Bibliographic Details
Title: |
Inhibition of IKK-β by epidioxysterols from the lowers of Calotropis gigantea (Niu jiao gua). |
Authors: |
Parhira, Supawadee1, Guo-Yuan Zhu1, Ting Li1, Liang Liu1, Li-Ping Bai1 lpbai@must.edu.mo, Zhi-Hong Jiang1 zhjiang@must.edu.mo |
Source: |
Chinese Medicine. 3/2/2016, Vol. 11, p1-8. 8p. |
Abstract: |
Background: Calotropis gigantea (Asclepiadaceae) (Niu jiao gua) has been used as a poultice in Chinese medicine for treating inflammatory skin diseases, e.g., neurodermatitis. This study aims to isolate the epidioxysterols from the lowers of C. gigantea, elucidate their structures and evaluate their possible inhibitory effects on the NF-κB pathway. Methods: The two epidioxysterols 9,11-dehydroergosterol peroxide (1) and ergosterol peroxide (2) were isolated from the powdered lowers of C. gigantea by ultrasonic-assisted extraction, followed by the purification of the crude extract by column chromatography (i.e., silica gel and MCI-gel CHP 20P open columns). The chemical structures of these compounds were identified through a comparison of their HRMS, ¹H and 13CNMR data with those in the literature. The in vitro IKK-β inhibitory activities of compounds 1 and 2 (1-100 µM) were evaluated using an IKK α and β Assay/Inhibitor Screening Kit, which is a single-site, semi-quantitative immunoassay. Berberine was used as a positive control. The IKK-β inhibitory activities between compounds 1 and 2 were compared by a two-tailed Student's t test to summarize the structure activity relationship. Results: Compounds 1 and 2 exhibited a dose-dependent inhibitory activity towards IKK-β in a similar manner to that of berberine. The IKK-β inhibitory activities of these two epidioxysterols were significantly stronger (P = 0.001 for compound 1 and P = 0.028 for compound 2) than that of berberine at the concentration of 100 µM. Furthermore, at the same concentration the suppressive effect of compound 1 towards IKK-β was greater than that of compound 2 (P = 0.041), while their activities at 10 and 50 µM were comparable. The difference in the results at 100 µM therefore suggested that the double bond between C-9 and C-11 in compound 1 could be responsible for its higher inhibitory activity towards IKK-β at this concentration. Conclusions: 9,11-dehydroergosterol peroxide (1) and ergosterol peroxide (2) were isolated from the lowers of C. gigantea and exhibited in vitro inhibitory activities towards IKK-β. [ABSTRACT FROM AUTHOR] |
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Database: |
Academic Search Complete |