Four isocedrenes (1: - 4: ), including one new compound (2: ), were isolated from an ethanolic extract of the aerial parts of Perezia multiflora by bioactivity-guided fractionation. For compounds 1: and 3: , a revised stereochemical assignment is proposed based on molecular modeling studies using DFT-NMR calculations. Antiparasitic activity of the four compounds was evaluated using an in vitro culture of Plasmodium falciparum and axenic amastigotes of Leishmania infantum. IC50 values ranged from 0.81 to 16.1 µM (P. falciparum) and 0.16 to 2.03 µM (L. infantum). Toxicity was evaluated against J774A.1 mouse macrophages or human macrophages generated from THP-1 monocytic cells (IC50 values ranging from 0.16 to 2.64 µM). Compound 4: exhibited weak selectivity against P. falciparum with a selectivity index (SI = CC50/IC50) of 3. No selectivity was observed for compounds 1: - 3: against both parasites.

中文翻译：

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来自 Perezia multiflora 的生物活性异油烯

通过生物活性引导的分馏，从多花草的地上部分的乙醇提取物中分离出四种异香树烯 (1: - 4: )，包括一种新化合物 (2: )。对于化合物 1: 和 3: ，基于使用 DFT-NMR 计算的分子建模研究提出了修正的立体化学分配。使用恶性疟原虫和婴儿利什曼原虫的无菌无鞭毛体的体外培养物评估了四种化合物的抗寄生虫活性。IC50 值范围为 0.81 至 16.1 µM（恶性疟原虫）和 0.16 至 2.03 µM（婴儿乳杆菌）。针对 J774A.1 小鼠巨噬细胞或由 THP-1 单核细胞产生的人类巨噬细胞评估毒性（IC50 值范围为 0.16 至 2.64 µM）。化合物 4：对恶性疟原虫表现出弱选择性，选择性指数 (SI = CC50/IC50) 为 3。