Journal of Pharmaceutical Negative Results

: 2014  |  Volume : 5  |  Issue : 1  |  Page : 19--21

Lack of diuretic activity of water extract of leaves of Pongamia pinnata L. in rats

SA Deraniyagala1, WD Ratnasooriya2, S Priyadharshini1, TRK Perera3,  
1 Department of Chemistry, Animal House, University of Colombo, Colombo 08, Sri Lanka
2 Department of Zoology, Animal House, University of Colombo, Colombo 08, Sri Lanka
3 Department of Medical Faculty, Animal House, University of Colombo, Colombo 08, Sri Lanka

Correspondence Address:
S A Deraniyagala
Department of Chemistry, University of Colombo, Colombo 03
Sri Lanka


Objective : To assess the diuretic potential of water extract (WE) of leaves of Pongamia pinnata L. Materials and Methods : Different doses (500, 1000, 1500, and 3000 mg/kg) of WE of the leaves of P. pinnata or vehicle or furosemide, reference drug was orally administered to hydrated rats (n = 6/group) and their cumulative urine output was monitored at hourly intervals for 6 h. Result : The WE of P. pinnata does not possess significant (P > 0.05) diuretic activity. Conclusion : The WE of the leaves of P. pinnata did not possess diuretic activity in rats as was claimed in traditional and folkloric medicine.

How to cite this article:
Deraniyagala S A, Ratnasooriya W D, Priyadharshini S, Perera T. Lack of diuretic activity of water extract of leaves of Pongamia pinnata L. in rats.J Pharm Negative Results 2014;5:19-21

How to cite this URL:
Deraniyagala S A, Ratnasooriya W D, Priyadharshini S, Perera T. Lack of diuretic activity of water extract of leaves of Pongamia pinnata L. in rats. J Pharm Negative Results [serial online] 2014 [cited 2020 Jul 5 ];5:19-21
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Pongamia pinnata L. (Family: Leguminosae), Indian beech in English, Pongam in Tamil and Magulkaranda in Sinhala is a large tree with a soft, grey bark, and slightly puberulous buds. The leaves are compound, large, rachis about 12.5 n cm long, glabrous, leaflets 5-9, each 7.5-12.5 cm long on thick stalks, oval, acute at base, acuminate, glabrous, and shining on both sides, thin, bright green. The flowers are irregular, bisexual, greenish pink or white with calyx purplish brown, 1.5 cm long, pedicel rather long, slender, swollen at base, articulated often in pairs, racemes often two together, elongated, about equaling the leaves. This plant occurs in India, Sri Lanka, Malaya, Polynesia, Australia, and Philippine Islands. It is common in the low-country in Sri Lanka on banks of streams and rivers, especially near the coast. [1]

P. pinnata has been used as folk medicinal plant, particularly in Ayurvedha and Siddha systems of Indian medicine. All parts of the plant have been used as a crude drug for the treatment of tumors, piles, skin diseases, itches, abscess, painful rheumatic joints wounds, ulcers, diarrhea, etc., Besides, it is well-known for its application as animal fodder, green manure, timber, and fish poison. It has also been recognized to possess applications in agriculture and environmental management, with insecticidal and nematicidal activity. More recently, the effectiveness of P. pinnata as a source of biomedicines has been reported, specifically as antimicrobial and therapeutic agents. [2],[3]

The decoction of this plant is claimed to be effective as a diuretic in Sri Lankan traditional medicine system. [4] However, no scientific investigation has been done to verify this claim. The objective of this study was to scientifically investigate the effectiveness of the decoction made from this plant as a diuretic. The leaves of the plant were used for this study as Sri Lankan traditional practioners usually recommend the leaves in the preparation of decoction.


Experimental animals

Healthy adult crossbred albino female rats (190-200 g) were used (n = 30). They were maintained in standard environmental conditions (temperature: 28-31 ° C, photo-period: Approximately 12 h natural light per day, and relative humidity: 50-55%) with free access to pelleted food (Ceylon Grain Elevators, Colombo, Sri Lanka) and clear drinking water. The experiment was conducted in accordance with the internationally accepted laboratory animal use and care, and guidance and rules of the Faculty of Medicine, University of Colombo, Sri Lanka, of animal experimentation. Ethical clearance was obtained from Faculty of Medicine, University of Colombo, Sri Lanka (EC/12/141).

Collection of plants

Fresh leaves were collected from the Faculty of Science, University of Colombo, Sri Lanka (N 6.90232 , E 79.85942 ), which is situated in the wet zone of Sri Lanka, in June 2012. The plant was identified by Prof. B.A. Abeyawikrama of the Department of Plant Science, University of Colombo, Sri Lanka. The voucher specimen (WDR/SAD/1008) was deposited at the Museum of the Department of Zoology, University of Colombo, Sri Lanka.

Preparations of the water extract

The leaves were washed under running water, air dried for 3 days and ground into small pieces. The pieces were refluxed with water for 16 h in a round bottom flask fitted with a Liebig condenser (1 kg of plant material in 12 L of water). The brownish red solution was filtered using a sintered funnel and concentrated up to 1 L. The concentrated sample was freeze dried (yield: 18.90 w/w) and stored in airtight bottles at 20°C. The freeze-dried powder (WE) was dissolved in 1 ml distilled water to obtain the required dosage concentrations (500, 1000, 1500, and 3000 mg/kg). [5],[6]

Evaluation of diuretic activity

Thirty six rats were deprived of water, but not food for 18 h. There urinary bladders were emptied by gentle compression of the pelvic area and by pull of their tails. [6] Each of these rats were then orally administered with 12.5 ml of isotonic saline (NaCl, 0.9% w/v) to impose a uniform water load. [7] Forty-five minutes later, these rats were randomly divided into six groups (n = 6/group) and treated orally in the following manner. Group 1: With 1 mL of distilled water, Groups 2, 3, 4, and 5: With 1 mL of 500, 1000, 1500, 3000 mg/kg of freeze-dried WE, respectively, and Group 6: With 1 mL of 13 mg/kg of furosemide (State Pharmaceutical Corporation, Colombo, Sri Lanka), the reference drug. [8] Each of these rats were individually placed in metabolic cages and cumulative urine output was determined at hourly intervals, for 6 h. The color and the appearance of urine were also noted. [5]

Phytochemical screening

All the phytochemical screening were done according to Farnsworth. [9]

Statistical analysis

Data are given as mean ± SEM Statistical comparisons were made by one-way analysis of variance (ANOVA) using Minitab 13.0 version statistical package. Significance was set at P < 0.05.


The results obtained are summarized in [Table 1] and [Table 2]. As shown, none of doses of WE of P.pinnata did not significantly (P > 0.05) affect the hourly urine output or cumulative urine output compared to the control. On the other hand Furosemide, the reference drug, significantly (P < 0.05) increase the both hourly and cumulative urine output.{Table 1}{Table 2}


This study has examined the diuretic activity of the water extraction of leaves of P. pinnata using a rat hydrated diuretic model. This technique is validated, reliable, sensitive, quick, and widely used to investigate the diuretic activity. [7],[10],[11] The results obtain are depicted in [Table 1] and [Table 2]. As shown, none of the doses of WE of P. pinnata significantly increased (P > 0.05) the cumulative urine output, at six hours or at hourly intervals of six hours. This indicates that the WE of P. pinnata does not function as a diuretic, in contrast to its claimed effect as a diuretic, in Sri Lankan traditional medicine. This is the novel, but an unexpected finding. On the other hand, the reference drug, furosemide evoked a rapid (within one hour) a marked (by 130%), and significant (P < 0.05) diuresis. The color and appearance of urine of all treated rats were similar to that of controls

The doses of WE of P. pinnata used in this study were approximately 1.25 (500 mg/kg), 2.50 (1000 mg/kg), 3.75 (1500 mg/kg), and 5.0 (3000 mg/kg) times to the human equivalent dose. Therefore, the absence of a diuretic effect of WE cannot be attributed to an insufficient dosage. Lack of diuretic activity is unlikely to be due to freeze drying of the WE as several studies have used freeze dried plant extracts and shown traditionally claimed diuretic action of these pharmacophores. [7],[10] Enhanced hepatic and/or renal clearance of the bioactive constituent/s responsible for inducing diuresis, is a potential mechanism for the absence of the diuretic action of WE in rats. [8] Production of metabolites, in rats, which over-rides the diuretic activity of the WE of P. pinnata is yet another possibility. In complete contrast, lack of diuretic activity of WE in rats could be due to species specificity. [12],[13]

Phytochemical screening of WE showed the presence of tannins, polyphenols, flavonoids, leucoanthocyanins, alkaloids, unsaturated steroids and terpenes.

Flavonoids and tannins have been found to increase the volume of urine by promoting blood flow to the kidneys, thereby raising the glomerular filtration rate. [14] Flavonoids and tannins are classes of compounds having a large array of structurally different compounds. It is well-known that even minute structural aspects of difference flavonoids and tannins can markedly affect the biological activity. [15] Therefore, it is not surprising that WE did not show diuresis even though tannins and flavonoids were detected in the extract.


The WE of leaves of P. pinnata does not possess diuretic activity in rats as it is claimed in traditional medicine in Sri Lanka.


1Jayaweera DM. Medicinal Plants used in Ceylon. 5 th ed. Colombo, Sri Lanka: The National Science Foundation; 1982.
2Meera B, Kumar S, Kalidhar SB. A review of the chemistry and biological activity of Pongamia pinnata. J Med Aromatic Plant Sci 2003;25:441-65.
3Brijesh S, Daswani PG, Tetali P, Rojatkar SR, Antia NH, Birdi TJ. Studies on Pongamia pinnata (L.) Pierre leaves: Understanding the mechanism (s) of action in infectious diarrhea. J Zhejiang Univ Sci B 2006;7:665-74.
4Ramanayaka L, De Silva G, Perera DL (Editors). Compendium of Medicinal Plants. A Sri Lankan Study. Department of Ayurveda: Colombo Sri Lanka; 2003; 3:24-9.
5Jayakody JR, Ratnasooriya WD, Fernando WA, Weerasekara KR. Diuretic activity of leaves extract of hot wateriInfusion of Ruta graveolens L in Rats. J Pharmacol Toxicol 2011;6:1-8.
6Ratnasooriya WD, Pieris KP, Samaratunga U, Jayakody JR. Diuretic activity of Spilanthes acmella flowers in rats. J Ethnopharmacol 2004;91:317-20.
7Ratnasooriya WD, Fernando TS, Ranatunga RA. Diuretic activity of Sri Lankan black tea (Camellia sinensis L.) in rats. Pharmacognosy Research 2009;1:4-10.
8Rang HP, Dale MM, Ritter JM, Moore PK. Pharmacology. 5 th ed. Edinburgh: Churchill Livingstone; 2003.
9Harry HS, Maung TW, Farnsworth NR. Phytochemical Screening. Department of Pharmacognosy and Pharmacology, University of Illinois: Chicago Illinois; 1996. p. 1-8.
10Wright CI, Van-Buren L, Kroner CI, Koning MM. Herbal medicines as diuretics: A review of the scientific evidence. J Ethnopharmacol 2007;114:1-31.
11Ratnasooriya WD, Obeysekera M, Jayakody JR, Ratnasooriya CD, Weerasekera KR. Lack of diuretic activity of hot water extraction of whole plant of Amaranthusviridis L. in rats. J Pharm Negat Results 2012;3:4-6.
12Ilayperuma I, Ratnasooriya WD, Weerasooriya TR. Effect of Withaniasomnifern root extraction on sexual behavior of male rats. Asian J Androl 2002;4:295-8.
13Singh D, Singh B, Goel RK. Hydroethonolic leaf extract of Ficusreligiosalacks anticonvulsant activity in acute electro and chemo convulsion mice models. J Pharm Negat Results 2011;2:58-61.
14Dennis VC. Awang Tyler's Herbs of Choice: The Therapetic use of Phytomedicinal. 3 rd ed. CRC press, London, New York.; 2009. p. 59.
15Silverman RB. The Organic Chemistry of Drug Design and Drug Action. 2 nd ed. Elsevier's Science and Technology, Department in Oxford: UK; 2004. p. 7-168.