Diuretic and laxative activity of ethanolic extract of Mollugo pentaphylla Linn.

S.K. Sahu¹*, D. Das², N.K. Tripathy¹ and H.K. Sundeep Kumar¹

¹School of Pharmaceutical Science & Research, Berhampur University, Berhampur, Odisha –760007

²School of Pharmaceutical Sciences, SOA University, Bhubaneswar, Odisha-754030

ABSTRACT:

Crude ethanolic extract of Mollugo pentaphylla Linn. (family- Aizoaceae) was investigated for diuretic and laxative activity in albino rats at 200 and 400 mg/kg p.o. Which was compared with standard drugs Furosemide (10mg/kg, p.o.) and Agar agar (300mg/kg, p.o.) respectively. The extract was found to produce significant diuretic as well as laxative activity at dose 400 mg/kg. The plant was also found to possess the phytoconstituents like carbohydrates, alkaloids, gums, saponins, flavanoids, tanins and steroids.

KEYWORDS: Mollugo pentaphylla; Acute toxicity study; Diuretic activity; Laxative activity

INTRODUCTION:

Herbal drugs are being proved as effective as synthetic drugs with lesser side effects. Herbal medicines are in line with nature, with less hazardous reactions. Mollugo pentaphylla Linn. (family- Aizoaceae) is commonly known as carpet weed (English), Pita-gohun (Oriya). It is an erect slender, much branched annual herb, up to 30 cm. high, commonly found in dry as well as moist areas. Leaves are falsely whorled or opposite, linear-lanceolate to obovate. Flowers are white, greenish, orange or pink, in terminal compound cymes. Capsules are globose with many dark reddish brown seeds. Roots are creaper and adventitious¹. The plant contains carotene, traces of vitamin C, saponin and potassium nitrate. It is also having numerous applications in traditional medicine as stomachic, aperient, antiseptic, emmenagogue and is also used in poultices for sore legs. An infusion of the plant is given to women to promote the menstrual discharge. Leaves are bitter and antiperiodic, they are warmed after smearing with oil and applied to the ear to relieve earache². It has been reported that the plant possesses antimicrobial³, whooping cough⁴, hepatitis⁵, spermicidal⁶, anti-inflammatory, anticancer and hepatoproductive⁷. Therefore, this present study was under taken to evaluate the diuretic and laxative activity of ethanolic extract of leaves of the plant on various animal models.

MATERIALS AND METHODS:

Plant material:

The plant M. pentaphylla was collected from the rural belt of Rayagada (Odisha) during the month of January and was authenticated by the Taxonomist of Botanical Survey of India, Howrah. The collected plant materials were washed under running tap to remove adhered dirt, and then shed dried. Then the aerial part was ground in to coarse powder

Preparation of extract:

The powered plant material was defatted with petroleum ether (60-80°c) and then extracted with 80% ethanol using soxhlet apparatus. The solvent was removed under reduced pressure to obtain dry extract, which gave a dark greenish-black coloured sticky residue. The extract was stored in desiccators for further use

Phytochemical Screening:

In this research work the ethanolic extract of both M. pentaphylla was qualitatively tested for the presence of chemical constituents. It shows the presence of carbohydrates, alkaloids, gums, saponins, flavanoids, tanins and steroids^8,9.

Animals:

Swiss albino mice (20-25 g) of either sex were used for acute toxicity study and adult wistar albino rats (150-200 g) of either sex were used for evaluation of pharmacological studies. The animals were kept in standard polypropylene cages at room temperature of 34 ± 2 ͦC and at 60-65 % relative humidity during the experimental work. The experiment has been performed in the CPCSEA approved laboratory of Institute of Pharmacy and Technology, Salipur (Regd. No. 1053/ac/07/CPCSEA) with the permission of Institutional animal ethics committee.

Acute toxicity study:

The acute toxicity of ethanolic extract of M. pentaphylla was determined as per the CPCSEA guideline no. 420 (fixed dose method). It was observed that the test extracts shows no mortality even at 2000 mg/kg dose hence, 1/10th (200 mg/kg) and 1/5th (400 mg/kg) of this dose were

selected for further study.

Evaluation of diuretic activity:

The method of Lipschitz et al., 1943 was employed for the assessment of diuretic activity¹⁰. In this method, albino rats of either sex weighing 150 to 200 gm were divided into four groups of six animals each. The animals were fasted for 24 hrs and water was given ad libitum during fasting. On the day of experiment the animal groups were received a primary dose of normal saline (25ml/kg) orally one hour prior to sample administration. Out of the four groups the 1st group of animals serving as control received 1% Tween-80 in normal saline (25 ml/kg, p.o.), The second group received furosemide orally at the dose of 10 mg/kg body weight and served as standard¹¹; Group-III and IV treated with ethanolic extract of M. pentaphylla (200 and 400 mg/kg) through oral route in a similar manner. Immediately after administration, the animals were placed in metabolic cages (2 per cage), specially designed to separate urine and faces, kept at 200 ± 0.50 C. The volume of urine collected was measured at the end of 5 h. During this period, no food and water was made available to animals. The parameters taken were the body weight before and after test period, total urine volume, concentration of Na⁺, K⁺ and Cl^- in the urine. Na⁺ and K⁺ concentrations were determined by flame photometer and Cl^- concentration was estimated by titration with silver nitrate solution (N/50) using 3 drops of 5% potassium chromate solution as indicator^12,13. The results are shown in Table-1.

Evaluation of laxative activity:

The laxative activity was performed according to Bose et al., 2006 ¹⁴ on rats of either sex, fasted for 12 hours before the experiment, but with water provided ad libitum. The animals were divided into four groups, each group consisting of six rats. The first group of animals, serving as control, received normal saline (25 ml/kg, p.o.); second group, serving as reference, received agar-agar (300 mg/kg, p.o.) in saline; the third and fourth groups received the ethanolic extract of M. pentaphylla at doses 200 and 400 mg/kg respectively. Immediately after dosing, the animals were separately placed in specially designed plastic containers suitable for collection of faces. After 8 hours of drug administration, the faces were collected and weighed. Thereafter, food and water were given to all rats and faecal outputs were again weighed after a period of 16 h (Table-2).

Statistical analysis:

All the results were statistically analyzed using one way ANOVA followed by Dunnet's t-test.

Values are expressed as mean ± S.E..M, (n=6). *P<0.05 and **P<0.01 compared with control was considered as significant.

RESULTS:

In the evaluation of diuretic activity, of ethanolic extract of M. pentaphylla was found to produce significant increase the volume of urine and excretion of sodium, potassium and chloride ions at the higher dose tested (400 mg/kg, p.o.). However, the test extract at lower dose (200 mg/kg) is not significant.

Table-1 Diuretic activity of ethanolic extract of aerial part of M. pentaphylla.

Group	Treatment	Dose	Urine Volume	Concentration of ions (mEq / l )			Na+/ K+ ratio
				Na+	K+	Cl-
I	Control	25ml/kg	2.41±0.50	47.23±1.74	131.64±1.99	99.36±0.71	0.35
II	Furosemide	10 mg/kg	7.05±0.68**	98.04±1.40**	161.83±1.96**	136.21±1.15**	0.6
III	Ethanolic extract of M.pentaphylla	200mg/kg	2.58±0.13	50.70±1.74	135.53±2.80	101.85±1.06	0.37
IV		400 mg/kg	5.90±0.39**	72.38±1.65**	156.83±1.36**	129.83±0.66**	0.46

Values are expressed as mean±S.E. (n=6). *P<0.05 and **P<0.01 compared with vehicle control (ANOVA followed by Dunnet’s t-test).

Table- 2 Laxative activity of ethanolic extract of aerial part of M. pentaphylla

Group	Treatment	Dose	Faecal Output (g)
			8h	8-16h
I	Control	25ml/kg	0.654±0.066	0.471±0.076
II	Agar agar	300 mg/kg	1.161±0.013**	0.530±0.011
III	Ethanolic extract of M.pentaphylla	200mg/kg	1.178±0.023**	0.494±0.019
IV		400 mg/kg	1.231±0.014**	0.511±0.016

Values are expressed as mean±S.E. (n=6). *P<0.05 and **P<0.01 compared with vehicle control (ANOVA followed by Dunnet’s t-test).

The diuretic activity demonstrated by the test extract at 400 mg/kg was lesser than the standard drug (Furosemide- 10 mg/kg). The results are compiled in the Table-1. The ethanolic extract of M. pentaphylla (200 and 400 mg/kg, p.o.) showed significant and dose dependant increase in faecal output of rats (Table-2). The effect was comparable with that of standard drug agar-agar (300mg/kg, p.o.).

DISCUSSION:

Diuretics relieve pulmonary congestion and peripheral edema and are useful in reducing the syndrome of volume overload, including orthopnea and paroxysmal nocturnal dyspnoea. They decrease plasma volume and subsequently venous return to the heart (preload). This decreases cardiac workload, oxygen demand and plasma volume, thus decreasing blood pressure^15-17. Thus, diuretics play an important role in hypertensive patients. In the present study, we can demonstrate that the ethanolic extract of M. pentaphylla significantly increased the urinary output as well as urinary electrolyte concentration at a dose of 400 mg/kg, p.o. but the effect was found to be the less potent in increasing the urinary output when compared with the reference standard. Further, the ethanolic extract of M. pentaphylla was found to be more effective in enhancing urinary electrolyte concentration for all the three ions tested (Na⁺, K⁺, Cl^-). The increase in the ratio of concentration of excreted sodium and potassium ions indicates that the extracts increase sodium ion excretion to a greater extent than potassium, which is a very essential requirement of an ideal diuretic with lesser hyperkalaemic side effect. The laxative activity study revealed significant activity of the ethanolic extract up to 8 h of drug administration. The results of the present study justify the use of the aerial part of the plant for diuretics and laxative purpose as suggested in the folklore remedies. The exact mechanism exhibited by the extracts can only be established after further investigation.

ACKNOWLEDGEMENTS:

The authors are very grateful to the School of pharmaceutical Science and Research Berhampur University, Berhampur and Institute of Pharmacy and Technology, Salipur, Cuttack, Odisha, India for providing required facilities of this work.

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Received on 21.07.2012

Modified on 29.07.2012

Accepted on 06.08.2012

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Research J. Pharmacology and Pharmacodynamics. 4(5): September –October, 2012, 278-280