Lycopus lucidus Turcz (LT), a perennial herb in the Lamiaceae family, has traditionally been used in East Asia for its anti-inflammatory and circulation-promoting effects and contains phenolic compounds with strong antioxidant activity. Despite this, in vivo studies verifying its efficacy are limited, and no research has directly compared extracts prepared with different solvents. This study compared the effects of LT water and ethanol extracts in HepG2 hepatocytes and evaluated the impact of LT water extract on oxidative stress, apoptosis, lipid metabolism, and liver function in diet-induced obese mice. In vitro, fatty acid-treated HepG2 cells exhibited marked lipid accumulation, which was reduced significantly by LT water and ethanol extracts without cytotoxic effects. In vivo, C57BL/6J mice were fed a normal diet (ND), high-fat diet (HFD), or HFD supplemented with low-dose (LLT) or high-dose (HLT) LT water extract for 12 weeks. LT supplementation reduced the levels of hepatic lipid droplets, plasma GOT and GPT, and inflammatory cytokines (IL-1β and TNF-α) elevated by the HFD. It also improved dyslipidemia and upregulated hepatic PPARα and PGC1α expression, promoting fatty acid oxidation. Furthermore, LT enhanced the antioxidant enzyme activities (SOD, CAT, GR, and GPx) and decreased caspase-3 and caspase-8 expression, alleviating hepatocellular apoptosis. These results suggest that LT supplementation improves the liver function by reducing oxidative stress, regulating lipid metabolism, and suppressing apoptosis, highlighting its potential as a functional food ingredient for preventing and managing non-alcoholic fatty liver disease (NAFLD).
The beneficial effects appear to occur regardless of the extraction solvent (hot water or ethanol).