Anti-Obesity Effects of Tisochrysis lutea Powder in High-Fat Diet-Induced Obese Mice Through the Regulation of Adipogenesis and Lipid Metabolism

Obesity is associated with excessive lipid deposition in adipose tissue and the liver, leading to systemic metabolic disturbances. In this study, we investigated the anti-obesity efficacy of Tisochrysis lutea (TL) powder, standardized to fucoxanthin (12.18 ± 0.21 mg/g DW) and docosahexaenoic acid (DHA) (16.03 ± 0.49 mg/g DW), in a high-fat diet (HFD)-induced obesity model in C57BL/6N mice. TL supplementation (50–150 mg/kg) over eight weeks significantly reduced body weight gain by up to 63.2%, total white adipose tissue mass by 53.4%, and liver weight by 38.2% compared to the HFD control, without affecting renal safety markers. Histological examination revealed smaller adipocytes and diminished hepatic steatosis in TL-treated groups. Serum triglycerides and leptin concentrations were significantly lowered by 38.5% and 70.1%, respectively, while HFD-induced elevations of ALT and AST were reduced by 61.7% and 38.6%, respectively. At the transcriptional level, TL downregulated adipogenic markers including PPARγ, C/EBPα, and SREBP-1c by 46~54%, as well as lipogenic regulators including FAS and ACC1 by up to 72%. Furthermore, TL treatment upregulated the mRNA levels of HSL and AMPK 2.3- and 2.1-fold, respectively, compared to the HFD control. These findings indicate that fucoxanthin- and DHA-enriched TL powder improves obesity-related metabolic alterations by modulating lipid storage and utilization pathways, supporting its development as a marine-derived functional ingredient for metabolic health management.