Concurrent administration of aqueous Azadirachta indica (neem) leaf extract with DOCA-salt prevents the development of hypertension and accompanying electrocardiogram changes in the rat

The effect of concurrent administration of Azadirachta indica leaf extract with DOCA-salt was investigated in the development of hypertension.Over 5-6 week old, inbred male Wistar rats with a starting weight of 190 g were given either: (1) twice weekly subcutaneous (s.c.) injections of vehicle (soyabean oil, 0.25 mL per animal) for the first 2 weeks, plus normal drinking water (controls); (2) twice weekly (s.c.) injections (weeks 1 and 2 only) of 15 mg/kg DOCA dissolved in vehicle, plus drinking water containing 1.0% NaCl and 0.03% KCl (DOCA-salt group); or (3) 20 mg/kg of aqueous neem extract daily, in addition to the DOCA-salt treatment (DOCA-salt-neem group). All groups (8-12 animals) received normal rat pellets ad libitum and their BP was measured weekly. Terminally, the animals were anaesthetized and ECGs recorded using s.c. pins in a lead II configuration.The mean arterial pressure was significantly lower (p < 0.05) in the control (97 +/- 3.7 mmHg) and DOCA-salt-neem (87 +/- 3.4 mm Hg) groups than in the DOCA-salt group (115 +/- 7.1 mm Hg). PR and RR intervals and the duration of the QRS complex were shorter (p < 0.05) in the DOCA-salt group than in the control and DOCA-salt-neem groups. Amplitude of the QRS complex was increased (p < 0.05) in the DOCA-salt group compared with both the DOCA-salt-neem and the control groups.Daily administration of 20 mg/kg neem-leaf extract concurrently with DOCA-salt for 5 weeks, prevents the development of hypertension and the accompanying alterations in the ECG patterns seen in DOCA-salt treated rats.