Lipid-Lowering Bioactivity of Microalga Nitzschia laevis Extract Containing Fucoxanthin in Murine Model and Carcinomic Hepatocytes

Abstract

Non-alcoholic fatty liver disease (NAFLD), characterized by hepatic steatosis, is one of the most common liver diseases worldwide. So far, no definitive medical treatment has been established to treat NAFLD except for lifestyle medication. Nitzschia laevis extract (NLE), a microalgal extract rich in fucoxanthin, has been previously demonstrated to reduce bodyweight in high-fat-diet (HFD) C57BL/6J mice, indicating potential for prevention of NAFLD. In the present study, we investigated the lipid-lowering effects of NLE in HFD-induced steatosis murine model and palmitate-treated HepG2 cells. The results showed that NLE significantly lowered inguinal fat and attenuated hepatic steatosis in C57BL/6J mice. Especially, NLE significantly prevented lipid accumulation in HepG2 cells. This was probably due to its capability to enhance hepatic mitochondrial function as evidenced by the increased oxygen consumption rate (OCR) and mitochondrial membrane potential (MMP), and repress fatty acid synthesis through phosphorylation of acetyl-CoA carboxylase (ACC). Moreover, fucoxanthin was identified to be responsible for the lipid-lowering effect of NLE. Taken together, NLE or other microalgal fucoxanthin-rich products are promising natural products that may help prevent against NAFLD.

Fucoxanthin improves serum lipids, liver metabolism and gut microbiota in hyperlipidemia mice

“…Hyperlipidemia easily leads to serious metabolic diseases, which credits to a higher TG, TC, LDL and/or lower HDL concentration in the serum. The current results showed significant increase of TG, TC, LDL and decreased of HDL in HFD-induced group, while fucoxanthin supplementation for 8 weeks largely reversed them (Table 1), which agrees with our previous report [19] . However, a dose-dependent effect of fucoxanthin was observed for TG and HDL, but not TC and LDL, which reminds that dosage effects should be carefully considered when supplied with fucoxanthin.…”

“…In the current study, both the histological and physiological results indicated reduced lipid accumulation by fucoxanthin (Fig. 2), which was in line with previous studies [19,24] .…”

“…Lowering the lipid content is the primary way to treat hyperlipidemia [18] . In our previous studies, we found fucoxanthin-rich extract could reduce the total lipid accumulation in HFD-fed mice [14,19] , showing its potential to attenuate hyperlipidemia. In the current study, it turned out that fucoxanthin could considerably improve the serum lipid profile by downregulating TG, TC, LDL but upregulating HDL cholesterol level in HFD-feeding mice.…”

Effects of Marine Natural Products on Liver Diseases

“…The experimental results showed that NLE significantly reduced body weight and hepatic steatosis and inhibited cellular lipid accumulation in mice, and NLE also achieved lipid-lowering effects by enhancing hepatic mitochondrial functions, such as increasing the oxygen consumption rate and mitochondrial membrane potential, as well as inhibiting fatty acid synthesis. Therefore, it is an extremely promising natural product for the prevention of NAFLD [69]. The chemical structures of compounds 16-22 are shown in Figure 6.…”

Bioactive Compounds from Brown Algae Alleviate Nonalcoholic Fatty Liver Disease: An Extensive Review

“…These results are consistent with those of Jeon et al, who showed that a microalgal extract from Nitzschia laevis rich in fucoxanthin significantly reduced inguinal fats and attenuated hepatic steatosis in HFD-fed mice. This was highly attributed to its ability to improve hepatic mitochondrial functions, as indicated by enhanced oxygen consumption rate (OCR), mitochondrial membrane potential (MMP), and inhibited fatty acid production via phosphorylation of acetyl-CoA carboxylase (ACC) . A fucoxanthin-rich extract from Undaria pinnatifida markedly suppressed hepatic lipid levels in DIO mice, which was correlated with decreased activities of enzymes involved in fatty acid synthesis, including FAS, ME, and G6PD, along with increased fatty acid oxidation in the liver .…”