Abstract
Opuntia ficus-indica var. saboten. is widely cultivated in Jeju Island (South Korea) for use in manufacture of health foods. This study described antidepressant effect of two flavonoids (kaempferol and quercitrin) isolated from the Opuntia ficus-indica var. saboten. The expression of the hypothalamic POMC mRNA or plasma β-endorphin levels were increased by extract of Opuntia ficus-indica var. saboten or its flavoniods administered orally. In addition, antidepressant activity was studied using tail suspension test (TST), forced swimming test (FST) and rota-rod test in chronically restraint immobilization stress group in mice. After restraint stress (2 hrs/day for 14 days), animals were kept in cage for 14 days without any further stress, bet with drugs. Mice were fed with a diet supplemented for 14 days and during the behavioral test period with kaempferol or quercitrin (30 mg/kg/day). POMC mRNA or plasma β-endorphin level was increased by extract of Opuntia ficus-indica var. saboten and its flavoniods. In addition, immobility time in TST and FST was significantly reduced by kaempferol or quercitrin. In rota-rod test, the time of permanence was maintained to the semblance of control group in turning at 15 rpm. Our results suggest that two flavonoids (kaempferol and quercitrin) isolated from the Opuntia ficus-indica var. saboten. show a potent antidepressant effect.