Piper nigrum extract retards tumor growth by reducing tumor-promoted cytokines/chemokines and modulating immune cells in blood circulation

Abstract

Abstract Piper nigrum, black pepper, has been widely used in traditional medicine to treat fevers and digestive system disease and is also applied to treat cancer in China. This study evaluated the breast cancer-preventive effect of a low piperine Piper nigrum extract (PFPE or LP-PE). Our findings showed that the incidence of tumors was 70% in the control group, 50% in the vehicle group, and 20% in the rats treated with PFPE at 50 and 100 mg/kg BW. Remarkably, no cancerous rats were found in the PFPE-treated at 150 mg/kg BW for approximately three months, with no significant changes in blood parameters, except for alkaline phosphatase (ALP). PFPE at 100 and 150 mg/kg BW suppressed cytokines/chemokines and increased ROS production compared to control and vehicle groups. PFPE stimulated IFN- γ promoted Th1 cells and inhibited Th2 and Treg compared to control and vehicle groups. In tumor-bearing rats, PFPE inhibited cancer progression by decreasing ER-α and NF-κB in the tumor tissue compared to control and vehicle groups. Our findings suggested PFPE has the potential to reduce tumor incidence and retardation of tumor growth by modulating Th1/Th2/Treg, ROS, cytokines/chemokines production and decreasing cancer-progression-related proteins in tumor rats.