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Original Research Article

Reproductive Physiology Section, Centre for Advanced Studies, Department of Zoology, University of Rajasthan, Jaipur, 302 004 India Department of Botany, University of Rajasthan, Jaipur, 302 004 India

Received: May 9, 2011 Accepted: July 18, 2011

ANTIDIABETIC AND RENOPROTECTIVE ACTIVITY OF MOMORDICA DIOICA IN DIABETIC RATS Rajnish Gupta1, P. Katariya2, M. Mathur2, V.K. Bajaj1, S. Yadav2, R. Kamal**2, R.S. Gupta1

Key words: glomerular capsule, glomerulus, hyperglycemia, Momordica dioica, renal tubules

SUMMARY The aim of the present study was to investigate the antidiabetic and renal protective effect of Momordica dioica extract (MDMtE) in streptozotocin-diabetic rats. MDMtE treatment markedly reduced serum glucose, increased serum insulin and urea levels. Study results indicated that the antioxidant enzyme activity of kidney was increased, while thiobarbituric acid reactive substances (TBARS) were reduced in MDMtE treated diabetic rats. Furthermore, histologic observation of kidney of diabetic rats showed degenerative changes in glomerulus and renal tubules and extract treatment rejuvenated kidney histoarchitecture. In conclusion, the present results suggest that MDMtE protects kidney in severe diabetes and thus may provide a promising antidiabetic drug for managing diabetic kidney disorders. Corresponding authors: Dr. R. S. Gupta, TR-03, Teacher’s Hostel, University of Rajasthan, Jaipur, 302004 India E-mail: [email protected] **Prof. Raka Kamal, 35 Geejgarh Vihar, Civil Lines, Jaipur, Email: [email protected], Phone No. +91-141-2212211; Fax +91-141-2331894.

Diabetologia Croatica 40-3, 2011

INTRODUCTION Severe diabetic nephropathy results in asymptomatic kidney failure and may cause narrow and clogged glomerulus; waste products cannot be excreted and remain in the blood and may cause cytotoxicity (1). Diabetes causes reduced nerve sensitivity including response to a filled bladder and the ensuing pressure can damage kidneys. Urinary tract may also cause bacterial infection due to high sugar concentration in urine. Kimmelstiel-Wilson and kidney hypertrophyhyperfunction syndromes are also well established in diabetic nephropathy (2). Currently there are over 240 million diabetics worldwide and about 40% of them develop severe diabetic nephropathy (3). Despite much research work, the diabetic kidney epidemic is increasing rapidly. Patients with diabetes kidney failure undergo either painful dialysis or kidney transplantation (4), which is both costly and harmful. Presently, researches to develop drugs that slow the progression of diabetic kidney damage with fewer side effects are being conducted, however, showing no significant outcome (5). This has led to increasing exploration of complementary and alternative medicine from natural sources having potent antidiabetic as well as nephroprotective activity with fewer side effects.

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R. Gupta, M. Mathur, V.K. Bajaj, P. Katariya, S. Yadav, R. Kamal, R.S. Gupta / ANTIDIABETIC AND RENOPROTECTIVE ACTIVITY OF MOMORDICA DIOICA IN DIABETIC RATS

Momordica (M.) dioica (family Cucurbitaceae) is a climbing creeper and reported as an important medicinal herb since ancient times for headache, urinary calculi, jaundice, asthma, bronchitis, leprosy, fever, tumors, urinary discharges, excessive salivation and heart troubles (6). Phytochemical investigations of M. dioica have shown the presence of lectins, β-sitosterol, saponin glycosides, triterpenes of ursolic acid, hederagenin, oleanolic acid, α-spiranosterol, stearic acid, gypsogenin and momodicaursenol (7-9). In the present study, M. dioica fruits were used to evaluate the antidiabetic and renoprotective activity using diabetes-oxidative damage in kidney.

MATERIALS AND METHODS Preparation of extract M. dioica fruits were freshly collected from University of Rajasthan and authenticated by deposition of specimen with herbarium (Department of Botany, University of Rajasthan, RUBL 20394). The fruits (3 kg) were cleaned, shade dried and powdered for methanol extraction at room temperature. The filtrate was vacuum dried and concentrated to obtain final extract (yield 25.7 g).

buffer. After 72 h of STZ administration, the rats with serum glucose levels >250 mg/dL were selected for the study. The MDMtE was dissolved in distilled water and orally given to the rats for 21 consecutive days. Group I: vehicle treated control group. Group II: diabetic group. Group III: diabetic rats treated with MDMtE (300 mg/kg b.w./day) dissolved in vehicle. Group IV: diabetic rats treated with glibenclamide (0.3 mg/kg b.w./day) dissolved in vehicle.

Estimation of serum glucose Serum glucose was measured in overnight fasted rats using a commercially available kit based on glucose oxidase method (10).

Measurement of kidney weight Relative kidney weight was expressed by using the following equation: Kidney weight (g) Relative kidney weight = ×100 (mg/100 g b.w.) Total body weight (g)

Experimental animals The present study was approved by the ethics committee (Centre for Advanced Studies, Department of Zoology, University of Rajasthan, Jaipur, India). INSA, New Delhi guidelines were followed throughout the experiment for the use of animals. Colony bred male albino rats of Wistar strain weighing 170-190 g were randomized into ten groups of seven rats each and provided free food access and water ad libitum.

Experimental design Streptozotocin (STZ; Sigma-Aldrich, USA) was dissolved in 0.1M sodium citrate buffer just prior to use and injected intraperitoneally to rats. Control rats (group I, n=9) received an equivalent volume of citrate

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Tissue and serum biochemical estimation After autopsy under mild ether anesthesia, kidneys were quickly removed from the sacrificed rat, placed on cotton presoaked in ice cold saline and trimmed of adipose tissue. Kidneys were finely minced, homogenized and used for protein (11), lipid peroxidation (LPO) (12), ascorbic acid (13), antioxidant defense system assays (superoxide dismutase (SOD) (14), catalase (CAT) (15), reduced glutathione (GSH) (16), glutathione peroxidase (GPx) (17) and glutathione-s-transferase (GST) (18) estimations. Kidney sample (200 mg) was homogenized with 5 mL of phosphate buffer with Na2EDTA and refrigerated, centrifuged at 10000 rpm for 20 min at 4

R. Gupta, M. Mathur, V.K. Bajaj, P. Katariya, S. Yadav, R. Kamal, R.S. Gupta / ANTIDIABETIC AND RENOPROTECTIVE ACTIVITY OF MOMORDICA DIOICA IN DIABETIC RATS

Table 1. Effect of methanolic extract of Momordica (M.) dioica (MDMtE) on tissue, serum and urine biochemical parameters in streptozotocin-diabetic rata

Treatment

Protein (mg/g)

GSH (n mole/g tissue)

SOD (μmole/mg protein)

LPO (n mole MDA/mg protein)

Ascorbic acid (mg/g)

Urine protein (mg/dL)

Uric acid (mg/dL)

Urea nitrogen (mg/dL)

Group I Control (vehicle treated)

202.37 ±8.93

4.41 ±0.17

10.18 ±0.63

2.19 ±0.78

5.27 ±0.14

17.81 ±0.14

3.14 ±0.02

18.52 ±1.28

108.54** ±10.14

2.86** ±0.15

4.54** ±0.52

9.91** ±0.83

3.18** ±0.12

31.55** ±0.21

5.19* ±0.04

33.28** ±3.27

Group III Diabetic + M. dioica (300 mg/kg b.w./day)

173.52nsa+ ±9.26

3.47nsa ±0.68

6.89*a+ ±0.81

6.23*a+ ±0.47

4.41*a ±0.15

21.57*a+ ±2.21

4.15*a ±0.05

24.63*a+ ±3.47

Group IV Diabetic + glibenclamide (0.3 mg/kg b.w./day)

193.74nsa+ ±6.52

4.57nsa+ ±0.14

8.79nsa ±0.77

4.73nsa ±0.41

5.11nsa ±0.11

17.12*a+ ±3.21

3.77*a ±0.06

19.45*a+ ±3.52

Group II Diabetic group

a

Values are given as mean ± SEM of 7 rats in each group; diabetic group compared with normal group; experimental groups compared with normal and diabetic groups; values statistically significant at * P