The study determine the in vivo antiplasmodial potential and protective properties of Azadirachta indica (Dongoyaro) ethanolic stem bark extract in mice infected with Plasmodium berghei NK65. The GC-MS, qualitative, quantitative and antioxidant scavenging activities of the stem bark extract of A. indica were determined using standard procedure. The acute toxicity and in vivo antiplasmodial activities of the extract were investigated in mice induce with P. berghei NK65. GC-MS assay of the stem bark revealed the presence of twenty one different compounds. The amount of flavonoids, alkaloids, total proanthocyanidins and total phenol present in the stem extract are: 0.97 %, 3.6 %, 0.53Â±0.07 mg quercetin/g of A. indica and 103.14 mg PE/g DW respectively. The in vitro antioxidant assay of A. indica ethanolic stem bark extract showed FRAP, H2O2, GSH, SOD%, and DPPH scavenging activities. A. indica stem extract contains Î²-carotene, vitamin A and lycopene. The median lethal dose (LD50) calculated was greater than 5000mg/kg body weight. The study consists of seven different groups of seven mice in each group. Group: 1, II, III and IV were healthy mice, infected mice without treatment, infected mice that were treated with chloroquine (10 mg/kg), mixture of chloroquine (10 mg/kg) and folic acid (10mg/mL) respectively. Group: V, VI and VII were infected mice treated with 250, 500 and 750 mg/kg body weight of A. indica ethanolic stem bark extract respectively. A. indica ethanolic stem bark extract showed a dose-dependent reduction of parasitemia in experimental mice. The highest dose of 750 mg/kg body weight, demonstrated high antiplasmodial activity of 69.60 %, 84.53 % and 78.04 % for repository, suppressive and curative test respectively. The result was significant when compared to negative control, though it was lower than that exhibited by CQ (87.28 %, 92.31 %, and 90.35 %) and CQ + FA (88.53 %, 92.64 %, and 91.00 %) for repository, suppressive and curative test respectively. Hematological parameters showed that A. indica possess hematopoietic activity and is not toxic since it significantly (P<0.05) increase HCT, HGB and RBC parameters. There were significant (P<0.0001) increase in plasma uric acid, ALT, AST and a decrease in albumin and total protein values in the untreated infected mice compared to the mice treated with the stem extract. GSH, SOD % inhibition, vitamin A and total protein values were significantly (P<0.0001) decreased in the liver homogenate while MDA values was significantly (P<0.0001) increased in group II mice compared to treated mice for both suppressive and curative test. A. indica possesses antioxidant and antimalarial activities in mice infected with P. berghei NK65.
Keywords: Azadirachta indica, antiplasmodial potential, antioxidant properties, Plasmodium berghei NK 65, Swiss mice.