ABSTRACT

Terminalia catappa L. commonly called Indian almond is a large spreading tree native to the coastal region of India. It is commonly called ukwu frutu in the southeast part of Nigeria and has been reported to possess a lot of pharmacological activities. This study was designed to investigate the in-vitro antioxidant and in-vivo diuretic activity of ethanol extract of Terminalia catappa L. in wistar albino rats. Ethanol extraction of the leaves by maceration yielded 9.8%w/w. Eighteen (18) Wistar albino rats were randomly selected and divided into nine (9) groups of two (2) rats each. Group one served as normal control (Received normal saline only). Four groups of two rats each (Group VI,VII,VIII,IX) were treated with the plant extract (500mg/kg, 250mg/kg, 125mg/kg and 62.5mg/kg) respectively, while the four remaining groups (group II,III,IV,V) served as positive control receiving furosemide, acetazolamide, hydrochiorothiazide and spironolactone respectively. The diuretic activity was carried out with slight modifications to methods described by Lipchitz. Anti-oxidant studies were conducted in-vitro using spectrophotometric investigation of DPPH radical scavenging, anti-lipid peroxidation and nitric oxide inhibition activity. Results of the diuretic study shows a significant (p<O.OS) increase in urine volume and electrolytes (Nat, K, CL and HCO3 ). Urine volume increased from 1.8 ± 0.14 in normal control to 6.35 ± 0.35 for 500mg/kg extract, 8.8 ± 0.4 in furosemide, 5.20 ± 0.14 in acetazolamide, 5.7 ± 0.14 in hydrochiorothiazide, and 3.40 ± 0.28 in spironolactone treated groups. Sodium ion concentration increased from 96.00 ± 1.84 in normal control to 154.90 ± 1.84 for 500mg/kg extract, 180.30 ± 3.25 for furosemide, 146.85 ± 2.90 for acetazolamide, 146.85 ± 2.90 for hydrochiorothiazide, and 134.55 ± 1.91 for spironolactone treated groups. Also potassium ion increased from 9.2 ± 0.42 in normal control to 20.95 ± 2.05 for 500mg/kg extract, 25.35 ± 2.19, 17.95 ± 2.05, 19.40 ± 0.99, 20.95 ± 2.05, in furosemide, acetazolamide, hydrochiorothiazide and spironolactone treated groups respectively. Furthermore, chloride ion increased from 86.80 ± 2.26 in normal control to 144.60 ± 3.11 in 500mg/kg extract, 169.95 ± 2.76, 139.50 ± 2.40, 141.60 ± 3.11, 124.20 ± 1.84 in furosemide, acetazolamide, hydrochiorothiazide and spironolactone treated groups. A significant (p<0.05) difference in bicarbonate ion exists between the test groups and controls with the highest concentration produced by acetazolamide and 500mg/kg extract. The diuretic activity increased with an increase in dose when compared between the treated groups. Results of anti-oxidant study for .DPPH radical scavenging activity, Antilipid peroxidation and nitric oxide inhibition activity at 100mg/ml was 51.80 ± 2.86, 43.23 ± 5.24, 50.03 ± 1.18 respectively when compared to the standard at 100mg/kg 97.43 ± 0.32, 98.13 ± 0.14, 98.80 ± 0.32, respectively. .The percentage inhibition increased with increasing concentration of extract. From the result, it can be inferred that the leaves of Terminalia catappa may possess anti-oxidant activity and also diuretic activity in fashion similar to hydrochiorothiazide based on the amount of urine, sodium, potassium, chloride, and bicarbonate ion voided. These pharmacological activities of Terminalia catappa can be of importance in development of novel therapeutics for the management of cardiovascular and renal disorders.