Twenty-nine derivatives of berberine (1) or pseudoberberine (2) were designed, semisynthesized, and evaluated for their up-regulatory activity on the low-density-lipoprotein receptor (LDLR) expression. SAR analysis revealed that (i) the methylenedioxy group at the 2- and 3-position is an essential element to keep the activity, (ii) the 7-position quaternary ammonium and planar structure of the compound are activity-required, and (iii) addition of electron-donating groups at the 7- or 13-position reduced the activity. Of the compound 1 analogues, compound 2 exhibited an increased activity on LDLR expression compared to 1. In the hyperlipidemic rats, compound 2 (100 (mg/kg)/day) reduced blood CHO and LDL-c by 42.6% and 49.4%, respectively, more efficient than 1 did (p < 0.01 for both). The results were confirmed in the hyperlipidemic mice. LD(50) of 2 in mice was over 5000 mg/kg (oral). We consider compound 2 a promising cholesterol-lowering drug candidate.
Background: Berberine (BBR), a natural product, was reported to inhibit platelet aggregation; however, the molecular mechanisms remain unclear. This study aims to investigate the effects and mechanisms of BBR in inhibiting platelet activation and thrombus formation.Methods: Flow cytometry, immunofluorescence, and Western blot were used to determine the inhibitory effects and mechanisms of BBR and its main metabolite berberrubine (M2) on platelet activation in vitro and ex vivo. Purified integrin αIIbβ3, class I PI3K kit, and molecular docking were used to identify the possible targets of BBR and M2. A carrageenan-induced mouse thrombosis model was used to evaluate the effects of BBR on thrombus formation in vivo.Results:In vitro, BBR and M2 significantly inhibited ADP-induced integrin αIIbβ3 activation, reduced the level of P-selectin on the platelet membrane, and suppressed the binding of fibrinogen to the platelets. In this process, BBR and M2 greatly suppressed the PI3K/Akt pathway and inhibited Rasa3 membrane translocation and Rap1 activation. Furthermore, BBR and M2 selectively inhibited class I PI3Kβ, perhaps through binding to its active site. The activities of BBR were stronger than those of M2. After oral administration, BBR significantly inhibited the PI3K/Akt pathway and Rap1 activation and suppressed ADP-induced platelet activation and carrageenan-induced thrombosis in mice without prolonging bleeding time.Conclusions: We reveal for the first time the possible targets and mechanisms of BBR and M2 in inhibiting platelet activation. Our research may support the future clinical application of BBR as an antiplatelet drug in the prevention or treatment of thrombotic diseases.
This study is designed to investigate the effects of berberine (BBR) on galectin-3 (Gal-3) and the relationships to its suppressive activities on adipocyte differentiation, proliferation and adiposity. Our results showed that BBR greatly suppressed the differentiation and proliferation of mouse primary preadipocytes isolated from epididymal white adipose tissue (eWAT), during which the expression level of Gal-3 was down-regulated significantly. Overexpression of Gal-3 totally abolished the suppressive activities of BBR on Gal-3 expression, preadipocyte differentiation and proliferation. BBR reduced Gal-3 promoter activity, destabilized its mRNA and inhibited firefly luciferase activity of a recombinant plasmid containing the Gal-3 3′ untranslated region (UTR). Furthermore, BBR up-regulated microRNA (miRNA) let-7d expression and the suppressive activity on Gal-3 3′UTR was abolished by point mutation on the let-7d binding site. In mice fed a high-fat diet (HFD), BBR up-regulated let-7d and down-regulated Gal-3 expression in eWAT; it also suppressed adipocyte differentiation and proliferation and reduced adiposity greatly. In summary, our study proves that BBR inhibits the differentiation and proliferation of adipocytes through down-regulating Gal-3, which is closely associated with its anti-obesity effect. Our results may support the future clinical application of BBR for the treatment of obesity or related diseases.
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