Assessment of Hypolipidemic Effect of Ardisia solanacea in high fat diet induced rats

 

Pradeep Kumar Samal*

SLT Institute of Pharmaceutical Sciences, Guru Ghasidas Vishwavidyalaya, Bilaspur, Chhattisgarh.

 

 

ABSTRACT:

Ardisia solanacea leaves were used for the evaluation of hypolipidemic effects against high fat diet induced hyperlipidemia in rats. The leaves were dried in shade for 20 days, powdered and extracted with Alcohol. Preliminary phytochemical analysis found the presence of phenolic compounds, glycosides and flavonoids in the alcoholic extract. Acute oral toxicity study of alcoholic extract of Ardisia solanacea leaves (AEAS) was conducted in mice by using OECD guideline no.425 and it was found to safe up to the dose label of 2000mg/kg of body weight p.o. The extract at dose of 100 and 200 mg/kg was administered orally once daily for 10 days. Gemfibrozil (50mg/kg p.o.) was used as reference standard. AEAS (200 mg/kg p.o) were potentially reduced average body weight gain and plasma lipids levels including Total cholesterol (TC), Triglycerides (TG), Low density lipoproteins (LDL), Very low-density lipoproteins (VLDL) and enhanced High-density lipoprotein (HDL) level than AEAS (100 mg/kg p.o) while AEAS were reduce plasma glucose levels in a dose dependent manner. The results of this study strongly indicate that AEAS has potent Hypolipidemic effects against high fat diet induced hyperlipidemia  in rats.

 

KEYWORDS: Ardisia solanacea, Hypolipidemia, Cholesterol, HDL, LDL, Triglycerides

 

1. INTRODUCTION:

Hyperlipoproteinemia is a condition in which there is increased concentration of total cholesterol (TC) and/or triglycerides (TG) carrying lipoproteins in plasma. Hyperlipidemia refers to elevated concentration of lipids in blood (Goyal et al., 2008). Hyperlipidemia is a leading risk factor that contributes to the development and evolution of atherosclerosis and subsequent cardiovascular disease, which is one of the most serious diseases in humans. It is also reported that almost 12 million people die of cardiovascular diseases and cerebral apoplexy each year all over the world. Therefore, it is very important to generate awareness in early stage for prevention and control of hyperlipidemia. Elevated plasma concentration of TC, TG and LDL and decreased plasma concentration of HDL appear to increases the risk of Coronary Heart Disease (CHD), atherosclerosis, and peripheral vascular disease (Mahley and Bersot, 2001; Walker, 2003). Risk of hyperlipidemia would be decline by consumption of flavonoids and their glycosides.

 

Despite the remarkable progress in the management of hyperlipidemia by synthetic drugs, there has been a renewed interest in medicinal plants attributed with therapeutic virtues. India has a rich heritage of medicinal plants of wide diversity, which are used by the local population and the traditional healers for the treatment of several diseases including hyperlipidemia. With the emerging worldwide interest in adopting and studying traditional system and exploiting their potential based on different health care system, the evaluation of the rich heritage of traditional medicine is essential. In this regard, one such plant is Ardisia solanacea (Myrsinaceae).

2. MATERIALS AND METHODS:

2.1 Plant Materials: -

The leaves of Ardisia solanacea (Myrsinaceae) were collected from Thakur Chedilal Barristor Agriculture College and Research Centre, Bilaspur, India, in the month of September 2011, and air dried at room temperature after wash with tape water. The Plant identification was done by Dr. H. B. Singh Chief Scientist Head of the Raw Materials Herbarium & Museum, NISCAIR, New Delhi (Ref.-NISCAIR/RMHD/Consult/2011-12/1812/112).

 

2.2 Drugs and Chemicals: -

Analytical grade chemicals and reagents were used. Cholesterol (Central Drug House P. Ltd, New Delhi), Gemfibrozil 300 mg capsules (Lopid, Pfizer), plasma TC, TG, Glucose kit (GOD/POD) and HDL kits (Span Diagnostics Ltd and Agappe Diagnostic Ltd) were purchased from local market.  Other Chemicals, phytochemical reagents and dietary supplements were provided by University.

 

2.3 Animals: -

Each experiment had separate set of animals and care was taken to ensure that animals used for one response were not employed elsewhere. Animals were habituated to laboratory conditions for 48 hours prior to experimental protocol to minimize if any of non-specific stress. The approval of the Institutional Animal Ethical Committee (IAEC) of SLT Institute of Pharmaceutical Sciences, Bilaspur (Chhattisgarh) was taken prior to the experiments (Reference No. IAEC/Pharmacy/2012/36). All the protocols and the experiments were conducted in strict compliance according to ethical principles and guidelines provided by Committee for the Purpose of Control and Supervision of Experiments on Animals (CPCSEA).

 

2.4 Preparation of plant Extracts: -

About 300 g of the leaves powder of Ardisia solanacea was extracted with 1.2 L of alcohol using Soxhlet apparatus for 72 hrs at 40-50°C. The extract was concentrated to ¼ of its original volume by distillation as it was adapted to recover the solvent, which could be used again for extraction (Kokate 1996). 

 

2.5 Acute toxicity study (AOT): -

Acute oral toxicity study was performed according to the procedure OECD guideline no. 425(OECD 425 2001).  AOT was performed on Swiss albino mice and the animal were kept fasting for overnight providing water ad libitum, after which the alcoholic extract of Ardisia solanacea (AEAS) was administered orally 2000 mg/kg and observed the mortality of animals.

 

2.6 Preliminary Phytochemical Analysis: -

The extracts obtained were subjected to various chemical tests to detect the chemical constituents present in extracts of Ardisia solanacea.( Trease GE. 1983, Kokate CK 1996, Khandelwal KR. 2000 and Oloyede OL. 2005)

2.7 Assessment of Hypolipidimic Activity: - Hyperlipidemia was induced in male albino rats (150-200 g) by feeding them with high fat diet for 2 weeks. High fat diet increased the plasma TC and TG significantly. After 2 weeks the normal rats and hyperlipidemic rats were divided into different groups each containing six animals. Each group were treated with their treatments as mentioned in Table 2.1 for 7 days (Vijay et al., 2009). Body weights of the animals were measured twice a week first and last day of the week during the experimental period. Blood sample of animals were collected on seventh day after 1 hr of dosing by cardiac puncture and serum was separated by centrifugation at 4000 rpm for 20 min. and different parameters like Triglycerides, Total Cholesterol, HDL, LDL and VLDL were estimated.

 

2.8 Statistical analysis: -

The experimental results were expressed as the Mean ± SEM for six animals in each group. The biochemical parameters were analysed statistically using one-way ANOVA followed by Tukey Kramer’s post hoc test. P value of < 0.05 was considered as statistically significant.

 

3. RESULTS:

The effects of the high fat diet on average body weight and plasma lipids are summarized in Table 1 and 2.  After 2 weeks average body weight and plasma lipids levels increased significantly in hyperlipidemic rats which were fed high fat diet than normal rats. It suggests that the hyperlipidemic system in the rats was established within 2 weeks.

 

The results of 7 days oral administration of AEAS on average body weight are presented in Figure 1. The AEAS reduced body weight gain significantly. The AEAS at the test doses 100 and 200 mg/kg average body weight gain reduced as compared to the hyperlipidemic control. The decrease in weight gain was dose dependent manner.

 

The AEAS were evaluated for hypolipidemic activity in high fat diet induced hyperlipidemia animal model and results are summarized in Table 3. The high fat diet increased significantly (p < 0.001) plasma lipids including TC, TG, LDL and VLDL it also decreased plasma HDL level in hyperlipidemic control rats than normal control. The plasma TC, TG, LDL and VLDL level after 7 days oral administration of AEAS at two different doses level 100 and 200 mg/kg were decreased significantly and plasma HDL level were increased significantly with dose dependent manner compared to hyperlipidemic control. The results indicate that the AEAS at dose of 200 mg/kg body weight has better hypolipidemic effects than AEAS 100 mg/kg body weight and gemfibrozil.

 

The results of effect on plasma glucose level are presented in Table 4. Hyperlipidemic control rats increased significantly plasma glucose than normal control and after 7 days oral administration of AEAS decreased plasma glucose level significantly. The AEAS reduced plasma glucose level at two doses level 100 and 200 mg/kg respectively as compared to hyperlipidemic control. The results indicate that the AEAS at dose of 200 mg/kg body weight has better hypoglycemic effects than AEAS 100 mg/kg body weight.

 

4. DISCUSSION:

The present study was designed to investigate the hypolipidemic effect of AEAS as well as its effect on hyperglycaemia and weight gain pattern in high fat diet induced hyperlipidemic rats. Nutritional factors including energy excess and an increasing consumption of carbohydrates and fat in the diet have been reported to lead to obesity (Rolls et al., 2002). Obesity elevates lipid concentration in the blood and it may lead to hyperlipidemia (Devlin et al., 2000). Hyperlipidemia is a major cause of the build-up of coronary atherosclerosis and atherosclerosis-associated conditions, such as coronary heart disease (CHD), ischemic cerebrovascular disease, and peripheral vascular disease (Mahley and Bersot, 2001). When male Wistar Albino rats were kept on high fat diet for 2 week, average body weight and plasma TC and TG levels were significantly increased whereas HDL levels were reduced significantly. Whether TC or TG levels increased, or both increased, they are referred to as hyperlipidemia. It suggests that high fat diet composition were sufficient to produce hyperlipidemia within 2 weeks.

Results of this study demonstrated that the AEAS reduced significantly weight gain and plasma lipids including TC, TG, LDL and VLDL. It also increased significantly of cardio protective HDL after 7 days of oral administration in dose dependent manner (Table 3). The observation indicates that AEAS at 200 mg/kg had potent hypolipidemic effects, the effects was more pronounced and better than the gemfibrozil. Results of the current study also showed the dose dependent lowering effects of HBAE on plasma glucose level (Table 4).

 

 

 

Table 1.  Effect of high fat diet on plasma lipids level after 2 weeks.

Groups

Plasma lipids (mg/kg)

Total cholesterol

Triglycerides

Normal rats

75.533 ± 0.630

84.732 ± 0.5178

Hyperlipidemic rats

116.58 ± 1.127

160.67 ± 1.088d

Values are expressed as mean ± S.E.M., (n= 6). c p<0.001 and d p<0.0001 significant values as compare to normal rats.

 

Table 2.  Effects of high fat diet on average body weight after 2 weeks.

 

Groups

Initial (1st day)  (g)

Final (14th day) (g)

Weight gain (g)

Normal rats

144.74 ± 0.89

210.11 ± 1.33

65.37 ± 0.93

Hyperlipidemic rats

145.88 ± 0.85

254.06 ± 1.48

107.84 ± 0.70c

Values are expressed as mean ± S.E.M., (n= 6). c p<0.001 and d p<0.0001 significant values as compare to normal rats.

 

Table 3 Hypolipidemic activity of alcoholic extract of Ardisia Solanacea  leaves on normal rats:

Group

Triglyceride

Total cholesterol

HDL

VLDL

LDL

Normal

98.07 ± 2.26

85.46 ± 1.31

36.27 ± 0.72

19.61 ± 0.45

29.14 ± 0.45

Control (HFD)

158.37 ± 0.57

125.12 ± 0.72

30.50 ± 0.61

31.64 ± 0.12

60.80 ± 1.15

Standard Gemfibrizil

(50 mg/kg)

102.37 ± 0.65

101.97 ± 1.48

41.15 ± 0.23

20.39 ± 0.13

37.35 ± 1.67

100mg/kg  (AEAS)

126.10 ± 0.99

110.72 ± 0.58

41.05 ± 0.28

25.46 ± 0.19

43.93 ± 0.85

200mg/kg (AEAS)

113.56 ± 0.82

98.398 ± 0.41

43.19 ± 0.69

22.71± 0.16

32.17 ± 0.66

Results are expressed as mean ± SEM. A treaded group animals compared with control (n=6)

 

 

 

Table 4 Effect on plasma glucose level of AEAS

Group

Plasma glucose concentration (mg/dL)

Normal

119.94  ± 2.98

Control (HFD)

141.01 ± 2.88

100mg/kg (AEAS)

122.34 ± 3.45

200mg/kg (AEAS)

117.34 ± 3.35

Values are expressed as mean ± S.E.M., (n= 6). Significant values as compared to hyperlipidemic control.

 

 

 

Fig 1. Effects of A. Solanacea leaves extract on body weight gain.

It is well established that reduced HDL is an independent risk factor for atherosclerosis, a leading cause of cardiovascular disease and death. HDL intervention study also showed that an increase of 1% in HDL is associated with a 3% reduction in the risk of developing clinical atherosclerosis and also several studies show that an increase in HDL cholesterol is associated with a decrease in coronary risk (Bainton et al., 1992). Lecithin cholesterol acyltransferase (LCAT) is a key enzyme in cholesterol and HDL metabolism and has been hypothesized as a potential therapeutic target for raising HDL and modulating atherosclerosis (Zhang et al., 2004). Considering the enhancement of cardio protective lipid HDL after administration of AEAS, it can be concluded that the leaves of Ardisia solanacea is a potent cardio protective agent and this effect may be due to the increase in activity of LCAT which may contribute to the regulation of blood lipids (Zhang et al., 2004). LCAT plays a key role in incorporating free cholesterol into HDL and transferring back to VLDL or IDL, which is taken back by the liver cells (Devi and Sharma, 2004).

 

In the present study the AEAS decreased plasma TC, TG, LDL and VLDL and enhanced the HDL significantly. This is an important advantage in the treatment of hypercholesterolemia. So AEAS would reduce the incidence of coronary events (Lipid Research Clinics Program, 1984).

 

The phytochemical results indicate that the presence of saponins, tannins and phenolic compounds, flavonoids and steroids. These compounds might be responsible for its hypolipidemic and hypoglycemic effects of AEAS.  Saponins were reported to reduce blood cholesterol by competing with cholesterol binding sites or interfering with cholesterol biosynthesis (Lanksy et al, 1993; Vijaya et al., 2009). Phenolic compounds and tannins have an anti-obesity effect through the suppression of dyslipidemia, hepatosteatosis, and oxidative stress in obese rats (Manach et al., 2004) thus it may responsible for lowering TC and LDL and elevating HDL in hypercholestrolaemic rats. Flavonoids have been shown to lower LDL levels and increase LDL oxidation resistance of the body, could inhibit the atherosclerosis (Chen and Li, 2007; Kaamanen et al., 2003). Flavonoids may inhibit the lipogenesis by stimulated lipoprotein lipase and plasma LCAT and enhance the degradation of cholesterol (Khosy et al., 2001).

 

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Received on 09.04.2013

Modified on 22.04.2013

Accepted on 10.05.2013

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Research J. Pharmacology and Pharmacodynamics. 5(3): May–June 2013, 147-150