In vitro: |
Eur J Pharmacol. 2015 Jan 5;746:63-9. | Antiplatelet activity of loureirin A by attenuating Akt phosphorylation: In vitro studies.[Pubmed: 25445049] | Loureirin A is a flavonoid extracted from Dragon׳s Blood that has been used to promote blood circulation and remove stasis in Chinese traditional medicine. However, the mechanisms of these effects are not fully understood. METHODS AND RESULTS: We explored the anti-platelet activity and underlying mechanism of loureirin A in vitro. Our results indicated that loureirin A negatively affected agonist-induced platelet aggregation such as collagen, collagen-related peptide (CRP), ADP and thrombin. Loureirin A inhibited collagen-induced platelet ATP secretion and thrombin-stimulated P-selectin expression in a dose-dependent manner. Platelet spreading on immobilized fibrinogen was significantly impaired in the presence of loureirin A. Immunoblotting analysis indicated that 100μM of loureirin A almost completely eliminated collagen-induced Akt phosphorylation at Ser473. Interestingly, a submaximal dose (50μM) of loureirin A had an additive inhibitory effect with the phosphoinositide 3-kinase (PI3K) inhibitor Ly294002 on collage-induced Akt phosphorylation in platelets. CONCLUSIONS: Taken together, loureirin A had an inhibitory effect on platelet activation, perhaps through an impairment of PI3K/Akt signaling. | Journal of Kunming Medical University, 2016 , 37 (6) :13-17. | Effect of Loureirin A on Proliferation and Frizzled-4Expression of Rat Hepatic Stellate Cells in vitro[Reference: WebLink] | To investigate the molecular mechanism of Loureirin A mediated anti- hepatic fibrosis by evaluting its effects on proliferation,secretion of α- smooth muscle actin(α- SMA) and transforming growth factor- beta1(TGF- β1), and expression of rat hepatic stellate cells in vitro. METHODS AND RESULTS: Primary hepatic stellate cells were isolated and cultured from Sprague- Dawley rats. After activating and inducing primary hepatic stellate cells from q HSC to a HSC, the activated hepatic stellate cells model in vitro was established. Then we observed the morphological changes of static hepatic stellate cells and activated hepatic stellate cells with inverted phase contrast microscope. Cultured hepatic stellate cells were treated with different concentrations of Loureirin A and the inhibitory rate of HSCs proliferation was measured by MTT assay. The expression of Frizzled- 4 was measured by western blot analysis. The content of α- SMA and TGF- β1 in the cultured HSCs' supernatant were measured by enzyme- linked immunosorbent assay(ELISA). Loureirin A the proliferation of inhibited activated hepatic stellate cells in a time- dose- dependent manner compared with the control group,IC50=0.30 μg/μL. After Loureirin A treatment of the HSCs, western blot analysis showed that Frizzled- 4 expression level was obviously lower than control group.Loureirin A also inhibited α- SMA and TGFβ1(P0.05) secretion in the cultured HSCs' supernatant in different degree by the assay of ELISA. CONCLUSIONS: The molecular mechanism of Loureirin A and Wnt signaling pathway mediated anti- hepatic fibrosis and anti- angiogenesis may involve down- regulation the expression of Frizzled- 4,inhibiting the synthesis and secretion of α- SMA,TGF- β1and the proliferation of HSCs. |
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