Curcumin alone not combined with piperine exerts cardioprotective effects in pressure-overload rats by increasing glucagon-like peptide-1 receptor signaling and additional properties

Abstract

Background and aim

Curcumin has shown significant cardiovascular protective effects. However, the low bioavailability limits its practical application. As a natural bioenhancer, piperine is expected to increase the bioavailability of curcumin, and then, enhance its beneficial effects. Meanwhile, glucagon-like peptide-1 receptor (GLP-1R) signaling has been confirmed to be involved in the regulation of cardiovascular events. Herein, this study aimed to investigate whether piperine could enhance the beneficial effects of curcumin in pressure-overload rats and whether GLP-1/GLP-1R signaling is involved in their action mechanism.

Methods and results

Male Sprague-Dawley (SD) adult rats were subjected to abdominal aortic constriction (AAC) surgery to 16 weeks, which elevated blood pressure and induced cardiac hypertrophy. Curcumin (100 mg/kg/day) or/and piperine (20 mg/kg/day) were orally given for 4 weeks from the 17th week after AAC surgery. Curcumin alone treatment significantly lowered blood pressure, ameliorated cardiovascular remodeling, improved left ventricular performance and endothelium-dependent vascular relaxation. Accompanied by these results, GLP-1R expression in the myocardium was up-regulated. Piperine alone also exhibited a certain positive inotropic cardiac activity, but the effect was less significant. The combination of curcumin and piperine didn't show enhanced cardiovascular protective effects relative to curcumin, along with decreased fasting serum GLP-1 level and GLP-1R expression in the myocardium.

Conclusion

Curcumin exerts cardiovascular protective effects in pressure-overload rats by upregulating GLP-1R, and inhibiting of GLP-1/GLP-1R signaling pathway may be related to the limited beneficial effects of combination of curcumin and piperine. This study provides a new thinking that oral administration of some spices may affect cardiovascular function by modulating the GLP-1/GLP-1R system in a mode of gut-heart axis regulation.