|Year : 2014 | Volume
| 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
|Date of Web Publication||16-Jul-2014|
S A Deraniyagala
Department of Chemistry, University of Colombo, Colombo 03
Source of Support: A Grant of S. A. Deraniyagala from University
of Colombo (AP/3/2/00/05) is greatly acknowledged., Conflict of Interest: None
| Abstract|| |
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.
Keywords: Diuresis, diuretic, Pongamia pinnata, traditional 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 2018 Jul 19];5:19-21. Available from: http://www.pnrjournal.com/text.asp?2014/5/1/19/136782
| Introduction|| |
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. 
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. ,
The decoction of this plant is claimed to be effective as a diuretic in Sri Lankan traditional medicine system.  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.
| Materials and methods|| |
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). ,
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.  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.  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.  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. 
All the phytochemical screening were done according to Farnsworth. 
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.
| Results|| |
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: Cumulative urine output in rats over a 6-h period following oral administration of water extract of leaves of Psoralea pinnata in rats. (mean±SED), (n=6) |
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|Table 2: Time course of diuresis in rats treated with different doses of water extract of leaves of Psoralea pinnata up to 6 h (mean±SEM), (n=6) |
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| Discussion|| |
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. ,, 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. , 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.  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. ,
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.  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.  Therefore, it is not surprising that WE did not show diuresis even though tannins and flavonoids were detected in the extract.
| Conclusion|| |
The WE of leaves of P. pinnata does not possess diuretic activity in rats as it is claimed in traditional medicine in Sri Lanka.
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[Table 1], [Table 2]