| Description: |
Loureirin B, a flavonoid extracted from Dracaena cochinchinensis, is an inhibitor of plasminogen activator inhibitor-1 (PAI-1), with an IC50 of 26.10 μM; Loureirin B also inhibits KATP, the phosphorylation of ERK and JNK, and has anti-diabetic activity.Loureirin B inhibits fibroblast proliferation and extracellular matrix deposition in hypertrophic scar via TGF-β/Smad pathway, loureirin B can suppress tetrodotoxin-sensitive (TTX-S) voltage-gated sodium currents in a dose-dependent way. |
| In vitro: |
| Exp Dermatol. 2015 May;24(5):355-60. | | Loureirin B inhibits fibroblast proliferation and extracellular matrix deposition in hypertrophic scar via TGF-β/Smad pathway.[Pubmed: 25683490] | 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.
METHODS AND RESULTS:
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.
CONCLUSIONS:
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. | | Sci China C Life Sci. 2004 Aug;47(4):340-8. | | Effects of dragon's blood resin and its component loureirin B on tetrodotoxin-sensitive voltage-gated sodium currents in rat dorsal root ganglion neurons.[Pubmed: 15493475] | Using whole-cell patch clamp technique on the membrane of freshly isolated dorsal root ganglion (DRG) neurons, the effects of dragon's blood resin and its important component loureirin B on tetrodotoxin-sensitive (TTX-S) voltage-gated sodium currents were observed.
METHODS AND RESULTS:
The results show that both blood resin and loureirin B could suppress TTX-S voltage-gated sodium currents in a dose-dependent way. The peak current amplitudes and the steady-state activation and inactivation curves are also made to shift by 0.05% blood resin and 0.2 mmol/L loureirin B.
CONCLUSIONS:
These results demonstrate that the effects of blood resin on TTX-S sodium current may contribute to loureirin B in blood resin. Perhaps the analgesic effect of blood resin is caused partly by loureirin B directly interfering with the nociceptive transmission of primary sensory neurons. | | J Cell Biochem . 2018 Feb;119(2):2012-2021. | | Loureirin B promotes insulin secretion through inhibition of K ATP channel and influx of intracellular calcium[Pubmed: 28817206] | | Abstract
The development of new diabetes drugs continues to be explored. Loureirin B, a flavonoid, extracted from Dracaena cochinchinensis, has been confirmed to increase insulin secretion and decrease blood glucose levels. For searching the promotion of insulin secretion with the treatment of loureirin B, experiments were employed based on cell experiments and computational methods. First, promotion of insulin secretion was dependent on extracellular glucose concentration. At the genetic level, loureirin B enhanced the relative mRNA level of Pdx-1 and MafA. Meanwhile the intracellular level of ATP increased due to the continuous absorption of glucose. Further experiments showed that the currents of KATP channel on Ins-1 cells were inhibited and the voltage-dependent calcium channels were subsequently activated. The increase of Cx43 protein expression might mediate the Ca2+ to the intracellular. Through computational simulation, we hypothesized that loureirin B might interact with KATP channels to promote insulin secretion. In conclusion, it could be concluded that loureirin B promoted insulin secretion mainly through increasing mRNA level of Pdx-1, MafA, intracellular ATP level, inhibiting the KATP current, influx of Ca2+ to the intracellular.
Keywords: KATP channel; influx of Ca; ins-1 cells; insulin secretion; loureirin B. |
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