Alcalase®-processed queen bee larvae hydrolysates and peptides HVPIFDRY, FPYQPPF exhibit potent antioxidant activity via Nrf2/NQO1/HO-1 pathway

The by-products of royal jelly processing, particularly queen bee larvae (QBL), represent a significant, underutilized protein resource. While QBL is known for its nutritional value, its potential as a source of bioactive compounds, specifically antioxidants, remains largely unexplored. Current antioxidant strategies often rely on synthetic compounds, which can have safety concerns. Identifying natural, food-derived antioxidants from sustainable sources like QBL could offer safer and more effective alternatives for mitigating oxidative stress, a key contributor to numerous chronic diseases.

Researchers investigated the structural characteristics and antioxidant activities of queen bee larvae hydrolysates (QBLHs) produced using eight distinct proteases. They compared the antioxidant efficacy of these hydrolysates, focusing on Alcalase® 2.4 L FG hydrolysates, against seven other protease-derived hydrolysates. Antioxidant activity was assessed using various in vitro assays, including ABTS and •OH radical scavenging, Fe2+ chelating ability, and ORAC (Oxygen Radical Absorbance Capacity). The most potent hydrolysates were further analyzed for their ability to protect HepG2 cells against AAPH-induced oxidative damage. Two specific peptides, HVPIFDRY and FPYQPPF, were identified and their mechanism of action in HepG2 cells was explored.

Enzymatic hydrolysis significantly altered the secondary and tertiary structure of QBL proteins, leading to a looser and more irregular protein conformation. Among the eight proteases tested, Alcalase® 2.4 L FG hydrolysates consistently exhibited the strongest antioxidant activity. This included superior ABTS and •OH radical scavenging activity, enhanced Fe2+ chelating ability, and higher ORAC values compared to the other seven hydrolysates. Importantly, these hydrolysates provided robust protection against cellular oxidative stress in HepG2 cells. Subsequent analysis identified two key peptides, HVPIFDRY and FPYQPPF, within the Alcalase® 2.4 L FG hydrolysates. These specific peptides were shown to effectively mitigate AAPH-induced oxidative damage in HepG2 cells. > The protective effect of these peptides was mediated through the activation of the Nrf2/NQO1/HO-1 pathway, a critical cellular defense mechanism against oxidative stress. This indicates a specific molecular pathway through which QBL-derived peptides exert their antioxidant effects.