore be a useful therapeutic candidate for AD due to its suppression of the plasma IgE level and degranulation of mast cells.
Keywords: Atopic dermatitis, Corchorus olitorius, immunoglobulin E, histamine, tryptase