Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland.
Department of Chemistry of Natural Products, Medical University of Lublin, 20-093, Lublin, Poland.
Phytochemistry. 2023 Sep;213:113770. doi: 10.1016/j.phytochem.2023.113770. Epub 2023 Jun 16.
Bioactivity-guided isolation of natural products from plant matrices is widely used in drug discovery. Here, this strategy was applied to identify trypanocidal coumarins effective against the parasite Trypanosoma cruzi, the etiologic agent of Chagas disease (American trypanosomiasis). Previously, phylogenetic relationships of trypanocidal activity revealed a coumarin-associated antichagasic hotspot in the Apiaceae. In continuation, a total of 35 ethyl acetate extracts of different Apiaceae species were profiled for selective cytotoxicity against T. cruzi epimastigotes over host CHO-K1 and RAW264.7 cells at 10 μg/mL. A flow cytometry-based T. cruzi trypomastigote cellular infection assay was employed to measure toxicity against the intracellular amastigote stage. Among the tested extracts, Seseli andronakii aerial parts, Portenschlagiella ramosissima and Angelica archangelica subsp. litoralis roots exhibited selective trypanocidal activity and were subjected to bioactivity-guided fractionation and isolation by countercurrent chromatography. The khellactone ester isosamidin isolated from the aerial parts of S. andronakii emerged as a selective trypanocidal molecule (selectivity index ∼9) and inhibited amastigote replication in CHO-K1 cells, though it was significantly less potent than benznidazole. The khellactone ester praeruptorin B and the linear dihydropyranochromones 3'-O-acetylhamaudol and ledebouriellol isolated from the roots of P. ramosissima were more potent and efficiently inhibited the intracellular amastigote replication at < 10 μM. The furanocoumarins imperatorin, isoimperatorin and phellopterin from A. archangelica inhibited T. cruzi replication in host cells only in combination, indicative of superadditive effects, while alloimperatorin was more active in fractions. Our study reports preliminary structure-activity relationships of trypanocidal coumarins and shows that pyranocoumarins and dihydropyranochromones are potential chemical scaffolds for antichagasic drug discovery.
基于生物活性的植物源天然产物分离广泛应用于药物发现。在此，我们应用该策略来鉴定对寄生虫克氏锥虫（恰加斯病（美洲锥虫病）的病原体）具有杀锥虫活性的香豆素。此前，杀锥虫活性的系统发育关系揭示了伞形科中与抗恰加斯病活性相关的香豆素热点。在此基础上，对 35 种不同伞形科植物的乙酸乙酯提取物进行了分析，以确定其在 10μg/mL 浓度下对 T. cruzi 滋养体相对于宿主 CHO-K1 和 RAW264.7 细胞的选择性细胞毒性。采用基于流式细胞术的 T. cruzi 锥虫细胞感染试验来测量对细胞内无鞭毛体阶段的毒性。在所测试的提取物中，Seseli andronakii 的地上部分、Portenschlagiella ramosissima 和 Angelica archangelica subsp. litoralis 的根表现出选择性杀锥虫活性，并通过逆流色谱进行了基于生物活性的分离和分离。从 S. andronakii 的地上部分分离出的开链酮酯异沙米丁是一种选择性杀锥虫分子（选择性指数约为 9），可抑制 CHO-K1 细胞中的无鞭毛体复制，但它的活性明显低于苯并咪唑。从 P. ramosissima 的根部分离出的开链酮酯praeruptorin B 和线性二氢吡喃并色酮 3'-O-乙酰哈马多醇和 ledebouriellol 更为有效，在 <10μM 时可有效抑制细胞内无鞭毛体的复制。从 A. archangelica 中分离出的呋喃香豆素，如花椒毒素、异花椒毒素和补骨脂素，仅在联合用药时才抑制宿主细胞中的 T. cruzi 复制，表明存在增效作用，而 alloimperatorin 在各部分中更为活跃。本研究报告了杀锥虫香豆素的初步结构-活性关系，并表明吡喃香豆素和二氢吡喃并色酮是抗恰加斯病药物发现的潜在化学支架。
