Preparation, Characterization, and In Vivo Anti-Fatigue Evaluation of Octacosanol Nanoemulsions

Octacosanol (OCT) is a natural aliphatic alcohol with multiple activities, but the poor solubility limited its wide applications. In this study, OCT nanoemulsions were prepared by a low-energy emulsification method. The particle size, polydispersity index, and Zeta potential of OCT nanoemulsions were 12.59 nm, 0.131, and -10.54 mV, respectively. OCT nanoemulsions could keep stable up to 180 days at 4 degrees C with particle size ranging from 12.61 to 16.57 nm. In addition, OCT nanoemulsions could remain stable upon exposure to autoclaving, acid-base (pH 2-8), freeze-thaw, ultraviolet (UV) irradiation, and low concentrations of ions. The grid test time and exhaustive swimming time of the OCT nanoemulsions group increased by 70% and 40% compared with the exercise control group, indicating that OCT nanoemulsions could enhance the muscle strength and endurance performance of mice. Compared with the exercise control group, the muscle glycogen, liver glycogen, superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) levels of the OCT nanoemulsions group increased by 97%, 45%, 62%, and 20%, while the blood lactic acid and lactate dehydrogenase levels of the OCT nanoemulsions group decreased by 33% and 22%, respectively, suggesting that OCT nanoemulsions had the anti-fatigue effect. Hematoxylin and eosin staining showed that OCT nanoemulsions could repair muscle damages induced by excessive exercise. These findings could pave the way for the development of OCT nanoemulsions with high stability and anti-fatigue potential.