Induction of heme oxygenase-1 by chamomile protects murine macrophages against oxidative stress.
OBJECTIVE
Protection of cells from oxidative insult may be possible through direct scavenging of reactive oxygen species, or through stimulation of intracellular antioxidant defense mechanisms by induction of antioxidant gene expression. In this study we investigated the cytoprotective effect of chamomile and elucidated the underlying mechanisms.


METHODS
The cytoprotective effect of chamomile was examined on H(2)O(2)-induced cellular stress in RAW 264.7 murine macrophages.


RESULTS
RAW 264.7 murine macrophages treated with chamomile were protected from cell death caused by H(2)O(2). Treatment with 50μM H(2)O(2) for 6h caused significant increase in cellular stress accompanied by cell death in RAW 264.7 macrophages. Pretreatment with chamomile at 10-20μg/mL for 16h followed by H(2)O(2) treatment protected the macrophages against cell death. Chamomile exposure significantly increased the expression of antioxidant enzymes viz. heme oxygenase-1 (HO-1), peroxiredoxin-1 (Prx-1), and thioredoxin-1 (Trx-1) in a dose-dependent manner, compared with their respective controls. Chamomile increased nuclear translocation of Nrf2 with increased phosphorylated Nrf2 levels, and binding to the antioxidant response element in the nucleus.


CONCLUSIONS
These molecular findings for the first time provide insights into the mechanisms underlying the induction of phase 2 enzymes through the Keap1-Nrf2 signaling pathway by chamomile, and provide evidence that chamomile possesses antioxidant and cytoprotective properties.
Department of Urology, Case Western Reserve University, Cleveland, OH 44106, United States.
Natarajan
N
Bhaskaran
Sanjeev
S
Shukla
Rajnee
R
Kanwal
Janmejai K
JK
Srivastava
Sanjay
S
Gupta
D000818:Animals; D002460:Cell Line; D020843:Chamomile / Q000502:physiology*; D019610:Cytoprotection / Q000187:drug effects* / Q000502:physiology; D004790:Enzyme Induction / Q000187:drug effects / Q000502:physiology; D035264:Flowers; D051547:Heme Oxygenase-1 / Q000096:biosynthesis*; D006861:Hydrogen Peroxide / Q000037:antagonists & inhibitors / Q000633:toxicity; D008264:Macrophages / Q000187:drug effects* / Q000201:enzymology; D051379:Mice; D018384:Oxidative Stress / Q000187:drug effects* / Q000502:physiology; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology*
D010936:Plant Extracts; D006861:Hydrogen Peroxide; D051547:Heme Oxygenase-1