A Fluorescence Study on the Extracts of Red Dragon Fruit Peel in Various Solvents

Abstract

Special attention has been given to red dragon fruit (Hylocereus polyrhizus) because of its unique natural compounds exhibiting wide biological activities. However, the potential use of the red dragon fruit peel has been less addressed. In the present work, simple extraction of red dragon fruit peel was carried out to study the fluorescence properties of the corresponding extracts in various solvents. The red dragon fruit peel was first separated, dried, and macerated for 24 hours using distilled water, ethanol, and acetone, separately. The results demonstrated that the peel extracts exhibited different photoluminescence properties depending on the solvent type. It was revealed that the ethanolic extract gave the highest fluorescence intensity among the other extracts. The ethanolic extract showed two excitation peaks at 290 and 359 nm, yielding different emission properties. Excitation at 290 nm gave one emission peak at 339 nm, while the excitation at 359 nm gave an emission peak at 436 nm. Such strong photoluminescence properties observed in the wide range of UV and visible regions demonstrated the potential use of the red dragon fruit peel as a photonic material. Spectroscopy study also proposed that the ethanolic extract would have polyphenol and chlorogenic acid as the main compounds.