HPTLC-UV densitometric detection method for quantification of xanthones in mangosteen (Garcinia mangostana) fruit hulls extracts

Mangosteen (Garcinia mangostana L., Clusiaceae) is a tropical tree native to Southeast Asia and largely distributed in India, Indonesia, Malaysia, and Thailand. The fruit, considered as the “queen of tropical fruits”, has a size as a little orange with a thick and red-purple pericarp that contains a famous and delicious pulp inside. The hull has been used for hundreds of years in Southeast Asia for a great variety of medicinal properties. More recently, mangosteen fruit products (juice or extract) are also used as raw materials for nutritional supplements and cosmetic applications. Previous phytochemical investigations reported that the major bioactive secondary metabolites are prenylated xanthones derivatives that occur in high concentration in the hull. Due to the increasing interest of this plant, the development of a convenient and reliable analysis method is needed to assess the quality control of fruit hulls extracts. The aim of our study was to develop a quantitative analysis of the main xanthones (α-, β-, γ-mangostins and 9-hydroxycalabaxanthone) in fruit hull extracts by HPTLC-UV. The method was performed on a TLC scanner apparatus on analytical RP-18 HPTLC plates. The mobile phase was acetonitrile/water/formic acid in the ratio (70/27/3, v/v/v) and the plates were scanned at 280nm and 320nm before derivatization with Neu reagent. We applied our method for quantification of xanthones on our fruit hull samples native from India and the results obtained were compared to those of HPLC-UV ones at 280nm. The total average amount of xanthones was about 55% (w/w) of dry matter. The concentration of the two main compounds α- and γ-mangostins could reach respectively 44% and 6% (w/w) of dry matter. This HPTLC-UV method could be considered as a powerful tool to confirm the quality control of mangosteen fruit hulls.

Keywords: Mangosteen, Garcinia xanthones, HPTLC