Inhibitory effect of naphthoquine phosphate on Babesia gibsoni in vitro and Babesia rodhaini in vivo

• Published in: Parasites & vectors 2022-01, Vol.15 (1), p.10-10, Article 10
• Main Authors: Ji, Shengwei, Liu, Mingming, Galon, Eloiza May, Rizk, Mohamed Abdo, Tuvshintulga, Bumduuren, Li, Jixu, Zafar, Iqra, Hasegawa, Yae, Iguchi, Aiko, Yokoyama, Naoaki, Xuan, Xuenan
• Format: Article
• Language: English
• Subjects: 1-Naphthylamine - analogs & derivatives; 1-Naphthylamine - pharmacology; 1-Naphthylamine - therapeutic use; Aminoquinolines - blood; Aminoquinolines - pharmacology; Aminoquinolines - therapeutic use; Anemia; Animals; Antimalarial agents; Antimalarials; Antiprotozoal Agents - blood; Antiprotozoal Agents - pharmacology; Antiprotozoal Agents - therapeutic use; Artemisinin; Babesia; Babesia - drug effects; Babesia - growth & development; Babesia gibsoni; Babesia rodhaini; Babesiosis; Babesiosis - blood; Babesiosis - drug therapy; Babesiosis - parasitology; Biocompatibility; Body weight; Cytochrome; Drug resistance; Drug resistance in microorganisms; Drug therapy; Drugs; Fluorescence; Growth; Hematocrit; Hematology; In vitro; In vitro methods and tests; In vivo; In vivo methods and tests; Infections; Inhibitory Concentration 50; Malaria; Mice; Mice, Inbred BALB C; Naphthoquine phosphate; Oral administration; Parasite resistance; Parasitemia; Parasitemia - parasitology; Parasites; Pharmaceutical research; Phosphates; Random Allocation; Short Report; Side effects; Stains & staining; Survival; Testing; Variance analysis
• ISSN: 1756-3305; 1756-3305
• DOI: 10.1186/s13071-021-05127-0

Drug resistance and toxic side effects are major challenges in the treatment of babesiosis. As such, new drugs are needed to combat the emergence of drug resistance in Babesia parasites and to develop alternative treatment strategies. A combination of naphthoquine (NQ) and artemisinin is an antimalarial therapy in pharmaceutical markets. The present study repurposed NQ as a drug for the treatment of babesiosis by evaluating the anti-Babesia activity of naphthoquine phosphate (NQP) alone. An in vitro growth inhibition assay of NQP was tested on Babesia gibsoni cultures using a SYBR Green I-based fluorescence assay. In addition, the in vivo growth inhibitory effect of NQP was evaluated using BALB/c mice infected with Babesia rodhaini. The parasitemia level and hematocrit values were monitored to determine the therapeutic efficacy of NQP and the clinical improvements in NQP-treated mice. The half maximal inhibitory concentration of NQP against B. gibsoni in vitro was 3.3 ± 0.5 μM. Oral administration of NQP for 5 consecutive days at a dose of 40 mg/kg of body weight resulted in significant inhibition of B. rodhaini growth in mice as compared with that of the control group. All NQP-treated mice survived, whereas the mice in the control group died between days 6 and 9 post-infection. This is the first study to evaluate the anti-Babesia activity of NQP in vitro and in vivo. Our findings suggest that NQP is a promising drug for treating Babesia infections, and drug repurposing may provide new treatment strategies for babesiosis.