Piper nigrum based diet had a chemopreventive antineoplastic effect potentiated by Curcuma longa in C57BL/6 mice

Background: Medicinal plants represent a proven alternative strategy to treat cancer.
Objective: To determine Curcuma longa (turmeric) and Piper nigrum (black pepper) effects in vitro and on the evolution of malignant melanoma B16F10 in C57BL/6 mice.
Methods: 103 female mice divided in 4 groups: Control (n=44), Turmeric (n=20), Pepper (n=21), Turpepp (n=18). Turmeric 5% and/or pepper 0.5% were mixed with a dough made of pre-cooked cornmeal, eggs and coconut milkshake and given ad libitum to experimental groups as main diet; control received dough based diet. 200,000 melanoma cells were transplanted into right leg hind paw. Clinical, psychological, pathological and biochemical parameters were evaluated in vivo to measure melanoma progression. In vitro, metabolic activity was measured by quantifying anaerobic glycolysis and viability through MTT assay.
Results: Combined preventive treatment with turmeric and pepper increased latency time for tumor onset, improved locomotor activity, preserved nociceptive response, decreased tumor volume and weight, reduced metastases and increased survival. These results were reproduced in the Pepper group, but with less statistical force; however, pepper showed greater potency in vitro experiments.
Conclusion: Pepper showed an antineoplastic chemopreventive activity in B16F10 malignant melanoma, which was enhanced by the synergistic effect of turmeric.