A Review of the Influence of Various Extraction Techniques and the Biological Effects of the Xanthones from Mangosteen (Garcinia mangostana L.) Pericarps

Xanthones are significant bioactive compounds and secondary metabolites in mangosteen pericarps. A xanthone is a phenolic compound and versatile scaffold that consists of a tricyclic xanthene-9-one structure. A xanthone may exist in glycosides, aglycones, monomers or polymers. It is well known that xanthones possess a multitude of beneficial properties, including antioxidant activity, anti-inflammatory activity, and antimicrobial properties. Additionally, xanthones can be used as raw material and/or an ingredient in many food, pharmaceutical, and cosmetic applications. Although xanthones can be used in various therapeutic and functional applications, their properties and stability are determined by their extraction procedures. Extracting high-quality xanthones from mangosteen with effective therapeutic effects could be challenging if the extraction method is insufficient. Although several extraction processes are in use today, their efficiency has not yet been rigorously evaluated. Therefore, selecting an appropriate extraction procedure is imperative to recover substantial yields of xanthones with enhanced functionality from mangosteens. Hence, the present review will assist in establishing a precise scenario for finding the most appropriate extraction method for xanthones from mangosteen pericarp by critically analyzing various conventional and unconventional extraction methods and their ability to preserve the stability and biological effects of xanthones.

Ultrasonically enhanced extraction of luteolin and apigenin from the leaves of Perilla frutescens (L.) Britt. using liquid carbon dioxide and ethanol

The present study reports on the ultrasonic enhancement of the liquid carbon dioxide (CO2) extraction of luteolin and apigenin from the leaves of Perilla frutescens (L.) Britt., to which ethanol is added as a cosolvent. The purpose of this research is also to investigate the effects of the particle size, temperature, pressure, irradiation power, irradiation time, and ethanol content in the liquid CO2 solution on the extraction yield using single-factor experiments. We qualitatively and quantitatively analyzed the yields in the extract using HPLC (high-performance liquid chromatography). The liquid CO2 mixed with ethanol was used at temperatures of 5, 20 and 25 °C with extraction pressures from 8 to 14 MPa. The yields of luteolin and apigenin in the extraction were clearly enhanced by the ultrasound irradiation, but the selectivity of the extract was not changed. The yields of luteolin and apigenin in the extract were also significantly improved by adjusting the operating temperature, the irradiation time, and the ethanol content in the liquid CO2 solution, but no change in the selectivity of the extract was observed.