Analytically Unsupervised Metabolomic Profile of the Premium Malgasy Pepper Voatsipérifery (Piper borbonense): Identification of Marker Components

The berries of Piper borbonense (Miq.) C. DC., a wild vine native to Madagascar, are prized for their distinctive aroma and flavor, considered superior to the ones of the domesticated peppers (P. nigrum L., P. longum L.). The scarcity of studies on P. borbonense, locally known as voatsipérifery, makes it difficult to secure the identity of its berries and complement its sensory analysis. This supports the need for a comprehensive phytochemical investigation utilizing complementary analytical techniques. Headspace gas chromatography highlighted differences in the "volatilome" of P. borbonense and P. nigrum, while an untargeted metabolomic analysis, based on the LC-MS2-based feature-based molecular networking tool, annotated different classes of compounds (monoterpenoids, sesquiterpenoids, monolignols, lignans, and piperamides). This analysis next guided the isolation of 40 fully characterized compounds, including two new natural products [the sesquiterpene lactone 4-hydroxyisogelehomanolide (29) and the hydroxycinnamate ester borbonensin (38)]. The phytochemical profile of voatsipérifery is remarkable for the presence of the nonvolatile monoterpene p-menth-5-en-1,2-diol (23), of sesquiterpene lactones, and of large amounts of sesamin (34), a marker trait that clearly distinguishes it from those of the cultivated peppers of commerce and was confirmed with a parallel investigation of P. nigrum. Overall, our study underlines the relevance of advanced metabolomic approaches to characterize the phytochemical profile of spices and identify specific marker compounds.