Purple sweet potato color protects mouse liver against d-galactose-induced apoptosis via inhibiting caspase-3 activation and enhancing PI3K/Akt pathway.

Purple sweet potato color (PSPC) has been shown to possess hepatoprotective effects in our previous study. To clarify the detailed mechanism of hepatoprotective effects of PSPC, we investigated the potential protective effect of PSPC against caspase-3 activation induced by d-gal, as well as its influence on Bcl-2 levels and PI3K/Akt cell survival pathway. The results of TUNEL assay showed that PSPC effectively suppressed the d-gal-induced hepatocytes apoptosis, suggesting that anti-apoptosis mechanism was involved in PSPC-mediated protection against d-gal-induced liver injury in mouse. PSPC significantly increased GSH levels and promoted a marked increase in the activities of GSH related enzymes including GR, GST in d-gal-treated mice. The activation and activity of caspase-3 were markedly inhibited by the treatment of PSPC in the livers of d-gal-treated mice. Furthermore, the level of Bcl-2 was significantly raised, and the levels of PI3K p110 and phosphorylated Akt were also largely enhanced by the treatment of PSPC in the livers of d-gal-treated mice. In conclusion, these results suggested that PSPC could protect mouse liver against d-gal-induced hepatocyte apoptosis via attenuating oxidative stress, inhibiting the activation of caspase-3 and enhancing cell survival signaling (enhancing the level of anti-apoptotic protein Bcl-2 and the activation of PI3K/Akt pathway).