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Empowering Science, Technology and Innovation Towards a Better Tomorrow Hypoglyceamic and Hypolipidemic Effects of Seaweed (Sargassum polycystum)
Ethanolic and Water Extracts in Type II Diabetic Rats
M. Moteshakeri1, M. Ebrahimi2, and S. Mohamed2* 1 Faculty of Food Science and Technology, Universiti Putra Malaysia, 43400, Selangor, Malaysia 2 Faculty of Veterinary Medicine, Universiti Putra Malaysia, 43400, Selangor, Malaysia *Corresponding author’s email: mohamed.suhaila@gmail.com Keywords: Type II diabetes mellitus, Seaweed, Streptozotocin, Sprague-Dawley.

Introduction: Diabetes mellitus is a chronic metabolic disorder suffered by more than 180 million
people worldwide. The number of affected people is expected to increase at least 366 million by year
2030 [1]. It is well characterized by hyperglycemia due to absolute or relative lack of insulin
secretion from pancreas [2]. The main reasons of morbidity and mortality in the diabetic patients are
heart disease and stroke as patients are 2 to 4 times more susceptible to have heart disease and 5
times more likely to have stroke [3,4]. Thus, different pharmacological and nonpharmacological
treatments have been applied to prevent further complications. Since chemical medications are
known with various side effects, seaweeds have been center of focus as a natural source of biological
compounds which have beneficial effects for human health [5]. Brown seaweed, Sargassum
polycystum (SP) has been reported to possess antioxidant properties with potential healing effects.
Feeding high calorie diets following low-dose of streptozotocin(STZ) has been found to mimic
natural history of the disease induced Type II diabet in Sprague-Dawley rats. The objective of this
study was to investigate the hypoglyceamic and hypolipidemic effects of ethanolic and water extracts
of SP in high-sugar, high-fat diet-fed with low-dose of STZ-induced type II diabetic rat model.

Methods: Male Sprague–Dawley rats (200–250 g) were randomly divided into seven groups (n=8):
normal control group (NC) fed standard rodent diet, diabetic control group (DC), diabetic rats treated
with ethanol extract 300 mg/kg (DE300), diabetic rats treated with ethanol extract 150 mg/kg
(DE150), diabetic rats treated with water extract 300 mg/kg (DW300), diabetic rats treated with
water extract 150 mg/kg (DW150), diabetic rats treated with metformin (DM). Diabetes was induced
in all diabetic rats by feeding high-sugar, high-fat diet similar to western diet for 16 weeks and then
intraperitoneal injection of low dose of streptozotocin. Rats were treated with seaweed extracts for
22 days.
Results: The blood glucose levels of rats (Figure 1) showed significant decreased (P<0.05) about
36%, 28%, 35%, and 85% in DE300, DE150, DW300, and DM groups, respectively, as compared to
DC group.
Empowering Science, Technology and Innovation Towards a Better Tomorrow Blood glucose level
Days of seaweed treatment

Figure 1: Blood glucose levels (mmol/L) of rats at the end of seaweed treatment.
Percentage of HbA1C (Table 1) was significantly (P<0.05) decreased in DE300, DE150, DW300,
and DM groups as compared to DC group. Plasma insulin level did not change significantly (P>0.05)
in all seaweed treated groups except in DM group (Table 2).
Table 1: The level of HbA1C (%) and plasma insulin concentration (ng/ml) in the experimental
animals at the end of trial (Mean± SE).
7.4±0.7 BC
7.5±0.3 B
7.5±0.6 B
7.0±0.9 BC
0.32± 0.12 C
0.77± 0.08 BC
1.50±0.17 A
A, B, C: Values with the same superscript/s within row do not differ significantly at P<0.05. Values are expressed as Mean ± SE. n=6. NC: Normal control group. DC: Diabetic control group. DE300: Diabetic group treated with 300 mg ethanolic extract/kg BW. DE150: Diabetic group treated with 150 mg ethanolic extract/kg BW. DW300: Diabetic group treated with 300 mg water extract/kg BW. DW150: Diabetic group treated with 150 mg water extract/ kg BW. All seaweed extracts reduced significantly (P<0.05) total cholesterol (TC) and triglyceride (TG) level compared to diabetic control (DC) group (Table 2). Low-density lipoprotein-cholesterol (LDL-C) level was significantly (P<0.05) reduced in DW300 group compared to DC group. High-density lipoprotein-cholesterol (HDL-C) did not change significantly (P>0.05) in all treated groups. HDL-C/TC ratio (HTR) improved significantly (P<0.05) in DE150, DW300, DW150 and DM groups compared to DC group. Empowering Science, Technology and Innovation Towards a Better Tomorrow
Table 2: Lipid profile of animals at the end of the treatment period.
1.75±0.16 BC
1.48±0.28 BC
2.05±0.17B
1.27±0.22 C
1.80±0.18 BC
1.85±0.15 B
0.85± 0.05 C
0.92±0.33 C
1.26±0.31BC
1.12±0.35 BC
0.95± 0.11 C
1.75±0.21B
0.89±0.07 A
0.70±0.07 AB
0.48±0.08 BC
0.66±0.15ABC
0.85±0.19 AB
0.24±0.07 C
0.80±0.18 AB
0.55±0.07 ABC
0.51±0.02 A
0.31± 0.04BC
0.44±0.08 AB
0.32± 0.03 BC
0.38±0.03 ABC
A, B, C: Values with the same superscript/s within row do not differ significantly at P<0.05. Values are expressed as Mean ± SE. n=6. HTR: HDL-C/TC ratio. NC: Normal control group. DC: Diabetic control group. DE300: Diabetic group treated with 300 mg ethanolic extract/kg BW. DE150: Diabetic group treated with 150 mg ethanolic extract/kg BW. DW300: Diabetic group treated with 300 mg water extract/kg BW. DW150: Diabetic group treated with 150 mg water extract/ kg BW. Discussion:
Various compounds in the seaweeds can be responsible for hypoglycemic effect. In comparison to
the other seaweeds, phytochemicals such as carotenoid fucoxanthin, sulfated polysaccharide
fucoidan, sulfated laminarine, alginic acids, and phlorotannins are specifically found in brown
seaweed. Previous study has reported the presence of flavonoids and teriterpenoids in ethanolic
extract of the seaweed [6]. Some seaweed flavonoids and polyphenols have been known to have
hypoglycemic properties [7, 8, 9, 10]. These findings suggest that seaweed ethanol extracts in dose
response manner and water extract (300 mg/kg) alleviate hyperglycemia with no significant changes
in insulin secretion. Furthermore, all seaweed extracts showed hypolipidemic effects in type II
diabetic rats that may reduce risks of cardiovascular disease. Therefore, the seaweed may be usefull
as an alternative medicine in the control of diabetes mellitus and prevention of complications such as
atherosclerosis.
References:
[1] S. Wild, G. Roglic, A. Green, R. Sicree and H. King: Diabetes Care Vol. 27 (2004), p. 1047- [2] O. Leonardi, G. Mints and M. A. Hussain: European Journal of Endocrinology/ European Federation of Endocrine Societies, Vol. 149(2) (2003), p. 99-102. [3] R. Bakri: Diabetes Epidemic in Malaysia: Second National Health and Morbidity Survey – Diabetes. Diabetes mellitus among adults aged 30 years and above. Public Health Institute, Vol. 9, (2007) [4] M. Tzagournis and J. M. Falko, in: Heart disease and cerebrovascular complications in diabetes. Edited by B. N. Brodoff, and S. J. Bleicher, Williams and Wilkins, Baltimore. Diabetes mellitus and obesity (1st edition), (1982), p. 741–748. [5] H. Marfaing, and Y. Lerat: Herbal medicine, Vol. 5(1) (2007), HS (51). [6] J. B. Harbone: Phytochemical methods. London: Chapman and Hall Ltd., (1973), p. 98-188. [7] E. Apostolidis and C.M. Lee: Journal of Food Science, Vol. 75(3) (2010), p. 97-102. Empowering Science, Technology and Innovation Towards a Better Tomorrow [8] S. I. Kang, M. H. Kim, H. S. Shin, H. M. Kim, Y. S. Hong, J. G. Park, H. C. Ko, N. H. Lee, W. S. Chung, and S. J. Kim: Journal of Nutritional Biochemistry, Article in Press, (2010). [9] K. Iwai: Plant Foods and Human Nutrition, Vol. 63, (2008), p. 163–169. [10] J. Zhang, C. Tiller, J. Shen, C. Wang, G. S. Girouard, D. Dennis, C. J. Barrow, M. Miaoand and H. S. Ewart: Canadian Journal of Physiology and Pharmacology, Vol. 85(11) (2007), p. 1116-1123.

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