Bunalema Lydia, Fotso Ghislain Wabo, Waako Paul, Tabuti John, Yeboah Samuel O
Department of Pharmacology and Therapeutics, College of Health Sciences, Makerere University, P.O Box 7072, Kampala, Uganda.
Department of Organic Chemistry, Faculty of Science, University of Yaoundé I, P.O Box 812, Yaoundé, Cameroon.
BMC Complement Altern Med. 2017 Feb 2;17(1):89. doi: 10.1186/s12906-017-1602-x.
Tuberculosis (TB) is still a global health problem mainly due to development of resistance and co-infection with the Human immune Virus (HIV). Treatment of multi and extensively drug resistant TB requires use of second line drugs which are less efficacious, expensive and very toxic. This has necessitated a need to search for new treatment regimens especially from medicinal plants. Zanthoxylum leprieurii, a plant species from Rutaceae is used locally in the treatment of tuberculosis in Uganda. The aim of the study was to isolate, identify and characterize bio active compounds from Z. leprieurii stem bark with antimycobacterial activity.
Crude extracts, fractions and compounds from air dried stem bark of Z. leprieurii were tested against pan sensitive (H37rv), isoniazid resistant (TMC 301) and rifampicin resistant (TMC 331) strains of M. tuberculosis using micro plate alamar blue assay. Isolation of active compounds was done by using column chromatography and thin layer chromatography. They were analysed using nuclear magnetic resonance spectroscopy and mass spectroscopy.
The methanol extract had minimum inhibitory concentrations (MIC) of 47.5, 75.3 and 125.0 μg/ml on the pan sensitive strain, rifampicin resistant and isozianid resistant strains of M. tuberculosis respectively. The chloroform extract had MIC values of 260 μg/ml agnaist the pan sensitive strain and 156 μg/ml on the rifampicin resistant strain. Of the sixteen fractions from the methanol extract, fraction Za (MIC = 6.3 μg/mL, 23.0 μg/mL, 11.7 μg/mL) and Za (MIC = 11.7 μg/mL 31.2 μg/ml, 31.2 μg/ml) were the most active. Three acridone alkaloids; hydroxy-1, 3-dimethoxy-10-methyl-9-acridone (1), 1-hydroxy-3-methoxy-10-methyl-9-acridone (2) and 3-hydroxy-1, 5, 6-trimethoxy-9-acridone (3) were isolated from Za and Za. The MIC of compound 3 was found to be 5.1 μg/ml, 4.5 μg/ml and 3.9 μg/ml on H37rv, TMC 331 and TMC 301 while that of 1 was found to be 1.5 μg/ml, 8.3 μg/ml and 3.5 μg/ml respectively.
The results of this study suggest that Z. leprieurii is active on resistant strains of M. tuberculosis and could be a potential source of new leads against resistant tuberculosis. It also verifies the local use of the plant in treatment of tuberculosis.
结核病仍然是一个全球性的健康问题，主要原因是耐药性的产生以及与人类免疫缺陷病毒（HIV）的合并感染。治疗多重耐药和广泛耐药结核病需要使用二线药物，这些药物疗效较差、价格昂贵且毒性很大。这就需要寻找新的治疗方案，特别是从药用植物中寻找。刺花椒是芸香科的一种植物，在乌干达当地被用于治疗结核病。本研究的目的是从刺花椒茎皮中分离、鉴定和表征具有抗分枝杆菌活性的生物活性化合物。
采用微孔板阿尔玛蓝法，对刺花椒风干茎皮的粗提物、馏分和化合物进行了针对结核分枝杆菌的泛敏感菌株（H37rv）、耐异烟肼菌株（TMC 301）和耐利福平菌株（TMC 331）的测试。通过柱色谱和薄层色谱法分离活性化合物。使用核磁共振光谱和质谱对它们进行分析。
甲醇提取物对结核分枝杆菌的泛敏感菌株、耐利福平菌株和耐异烟肼菌株的最低抑菌浓度（MIC）分别为47.5、75.3和125.0μg/ml。氯仿提取物对泛敏感菌株的MIC值为260μg/ml，对耐利福平菌株的MIC值为156μg/ml。在甲醇提取物的16个馏分中，馏分Za（MIC = 6.3μg/mL、23.0μg/mL、11.7μg/mL）和Za（MIC = 11.7μg/mL、31.2μg/ml、31.2μg/ml）活性最强。从Za和Za中分离出三种吖啶酮生物碱；羟基-1,3 - 二甲氧基-10 - 甲基-9 - 吖啶酮（1）、1 - 羟基-3 - 甲氧基-10 - 甲基-9 - 吖啶酮（2）和3 - 羟基-1,5,6 - 三甲氧基-9 - 吖啶酮（3）。化合物3对H37rv、TMC 331和TMC 301的MIC分别为5.1μg/ml、4.5μg/ml和3.9μg/ml，而化合物1的MIC分别为1.5μg/ml、8.3μg/ml和3.5μg/ml。
本研究结果表明，刺花椒对结核分枝杆菌的耐药菌株具有活性，可能是抗耐药结核病新先导化合物的潜在来源。这也证实了该植物在当地治疗结核病中的应用。
