Adia Madina Mohamed, Emami Seyedeh Noushin, Byamukama Robert, Faye Ingrid, Borg-Karlson Anna-Karin
Department of Chemistry, Makerere University, P.O. Box 7062, Kampala, Uganda.
Department of Molecular Biosciences, The Wenner-Gren Institute (MBW) Stockholm University, Stockholm, Sweden.
J Ethnopharmacol. 2016 Jun 20;186:14-19. doi: 10.1016/j.jep.2016.03.047. Epub 2016 Mar 24.
Resistance of the parasites to known antimalarial drugs has provided the necessity to find new drugs from natural products against malaria. The aim of the study was to evaluate the in vitro antiplasmodial activity of some plants used by Traditional Medical Practitioners (TMPs) of Prometra and Rukararwe in malaria treatment in Uganda to provide scientific proof of the efficacies claimed by these Herbalists.
The air dried samples of Clerodendrum rotundifolium (leaves), Microglossa pyrifolia (leaves), Momordica foetida (leaves) and Zanthoxylum chalybeum (stem bark) used for malaria treatment by TMPs were successively extracted with ethyl acetate, methanol and water to yield twelve extracts. The extracts were tested against the chloroquine-sensitive (NF54) and chloroquine-resistant (FCR3) Plasmodium falciparum strains in vitro using the micro Mark III test which is based on assessing the inhibition of schizont maturation. A compound A was extracted and purified from the stem bark of Z. chalybeum and its structure was identified and confirmed by spectroscopic methods.
Most of the extracts tested (92%) showed an antiplasmodial activity with IC50<50µg/mL. In spite of successive extractions with different solvents, potent anti-plasmodial activity (IC50<5µg/mL) was observed in the ethyl acetate, methanol and aqueous extracts of M. pyrifolia and C. rotundifolium. Preferential enrichments of activity into water (IC50<15µg/mL) and Ethyl acetate (IC50<5µg/mL) were seen in the case of M. foetida and Z. chalybeum respectively. The most active extracts were from C. rotundifolium and M. pyrifolia with IC50 values less than 2µg/mL. Phytochemical analysis of the extracts revealed the presence of saponins, tannins, flavonoids, alkaloids and cardiac glycocides. Fagaramide isolated from Z. chalybeum had a higher activity (IC50 2.85µg/mL) against the chloroquine-resistant strain than against the chloroquine-senstive (IC50 16.6µg/mL) strain used in the study.
The plant extracts analysed in this study presented an average antiplasmodial activity (58%). This study revealed for the first time the antiplasmodial activity of the plant C. rotundofolium. It's the first time the compound fagaramide (N-isobutyl-3-(3,4-methylene dioxyphenyl)-2E-propenamide) has been isolated from Z. chalybeum as one of the compounds that contribute to the activity of this plant against P. falciparum.
疟原虫对已知抗疟药物产生耐药性，这使得有必要从天然产物中寻找抗疟疾新药。本研究的目的是评估乌干达普罗梅特拉和鲁卡拉尔韦的传统医学从业者（TMPs）用于治疗疟疾的某些植物的体外抗疟活性，以提供这些草药师所宣称疗效的科学证据。
TMPs用于治疗疟疾的圆叶大青（叶）、毛果小舌菊（叶）、恶臭苦瓜（叶）和灰毛花椒（茎皮）的风干样品，依次用乙酸乙酯、甲醇和水进行提取，得到12种提取物。使用基于评估裂殖体成熟抑制的微型Mark III试验，在体外对提取物进行氯喹敏感（NF54）和氯喹耐药（FCR3）恶性疟原虫菌株测试。从灰毛花椒茎皮中提取并纯化了化合物A，通过光谱方法鉴定并确认了其结构。
测试的大多数提取物（92%）显示出抗疟活性，IC50<50μg/mL。尽管用不同溶剂进行了连续提取，但在毛果小舌菊和圆叶大青的乙酸乙酯、甲醇和水提取物中观察到了强效抗疟活性（IC50<5μg/mL）。对于恶臭苦瓜和灰毛花椒，活性分别优先富集到水（IC50<15μg/mL）和乙酸乙酯（IC50<5μg/mL）中。活性最强的提取物来自圆叶大青和毛果小舌菊，IC50值小于2μg/mL。提取物的植物化学分析表明存在皂苷、单宁、黄酮类、生物碱和强心苷。从灰毛花椒中分离出的法加酰胺对氯喹耐药菌株的活性（IC50 2.85μg/mL）高于对本研究中使用的氯喹敏感菌株（IC50 16.6μg/mL）的活性。
本研究中分析的植物提取物呈现出平均抗疟活性（58%）。本研究首次揭示了圆叶大青的抗疟活性。这是首次从灰毛花椒中分离出化合物法加酰胺（N-异丁基-3-(3,4-亚甲二氧基苯基)-2E-丙烯酰胺），作为该植物对恶性疟原虫具有活性的化合物之一。
