Effect of black pepper (Piper nigrum Linn) and piperine on growth, blood constituents and organ weight in rats.

The food efficiency of rats given black pepper at 0.02 to 0.5% in a synthetic diet was not affected adversely. At 2 and 5% the food efficiency was significantly decreased due mainly to reduced food intake. Piperine (the main pungent principle) at 0.05% in a similar diet did not affect the food efficiency but increased food intake. Black pepper at 2 and 5% and piperine at 0.05% increased liver weight mainly due to higher total and neutral lipids content. The increase in liver total and neutral lipids with 0.5% black pepper, was abolished when the protein content of diet was increased to 18%. With 0.02 of 0.15% black pepper (values corresponding to human intake or 10 times higher) there was no adverse effect on liver weight and liver lipids.