ROS-Triggered Self-Aggregation of a β-Elemene Olefin-Rich Nanoemulsion for Mitochondrial-Targeted Metabolic Reprogramming and Colitis Inflammation Alleviation

Purpose: Inflammatory bowel disease (IBD) is a chronic condition driven by pro-inflammatory macrophages. Although natural compounds with carbon–carbon double bonds (C=C bonds), such as β‑elemene, exhibit anti-inflammatory properties, their precise subcellular targets and mechanisms remain elusive. This study aimed to develop a targeted nanomedicine to elucidate the anti-inflammatory mechanism of β‑elemene and establish a novel therapeutic strategy for colitis. Patients and Methods: We engineered a reactive oxygen species (ROS)-responsive β‑elemene nanoemulsion (ELE-NE) for targeted drug delivery. Its therapeutic efficacy and mechanism were evaluated in a murine model of dextran sulfate sodium (DSS)-induced colitis. A mitochondria-targeted, ROS-activatable near-infrared probe was also developed for in vivo imaging tracking of inflammatory foci and assessment of therapeutic efficacy. Results: In DSS-induced colitis mice, ELE-NE preferentially accumulated in inflamed colon tissue and effectively alleviated disease pathology. Mechanistically, upon reaching inflammatory macrophages, ELE-NE utilized the pathological ROS surge to undergo spatially confined aggregation at mitochondrial sites. This nano-aggregation directly disrupted the electron transport chain (ETC), potently suppressing oxidative phosphorylation and reprogramming cellular energy metabolism. Consequently, this mitochondria-focused metabolic intervention attenuated M1 macrophage polarization, reduced pro-inflammatory cytokine secretion. Conclusion: This is the first report demonstrating that β‑elemene acts via ROS‑triggered mitochondrial aggregation and metabolic reprogramming. We deciphered the mechanism of β-elemene, revealing that its olefinic (C=C) functional group enables bioresponsive mitochondrial aggregation and metabolic reprogramming, thereby proposing the concept of “olefinic drugs” as a distinct therapeutic class. Furthermore, we established a novel theranostic paradigm for treating inflammatory diseases using olefinic nanomedicines, enabled by a companion imaging tool for non‑invasive detection of inflammatory foci and dynamic monitoring of the treatment process. Diagram: DSS colitis mouse model, inflammatory macrophage with ROS and colitis relief process.The image illustrates a biochemical pathway involving a DSS-induced colitis mouse model. On the left, a mouse with an inflamed colon is shown, indicating colitis induced by dextran sulfate sodium. An arrow points to the inflamed colon and another arrow indicates the administration of elemene nanoemulsion. In the center, an inflammatory macrophage is depicted with a mitochondrion inside. The macrophage is labeled with ’ROS-triggered self-aggregation,’ and ’High ROS’ is noted. The mitochondrion shows decreases in mitochondrial membrane potential, ATP, tumor necrosis factor alpha, interleukin 1 beta and interleukin 6, indicated by downward arrows. On the right, an arrow leads to a depiction of colitis alleviation, showing a healthy colon. The diagram highlights the decrease or inhibition of inflammatory responses and mitochondrial dysfunction in the macrophage, contributing to colitis alleviation.