The ethanolic extract of Resina Draconis (RDEE) has been reported beneficial to normal wound healing yielding more regularly arranged
collagen fibres.
Loureirin B, a major component in RDEE, has been supposed to be effective on the prevention and treatment of pathological
scars. To investigate the
therapeutic effects of
loureirin B on
hypertrophic scar (HS), fibroblasts from human HS and normal skin (NS) were isolated. Results showed that
loureirin B dose-dependently downregulated both
mRNA and
protein levels of
type I collagen (ColI),
type III collagen (ColIII) and α-smooth muscle actin (α-SMA) in HS fibroblasts.
Loureirin B also suppressed fibroblast proliferative activity and redistributed cell cycle, but did not affect cell apoptosis. In vivo rabbit ear
scar model,
loureirin B significantly improved the arrangement and deposition of
collagen fibres, decreased
protein levels of ColI, ColIII and α-SMA and suppressed myofibroblast differentiation and
scar proliferative activity. In NS fibroblasts,
loureirin B effectively inhibited TGF-β1-induced upregulation of ColI, ColIII and α-SMA levels, myofibroblast differentiation and the activation of Smad2 and Smad3.
Loureirin B also affected
mRNA levels of major
MMPs and TIMPs in TGF-β1-stimulated fibroblasts. Taken together, this study demonstrates that
loureirin B could downregulate the expression of
fibrosis-related molecules by regulating
MMPs and TIMPs levels, inhibit
scar fibroblast proliferation and suppress TGF-β1-induced
fibrosis, during which TGF-β1/Smad2/3 pathway is likely involved. These findings suggest that
loureirin B is a potential therapeutic compound for HS treatment.