|Year : 2012 | Volume
| Issue : 1 | Page : 26-28
Lack of diuretic activity of hot water extract of whole plant of Amaranthus viridis L. in rats
WD Ratnasooriya1, M Obeysekera2, J. R. A. C. Jayakody1, C. D. T. Ratnasooriya1, KR Weerasekera3
1 Department of Zoology, University of Colombo, Nugegoda, Sri Lanka
2 Department of Zoology University of Sri Jayawardenapura, Nugegoda, Sri Lanka
3 Department of Zoology Nidhana Chikitsa, Institute of Indigenous Medicine, University of Colombo, Rajagiriya, Sri Lanka
|Date of Web Publication||11-Aug-2012|
W D Ratnasooriya
Department of Zoology, University of Colombo, Colombo 03
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Objective: To assess the diuretic potential of hot water extract (HWE) of a whole plant of Amaranthus viridis L. Materials and Methods: Different doses (25, 50, and 100 mg / kg) of HWE of the whole plant of A. viridis or vehicle or furosemide, reference drug, was orally administered to hydrated rats (n = six / group) and their cumulative urine output was monitored at hourly intervals for five hours. Result: The HWE of A.viridis does not possess significant (P > 0.05) diuretic activity. Conclusion : The HWE of the whole plant of A. viridis did not possess diuretic activity in rats, as was claimed in traditional and folkloric medicine.
Keywords: Amaranthus viridis , diuresis, diuretic, traditional medicine
|How to cite this article:|
Ratnasooriya W D, Obeysekera M, Jayakody J, Ratnasooriya C, Weerasekera K R. Lack of diuretic activity of hot water extract of whole plant of Amaranthus viridis L. in rats. J Pharm Negative Results 2012;3:26-8
|How to cite this URL:|
Ratnasooriya W D, Obeysekera M, Jayakody J, Ratnasooriya C, Weerasekera K R. Lack of diuretic activity of hot water extract of whole plant of Amaranthus viridis L. in rats. J Pharm Negative Results [serial online] 2012 [cited 2019 Sep 23];3:26-8. Available from: http://www.pnrjournal.com/text.asp?2012/3/1/26/99646
| Introduction|| |
Amaranthus viridis L. (Family: Amaranthceae), Kurathampala in Sinhala and Araikkirai in Tamil is an annual herb, 30 - 56 cm tall. Its stem is erect, cylindrical, glabrous, shining, and considerably branched. The leaves are simple, glabrous, faintly serrated, and alternate, with a notch at the apex and a long petiole. The flowers are unisexual, small, green in color, sessile in clusters, on slender, tapering, terminal or auxiliary peniculate spikes. This plant occurs in tropical and subtropical countries, including Sri Lanka.  In Sri Lanka, it is a very common gregarious weed along road sides, railway lines, and waste ground.
In traditional and folkloric medicine of several countries, including India, Nepal, Philippines, Brazil, and Sri Lanka, this plant is used to treat many ailments and disorders. It is claimed to be used as an analgesic (especially in labor pains, menorrhagia, and stomach aches), anti-inflammatory agent, antipyretic, antiulcer, an antiemetic, antileprotic, antianemic, anti-rheumatic, vermifuge, laxative hemostatic, galactagogue, and diuretic. It is also used as an antidote for snake bite, stings of wasps, and bites of centipeds. , Some of these claimed activities are experimentally proven , and others are not. The diuretic action is one such claimed activity, which has not been experimentally investigated and validated by rigorous scientific testing. Thus, this study was launched to investigate the diuretic potential of the whole plant of A. viridis, using a freeze-dried aqueous extract in rats.
| Materials and Methods|| |
Adult Wistar strain male rats (200 - 225 g) from our colony were used (n = 30). They were maintained in an animal house under standard conditions (temperature: 28 - 31°C, photoperiod: approximately 12 hours natural light per day, and relative humidity: 50 - 55%) with free access to pelleted food (Ceylon Grain Elevators, Colombo, Sri Lanka) and drinking water. The experiment was conducted in accordance with the internationally accepted laboratory animal use and care, and guidelines and rules of the Department of Zoology, Faculty of Science, University of Colombo, Sri Lanka, of animal experimentation.
Collection of plants
Fresh plants were purchased from a vegetable market at Nugegoda, Colombo district, Sri Lanka, in June, 2011. The plant was identified and authenticated by Dr. (Ms) S. Ranawala, Department of Plant Science, University of Colombo, Sri Lanka. A voucher specimen (WDR / AMR 03 / 2011) was deposited at the Museum of the Department of Zoology, University of Colombo, Sri Lanka.
Preparation of hot water extract
The plants were washed thoroughly in tap water and were cut into small pieces. Sixty grams of these were added into 1920 ml of tap water and boiled slowly (about three hours) until the volume was reduced to 240 ml. The resulting reddish-brown colored extract was filtered using muslin cloth and the filtrate was freeze dried (for about five days) (yield: 0.90 w / w) and stored in airtight containers at 4 0 C. The freeze-dried hot water extract (HWE) was dissolved in 1 ml distilled water to obtain the desired concentrations (25, 50, and 100 mg / kg).
Evaluation of diuretic activity
Thirty rats were deprived of water, but not food for 18 hours. There urinary bladders were emptied by gentle compression of the pelvic area and by pull of their tails. Each of these rats was then orally administered with 15 ml isotonic saline (NaCl, 0.9% w / v) to impose a uniform water balance.  Forty-five minutes later, these rats were randomly assigned into five groups (n = six per group) and treated orally in the following manner. Group 1: With 1 ml of distilled water, Groups 2, 3, and 4: with 25, 50, 100 mg / kg of freeze-dried HWE, respectively, and Group 5: With 13 mg / kg of furosemide (State Pharmaceutical Corporation, Colombo, Sri Lanka), the reference drug.  Each of these rats was individually placed in metabolic cages and their cumulative urine output was determined at hourly intervals, for five hours. The color and the appearance of the urine were also noted.
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 and Discussion|| |
This study has examined the diuretic potential of the HWE of the whole plant of A. viridis, using a rat hydrated diuretic model. This model is validated, quick, reliable, sensitive, and widely used in assessing the diuretic potential of drugs. , The results obtained are depicted in [Table 1] and [Table 2]. As shown, none of the doses of HWE of A. viridis significantly (P < 0.05) increased the cumulative urine output, at five hours or at hourly intervals of five hours. This indicates that the HWE of A. viridis does not function as a diuretic, in contrast to its claimed effect as a diuretic, in traditional and folkloric medicine, in several countries. This is a novel, but an unexpected finding. On the other hand, the reference drug, furosemide, evoked a rapid (within one hour), marked (by 129%), and significant (P < 0.05) diuresis.
|Table 1: Cumulative urine output in rats over a five-hour period following oral administration of hot water extracts of Amaranthus viridis in rats.(mean ± SEM), (n = 6)|
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|Table 2: Time course of diuresis in rats treated with different doses of hot water extract of Amaranthus viridis up to five hours (mean ± SEM), (n = 6)|
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The doses of HWE of A. viridis used in this study were four times (100 mg / kg), double (50 mg / kg), and identical (25 mg / kg) to the human equivalent dose. Therefore, the absence of a diuretic effect of HWE cannot be attributed to an insufficient dosage. Lack of diuretic activity is unlikely to be due to freeze drying of the HWE, as several studies have used freeze dried plant extracts and shown traditionally claimed diuretic actions 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 HWE in rats.  Production of a metabolite, in rats, which overrides the diuretic activity of the HWE of A. viridisis is yet another possibility. In complete contrast, lack of diuretic activity of HWE in rats could be due to species specificity. For example, the root extracts of Withania somnifera and leaf extracts of
Ficus religiosa, which are claimed to possess aphrodisiac and anticonvulsant actions, respectively, in traditional medicine, have no such activities in rats.
| Conclusion|| |
The HWE of whole plant of A.viridis does not possess diuretic activity in rats, as is claimed in traditional and folkloric medicine.
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[Table 1], [Table 2]