Abstract
Hypercholesterolemia plays an important role in atherosclerosis and cardiovascular diseases (CVD) that represent one of the greatest worldwide medical problems nowadays. Recently, an increased attention/ interest for natural antioxidant/ hypercholesterolemia as WG/WGO is increasing. Wheat germ/ Wheat germ oil (WG/WGO) is an excellent source of essential and polyunsaturated fatty acids and vitamin E. It is one of the richest natural sources of tocopherol. This work aims to evaluate the effect of administration of wheat germ (WG) /wheat germ oil (WGO) for 6 weeks on serum lipid profile, lipid peroxidation (liver malondialdehyde) in hypercholesterolemic rats. One hundred and twenty maleSprague Dawelyrats weighing 180-192 gm were used in this study. They were randomly distributed into six groups (20 rats/ group) as follow: g1: normal control, G2: hypercholesterolemic rats; G3: Normal rats treated with WG; G4: hypercholesterolemic rats treated with WG; G5: Normal rats treated with WGO; G6: hypercholesterolemic rats treated with WGO for 6 weeks. Also WG was analysed for its nutritive value, while WGO was analysed for fatty acid profile, and studied for its physico-chemical properties. The results showed significant elevation of liver malondialdehyde (MDA) and serum lipid profile in untreated rats fed on hypercholesterolemic diet. Hypercholesterolemic rats treated with WG/WGO showed an improvement in the biochemical assay of their lipid profile compared with untreated hypercholesterolemic rats. WG/WGO may be able to protect against atherosclerosis and CVD. The administration of WG /WGO to diets of rats caused a marked reduction in TC, LDL-C, VLDL-C, TG and MDA. This improvement effect may be mediated via enhancement of the antioxidant defence system and other factors. However, further clinical studies on human beings are required to assess the efficacy and safety of the WG/WGO.
Author Contributions
Copyright© 2020
Z A Soliman Ghada.
License
This work is licensed under a Creative Commons Attribution 4.0 International License.
This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Competing interests The authors have declared that no competing interests exist.
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Introduction
Body can get cholesterol through diet (exogenous) or synthesis (endogenous). Dietary cholesterol can affect lipid profile in human and animals. Feeding cholesterol-rich diets leads to hypercholesterolemia. Cholesterol homeostasis is controlled through absorption, synthesis and excretion. Hypercholesterolemia plays an important role in heart damage, stroke and atherosclerosis The National Cholesterol Education program Wheat germ is a by-product of the flour milling industry and is an excellent source of vitamins, minerals, fibre and proteins Wheat germ oil (WGO) is an excellent source of essential polyunsaturated fatty acids and vitamin E Wheat germ oil might reduce plasma and liver cholesterol in animals, Therefore the aim of the present study was to evaluate the effect of administration of wheat germ (WG) /wheat germ oil (WGO) for 6 weeks on serum lipid profile, lipid peroxidation (liver malondialdehyde) in hypercholesterolemic rats. Also would WG / WGO provide protection against oxidative stress in rats?
Materials And Methods
One hundred and twenty (120) male albino rats, average body weight 180-192 gm were used in the experiment. Rats were housed in separate wire mesh cages and kept at constant environmental and nutritional conditions throughout the period of experiment. The diet and water were ad libitum. The animals were left 10 days for acclimatization before the beginning of the experiment. The standard rat diet (AIN-93 M diet) was prepared according to After acclimatization period, 120 adult male Sprague Dawely rats were divided into 6 groups, (20/ group) as follow: Group 1: Normal, - ve control group, rats were fed on control diet. Group 2: + ve control group, rats were fed on hypercholesterolemic diet. Group 3: Normal rats fed on control diet supplemented with wheat germ (30%). Group 4: Hypercholesterolemic rats treated with wheat germ (30%). Group 5: Normal rats fed on control diet supplemented with wheat germ oil (1 g/kg BWt). Group 6: Hypercholesterolemic rats treated with wheat germ oil (1 g/kg BWt). After the end of the experiment (6 weeks), rats were fasted overnight, and then scarified under ether anaesthesia (Sigma, USA). Blood samples were taken by cardiac puncture. Fasting blood samples were collected in plain tubes, centrifuged for separation of serum at 3,000 rpm for 15 minutes, and sera were stored at -20 C for determination of the following biochemical measurements: total cholesterol, HDL-C, LDL-C, VLDL-C, triacylglycerol. Rat livers were excised to be used for determination of malondialdehyde after being washed with saline, dried and weighed. They were kept at -20 C till analysis. Total cholesterol, TC; Serum HDL-C; and Serum LDL-C; was determined using SGM Italia, Rome, kit (Italy) according to the method of Allian Rats were weighed twice/week to calculate Body weight gain (BWG) using the equation: BWG = Final body weight - initial body weight. Wheat Germ/ wheat germ oil Wheat germ was analysed for its proximate composition: moisture, ash, fat, fibre, dietary fibre and protein according to AOAC Data are expressed as Mean ±SEM. All statistical data and significance tests (T Test for comparison between individual groups and control group; and post hoc Duncan test analysis for comparison between groups) were performed using the Statistical Package for the Social Sciences version 11 (SPSS Inc, Chicago, IL, USA). Statistical significance was accepted at P < 0.05
Results
Results of Results of Results of Results of
Protein
23.0
Fat
10.0
Dietary fibre
16.0
Ash
4.21
Moisture
11.12
CHO
50.35
Fibre
1.32
Folate
270.0 mg
Folic acid
0.00 mg
Niacin
5.2 mg
Pantothenic acid
1.91 mg
Riboflavin B2
0.71 mg
Thiamin B1
1.52 mg
Vitamin A
0.00 IU
B 11
82.0 mg
Vitamin B12
0.00 mg
Vitamin B6
1.300 mg
Vitamin C
0.0 mg
Vitamin D
0.00 IU
Vit E(tocopherols)
21.0 mg
mg
Calcium, Ca
40.5mg
Copper, Cu
0.91mg
Iron, Fe
5.9 mg
Magnesium, mg
250 mg
Manganese, Mn
15.1mg
Phosphorus, P
990.0mg
Potassium, K
1050.0mg
Selenium, Se
79.0 mg
Sodium, Na
8.0 mg
Zinc, Zn
14.7mg
Calcium, Ca
40.5mg
Copper, Cu
0.91mg
Iron, Fe
5.9 mg
Acid value (mg/g oil)
0.6
Acidity (as %oleic acid)
0.83
Saponification value (mg/goil)
187.25
Ester value (mg/g oil)
186.65
Iodine value (g I2/100 g of oil)
114.21
Peroxide value (meqO2/kg oil)
3.5
Unsaponifable matter (%)
4.33
Fatty acids
WGO %
Lauric
C 12:0
0.02
myristic
C 14:0
0.12
pentadecanoic
C 15:0
0.15
Palmitic
C16:0
16.7
Palmitoleic
C16:1
0.24
Margaric acid
C 17:0
0.04
Stearic
C18:0
2.06
eliadic
C18:1n-9t
0.8
Oleic
C18:1
15.36
Linoleic (ω-6 )
C18:2
53.21
Linolenic (ω-3)
C18:3
3.5
linolenic
C18:3n-3
4.42
Arachidic
C20:0
0.25
Gadoleic
C20:1
1.21
11-Eicosenoic acid (ω-9 )
C20:1
0.08
heneicosylic
C21
1.3
Behenic
C22:0
0.29
Total saturated
20.93
Total unsaturated
79.07
∑MUFA
17.86
∑PUFA
61.21
ω-6
53.21
ω-3
7.92
ω-6/ω-3
6.72
pufa/sfa
2.92
sfa/pufa
0.34
oleic/linoleic
0.29
S/U
0.26: 1
U/S
3.78: 1
-ve Cont
+ve Cont
Norm & WG
Cholest & WG
Norm & WG
Cholest& WGO
G 1
G 2
G 3
G 4
G 5
G 6
ZeroTime
184.70±0.70a
184.95±0.72a
183.95±0.70a
184.65±0.77a
183.70±0.45a
183.65±0.48a
End
261.70±2.26a
221.85±0.85b
255.40±0.87c
247.05±0.64d
250.90±0.92e
239.20±0.92f
BWG
77.00±2.25a
36.90±1.01b
71.45±1.18c
62.40±0.86d
67.20±1.00e
55.55±1.24f
-ve Cont
+ve Cont
Norm &WG
Cholest&WG
Norm &WGO
Cholest& WGO
G 1
G 2
G 3
G 4
G 5
G 6
Cholesterol
94.7±0.70 a
164.95±0.72b
87.55±1.20a,c
119.65±0.77d
89.30±0.97 c,e
128.65±0.48f
HDL-C
44.08±0.25 a
39.65±0.09 b
43.72±0.11a
42.45±0.07c
42.83±0.11 d
41.58±0.10e
LDL-C
32.55±0.88 a
89.68±0.66 b
23.76±1.31 c
56.45±0.96d
25.95±0.67 c,e
63.75±0.50f
VLDL-C
18.07±0.28 a
35.62±0.34 b
20.07±0.28 c
20.75±0.42c,d
21.27±0.38 d,e
23.32±0.38f
TG
90.35±1.39 a
181.64±1.75b
81.35±1.39 c
105.82±2.13 d
85.98±1.53 e
118.94±1.93f
Liver MDA
14.87±0.24 a
22.70±0.22 b
15.03±0.14 a,
20.07±0.28 c
16.57±0.14 d
21.39±0.17 e
AI
1.15±0.02 a
3.16±0.02 b
1.00±0.03 c
1.82±0.02 d
1.09±0.02 e
2.09±0.01 f
TG/HDL-C
2.05±0.03 a
4.58±0.05 b
1.86±0.03 c
2.49±0.05 d
2.01±0.04 d
2.86±0.05 e
Discussion
The nutritive value and physicochemical properties of WG agree with Sakhawat Analysis of wheat germ oil showed that WGO is a good source of Linolenic, ω-3 (7.92) and Linoleic, ω-6 (53.21) and the ω-6/ ω-3 ratio of WGO was 6.7. It has been also suggested that ω-6/ ω-3 ratio of 10 or less results in a reduction in fatal CHD risk Wheat germ reduction of cholesterol, LDL-C, VLDL-C and TG may be due to presence of some proteins with pancreatic lipase inhibiting properties; interfere with lipid hydrolysis in the stomach and small intestine, thus inducing a decrease in the intestinal absorption of lipids and dietary cholesterol Wheat germ has a high content of biologically active phytosterol (340.7 mg %) that might have a role in reducing cholesterol absorption leading to lower serum cholesterol level and LDL-C Wheat germ oils are rich in linolenic acid which aid in a higher cholesterol secretion into the bile and depletion of the intra-hepatic pool of cholesterol, leading to an increase in cholesterol synthesis and turnover Essential fatty acids, ω 3, of WGO exert antioxidant effect as by inhibiting certain enzymes, which mediate the generation of free radicals, thus reducing the amount of free radicals generated WG/ WGO reduction of triacylglycerol may be due to presence of monounsaturated fatty acid, vitamin E and phytosterol. Also may be due to an increase in membrane permeability and fluidity Wheat germ reduction of cholesterol, LDL-C, VLDL-C and TG may be due to high dietary fibre content (16.0%) which might have some effects on cholesterol metabolism. The consumption of dietary fibre has been shown to be inversely associated with CHD The WG/ WGO induce the tocopherol-mediated redox system and inhibit the synthesis of eicosanoid, which activates the lipid peroxidation (LPO) process Hypercholesterolemia induces oxidative stress resulting in increased risk for atherosclerosis development The antiatherogenic effect of WGO was attributed to tocopherols, phytosterols, phenolic compounds and unsaturated fatty acids. Tocopherols considered as strong antioxidant due to its radical scavenging activity preventing cell membranes lipid peroxidation Malondialdehyde is a good indicator of lipid peroxidation and reflects the degree of oxidation in the body. In the current study increase in MDA level was observed in the hypercholesterolemic positive control group as compared to normal negative control group. Also, data showed a significant decrease in total antioxidant capacity level in the positive control as compared to negative control. Addition of WG / WGO to diets of rats caused a marked reduction in MDA concentration and an improvement in total antioxidant capacity. Juskiewicz
Conclusion
WG/WGO may be able to protect against atherosclerosis and CVD. The administration of WG /WGO to diets of rats caused a marked reduction in TC, LDL-C, VLDL-C, TG and MDA. This improvement effect may be mediated via enhancement of the antioxidant defence system and other factors. However, further clinical studies on human beings are required to assess the efficacy and safety of the WG/WGO.