Identification of Essential Oils Including Garlic Oil and Black Pepper Oil with High Activity against <i>Babesia duncani</i>

• Main Authors: Yumin Zhang, Chunxiang Bai, Wanliang Shi, Hector Alvarez Manzo, Ying Zhang
• Format: Article
• Language: English
• Published: MDPI AG 2020-06-01
• Series: Pathogens
• Subjects: Babesia duncani; essential oil screen; garlic oil; black pepper oil; diallyl disulfide (DADS); β-caryophyllene (BCP)
• Online Access: https://www.mdpi.com/2076-0817/9/6/466

Some evidence indicated that human babesiosis caused by <i>Babesia duncani</i> has spread widely in North America. However, current therapeutic regimens (atovaquone + azithromycin) for human babesiosis are suboptimal with frequent recrudescence and side effects, and furthermore, there is no specific treatment for human babesiosis caused by <i>B. duncani</i>. Here, we screened 97 essential oils and identified 10 essential oils (garlic, black pepper, tarragon, palo santo, coconut, pine, meditation, cajeput, moringa, and stress relief) at a low concentration (0.001%; v/v) that showed good inhibitory activity against <i>B. duncani</i> in the hamster red blood cell culture model. Among them, garlic oil and black pepper oil performed best, as well as their potential active ingredients diallyl disulfide (DADS) and β-caryophyllene (BCP), respectively. Interestingly, further subculture study indicated that <i>B. duncani</i> could relapse after treatment with current therapeutic drugs atovaquone or azithromycin even at high concentrations. In contrast, the combination of garlic oil or DADS and azithromycin showed eradication of <i>B. duncani</i> at low concentrations without regrowth. These results are encouraging and suggest that the garlic-derived sulfur compound DADS and β-caryophyllene (BCP) may be promising drug candidates for evaluation of their ability to cure persistent <i>B. duncani</i> infections in the future.