# Secondary Metabolites Composition and Their Histochemical Localization in the Fruit of Piper malgassicum Papini, Palchetti, Gori and Rota Nodari (Piperaceae)

## TL;DR

This study examines the chemical composition and localization of compounds in the fruit of Piper malgassicum, a pepper species, and suggests potential medicinal uses.

## Contribution

The study identifies and localizes secondary metabolites in Piper malgassicum fruit and proposes their ecological and medicinal roles.

## Key findings

- Piperine is localized in idioblasts of the fruit mesocarp and decreases with ripening.
- β-carotene concentration peaks at an intermediate maturity stage and remains stable at full maturity.
- Terpenes like α-phellandrene and linalool are highest at mid-ripening and have antimicrobial and anti-inflammatory properties.

## Abstract

The anatomy, histochemistry, and secondary metabolite composition were investigated on the drupes of Piper malgassicum, one of the components of the spice voatsiperifery pepper. The high amount of piperine recorded with high‐performance liquid chromatography with photodiode‐array detection analysis was localized with histochemistry mainly along the fruit mesocarp in idioblasts, since they were positive to alkaloids (Wagner reaction). The fruit was analyzed at different stages of maturation. β‐carotene reached the highest concentration when the drupe was at an intermediate stage of maturity (orange color) and maintained the same concentration also at full maturation (red color). The terpenes fraction present in higher amounts decreased with fruit ripening (as also piperine). Terpenes are presumably at their maximal concentration at the middle stage of fruit ripening to avoid damage to the pericarp by fungi and bacteria, while piperine would avoid feeding by animals. The reduction in concentration of these two components is linked to the seed dispersal stage after full fruit maturation. Both the most abundant terpenes, α‐phellandrene and linalool, show antimicrobial properties. These compounds are also known for anti‐inflammatory properties in vivo and in vitro, and hence, this plant may have medicinal properties. Since the total amount of terpenes is highest at an intermediate stage of fruit maturation, the optimal timing of collection would be prior to full maturation.