Olanlokun J O, Bolaji O M, Agbedahunsi J M, Olorunsogo O O
Department of Biochemistry, Faculty of Science, Ekiti State University, Ado Ekiti, Nigeria.
Afr J Med Med Sci. 2012 Dec;41 Suppl:27-33.
Malaria, the most important parasitic disease afflicting man is the leading cause of mortality and morbidity in the world. Chemotherapy remains the mainstay for the treatment and prevention of the disease in the absence of an effective vaccine. The incidence of resistance of malaria parasites to chemotherapy is increasing and complicated. This study was therefore undertaken in order to evaluate the therapeutic effects of fractions of the stem bark of A. boonei on P. berghei-induced malaria using chloroquine as control. Different doses (200 mg/kg and 400 mg/kg body weight) of methanolic extract (ME), n-hexane (HF), chloroform (CF), ethylacetate(EF) and aqueous (AF) fractions of the stem bark of A. boonei were administered orally to albino mice. Five milligrammes chloroquine base per kilogramme body weight (5 mg/kg bw) was used as positive control while the negative control mice received only the vehicle (5% v/v tween 80). The results obtained showed that the 400 mg/kg bw dose was more effective with respect to the parasite clearance than the 200 mg/kg bw dose. The 400 mg/kg bw dose of ME gave 68.1% percent parasite clearance. The CF gave the highest clearance of 98.4% at 400 mg/kg bw after 7 days treatment while chloroquine at 5 mg/kg bw gave 100% parasite clearance. The order of increasing potency of the fractions (parasite clearance) was (EF 50.0% < AF 60.3% < HF 63.1%, < CF 98.4%) indicating that the active principle in the stem bark was highest in the CF. Percentage parasitemia following exposure to these fractions also decreased in all groups in the same order and was only significant (p < 0.05) in CF (0.11%) compared to the untreated control group. The ME of A. boonei also caused increase in PCV by 15.5%. Purification enhanced PCV value as the HF and CF fractions gave 19.0% and 24.5% increases, respectively. However, 31.5% increase in PCV was obtained in the albino mice treated with chloroquine. The EF and AF gave increase of 10.0% and 11.0% increase relative to the negative control treated mice. The high bioactivity of CF and HF indicate that the putative compound(s) in A. boonei are lipophillic and further purification could enhance greater activity. Further work is required to isolate the bioactive compound for a promising antimalarial drug from the chloroform fraction.
疟疾是困扰人类的最重要的寄生虫病，是全球死亡和发病的主要原因。在缺乏有效疫苗的情况下，化疗仍然是治疗和预防该疾病的主要手段。疟原虫对化疗的耐药性发生率正在上升且情况复杂。因此，本研究旨在以氯喹为对照，评估布氏非洲楝茎皮提取物各组分对伯氏疟原虫诱导的疟疾的治疗效果。将不同剂量（200毫克/千克和400毫克/千克体重）的布氏非洲楝茎皮甲醇提取物（ME）、正己烷提取物（HF）、氯仿提取物（CF）、乙酸乙酯提取物（EF）和水提取物（AF）口服给予白化小鼠。每千克体重5毫克氯喹碱（5毫克/千克体重）用作阳性对照，而阴性对照小鼠仅接受赋形剂（5% v/v吐温80）。所得结果表明，400毫克/千克体重剂量在清除寄生虫方面比200毫克/千克体重剂量更有效。400毫克/千克体重剂量的ME使寄生虫清除率达到68.1%。CF在400毫克/千克体重剂量下经7天治疗后清除率最高，为98.4%，而5毫克/千克体重的氯喹使寄生虫清除率达到100%。各组分（寄生虫清除率）效力增强的顺序为（EF 50.0% < AF 60.3% < HF 63.1% < CF 98.4%），表明茎皮中的活性成分在CF中含量最高。暴露于这些组分后，所有组的疟原虫血症百分比也按相同顺序下降，与未治疗的对照组相比，仅CF组（0.11%）有显著差异（p < 0.05）。布氏非洲楝的ME还使红细胞压积增加了15.5%。纯化提高了红细胞压积值，因为HF和CF组分分别使红细胞压积增加了19.0%和24.5%。然而，用氯喹治疗的白化小鼠红细胞压积增加了31.5%。相对于阴性对照处理的小鼠，EF和AF分别使红细胞压积增加了10.0%和11.0%。CF和HF的高生物活性表明，布氏非洲楝中的假定化合物是亲脂性的，进一步纯化可能会增强活性。需要进一步开展工作，从氯仿组分中分离出具有前景的抗疟药物的生物活性化合物。
