Total Flavonoids of Crocus sativus Petals Release tert-Butyl Hydroperoxide-Induced Oxidative Stress in BRL-3A Cells

Antioxidant and hepatoprotective activities in vitro of saffron petals were examined in this study for better utilizing saffron (Crocus sativus L.) biowaste. Using the DPPH and ABTS radical scavenging method, we compared the antioxidant activity and the content of total flavonoid extracts from petals (TFESP), stamens (TFESS), and both saffron petals and stamens (TFEMS). The results showed that the antioxidant capacity and the flavonoid content of TFESP were higher than those of TFESS and TFEMS. Then, the hepatoprotective activity of TFESP was determined, and the silymarin was used as a positive control. The main components of TFESP were analysed by ultrahigh performance liquid chromatography (UPLC) photodiode array (PDA)/mass spectrometry (MS) and nuclear magnetic resonance (NMR). The result showed that (1) TFESP could release oxidative liver injury induced by tert-butyl hydroperoxide (t-BHP). (2) TFESP could reduce the accumulation of reactive oxygen species (ROS); enhance the activity of superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH); and then improve the total antioxidant capacity (T-AOC) in BRL-3A cells. (3) TFESP could enhance the expression of B-cell lymphoma-2 (BCL-2) and decrease the expression of caspase-3 and caspase-9; increase the expression of Kelch-like ECH-associated protein-1 (Keap-1), nuclear factor, erythroid 2-related factor 2 (Nrf2), superoxide dismutase, and heme oxygenase 1 (HO-1); and downregulate inducible nitric oxide synthase (INOS), interleukin-6 (IL-6), and nuclear factor kappa B-9 (NF-κB-9). (4) The main hepatoprotective component of TFESP was identified as kaempferol-3-o-sophoroside. The mechanism may be that kaempferol-3-o-sophoroside can protect t-BHP-induced cell injury by regulating the expression of antioxidant, antiapoptotic, and anti-inflammatory genes. Thus, saffron petals are a potential hepatoprotective resource worthy of development.