Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA; Facultad de Ciencias de la Vida, Escuela Superior Politécnica del Litoral, Guayaquil, Ecuador.
Int J Parasitol Drugs Drug Resist. 2021 Apr;15:126-133. doi: 10.1016/j.ijpddr.2021.02.003. Epub 2021 Feb 18.
Cryptosporidium parvum is a protozoan parasite that infects intestinal epithelial cells causing malabsorption and severe diarrhea. The monoterpene thymol has been reported to have antifungal and antibacterial properties but less is known about the antiparasitic effect of this compound. Terpenes are sometimes unsuitable for therapeutic and food applications because of their instability. Esterification of terpenes eliminates this disadvantage. The present study evaluates the effects of thymol (Th) and a thymol ester, thymol octanoate (TO), against C. parvum infectivity in vitro. The cytotoxicity IC value for TO after 24 h of treatment was 309.6 μg/mL, significantly higher than that of Th (122.5 μg/mL) in a human adenocarcinoma cell line (HCT-8). In the same way, following 48 h of treatment, the cytotoxicity IC value for TO was significantly higher (139 μg/mL) than that of Th (75.5 μg/mL). These results indicate that esterification significantly reduces Th cytotoxicity. Dose-dependent effects were observed for TO and Th when both parasite invasion and parasite growth assays were evaluated. When evaluated for their activity against C. parvum growth cultured in vitro in HCT-8 cells, the anti-cryptosporidial IC values were 35.5 and 7.5 μg/mL, for TO and Th, respectively. Together, these findings indicate that esterified thymol has anti-cryptosporidial effect comparable with its parental compound thymol, but with improved safety margins in mammalian cells and better physicochemical properties that could make it more suitable for diverse applications as an antiparasitic agent.
微小隐孢子虫是一种感染肠道上皮细胞的原生动物寄生虫，导致吸收不良和严重腹泻。单萜百里香酚已被报道具有抗真菌和抗菌特性，但对该化合物的抗寄生虫作用知之甚少。萜类化合物由于其不稳定性，有时不适合治疗和食品应用。萜类化合物的酯化消除了这一缺点。本研究评估了百里香酚（Th）和百里香酚辛酸酯（TO）对体外微小隐孢子虫感染的影响。TO 在 24 h 治疗后对人结肠腺癌细胞系（HCT-8）的细胞毒性 IC 值为 309.6μg/mL，明显高于 Th（122.5μg/mL）。同样，在 48 h 治疗后，TO 的细胞毒性 IC 值（139μg/mL）明显高于 Th（75.5μg/mL）。这些结果表明酯化显著降低了 Th 的细胞毒性。当评估 TO 和 Th 对寄生虫入侵和寄生虫生长的影响时，观察到剂量依赖性效应。当评估它们对体外培养在 HCT-8 细胞中的微小隐孢子虫生长的活性时，TO 和 Th 的抗隐孢子虫 IC 值分别为 35.5 和 7.5μg/mL。这些发现表明酯化百里香酚具有与母体化合物百里香酚相当的抗隐孢子虫作用，但在哺乳动物细胞中的安全性边际改善，并且具有更好的物理化学性质，使其更适合作为驱虫剂的各种应用。
