Abdalla256(revkhor)(edsp)419-429(pr)rv10.pmd

Purslane Extract Effects on Obesity-Induced Diabetic Rats Fed a High-Fat Diet Purslane Extract Effects on Obesity-Induced Diabetic Rats
Fed a High-Fat Diet
Abdalla Hussein M
Biochemistry Department, Faculty of Pharmacy, October 6 University, October 6 City, Egypt ABSTRACT
Purslane extract in the form of ethanolic formulation is rich in polyphenols,flavonoids and anthocyanin, w-3 fatty acids and melatonin. The present studywas designed to investigate the anti-obesity and anti-diabetic effects of purslaneusing obese diabetic rats. The rats received either regular diet, high-fat diet orhigh-fat diet with additional purslane (150 and 300 mg/kg body weight) for 8weeks. Purslane, co-administered with a high fat diet, significantly inhibitedbody weight gain, blood glucose, triglyceride, total cholesterol, LDL-C, HDL-C,free fatty acids and the atherogenic index levels in a dose dependent manner.
Purslane-treated rats at doses of 150 and 300 mg/kg body weight improved theinsulin resistance index when compared to high fat diet control. In conclusion,purslane ethanolic extract showed effects indicative of potential anti-obesityand anti-diabetic actions in rats fed a high fat obesity-induced diet.
Keywords: Atherogenic index, insulin resistance index, purslane
INTRODUCTION
Peninsula and adjacent areas including,United Arab Emirates and Oman. Purslane Insulin resistance, a term used to describe provinces of China (Chan et al., 2000; Hu, insulin action, is associated with a number Xu & Wang, 2003). It is also used as an anti- of multifactorial diseases including obesity bacterial and anti-viral agent, as well as for and Type-2- diabetes mellitus (T2DM). The the treatment of viral hepatitis and diabetes latter two diseases have long been presumed management in China (Meng & Wu, 2008).
to be related, even though the link between Purslane is reported to be rich in á- them has not been identified (Procopiou & linolenic acid and ß-carotene and used as a
Philippe, 2005). In recent years, polyphenols health food for patients with cardiovascular diseases (Liu et al., 2000). It contains several types of vitamins and minerals (Mohammad, including anti-obesity (Ohta et al., 2006) and Mohammad & Farhad, 2004), fatty acids (Xin anti-diabetic activities (Klein et al., 2007; et al., 2008), glutathione, glutamic acid, and Tomonori, Tadashi & Ichiro, 2007).
aspartic acid. Other constituents include a The plant purslane, in Arabic ‘Rejlah’, mucilage composed of a neutral fraction with (Portulaca oleraceae L.) occurs in the Arabian Correspondence author: Dr Mohammed A HusseinEmail : [email protected]; [email protected] coumarins, flavonoids, alkaloids, saponins, animal was raised on a regular diet (Dyets Inc., Bethlehem, PA) ad libitum.
Yanardag, 2006). Recently, Hussein &
Abdel-Gawad (2010) studied the potential
Experimental set up
hepato-protective effect of ethanolic and This experiment was carried out to examine the anti-obesity and anti-diabetic affects of purslane ethanolic extract in obese diabetic rats fed a high-fat diet. Ethanolic extract of ethanolic and aqueous extracts of purslane purslane leaves was given repeatedly for an leaves can generate antioxidants. The effect 8-week period in vivo. A suspended solution compared to aqueous extract. Large amounts randomly divided into five groups of 6 rats ethanolic extract may contribute towards the antioxidant properties (Sakai et al., 1996).
Purslane has been described as a ‘power + 1 ml tween 80 for an 8-week period, while food’ of the future because of its high Control Group-II received a high-fat diet + nutritive and anti-oxidant properties (Al- III was fed a high-fat diet with purslane ethanolic extract (150 mg/kg body weight/ therapeutic evaluation of plants of medical ml tween 80) suspended in tween 80 orally in a single daily dose for an 8-week period 2010), I report herein a facile route to explain high-fat diet with purslane ethanolic extract diabetic effects of purslane ethanolic extract in obese diabetic rats fed a high-fat diet.
tween 80 orally in a single daily dose for an8-week period (Al-Howiriny, 2008). Group MATERIALS AND METHODS
V was given a high-fat diet with metformin(500 mg/kg body weight/ml tween 80) Fresh leaves of purslane were collected from the Horbite farms in El-sharkia, Egypt. The daily dose for an 8-week period (Lee & leaves (1.5kg) were air-dried and crushed to in a Soxhlet with 95% ethanol. The extract to yield a viscous mass. The ethanolic extract nutrition contents of the high fat diet were was kept in airtight containers at 40 oC until similar to those of the regular diet except for (Assinewe et al., 2003). Body weights were ± 5 gms were purchased from the Faculty of Veterinary Medicine, Cairo University. The analysis. At the end of the study, blood was with free access to water in a temperature- controlled facility with a 12:12-hour light- plasma insulin and lipid levels, after which dark cycle, and were weighed periodically.
Purslane Extract Effects on Obesity-Induced Diabetic Rats Fed a High-Fat Diet Table 1. Composition of the diets fed to the rats
aAIN 76A Rodent Purified Diet (Assinewe et al., 2003) Blood sampling and plasma assay
plexus every other week using a heparinised capillary tube without anesthesia. The blood samples were placed on ice, centrifuged, and the plasma was stored at -20oC until assayed.
The plasma glucose concentration was Measurement of liver triglyceride and
cholesterol contents
Liver triglyceride and cholesterol contents were measured as described in Park, Ko & Chung (2005). Briefly, a portion (100 mg) of described by the manufacturer of the mouse liver tissue was homogenised in phosphate insulin ELISA kit (Shibayagi Co., Japan). The buffer saline (pH 7.4, 1 ml). The homogenate insulin resistance index, a simple method to (0.2 ml) was extracted with isopropyl alcohol measure insulin sensitivity usually used in (1 ml), and the extract was analysed using a clinical and animal studies (Sasaki et al., 2009), was calculated by insulin (mU/ml) X Industries) to determine liver triglyceride glucose (mM)/22.5 (Matthew et al., 1985).
Plasma triglyceride, total cholesterol, HDL- extracted with chloroform-methanol (2: 1, 1 cholesterol, LDL-cholesterol and free fatty ml), and the extract was concentrated under acid concentrations were determined using a nitrogen stream. The residue was dissolved in isopropyl alcohol and analysed using a Youngdong Pharmaceutical Co., Korea). The also calculated (Dobiasova & Frohlich, 2001).
Table 2. Effect of purslane ethanolic extract on weight gain, food intake, and feed efficiency
Values represent the mean ± SE (n=6). High-fat diet (HFD) control rats were compared with regular diet(RD) control rats. Experimental groups were compared with the high-fat diet control rats.
• *Significantly different from normal group at p< 0.05.
• @ Significantly different from control group at p< 0.01.
Feed efficiency = [weight gain (g/8 wk)]/[food intake (g/8 wk)] Statistical analysis
ethanolic extract showed a gradual increase significantly less than that detected for the least significant difference (LSD) test was continued and prolonged access to the high used to test treatment differences among the fat diet (Table 2; Figure. 1). Purslane 150 groups. P value of less than 0.05 was considered to indicate statistical signi- inhibit rapid weight gain, compared to the ficance. All the results were expressed as body weight gain shown by the high fat diet mean ± SD for six separate determinations.
control group, by 11.45% and 35.41%respectively.
gain divided by total food intake, during the weight of the normal rats in the regular diet intake and weight gain. As shown in Table group gradually increased as the rats grew 2, weight gain of the high fat diet control during the 8-week trial. By contrast, the body rats was actually due to the increased food purslane extract fed rats were significantly of the trial (Table 2; Figure. 1). Weight gains reduced, despite a larger increase in food in the regular diet and high fat diet control intake compared to the high fat diet control rats. Feed efficiency of the purslane ethanolic 17.7±2.4g and 56.3±4.1g, respectively.
Animals fed the high fat diet and purslane which is lower than that for the high fat diet Purslane Extract Effects on Obesity-Induced Diabetic Rats Fed a High-Fat Diet Figure 1. Body weight of rats on regular diet, high fat diet, high fat diet plus purslane ethanolic extracts
(150 mg/kg b.w & 300 mg/kg b.w.) or fed with high fat diet plus 500 mg/kg of metformin during the 8-
week period. Values represent the mean ± SE (n=8).
extract has the potential to control body weight gain despite increased food intake.
by insulin (mU/ml) X glucose (mM)/22.5, of metformin fed group was similar to that of the high fat diet control group was 3.5 times higher than that of the regular diet group, compared to the high fat diet control group.
purslane 150 and 300 mg/kg body weightwere significantly reduced by 55.5% and Insulin resistance index
Plasma glucose was determined every other high fat diet control group (Table 3). Plasma insulin levels in purslane 150 and 300 mg/ glucose levels were barely increased in the marked increase after 8 weeks was observed respectively when compared to the high fat for rats fed with the high fat diet (Table 3).
diet control group. Improvement of insulin Purslane ethanolic extract fed rats, however, resistance in the purslane ethanolic extract glucose levels in a dose dependent manner significant when compared to the metformin when compared to the high fat diet control group. Plasma glucose levels in purslane 150 suggest that the purslane extract was able to lower the blood glucose level partially due were also markedly decreased by 28.4% and to the improvement in insulin resistance.
Table 3. Effect of purslane ethanolic extract on plasma insulin, plasma glucose, and insulin resistance
index (IRI
Values represent the mean ± SE (n=6). High-fat diet (HFD) control rats were compared with regular diet(RD) control rats. Experimental groups were compared with the high-fat diet control rats.
• *Significantly different from normal group at p< 0.05.
• @ Significantly different from control group at p< 0.01.
Insulin Resistance Index = insulin (mU/ml) x glucose (mM) / 22.5.
Table 4. Effect of purslane ethanolic extract on liver triglyceride and cholesterol content, plasma
glutamate oxaloacetate transaminase (GOT) and glutamate pyruvate transaminase (GPT)activities.
Liver triglyceride Liver cholesterol Plasma GOT Plasma GPT (mg/ g liver) Control group-II 178.92± 13.55@ 6.42± 1.37@ HFD+ Metformin 84.09± 7.46@ 4.09± 5.24@ Values represent the mean ± SE (n=6). High-fat diet (HFD) control rats were compared with regular diet(RD) control rats. Experimental groups were compared with the high-fat diet control rats.
• *Significantly different from normal group at p< 0.05.
• @ Significantly different from control group at p< 0.01.
Liver triglyceride and cholesterol contents
significantly higher for the high fat diet fed Purslane Extract Effects on Obesity-Induced Diabetic Rats Fed a High-Fat Diet HDL-cholesterol (HDL-C), LDL- cholesterol Effect of purslane ethanolic extract on plasma triglyceride (TG), total Cholesterol (TC), *Significantly different from normal group at Significantly different from control group at @ Values represent the mean ± SE (n=6). High-fat diet (HFD) control rats were compared with regular diet (RD) control rats. Exper compared with the high-fat diet control rats.
group), while they showed an increased level treated groups were markedly decreased by of HDL-C compared to that in high fat diet fed control group (68.88% in purslane 300 compared to the high fat diet control group.
Liver total cholesterol levels in purslane 150 were also markedly decreased by 20.4% and group, was 6.9 times higher than that of the regular diet group, while the atherogenic GPT activities were significantly higher for weight was significantly reduced by 37.4% and 53.1%, respectively, when compared to regular diet fed group by 3.85-fold and 2.66- the high fat diet control group (Table 5).
fold. Purslane ethanolic extract adminis- tration significantly suppressed increases in related plasma parameters in the metformin 48.6% and 56.6%, respectively whencompared to the high fat diet control group.
DISSCUSSION
Plasma GPT activity in purslane 150 and300 mg/kg body weight treated groups was The anti-obesity effects of purslane ethanolic 76.12%, respectively when compared to the diabetic rats fed a high-fat diet as a model of obese type-II diabetes. When fed a high-fatdiet, these rats developed obesity and type- Plasma lipid levels
II diabetes by 12-weeks old (Hayashi & Ito, The effects of purslane ethanolic extract on 2002), and are thus widely used for research plasma lipid levels were examined at the end in obesity and diabetes (Tsuchida et al., of the treatment. The plasma lipid levels in 2005). In the present study, a high-fat diet the high fat diet fed rats were substantially induce severe obesity and diabetes and the regular diet fed rats, except for the HDL- effects of purslane ethanolic extract were cholesterol (HDL-C) level (Table 5). In the evaluated. A high-fat diet is widely used in triglyceride (TG) was increased by 1.7 times brandt, Kelly-Sulliwan & Black, 2003).
(115 to 195 mg/dl), total cholesterol by 2.2- fold, LDL-cholesterol by 6.8-fold, free fatty suppress increases in body weight, showing acid by 1.9-fold, and total cholesterol (TC) potential for anti-obesity actions. Plasma increased as reflected in the increase in LDL- glucose and insulin levels were significantly higher for the high-fat diet group than for the regular diet group, and when severe type mg/kg body weight treated groups, however, showed considerably reduced levels of TG, glucose and insulin levels. The insulin index was significantly decreased in the purslane- treated groups compared to the high-fat diet Purslane Extract Effects on Obesity-Induced Diabetic Rats Fed a High-Fat Diet such as inhibition of carbohydrate digestion stimulation of insulin secretion from the significantly suppress increases in liver pancreatic ß-cell, modulation of glucose
release from liver, activation of insulin showing apparent anti-obesity actions. The receptors and glucose uptake in the insulin- sensitive tissues, and modulation of hepatic accumulation and induced fatty liver, but polyphenols and ω-3 fatty acids may act on ethanolic extract suppressed TG, TC, LDL- the liver to increase energy expenditure of related fatty liver degradation. Furthermore, high-fat diet fed control group. The elevation of TG, TC, LDL-C, and free fatty acids values oxylase (ACC) and fatty acid synthase (FAS), on high fat diet feeding is in agreement with binding protein (SREBP)-1c (Kim et al., 2001), clinical benefit of the purslane extract.
enzymes (Guillou, Martin & Pineau, 2008).
purslane was found to exceed that reported in a number of other fruits and vegetables anti-obesity actions of purslane ethanolic (Simopouloes et al., 2005). Melatonin has a expenditure-related fatty liver degradation and decreased fatty acid synthesis and fat inflammatory properties (Rodriguez et al., intake in the liver. On the other hand, insulin 2004). Hayos et al. (2000) showed that adiponectin secretion (Kadowaki et al., 2006).
The purslane used in the present study acted significantly by melatonin administration.
on fatty liver and was shown to possess anti- role in the observed anti-obesity and anti- many studies have described plant extracts exhibiting hypolipidemic and anti-diabetic actions, to the best of my knowledge, none diabetic actions via reduction of insulin cardiovascular diseases and cancer (Crozier, Jaganath & Clifford, 2009). Among these purslane revealed the presence of flavonoids or bioflavonoids which are natural products having the highest concentration of ω-3 fatty acids among leafy vegetables (Xin et al., 2008).
Other bioactives found in purslane aredopamine, dopa, coumarins, alkaloids and CONCLUSION
saponins (Sakai et al., 1996), polyphenols,flavonoids and anthocyanin (Peksel et al., 2006). These compounds may influence
showed effects indicative of potential anti- glucose metabolism by several mechanisms, obesity and anti-diabetic actions in rats fed a high fat obesity-induced diet. High content Guillou H, Martin PG & Pineau T (2008).
melatonin and omega-3 fatty acids found in fatty acid metabolism. Subcell Biochem 49: these effects. Further studies are in progress Hayashi K & Ito M (2002). Anti-diabetic hypoglycemic effects of different fractions of in genetically obese diabetic KKAy mice.
Biol Pharm Bull 25: 188–192.
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