Garcinia mangostana Fruit: Determination of the Total Antioxidant Activity in Extracts and Phenolic Compound Characterization using CE-MS(TOF)

Xanthones are an important family of polyphenols present in Garcinia mangostana fruit. Products of G. mangostana have begun to be commercialized as a dietary supplement because of their potent antioxidant properties. Interest in their beneficial health effects such as antioxidant characteristics, lipid profile and anticarcinogenic activity, etc., has encouraged scientific research to determine compounds responsible for these properties. The antioxidant capacity determination and the phenolic compound characterization in extracts of G. mangostana were investigated. High antioxidant capacity was determined in whole fruit dried extract by ORAC, FRAP and ABTS + assays. The values obtained by FRAP, ORAC and ABTS assays were 1222 and 4088 and 3590 μM TE/g, respectively. Phenolic compound identification in these extracts was carried out by capillary electrophoresis coupled to ionization by electrospray-mass spectrometry (CE-ESI-MS) with a time of flight analyzer (Micro TOF), and a sensible, fast and efficient method was developed. The CEESI parameters were optimized to obtain good separation and suitable sensitivity. The CE parameters were: 80 mM ammonium acetate, pH 10.5, 30 kV, 15 s for injection and fused-silica capillary of 50 m i.d. and 100 cm in length. The ESI-MS parameters were also optimized: drying gas flow of 4L/min, 300°C, nebulization gas pressure at 4 psi, sheath liquid composition and flow (60:40) isopropanol/water + 0.1% triethylamine to 0.18 mL/h. Spectrometric determination was achieved in negative polarity and the mass range was between 100-800 m/z. Considering the scarcity of commercial standards and the scanty bibliography references, some of the most important xanthones from G. mangostana fruit have been identified using CE-ESI-MS (micro TOF), such as Garcinine C, Garcinone E, Mangostenone C and -mangostin. _____________________________________________________________________________________________________________