Oral diuretic activity of hot water infusion of Sri Lankan black tea (Camellia sinensis L.) in rats

Abstract

Background:Black tea [Camellia sinensis (L.) O. Kuntze (family: Theaceae)] has been used by Sri Lankan traditional practitioners to promote diuresis. However, the type and grade of tea is not specified.Materials and Methods:This study investigates the diuretic activity of black tea infusion (BTI) in rats using Broken Orange Pekoe Fannings (BOPF) grade from major agroclimatic elevations: high-, mid-, and low-grown. Different concentrations of BTI, furosemide (positive control), and water (vehicle) were orally administered to starved (18 h) male rats (n = 9/group), then hydrated. Acute and chronic (28 days) diuretic activities were assessed by measuring cumulative urine output at hourly intervals for 6 h. Electrolyte levels (Na+, K+, Ca2+, H+, Cl−, HCO3−), pH, osmolarity of urine, and glomerular filtration rate (GFR) of treated rats were determined.Results:Administration of BTI induced a significant (P < 0.05) and dose-dependent diuretic activity, which varied with the tea produced in different agroclimatic elevations. Diuretic activity had a rapid onset (1st h), peaked at 2nd h and maintained up to 4th h (except the low dose). Furthermore, there was a dose-dependent increase in micturition frequency, which peaked at 2nd h. A close association between the caffeine content of tea and diuretic activity was evident. BTI-induced diuresis was accompanied with an increased urine Na+ level and GFR. The diuretic activity of BTI was mediated via multiple mechanisms: inhibition of both aldosterone secretion (with increased Na+/K+ ratio) and carbonic anhydrase [with decreased Cl−/(Na+ + K+) ratio] and via thiazide type of diuretic action (evaluated with increased Na+/Cl− ratio).Conclusion:The Sri Lankan BOPF grade black tea possesses mild oral diuretic activity whose efficacy differs with the agroclimatic elevation of production. Furthermore, it supports the traditional claim that the black tea acts as a diuretic.

Aqueous Extract of <i>Flueggea leucopyrus</i> Increases Urine Output in Rats

“…45 min later, these rats were randomly divided into five equal groups (n = 6 per group) and treated orally in the following manner, (Group 1) 1 mL of 500 mgkg -1 of FLAE; (Group 2) 1 mL of 1000 mgkg -1 of FLAE; (Group 3) 1 mL of 1500 mgkg -1 of FLAE; (Group 4) 1 mL of distilled water; (Group 5) 1 mL of 13 mgkg -1 of furosemide. Each of these rats was individually placed in metabolic cages and cumulative urine output was determined at hourly intervals over 6 h. To investigate the possible mode of action, the urine collected from group III (1500 mgkg -1 ) and group IV (water control) were subjected to further investigations [11][12][13][14].…”

“…Examination of serum urea and creatinine (to examine renal toxicity), alanine transaminase (ALT) and aspartate transaminase (AST) (to examine liver toxicity), were made using respective kits [8][9][10][11][12][13][14].…”

“…Creatinine clearance was computed as per instructions given by the manufacturer using data obtained. Creatinine clearance was taken as an estimation of the glomerular filtration rate [11][12][13][14].…”

A review of studies on bioactive compounds isolated from Sri Lankan flora

“…This anti-inflammatory activity was dose-dependent in the carrageenan-induced paw oedema test and cotton pellet granuloma test. Further, in the carrageenan paw oedema model, the anti-inflammatory activity of BTB was almost identical to the green tea brew of both Chinese and Japanese types (Ratnasooriya & Fernando, 2009). …”

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

“…[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.…”