Discovery and Evaluation of Novel Calenduloside E Derivatives Targeting HSP90β in Ox-LDL-Induced HUVECs Injury

Background: Atherosclerosis (AS) serves as the primary pathological basis for cardiovascular disease-related deaths worldwide, posing a severe threat to public health security. Heat shock protein 90 (HSP90) plays a crucial regulatory role in the pathological progression of AS, emerging as a potential target for anti-atherosclerosis drug development in recent years. Calenduloside E (CE) is a pentacyclic triterpenoid saponin isolated from Aralia elata (Miq.) Seem. Previous studies have confirmed its anti-atherosclerotic activity, but its weak efficacy and narrow therapeutic index limit its clinical application. In this study, the CE scaffold was hybridized with a ticagrelor-derived fragment to enhance anti-atherosclerotic activity. In this study, the CE scaffold was hybridized with a ticagrelor fragment to achieve improved activity. Methods: Based on the principle of molecular hybridization, CE was linked to the active fragment of ticagrelor via a PEG chain. Ten CE derivatives were synthesized by modifying the sugar substituents. In vitro experiments were conducted to detect cytotoxicity and protective activity against ox-LDL-induced HUVECs injury. Molecular docking and Surface Plasmon Resonance (SPR) assays were used to evaluate the interaction between CE derivatives and the known target HSP90β. Combined with Microscale Thermophoresis (MST), SwissTargetPrediction, and molecular docking, other potential targets of CE derivatives were identified. Results: In the ox-LDL-induced HUVECs injury model, all compounds except C2 and C9 exhibited protective activity. Among these compounds, compound C5 exhibited the optimal protective effect, with an EC₅₀ value of 1.44 μM. Molecular docking results revealed that both C5 and CE could bind to HSP90β by forming hydrogen bonds with the key amino acid Asp93. Additionally, SPR results indicated that C5 and CE had similar binding affinities to HSP90β, with dissociation constants (K_D) of 1.73 μM and 1.72 μM, respectively. MST demonstrated that C5 binds to HSP90β with an affinity 111 times higher than that of ticagrelor. SwissTargetPrediction and molecular docking identified P2Y12 as another potential target of derivative C5. Conclusions: Compound C5 exerts protective effect against ox-LDL-induced HUVECs injury by targeting HSP90β. Its effective concentration is significantly improved compared with that of the parent CE, which provides a possibility for reducing clinical dosage and toxic side effects in subsequent studies. Furthermore, C5 may exert its effects by targeting another potential target, P2Y12, offering references for the rational design of novel anti-atherosclerotic drugs.