Abstract:Roselle was used as a raw material for extracting anthocyanins. The anthocyanins were purified using Amberlite XAD-7 macroporous resin. Purified roselle anthocyanins (PRA) were identified using Fourier-transform infrared spectroscopy and ultrahigh-performance liquid chromatography-quadrupole time-of-flight mass spectrometry. The antioxidant activity of PRA in vitro and in HepG2 cells was evaluated. The results showed that the anthocyanin content in PRA increased by 6.35-fold, reaching 175.27 mg/g. PRA contained five anthocyanins, of which delphinidin-3-sambubioside was the most abundant, accounting for 57.35% (m/m) of the total anthocyanins. PRA exhibited high antioxidant activity in vitro. The DPPH scavenging rate reached 90% when the PRA concentration was 0.23 mg/mL, and the hydroxyl radical scavenging rate was 97.85% at a PAR concentration of 2.0 mg/mL. Additionally, PRA showed high intracellular antioxidant activity in HepG2 cells. Treatment with 200 μg/mL PRA significantly reduced the H2O2-induced HepG2 intracellular reactive oxygen species level and nitric oxide content from 117.47% (taking the 2′,7′-dichlorofluorescein fluorescence intensity of the control group as 100%) and 53.18 nmol/mL to 102.09% and 45.79 nmol/mL, respectively. PRA treatment significantly increased the superoxide dismutase and catalase activities from 18.19 and 10.10 U/mg prot to 35.05 and 19.38 U/mg prot, respectively. The main component of PRA anthocyanins was delphinidin-3-sambubioside, which exhibited strong antioxidant activity in vitro and anti-oxidative stress response effects in vivo. These results provide a theoretical basis for the high-value development and the potential health benefits of roselle anthocyanins.
