Effect of ultrasound treatment on the extraction of antioxidants from Kunth fruits and identification of phytochemicals by HPLC-ESI-MS.

The influence of ultrasound-assisted extraction of phytochemicals from Kunth on the antioxidant capacity was investigated. The factors evaluated were: ultrasound extraction time (10, 20 and 30 min), ethanol concentration (0, 35, 70 %) and solid/liquid ratio (1:4, 1:8 and 1:12 g mL). The L (3) array was applied, and the DPPH scavenging capacity of treatments was evaluated to obtain optimal extraction conditions. Finally, the phytochemicals were characterized by high-performance liquid chromatography electrospray ionization mass spectrometry (HPLC-ESI-MS). Ten minutes of ultrasound extraction using 0 % of ethanol and solid/liquid ratio 1:12 g mL were the optimal conditions of extraction. The HPLC-ESI-MS analysis revealed the presence of gluconic acid, quercetin-3--glucoside, isorhamnetin-3--rutinoside, demethylligstroside, ponicidin, 4-caffeoylquinic acid, rosmarinic acid, and galloyl-hexoside. The optimal ultrasound-assisted extraction conditions were defined by applying the Taguchi methodology. The phytochemicals identified in fruits suggest its use as a potential source of bioactive compounds.