الفهرس 
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Abstract
Brown algae belong to Family, Phaeophyceae are a large group of mostly marine multicellular algae, including many seaweeds located in different countries around the world including Egypt. They are a diverse group of aquatic organisms, which are described as having the ability to perform photosynthesis. Some types of Brown algae are also familiar to most people as food and as habitats. Despite this, there is a vast and diverse world of algae including Brown algae that not only help us with life, but are essential to our existence in it. Brown algae are members of the Heterokontophyta category of eukaryotic creatures, which are identified by their chloroplasts being surrounded by four membranes, implying that they evolved through a symbiotic interaction between a basic eukaryote and another eukaryotic cell. Most Brown algae contains the pigment fucoxanthin, which gives them their name and gives them their unique greenish-brown hue. In the littoral zone of the Egyptian coast, Brown algae is currently the most dominant group. Sargassum subrepandum, a members of Sargassum genus represent valuable source of a several nutritional and nutraceuticals compounds. Our previous studies indicated that Sargassum subrepandum powder (SSP) contains proteins, lipids, minerals, fiber, carbohydrates and bioactive compounds including polysaccharides, phenolics, dietary fiber, anthocyanins, carotenoids, tannins and flavonoids. Other components include free mannitol, minerals such as iodine and arsenic (inorganic and organic), peptides, fatty compounds, free fatty and amino acids and various pigments were also determined. from a nutritional and therapeutic point of view, Brown algae including Sargassum subrepandum are used dried in condiment and soup bases or eaten fresh in salads, rolls, or stews, or with rice. It is thought that the overall content of certain traditional Asian diets contributes to the low incidence of cancer, particularly breast cancer. SSP dietary intervention reduced blood pressure and cholesterol levels, suppressed the urinary markers of bone resorption, and attenuated a tendency toward diabetes. On the other side, several studies have discovered the protective effect of SSP on different complications including serum lipid profile, hyperglycemia, cardiovascular disease, atherosclerosis, liver and kidney functions in obese experimental animal model.
Obesity definition varies depending on what one reads. In general, overweight and obesity indicate a weight greater than what is considered healthy. Obesity is a medical condition in which excess body fat has accumulated to the extent that it may have an adverse effect on health, leading to reduced life expectancy and/or increased health problems. Obesity is best defined by using the body mass index. The body mass index is calculated using a person’s height and weight. The body mass index (BMI) equals a person’s weight in kilograms (kg) divided by their height in meters (m) squared. Since BMI describes body weight relative to height, it is strongly correlated with total body fat content in adults. An adult who has a BMI of 25-29.9 is considered overweight, and an adult who has a BMI over 30 is considered obese. It is becoming increasingly clear that obesity has become one of the 21st century’s most significant public health concerns. It is considered as a top risk factor to develop deleterious associated pathologies as type 2 diabetes, liver, coronary heart diseases, and certain types of cancer, osteoarthritis and asthma. Also, obesity increases the risk of many physical and mental conditions. In this context, several studies reported that obesity is associated with an approximately 25% increase in odds of mood and anxiety disorders and an approximately 25% decrease in odds of substance use disorders. Furthermore, several studies reported that obesity may accelerate the aging process through accelerates epigenetic changes associated with aging in the human liver resulting in an apparent age acceleration of 2.7 years for a 10-point increase in BMI. All of those co-morbidities are most commonly shown in metabolic syndrome, a combination of medical disorders which includes: diabetes mellitus type 2, high blood pressure, high blood cholesterol, and high triglyceride levels. Complications are either directly caused by obesity or indirectly related through mechanisms sharing a common cause such as a poor diet or a sedentary lifestyle.
Aim of study
The present study was carried out to investigate the chemical composition, nutritional evaluation, bioactive compounds content and antioxidant activity of Sargassum subrepandum powder (SSP). Also, the effect of SSP on obesity and its complications in rats will be in the scope of this study.
Methods
Sargassum subrepandum samples
Sargassum subrepandum were collected from the coasts of Mediterranean Sea, Alexandria, Alexandria Governorate, Egypt. The algae samples were verified by the staff in Faculty of Agriculture, Alexandria University, Alexandria, Egypt.
Preparation of Sargassum subrepandum powder (SSP)
Sargassum subrepandum collecting samples were cleaning and sorting manually and then dried in a hot air oven (Horizontal Forced Air Drier, Proctor and Schwartz Inc., Philadelphia, PA) at 55 0C until arriving by the moisture in the final product to about 10%. The dried samples were ground into a fine powder in high mixer speed (Moulinex Egypt, ElAraby Co., Benha, Egypt). The material that passed through an 80 mesh sieve was retained for Feeding/intervention rats protocol.
Preparation of SSP extracts
SSP was used for their different types extracts as follow: A 20 g from dried SSP plus 180 ml water were homogenized and transferred to a beaker and stirred at 200 rpm in an orbital shaker for 1 h at room temperature. The extract was then separated from the residue by filtration through Whatman No. 1 filter paper. The remaining residue was re-extracted twice, and then the two extracts were combined. The residual solvent of was removed under reduced pressure at 55°C using a rotary evaporator. The same protocol was followed as before with changing the extraction medium with Metanol (80%, v/v) and Ethanol (80%, v/v) respectively. The residual solvent of was removed under reduced pressure at 45°C using a rotary evaporator. All extracts (Aqueous, Mehanolic and Ethanolic) could be ready for physical and chemical studies as well as the basil diet blending purpose (Feeding rats protocol).
Biological Experiments Design
Rats (n=36 rats), were housed individually in wire cages in a room maintained at 25 ± 3 0C, relative humidity (53±3%), a 12-hr lighting cycle and kept under normal healthy conditions. All rats were fed on BD for one-week before starting the experiment for acclimatization. After one week period, the rats were divided into two main groups, the first group, normal control, (group 1, 6 rats) still fed with a basic/standard diet (BD) and the other main group (30 rats) was used for obesity induction and classified into five sub groups as follow: group (2), model control, fed on BD only as a positive control (rats with obesity) and groups (3-6) fed on BD and administered by oral gavages, using a feeding needle with 2, 3, 4 and 5 g SPP /100 g diet, respectively. Rats were weighted at the beginning of experimental then weekly and at the end of the experimental period.
Results
Chemical and nutritional study of Sargassum subrepandum powder (SSP)
Carbohydrates were the largest compound (55.83 – 62.19%) followed by crude fiber (11.76 - 15.69%), ash (9.33 - 13.06%), total protein (4.74 - 5.95%) and crude fat (0.51 -1.07%.).
Total energy was ranged 262.90 to 274.78 Kcal/100g, G.D.R. (g) for protein (63 g) was 1180.17 – 1281.11g, G.D.R. (g) for energy (2900 Kcal) was 1043.00 – 1104.76, P.S./ 100 g for protein (63g) was 7.69 – 9.02% and P.S./100 g for energy (2900 Kcal) was 8.90 – 9.77%.
Phytochemistry and biological activity of Sargassum subrepandum powder (SSP)
Polysaccharides were the largest compound ranged 132.45 to 173.7 mg starch equvalent. g-1 followed by phenolics (103.66 to 158.98 mg gallic acid equvalent. g-1), carotenoids (27.84 to 49.17 mg .g-1), flavonoids (27.11 to 37.98 mg catechin equivalent. g-1) and anthocyanin’s (5.91 to 8.03 mg Cyanidin 3-glucoside, CCy3G equivalent.100g-1). Also, brown algae (Sargassum subrepandum) were riched in dietary fiber ranged 38.05 - 46.42 g/100g.
Antioxidants activity (β -Carotene Bleaching, BCB): The decrease in absorbance of β-carotene in the presence of different SSP extracts and α-tocopherol used as standards with the oxidation of β-carotene and linoleic acid indicated that SSP ethanol extract (SSP-EtE) recorded the lowest decreasing followed by SSP methanol extract (SSP-MtE) and SSP aquatic extract (SSP-AqE). The values of SSP-EtE and SSP-MtE absorbance’s through 120 min are coming well i.e. closing to the line of 50 mg α-tocopherol compared with SSP-AqE. Also, such data proves the high stability of the SSP organic extracts when comparing with that most common antioxidant standards, α-tocopherol.
DPPH radical scavenging activity: The free radical scavenging activity (FRSA) of the different extracts of BA and standard BHT reported that among the extracts, MtE possessed the highest activity. At a concentration of 100 μg/mL, the scavenging activity of AqE, EtE and MeE was 82.52, 87.82 and 91.23%, respectively, whereas at the same concentration, the standard BHT was 96.62%. For the IC50, the AqE, EtE and MeE recorded 19.92, 10.41 and 12.52 μg/mL, respectively. The IC50 of BHT (standard) was 7.78 μg/mL. The FRSA of different tested extracts and standard was in the following order: BHT > EtE > MeE > AqE.
Biological experiments data
The effect of Sargassum subrepandum powder (SSP) on body weight of obese rats
Feeding of rats on diet induced obesity (DIO) leads to increase the BW than the normal control group. At the end of the experimental feeding period (8 weeks), rats of the normal control group recorded 241.68 g i.e. an increase in its amount by 80.79% when compared to the baseline. At the same period, the model control group (obese rats) recorded 330.22 g i.e. increased by the rate of 147.02% when compared to the baseline. The intervention with SSP by 2, 3, 4 and 4% in the obese group resulted in significant (p≤0.05) decrease in BW by the rate of 128.60, 117.96, 102.93 and 95.85%, respectively. The rate of decreasing in BW amounts were exhibited a dose- dependent increase with SSP intervention.
The effect of Sargassum subrepandum powder (SSP) on blood lipids profile concentration of obese rats
Obesity induced a significant increased (p≤0.05) in TG (35.08%), TC (29.02), LDL (80.06%), and VLDL (35.08%) while significant decreased (p≤0.05) in HDL (-37.20%) compared to normal controls. Intervention of the rat’s diets with 2 to 5% induced significant improvements on blood lipid profile through decreasing the TG, TC, LDL and VLDL by different ratios. The opposite direction was recorded for the HDL levels. The rate of improvement in blood lipid profile disorders of obese rats were exhibited a dose- dependent increase with SSP intervention.).
The effect of Sargassum subrepandum powder (SSP) on serum oxidative stress parameters of obese rats
Reduced glutathione concentration
Serum levels of GSH, as an important immunological parameter, was measured and compared in normal control and intervened obese rats. GSH levels of obese rats and BAE was shown in Table (1) and Figure (1). from such data it could be noticed that treatment of animals with DIO caused a significant decreased (p≤0.05) in GSH (-26.64%) compared to normal controls. Intervention of the rat diets with SSP (2 to 5 g/100 g diet) prevented the decreasing of serum GSH level. The rate of prevention effect was lowered with the increasing of the SSP concentration i.e. Dose-response behavior.
Serum biological oxidants (Malondialdehyde, MDA) content
Feeding of DIO for 8 weeks caused a significant (p≤0.05) increased in serum MDA concentration by the ratio 92.24% compared to normal controls. Intervention with SSP on rat diets by concentrations of 2, 3, 4 and 5% leads to decrease MDA value by the rate of 83.23, 72.05, 43.17 and 33.23 as a compared with the normmproal control group, respectively. The rate of decreasing in MDA of rats was exhibited a dose- dependent increase with SSP level intervention.