Date of Publication: 01-Sep-2022
Effects of piperine, a component of pepper (Piper nigrum), on herpes simplex virus type-1 in Vero cells
Author: Seikou Nakamura, Tomoyo Namura, Yuka Nishimura
The fruit of pepper (Piper nigrum, Piperaceae) is used as a spice for its pungency and aroma all over the world. Piperine is the major secondary metabolite responsible for the strong pungency. We found that piperine activates herpes simplex virus type-1 (HSV-1) in Vero cells. Specifically, piperine increased both the number and size of plaques formed by HSV1 replication (175% activation at 100 __ampersandsignmu;M compared with control cells) in a plaque assay. To confirm the effect of piperine on the activation of HSV-1, we synthesized 15 piperine derivatives. The synthesis of the piperine derivatives with an amide moeity [four 5-(3.4- methylenedioxyphenyl)penta-2,4-dienamides, a 5-(3.4-methylenedioxyphenyl)pentanamide, and eight 5-phenylpenta-2,4-dienamides] was accomplished by the condensation reactions of carboxylic acids with various amines in the presence of condensing agents. Next, we conducted plaque assays to examine their effects on HSV-1. Piperine derivatives having an amide moiety increased the number of plaques, suggesting that they activate HSV-1. To the best of our knowledge, this is the first example of a plant component with the ability to activate HSV-1. The mechanism of HSV-1 activation by piperine remains unclear. Since piperine is the major secondary metabolite of pepper (P. nigrum), an excessive intake of pepper may have an effect on HSV-1 infection. The detailed mechanistic studies are needed to determine whether piperine affects the virus or the host (i.e., Vero cells).
Keywords: pepper, Piper nigrum, Piperaceae, piperine, herpes simplex virus type-1, plaque assay, aggravation of HSV-1 infection