Sea Cucumber Saponin Echinoside A (EA) Stimulates Hepatic Fatty Acid β-Oxidation and Suppresses Fatty Acid Biosynthesis Coupling in a Diurnal Pattern.

Circadian rhythms control aspects of physiological events, including lipid metabolism, showing rhythmic fluctuation over 24 h. Therefore, it is not sufficient to evaluate thoroughly how dietary components regulate lipid metabolism with a single time-point assay. In the present study, a time-course study was performed to analyze the effect of sea cucumber saponin echinoside A (EA) on lipid metabolism over 24 h. Results showed that EA lowered the levels of TC and TG in both serum and liver at most time-points during the 24 h. Activities of hepatic lipogenic enzymes and lipolytic enzymes were inhibited and elevated respectively by EA to varied degrees at different time-points. Meanwhile, parallel variation trends of gene expression involved in fatty acid synthesis and β-oxidation were observed accordingly. The interaction between EA and lipid metabolism showed a time-dependent effect. Overall, EA impaired fatty acid synthesis and enhanced mitochondrial fatty acid β-oxidation in ad libitum feeding over 24 h.