Bioactivity-guided isolation of the major anthocyanin from Lycium ruthenicum Murr. fruit and its antioxidant activity and neuroprotective effects in vitro and in vivo .

Lycium ruthenicum Murr. fruit (LRF) is an edible berry known for its rich anthocyanin content. Our previous study has shown that LRF-derived anthocyanins have neuroprotective effects in rats, which may be due to their effective antioxidant activity. Therefore, this study performed online HPLC-DPPH screening as a bioactivity-guided method for the preparative separation of anthocyanins from LRF. Finally, the main fraction was isolated and identified as petunidin-3,5- O -diglucoside (Pn3G5G). Pn3G5G exhibited strong antioxidant capacity during DPPH and ABTS free radical scavenge assays. Furthermore, Pn3G5G exhibited protective effects on N ε -carboxymethyllysine (CML)-treated Neuro-2a cells by enhancing cell viability in a dose-dependent manner. CML-induced apoptosis was also reduced by Pn3G5G potentially by suppressing oxidative stress and inflammation. More importantly, Pn3G5G significantly improved cognitive impairment, neuroinflammation and neuronal apoptosis in D-galactose-induced aging mice. The result suggests the development of Pn3G5G as a healthcare product or a potent dietary supplement with antioxidant and neuroprotective effects.