Hyperlipidemia, a disease that sees an increase in its number of patients each year, is a growing concern. The adverse effects of this condition are not limited to the diminished quality of life of patients, but it can also pave the way for life-threatening arteriosclerotic ailments such as cerebral and myocardial infarction. Clinical treatment of hyperlipidemia usually involves pharmaceutical drugs, which often have side effects and adversely affect the physical and mental well-being of patients. However, one beneficial supplement is fucoidan, which is extracted from brown algae and is a macromolecular polysaccharide. As a matter of fact, numerous studies have demonstrated its clinical efficacy with no known side effects. It has also been suggested that fucoidan has an excellent effect on hyperlipidemia. The complete knowledge about the action mechanism of fucoidan’s lipid-lowering effect is still insufficient. Hence, in this blog, I would like to share the study “Hypolipidemic effects of fucoidan fractions from Saccharina sculpera (Laminariales, Phaeophyceae)” by Dandan Ren et al.

The monosaccharide composition and structural characterization of the isolated fractions (F1, F2, F3) were conducted through the utilization of high-performance liquid chromatography (HPLC), Fourier transform infrared spectroscopy (FTIR), and nuclear magnetic resonance spectroscopy (NMR). The lipid-lowering effect of the fucoidan fraction of Saccharina sculpera (Gagome Kelp) cultured in northern China was revealed by measuring cholesterol levels, antioxidant indices, and hepatic gene mRNA expression using an established hyperlipidemia Wistar rat model.

Initially, fucoidan was isolated and purified from kelp, resulting in the acquisition of three fucoidan fractions, namely F1, F2, and F3. A control group of 60 rats fed with normal saline and a normal diet, a negative control group fed with a saline-filtered high-fat diet, a positive control group fed with a low-fat-lowering drug and a high-fat diet, F1, F2, F3, and fucoidan groups fed with high-fat diet were divided into 6 groups and raised for 8 weeks. Blood samples from rats were collected and analyzed for the serum lipid-lowering effect of the fucoidan fraction. In comparison to the negative control group, the positive control group and the fucoidan group exhibited a reduction in cholesterol, triglycerides, and low-density lipoprotein, which are critical factors in the development of arteriosclerosis, and a rise in high-density lipoprotein. In particular, F2 showed a very effective blood lipid adjustment action. Next, liver fat was collected from the rats and observed under an optical microscope. Consequently, hepatic steatosis was observed in the negative control group in contrast to the control group, and lipid droplets were detected. Compared to the negative control group, the number of lipid droplets decreased in the fucoidan group, suggesting that fucoidan effectively prevents the progression of fatty liver due to a high-fat diet. (See Figure. 1)

Following this, the fucoidan group was studied to observe the effects of fat-related factors on mRNA expression. First, they examined the expression of HMG-CoA-R (precursor for cholesterol synthesis), which is involved in cholesterol production, LCAT (LCAT enzyme helps transport cholesterol out of the blood). The LCAT enzyme helps HDL-C to transport unused cholesterol to the liver, and SREBP-1c (a transcription factor that responds to insulin), a factor that increases the synthesis of fatty acids and TGs (Triglyceride molecules) in the liver.

The positive control group and the fucoidan group exhibited a decrease in mRNA expression compared to the negative control group. Finally, they analyzed the mRNA expression of PPARα, which is involved in the reduction of blood TG levels, PPARγ, which is involved in adipose tissue differentiation and cholesterol excretion, and LPL(Lipoprotein lipase), an important enzyme in fat metabolism. As a result, the expression of three types of mRNA increased in the positive control group and fucoidan group compared to the negative control group. (See Figure – 2) The results suggest that Gagome kelp fucoidan has an outstanding effect in regulating blood lipids, and it holds the potential to be utilized in the treatment of hyperlipidemia.

Source: Int J Biol Macromol PMID: 31381913 DOI: 10.1016/j.ijbiomac.2019.08.002