Abstract:
OBJECTIVE To investigate the main chemical components of the ethyl acetate extract of Rhodiola crenulata (EAERC) and its neuroprotective effects on Alzheimer's disease (AD) model cells.
METHODS EAERC was prepared using liquid-liquid extraction. Qualitative analysis of its chemical components was performed via UPLC-Q-Exactive Orbitrap MS, and the contents of six components, including gallic acid and salidroside, were simultaneously determined using HPLC. Subsequently, an AD cell model was established by inducing PC12 cells with Aβ25-35. Methods such as MTT, ELISA, and fluorescence staining were employed to evaluate the effects of EAERC on cell viability, inflammatory factors (TNF-α, IL-1β, IL-6), oxidative stress markers (ROS, MDA, GSH-Px), and apoptosis. Additionally, Western blot analysis was used to detect the expression or phosphorylation levels of proteins related to apoptosis (Bax/Bcl-2, Caspase-3), the NF-κB pathway (IκBα, p65), and the MAPK pathway (ERK, p38, JNK, GSK-3β, Tau).
RESULTS A total of 56 compounds (including flavonoids, organic acids, etc.) were identified. Six components, including gallic acid and salidroside, were successfully quantified, and the method showed good linearity (r≥0.999 7). Cellular experiment results demonstrated that EAERC (25 μg·mL⁻¹) significantly increased the viability of AD model cells (P0.01), reduced the levels of inflammatory cytokines TNF-α, IL-1β, and IL-6 (P0.000 1), decreased levels of oxidative stress markers ROS and MDA while increasing GSH-Px activity (P0.000 1), inhibited apoptosis (P0.000 1), reduced Bax/Bcl-2 ratio (P0.000 1), and downregulated Cleaved caspase-3/Caspase-3 (P0.01). Furthermore, EAERC inhibited the phosphorylation of p-IκBα/IκBα and p-p65/p65 in the NF-κB signaling pathway (P0.000 1) and the phosphorylation of p38, Tau, and JNK proteins (P0.000 1), while activating the phosphorylation of ERK and GSK-3β in the MAPK signaling pathway (P0.000 1), suggesting that it might alleviate Aβ25-35-induced neurotoxicity by modulating the NF-κB/MAPK signaling pathway.
CONCLUSION EAERC effectively ameliorates Aβ25-35-induced AD-like cellular damage by inhibiting inflammatory responses, regulating oxidative stress and apoptotic processes, and modulating the NF-κB/MAPK pathway.