Catapult steam explosion significantly increases cellular antioxidant and anti-proliferative activities of Adinandra nitida leaves

Abstract

Leaves of Adinandra nitida, traditionally brewed as a health tea beverage in China, were treated with instant catapult steam explosion (ICSE) under various steam pressures (0.5–3.0 MPa) and residence times (30–120 s). The effects of ICSE on the flavonoids of the leaves and their cellular antioxidant and anti-proliferative activities and cytotoxicity against HepG2 cells were investigated. HPLC analysis showed that the treatment caused decreases and eventual disappearance of camellianin A and B with consequent formation of apigenin, which was attributed to discrepancy in the thermal stability of these flavonoids. The conversion of camellianin A and B to apigenin resulted in significant increases in the cellular antioxidant and anti-proliferative activities of Adinandra nitida leaves, with the EC50 values reduced by 53.7 and 68.1%, respectively. The study shows that ICSE could be an efficient, economical and environment-friendly method for modifying the polyphenolic composition and improve the bioactivities of Adinandra nitida leaves.