Subscribe Now Subscribe Today
Abstract
Fulltext PDF
References
Research Article
 
Effects of Piper sarmentosum (Kaduk) Water Extract on Adiponectin and Blood Glucose Levels in Ovariectomy-Induced Obese Rats



A. Aida Azlina, S. Farihah, M.S. Qodriyah and M.F. Nur Azlina
 
ABSTRACT

This study was conducted to evaluate the effects of Piper sarmentosum (PS) extract and glycyrrhizic acid (GCA) on plasma adiponectin and blood glucose in ovariectomy-induced obese rats. Twenty eight female Sprague-Dawley rats were randomly divided into four groups. Three groups were ovariectomized (OVX), while the remaining group underwent sham operation. The OVX groups were given PS water extract (0.125 g kg-1), GCA (0.120 g kg-1) and water (CTRL), respectively, while the Sham-Operated (SHM) group received only water. Plasma adiponectin and blood glucose were measured at zero, three and five months of treatment, while body weight was measured weekly. All the OVX groups had a significant reduction (p<0.05) in the plasma adiponectin compared to the SHM group. After three and five months of treatment, both PS and GCA treated group showed a significant increment (p<0.05) in the plasma adiponectin level compared to CTRL group. While, the blood glucose level, only PS treated group showed significant reduction (p<0.05) after three and five months of treatment compared to CTRL group but no significant difference (p<0.05) occurred in body weight compared to CTRL group. Our finding suggests that water extract of Piper sarmentosum may have the ability to reduce the amount of visceral fat in the body as shown by the increment of plasma adiponectin and improve blood glucose levels in obese rats.

Services
Related Articles in ASCI
Similar Articles in this Journal
Search in Google Scholar
View Citation
Report Citation

 
  How to cite this article:

A. Aida Azlina, S. Farihah, M.S. Qodriyah and M.F. Nur Azlina, 2009. Effects of Piper sarmentosum (Kaduk) Water Extract on Adiponectin and Blood Glucose Levels in Ovariectomy-Induced Obese Rats. Research Journal of Medicinal Plants, 3: 109-115.

DOI: 10.3923/rjmp.2009.109.115

URL: https://scialert.net/abstract/?doi=rjmp.2009.109.115

INTRODUCTION

Adipose tissue is an endocrine organ that plays a role in energy homeostasis. Adipocytes does not only secrete Free Fatty Acid (FFA) but also releases a large variety of different protein factors, including leptin, plasminogen inhibitor 1 (PAI-1), angiotensin II, Acylating Stimulating Protein (ASP), tumor necrosis factor-alpha (TNF-α), resistin, interleukin-6 (IL-6), adiposin and also adiponectin. All this protein factors are collectively termed as adipocytokines (Greenberg and McDaniel, 2002; Tsao et al., 2002; Steppan and Lazar, 2002; Havel, 2002; Berg et al., 2002). Dysregulated secretion of adipocytokines has been shown to results in metabolic pertubations associated with pathophysiology of obesity and type-2 diabetes (Berg et al., 2002).

Adiponectin is a protein hormone that modulates a number of metabolic processes including glucose regulation and fatty acid catabolism, which is exclusively expressed and secreted from visceral, subcutananeous and bone marrow fat depots (Weyer et al., 2001; Arita et al., 1999) into the bloodstream and abundant in plasma. It plays a role in the suppression of the metabolic derangements that may result in the development of type-2 diabetes, obesity, atherosclerosis and non-alcoholic fatty liver disease. Previous studies have demonstrated that adiponectin levels are inversely related to visceral area and low levels have been associated with obesity, type-2 diabetes and cardiovascular diseases (Arita et al., 1999; Hotta et al., 2001).

In Malay traditional society, water decoction of the Piper sarmentosum leaves are being used for the treatment of cough, headache, waist pain and arthritis, while the water decoction of the roots are used in treatment of menstrual pain and to improve urination. Moreover, the pounded leaves are useful in the treatment of eczema. Most parts of the plant have potential benefits. The water extract of the whole plant had been shown to induce hypoglycemic effect in streptozocin-diabetic rats (Peungvicha et al., 1998). While the methanolic extract of the leaves was found to possess a marked neuromuscular blocking activity in the rat phrenic nerve-hemidiaphragm preparation (Ridtitid et al., 1998). Furthermore, the chloroform and methanol extracts of the leaves have the ability to act as an antiplasmodial agent against Plasmodium falciparum and Plasmodium berghei parasites (Najib Nik et al., 1999). In addition, the methanolic extracts of the leaves was found to have higher level of antioxidant activity compared to other traditional medicine plants (Chanwitheesuk et al., 2005). Therefore, the present study investigates the effects of water extracts of Piper sarmentosum on the adiponectin and blood glucose levels in ovariectomy-induced obese rats.

MATERIALS AND METHODS

Preparation of Piper sarmentosum Water Extract
Fresh leaves (3 kg) of Piper sarmentosum were collected from the Ethnobotanic Garden, Forest Research Institute Malaysia (FRIM) after being identified and confirmed by a plant taxonomist from the Medicinal Plant Division (voucher specimen, FRI 45870) FRIM. All the extraction procedures were performed at the FRIM laboratory. Fresh leaves of the plants were cleaned with tap water and dried at room temperature before been chopped into small pieces. The leaves were then boiled with distilled water (90%,v/v) at 80°C for 3 h. The water extract was then concentrated and followed by freeze-drying to form powder. The powdered extract was stored at 4°C until further use.

Animals Preparation
All procedures were carried out in accordance with the institutional guidelines for animal research of the Universiti Kebangsaan Malaysia (FAR/2006/AZLINA/19-APRIL/168-MARCH-2007). Twenty-eight female Sprague-Dawley rats weighing 180-200 g were maintained in normal room temperature with adequate ventilation and illuminated for 12 h daily (lights on from 0700 to 1900). Two rats were kept in each cage and allowed free access to rat chow (Gold Coin, Malaysia) and water. The rats were randomly divided into four experimental groups. Three groups underwent an experimental ovariectomy and one group underwent a sham operation. The ovariectomized groups were given Piper sarmentosum water extract (PS), glycyrrhizic acid (GCA) and water (CTRL) respectively, while the sham-operated (SHM) group received only water.

Experimental Protocol
The procedures were carried out in accordance with the institutional guidelines for animal surgery of the Universiti Kebangsaan Malaysia Animal Ethics Committee (UKMAEC).

The rats were anaesthetized with intramuscular injection of ketamine (Troy Laboratories, Australia) and xylazine (Troy Laboratories, Australia) cocktail (1:1). The hairs on the both sides of the body were shaved off from the lowest rib to the hip region. For the rats which underwent a sham operation, only skin and muscles were cut but the ovaries were spared. Meanwhile for rats in the ovariectomized groups, bilateral ovariectomy was performed using an incision 1.5 cm inferior to the palpated rib cage. The ovaries and surrounding tissue were removed; the incision was closed by suturing the muscles and stapling the skin. Antibiotic cream was applied on the wound and the animal was placed on paper towels in a cage until awake. Piper sarmentosum and glycyrrhizic acid were administered by oral gavage at a dose of 1.25 mg kg-1 (Peungvicha et al., 1998) and 1.20 mg kg-1 (Al-Wahaibi, 2007) respectively for five months. The control groups were sham administered water by oral gavage. Blood sampling were collected from orbital sinus on 0, 3 and 5 months of treatments.

Plasma Adiponectin and Blood Glucose Measurement
Blood glucose levels were monitored using the Glucometer (Optium). Plasma adiponectin levels were determined using the rat adiponectin enzyme-linked immunoabsorbent assay (ELISA) kit (Linco Research, USA).

Body Weight Measurement
Body weight was taken every week by using the electronic weighing scale (Tanita, Japan) in order to obtain the weight measurement.

Statistical Analysis
All data were tested for normal distribution and presented as Mean±SD. Differences in the body weights and blood pressure were analyzed by a one-way Analysis of Variance (ANOVA) followed by Tukey test for multiple group comparisons. A value of p<0.05 was taken as significant. All statistical analysis was conducted using the SPSS version 11.5 software.

RESULTS AND DISCUSSION

All the ovariectomized groups had a significant reduction (p<0.05) in the plasma adiponectin compared to the sham-operated group. However, after 3 and 5 months of treatment, both Piper sarmentosum water extract (PS) and glycyrrhizic acid (GCA) treated group showed a significant increment (p<0.05) in the plasma adiponectin level compared to CTRL group (Fig. 1).

Meanwhile, only the blood glucose level in Piper sarmentosum water extract (PS) treated group showed significant reduction (p<0.05) after 3 and 5 months of treatment compared to CTRL group (Fig. 2).

The results also showed that ovariectomized rats had a significant increased in body weight after three months compared to the sham-operated rats. However, there was no significant increased between all the treated groups in body weight after three months of treatment (Fig. 3).

Visceral obesity and features of the metabolic syndrome are caused by highly production of glucocorticoid exclusively within visceral adipose tissues (Masuzaki et al., 2001). Glucocorticoid potentiates the adipogenic process and anabolic lipid metabolism in adipocytes (Berger et al., 2001). During differentiation and maturation process, adipocytes release a variety of adipocytokines (Greenberg and McDaniel, 2002; Tsao et al., 2002; Steppan and Lazar, 2002; Havel, 2002; Berg et al., 2002).


Fig. 1: Plasma adiponectin levels on 0 month, 3 months and 5 months of treatment (N = 7). Values are Mean±SD. The ovariectomized groups are CTRL, PS and GCA, while the sham-operated group is SHM. The data are the Mean±SD. Same letters shows statistically significant between groups (p<0.05). Same numbers are statistically significant within group (p<0.05)

Fig. 2: Blood glucose levels on 3 months and 5 months of treatment (N = 7). Values are Mean±SD. The ovariectomized groups are CTRL, PS and GCA, while the sham-operated group is SHM. The data are the Mean±SD. Same letters shows statistically significant between groups (p<0.05). Same numbers are statistically significant within group (p<0.05)

Adiponectin is an adipocyte-derived protein that is abundantly expressed and secreted from adipocytes. Recent preclinical and clinical studies have implicated adiponectin as an important mediator of insulin sensitivity in peripheral tissue (Tsao et al., 2002; Steppan and Lazar, 2002; Havel, 2002; Berg et al., 2002). Plasma adiponectin concentrations are markedly reduced with increasing insulin resistance in obese patients with type-2 diabetes (Weyer et al., 2001; Arita et al., 1999; Hotta et al., 2001; Nadler et al., 2000; Hara et al., 2002; Comuzzie et al., 2001; Stefan et al., 2002; Lindsay et al., 2002; Rolland et al., 2007).

Present findings showed that plasma adiponectin levels (Fig. 1) were reduced and the blood glucose levels (Fig. 2) were increased in all ovariectomized groups compared to the sham-operated group. The reduction of the plasma adiponectin levels and the increment of the blood glucose levels are caused by obesity due to ovariectomy procedure. These results were comparable with Almonte et al. (2003) finding, which reported that adiponectin expression was significantly reduced in Zucker diabetic fatty (ZDR) rats. They also reported that plasma adiponectin levels correlated positively with insulin sensitivity and negatively with the degree of hyperglycemia, hyperinsulinemia, hyperlipidemia and percentage of visceral fat pad mass (Almonte et al., 2003).


Fig. 3: Weight difference between group over time. Same letters are statistically significant (p<0.05) between groups. *Shows significant difference between 0 month (*p<0.05). N = 7 in each group. The data are the Mean±SD

However, after 3 and 5 months of treatment, both PS and GCA treated group showed a significant (p<0.05) increment in plasma adiponectin levels compared to CTRL group (Fig. 1). This increment led to the idea that the adipocytes had been reduced. In support of this idea, our previous studies provides additional data showing that both PS and GCA treated group showed an improvement in lipid profile compared to CTRL group in ovariectomized induce obese rats.

Meanwhile, only the blood glucose levels in the PS treated group showed a significant reduction (p<0.05) compared to the CTRL group (Fig. 2). This reduction was predictable since Peungvicha et al. (1998) reported that Piper sarmentosum water extract shown hypoglycemic effects in diabetic induced rats (Peungvicha et al., 1998). Even though the GCA treated group showed an increment plasma adiponectin levels, but it did not show any reduction in blood glucose levels (Fig. 2). This can probably be explained by the fact that glycyrrhizic acid is known to be derived from licorice which is commercially used as artificial food sweetener in food industry. Thus, prolonged consumption could possibly lead to the increased in blood glucose levels.

Ovariectomy is known to cause the increase in body weight which results in obesity (Chu et al., 1999). Present finding showed that the body weight was increase in the ovariectomized rats by up to 20% as compared to the SHM group after one month of surgery. This finding was comparable with a study by Kano and Doi (2006). The weight difference for ovariectomized rats increased almost double between weeks 4 to weeks 8 compared with the sham-operated rats.

After five months of treatment, significant (p<0.05) reduction in body weight only occurred in GCA treated group. There was no dissimilarity for the PS treated group, as compared to CTRL group. However this result was not correlated with the adiponectin plasma level. A probable explanation could be that the body weight that we measured was the total body weight of the rats which included the subcutaneous fat as well as the visceral fats and it is known that adiponectin plasma level is more correlated with the visceral fat.

In conclusion, we showed that both Piper sarmentosum water extract and glycyrrhizic acid increased the plasma adiponectin levels but only Piper sarmentosum water extracts improved blood glucose levels. This finding suggests that Piper sarmentosum water extract may have the ability to reduce the amount of visceral fat as well as the ability to improve blood glucose levels in ovariectomy-induced obese rats.

ACKNOWLEDGMENTS

The researchers would like to thank Pn. Azizah Osman, Pn. Sinar Suriya Muhamad, Pn. Mazliadiyana Mazlan, Pn. Norhayati Md. Yasin and all the technical staff of the Department of Pharmacology, UKM for their help. We would also like to thank the Ministry of Science, Technology and Innovation for the grant IRPA 06-02-02-10026EAR; and to Universiti Kebangsaan Malaysia for the research grant FF-086-2004. We are also grateful to the Forest Research Institute Malaysia (FRIM) for the supply of Piper sarmentosum extract.

REFERENCES
Al-Wahaibi, A., 2007. The role of 11beta-hydroxysteroid dehydrogenase type-1 (11BHSD-1) in ovariectomy-induced obesity rats and its modulation by estrogen replacement theraphy, glycyrrhizic acid and kacip fatimah. Ph.D. Thesis, Universiti Kebangsaan Malaysia.

Almonte, J., S. Harbarum, A. Richter and H. Dong, 2003. Fat depot-specific expression of adiponectin is impaired in Zucker fatty rats. Metabolism, 52: 958-963.
CrossRef  |  PubMed  |  Direct Link  |  

Arita, Y., S. Kihara, N. Ouchi, M. Takahashi and K. Maeda et al., 1999. Paradoxical decrease of an adipose-specific protein, adiponectin, in obesity. Biochem. Biophys. Res. Commun., 257: 79-83.
CrossRef  |  PubMed  |  Direct Link  |  

Berg, A.H., T.P. Combs and P.E. Scherer, 2002. ACRP30/adiponectin: An adipokine regulating glucose and lipid metabolism. Trends Endocrinol. Metab., 13: 84-89.
CrossRef  |  PubMed  |  

Berger, J., M. Tanen, A. Elbrecht, A. Hermanowski-Vosatka, D.E. Moller, S.D. Wright and R. Thieringer, 2001. Peroxisome proliferator-activated receptor-gamma ligands inhibit adipocyte 11beta-hydroxysteroid dehydrogenase type 1 expression and activity. J. Biol. Chem., 276: 12629-12635.
CrossRef  |  PubMed  |  Direct Link  |  

Chanwitheesuk, A., A. Teerawutgulrag and N. Rakariyatham, 2005. Screening of antioxidant activity and antioxidant compounds of some edible plants of Thailand. Food Chem., 92: 491-497.
CrossRef  |  Direct Link  |  

Chu, S.C., Y.C. Chou, J.Y. Liu, C.H. Chen, J.C. Shyu and F.P. Chou, 1999. Fluctuation of serum leptin level in rats after ovariectomy and the influence of estrogen supplement. Life Sci., 64: 2299-2306.
CrossRef  |  Direct Link  |  

Comuzzie, A.G., T. Funahashi, G. Sonnenberg, L.J. Martin and H.J. Jacob et al., 2001. The genetic basis of plasma variation in adiponectin, a global endophenotype for obesity and the metabolic syndrome. J. Clin. Endocr. Metab., 86: 4321-4325.
PubMed  |  Direct Link  |  

Greenberg, A.S. and M.L. McDaniel, 2002. Identifying the links between obesity, insulin resistance and -cell function: Potential role of adipocyte-derived cytokines in the pathogenesis of type 2 diabetes. Eur. J. Clin. Invest., 32: 24-34.
PubMed  |  Direct Link  |  

Hara, K., P. Boutin, Y. Mori, K. Tobe and C. Dina, et al., 2002. Genetic variation in the gene encoding adiponectin is associated with an increased risk of type 2 diabetes in the Japanese population. Diabetes, 51: 536-540.
PubMed  |  Direct Link  |  

Havel, P.J., 2002. Control of energy homeostasis and insulin action by adipocyte hormones: Leptin, acylation stimulating protein and adiponectin. Curr. Opin. Lipidol., 13: 51-59.
PubMed  |  Direct Link  |  

Hotta, K., T. Funahashi, N.L. Bodkin, H.K. Ortmeyer, Y. Arita, B.C. Hansen and Y. Matsuzawa, 2001. Circulating concentrations of the adipocyte protein adiponectin are decreased in parallel with reduced insulin sensitivity during the progression to type 2 diabetes in rhesus monkeys. Diabetes, 50: 1126-1126.
PubMed  |  

Kano, S. and M. Doi, 2006. NO-1886 (ibrolipim), a lipoprotein lipase-promoting agent, accelerates the expression of UCP3 messenger RNA and ameliorates obesity in ovariectomized rats. Metabol. Clin. Exp., 55: 151-158.
Direct Link  |  

Lindsay, R.S., T. Funahashi, R.L. Hanson, Y. Matsuzawa and S. Tanaka et al., 2002. Adiponectin and development of type 2 diabetes in the Pima Indian population. Lancet, 360: 57-58.
CrossRef  |  PubMed  |  Direct Link  |  

Masuzaki, H., J. Peterson, H. Shinyama, N.M. Morton, J.J. Mullins, J.R. Seckl and F.S. Flier, 2001. A transgenic model of visceral obesity and the metabolic syndrome. Science, 294: 2166-2170.
CrossRef  |  PubMed  |  Direct Link  |  

Nadler, S.T., J.P. Stoehr, K.L. Schueler, G. Tanimoto, B.S. Yandell and A.D. Attie, 2000. The expression of adipogenic genes is decreased in obesity and diabetes mellitus. Proc. Natl. Acad. Sci. USA., 1997: 11371-11376.
PubMed  |  Direct Link  |  

Peungvicha, P., S.S. Thirawarapan, R. Temsiririrkkul, H. Watanabe, J.K. Prasain and S. Kodata, 1998. Hypoglycemic effect of the water extract of Piper sarmentosum in rats. J. Ethnopharmacol., 60: 27-32.
CrossRef  |  PubMed  |  

Rahman, N.N.N.A., T. Furuta, S. Kojima, K. Takane and M.A. Mohd, 1999. Antimalarial activity of extracts of Malaysian medicinal plants. J. Ethnopharmacol., 64: 249-254.
CrossRef  |  PubMed  |  Direct Link  |  

Ridtitid, W., W. Rattanaporn, P. Thaina, S. Chittrakarn and M. Sunbhanich, 1998. Neuromuscular blocking activity of methanolic extract of Piper sarmentosum leaves in the rat phrenic nerve-hemidiaphragm preparation. J. Ethnopharmacol., 61: 135-142.
CrossRef  |  PubMed  |  

Rolland, Y.M., M.T. Haren, P. Patrick, W.A. Banks, T.K. Malmstrom, D.K. Miller and J.E. Morley, 2007. Adiponectin levels in obese and non-obese middle-aged African-American Women. Obesity Res. Clin.l Practice, 1: 27-37.
CrossRef  |  PubMed  |  

Stefan, N., B. Vozarova, T. Funahashi, Y. Matsuzawa and C. Weyer et al., 2002. Plasma adiponectin concentration is associated with skeletal muscle insulin receptor tyrosine phosphorylation and low plasma concentration precedes a decrease in whole-body insulin sensitivity in humans. Diabetes, 51: 1884-1888.
CrossRef  |  PubMed  |  Direct Link  |  

Steppan, C.M. and M.A. Lazar, 2002. Resistin and obesity-associated insulin resistance. Trends Endocrin., Met., 13: 18-23.
CrossRef  |  PubMed  |  

Tsao, T.S., H.F. Lodish and J. Fruebis, 2002. ACRP30, a new hormone controlling fat and glucose metabolism. Eur. J. Pharmacol., 440: 213-221.
CrossRef  |  PubMed  |  Direct Link  |  

Weyer, C., T. Funahashi, S. Tanaka, K. Hotta, Y. Matsuzawa, R.E. Pratley and P.A. Tataranni, 2001. Hypoadiponectinemia in obesity and type 2 diabetes: Close association with insulin resistance and hyperinsulinemia. J. Clin. Endocrine Metab., 86: 1930-1935.
CrossRef  |  PubMed  |  

©  2019 Science Alert. All Rights Reserved
Fulltext PDF References Abstract