Loganin, an Iridoid Glycoside, Alleviates Paclitaxel-Induced Skeletal Muscle Toxicity by Enhancing Mitochondrial Function, Boosting Antioxidant Defenses, and Reducing Cellular Senescence.

Mitochondrial dysfunction and energy imbalance caused by chemotherapy are key contributors to skeletal muscle atrophy, which severely impacts the quality of life in cancer patients. Paclitaxel, a commonly used chemotherapeutic agent, is known to promote muscle wasting and cellular senescence, largely by impairing mitochondrial function. In this study, we investigated the protective role of loganin, a naturally occurring iridoid glycoside, in preventing paclitaxel-induced damage to skeletal muscle cells. Using C2C12 cells, we assessed whether loganin could counteract the harmful effects of paclitaxel. Our results demonstrated that loganin significantly improved cell viability and protected mitochondrial function, as reflected by better preservation of mitochondrial DNA content, membrane potential, and ATP production, while further enhancing mitochondrial biogenesis through upregulation of PGC-1α, TFAM, and NRF1. In parallel, loganin activated metabolic regulators SIRT1 and AMPK, while restoring PDK4 expression, suggesting improved energy regulation. Additionally, glycogen levels and myotube morphology were maintained, alongside sustained myosin heavy chain expression. Loganin effectively reduced both cellular and mitochondrial reactive oxygen species and increased antioxidant defenses, including superoxide dismutase activity and glutathione levels. Notably, it also suppressed paclitaxel-induced senescence and inflammation, as shown by decreased p21 expression, reduced NFκB phosphorylation, and lower levels of Cdkn1a and Il6 as well as reduced SA-β-gal staining. Overall, our findings demonstrate that loganin offers comprehensive protection against paclitaxel-induced skeletal muscle injury by preserving mitochondrial function, supporting metabolic homeostasis, reducing oxidative stress, and limiting senescence. These results highlight the potential of loganin as a preventive adjunctive agent to mitigate chemotherapy-related muscle toxicity.