Protective effects of alginate-free residue of sea tangle against hyperlipidemic and oxidant activities in rats
Yim et al. Fisheries and Aquatic Sciences
Protective effects of alginate-free residue of sea tangle against hyperlipidemic and oxidant activities in rats
Mi-Jin Yim 0
Grace Choi 0
Jeong Min Lee 0
Soon-Yeong Cho 1
Dae-Sung Lee 0
0 Department of Applied Research, National Marine Biodiversity Institute of Korea , Seocheon 33662 , South Korea
1 Department of Food Processing and Distribution, Gangneung-Wonju National University , Gangneung 25457 , South Korea
The antihyperlipidemic and antioxidant activities of dietary supplementation of sea tangle from Goseong and the alginate-free residue of sea tangle were investigated in Sprague Dawley rats treated with a high-fat diet, streptozotocin, poloxamer 407, and bromobenzene. The alginate-free residue of Goseong sea tangle induced a significant reduction in triglycerides and total cholesterol levels, as well as a significant increase in high-density lipoprotein cholesterol levels. Alginate-free Goseong sea tangle residue reduced the activities of the phase I enzymes aminopyrine N-demethylase and aniline hydroxylase, which had been increased by intraperitoneal injection of bromobenzene. Pretreatment with Goseong sea tangle residue prevented a bromobenzene-induced decrease in epoxide hydrolase activity. Bromobenzene reduced hepatic glutathione content and increased hepatic lipid peroxide levels. Pretreatment with alginate-free Goseong sea tangle residue prevented lipid peroxidation induced by bromobenzene, but pretreatment with Goseong sea tangle did not. These results suggest that Goseong sea tangle residue exerted antihyperlipidemic and antioxidant activities that were higher than those induced by alginate-containing sea tangle. Therefore, the alginate-free residue may contain physiologically unknown active components, other than alginic acid, which may potentially be used to prevent hyperlipidemic atherosclerosis.
Saccharina japonica; Sea tangle; Hyperlipidemia; Antioxidant activity
Background
Hyperlipidemia is considered a major risk factor for
cardiovascular diseases and events such as atherosclerosis
and myocardial infarction
(Wald and Law 1995; Talbert
1997)
. Rates of hyperlipidemia-related diseases are
increasing with lifestyle changes. Low-density
lipoprotein cholesterol (LDL-C) is regarded as the primary risk
factor for atherosclerosis and coronary heart disease
(Baigent et al. 2010), and elevated circulating levels of
free fatty acids and triglycerides (TG) can lead to these
diseases
(Pilz et al. 2006; Harchaoui et al. 2009)
.
Therefore, modulating the dysregulation of lipid metabolism
and decreasing the levels of serum total cholesterol
(TC), TG, and LDL-C are considered beneficial in
treating and preventing cardiovascular diseases
(Derosa et al.
2006; Zhang et al. 2013)
. Identifying effective food
sources to treat hyperlipidemia would promote this
objective
(Murata et al. 1999)
.
The brown alga sea tangle (Saccharina japonica) has
been used in Korea to promote maternal health
(Jin et
al. 2004)
. Sea tangle is also popular in Korea and Japan
as a food and has been reported to exhibit hypotensive,
antioxidant, antimutagenic, and antibacterial activities
(Okai et al. 1993; Han et al. 2002; Wang et al. 2006; Park
et al. 2009)
. Moreover, aqueous extracts of sea tangle
and alginate have also been shown to exhibit antioxidant
activity and lower hypercholesterolemia
(Torsdottir et al.
1991; Lee et al. 2004)
. However, the alginate-free residue
of sea tangle has not been investigated for its biological
activities.
In the present study, we evaluated the biological
activities of sea tangle residue from which alginate
had been removed. The antihyperlipidemic effects of
sea tangle residue were assessed in three different
experimental rat models, one in which hyperlipidemia
was induced by a high-fat diet and two in which
hyperlipidemia was induced by streptozotocin and
poloxamer 407. In addition, the effects of sea tangle
residue on lipid peroxidation and the activities of
enzymes involved in drug metabolism were examined
in the livers of bromobenzene-treated rats.
Methods
Materials
Goseong sea tangle (Goseong, Gangwon-do, South
Korea; S. japonica) was obtained from a local supplier
(Gangneung, Gangwon-do, South Korea) in March 2007.
Alginate-free residue from Goseong sea tangle was also
used in this study. All samples were powdered after
freeze-drying.
Animals and treatments
Male Sprague Dawley rats (Daehan Biolink, Eumsung,
South Korea) weighing 190–210 g were housed
individually in stainless steel mesh cages in a room maintained
at 22 ± 1 °C and 55 ± 3% relative humidity with a
normal 12-h light/dark cycle. Rats were fed a commercial
standard rat diet (AIN-76). The composition of the
experimental diets is shown in Table 1. The high-fat
diettreated rats were orally administered for the last week
with a high-fat diet that fed daily for 6 week. Rats were
orally administered 100 or 200 mg/kg of body weight of
the sea tangle powder in 5% Tween (...truncated)