Anti-inflammatory effects of the extract of indigo naturalis in human neutrophils.
BACKGROUND
Indigo naturalis is used by traditional Chinese medicine to treat various inflammatory diseases.


OBJECTIVE
Topical indigo naturalis ointment showed efficacy in treating psoriasis in our previous clinical studies. In this study, we investigated the anti-inflammatory effects of the extract of indigo naturalis (QD) and its main components indirubin, indigo, and tryptanthrin in human neutrophils.


METHODS
Superoxide anion (O2(.-)) generation and elastase release were measured by spectrophotometry. Some important signals including mitogen-activated protein kinase (MAPK), cAMP, and calcium were studied by Western blot analysis, an enzyme immunoassay, and spectrofluorometry.


RESULTS
QD significantly inhibited O2(.-) generation and elastase release in formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP)-activated human neutrophils in a concentration-dependent fashion, while neither indirubin, indigo, nor tryptanthrin produced a comparable result. QD attenuated the FMLP-induced phosphorylation of extracellular regulated kinase, p38 MAPK, and c-Jun N-terminal kinase. Furthermore, QD inhibited calcium mobilization caused by FMLP. However, QD did not affect cellular cAMP levels. On the other hand, neither indirubin, indigo, nor tryptanthrin produced similar changes in human neutrophils.


CONCLUSIONS
Taken collectively, these findings indicate that QD, but not indirubin, indigo, or tryptanthrin, inhibited O2(.-) generation and elastase release in FMLP-induced human neutrophils, which was at least partially mediated by the inhibition of MAPK activation and regulation of calcium mobilization.
Lin
Yin-Ku
YK
Department of Traditional Chinese Medicine, Center for Traditional Chinese Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan.
Leu
Yann-Lii
YL
Huang
Tse-Hung
TH
Wu
Yi-Hsiu
YH
Chung
Pei-Jen
PJ
Su Pang
Jong-Hwei
JH
Hwang
Tsong-Long
TL
D000328:Adult; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism; D006801:Humans; D007124:Immunoenzyme Techniques; D007203:Indigo Carmine; D007211:Indoles / Q000737:chemistry*; D009504:Neutrophils / Q000187:drug effects* / Q000378:metabolism; D010766:Phosphorylation; D010936:Plant Extracts / Q000494:pharmacology*; D017382:Reactive Oxygen Species; D013050:Spectrometry, Fluorescence
D000893:Anti-Inflammatory Agents; D007211:Indoles; D010936:Plant Extracts; D017382:Reactive Oxygen Species; D007203:Indigo Carmine; D000242:Cyclic AMP; D002118:Calcium