REN Lining, LIU Guochen, ZHANG Huimin, GAO Weiman, MA Xinyu, SUN Aidong
This study aims to investigate the protective effects of royal jelly (RJ) and its functional components, major royal jelly proteins (MRJPs) and royal jelly lipids (RJL), against ethanol-induced oxidative damage in HepG2 cells, and to identify the core functional constituents responsible for the hepatoprotective activity of royal jelly. An oxidative damage model was established using 600 mmol/L ethanol. The effects of different concentrations (0.2, 0.4 mg/mL) of royal jelly and its extracts on cell viability, aspartate aminotransferase (AST), alanine aminotransferase (ALT), superoxide dismutase (SOD), glutathione (GSH), and malondialdehyde (MDA) levels in ethanol-exposed HepG2 cells were evaluated to systematically assess their regulatory roles in oxidative stress. Furthermore, RT-qPCR was employed to examine the influence of the bioactive hepatoprotective components of royal jelly on the mRNA expression levels of Nrf2, HO-1, TNF-α, IL-6, ADH, and PPARα, thereby elucidating the underlying molecular mechanisms of hepatoprotection. The results showed that the cell viability of the model group decreased to 45.61% after 24 hours of exposure to 600 mmol/L ethanol. At a treatment concentration of 0.4 mg/mL, RJ, MRJPs, and RJL increased the viability of ethanol-damaged HepG2 cells by 46.81%, 69.29%, and 93.57%, respectively, with the overall protective efficacy ranking as follows: RJL>MRJPs>RJ. Compared with the model group, pretreatment with RJ, MRJPs, and RJL dose-dependently inhibited the leakage of ALT and AST, and significantly elevated intracellular endogenous antioxidant levels across all treatment groups. Specifically, treatment with RJL at 0.2, 0.4 mg/mL reduced MDA levels by 43.02% and 67.07%, respectively, demonstrating a significantly stronger inhibitory effect on lipid peroxidation than RJ and MRJPs treatments at equivalent concentrations. Overall, RJL exhibited markedly superior performance in hepatocyte protection, antioxidant defense, and inhibition of lipid peroxidation compared to RJ and MRJPs, indicating that RJL may represent the principal hepatoprotective bioactive substance in royal jelly, with MRJPs playing a synergistic auxiliary role. Molecular mechanism studies revealed that RJL exerts its hepatoprotective effects primarily through direct modulation of the expression of genes associated with oxidative stress, inflammatory responses, and alcohol and lipid metabolism. This research provides a crucial theoretical basis for the development of functional hepatoprotective products and the high-value utilization of royal jelly.
