Subcritical water extraction of bioactive compounds from Orostachys japonicus A. Berger (Crassulaceae)

Subcritical-water extraction is an ecofriendly method for extracting antioxidant compounds only using water. The Subcritical-water extraction was employed for the extraction of bioactive compounds from Orostachys japonicus known as rock pine by investigating the use of various temperatures (110-260 degrees C) and extraction times (5-20 min). The Subcritical-water extraction condition at 220 degrees C for 15 min; the total phenolics content (39.9 +/- 4.1 mg/g), flavonoids content (11.4 +/- 0.6 mg/g), and antioxidant activities (90.3 +/- 2.2%, 96.0 +/- 2.9%, and 662.4 +/- 17.2 mg/g) of Subcritical-water extract were higher under this condition than for extraction with either methanol or ethanol. Triterpene saponins were observed only in subcritical-water extraction condition at 220 degrees C for 15 min. Further, some of its phenolic constituents; gallic acid, quercetin, and kaempferol were quantified by high performance liquid chromatography. Subcritical-water extraction is an effective method for extracting valuable bioactive compounds from Orostachys japonicus.