In April 2015, “Foods with Functional Claims (FFCs)” was established as a new category of voluntary labeling in health food products sold in Japan. Several products comprising piperine as a functional substance, which is found in plants such as pepper, long pepper, and Java long pepper, have been categorized as FFCs. Health food products such as dietary supplements and spices derived from the above-mentioned peppers have also been sold commercially. Although piperine has been reported to improve blood flow and induce other positive effects, some reports showed that it exhibits acute toxicity values that are equivalent to those of powerful drugs. Therefore, ensuring the quality of piperine-containing food products is important. In this study, a quantitative analysis using HPLC was conducted for 28 piperine-containing products belonging to three product categories (FFCs, health food products, and spices) with a commercially available piperine reagent that was determined its absolute purity via quantitative NMR analysis. Four health food products and seven spices contained piperine at daily intake levels fifty times greater than those of FFCs. Conversely, piperine was not detected in two spice products; these products might have been made using different ingredients than those on the labels. We will continue to pay attention to the market trends of piperine-containing food products.
