Inhibitory effects of pepstatin A and mefloquine on the growth of Babesia parasites.

Tserendorj Munkhjargal, Mahmoud AbouLaila, Mohamad Alaa Terkawi, Thillaiampalam Sivakumar, Madoka Ichikawa, Batdorj Davaasuren, Tserendorj Nyamjargal, Naoaki Yokoyama, Ikuo Igarashi

The American journal of tropical medicine and hygiene 2012 Oct

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We evaluated the inhibitory effects of pepstatin A and mefloquine on the in vitro and in vivo growths of Babesia parasites. The in vitro growth of Babesia bovis, B. bigemina, B. caballi, and B. equi was significantly inhibited (P < 0.05) by micromolar concentrations of pepstatin A (50% inhibitory concentrations = 38.5, 36.5, 17.6, and 18.1 μM, respectively) and mefloquine (50% inhibitory concentrations = 59.7, 56.7, 20.7, and 4 μM, respectively). Furthermore, both reagents either alone at a concentration of 5 mg/kg or in combinations (2.5/2.5 and 5/5 mg/kg) for 10 days significantly inhibited the in vivo growth of B. microti in mice. Mefloquine treatment was highly effective and the combination treatments were less effective than other treatments. Therefore, mefloquine may antagonize the actions of pepstatin A against babesiosis and aspartic proteases may play an important role in the asexual growth cycle of Babesia parasites.

Citation

Tserendorj Munkhjargal, Mahmoud AbouLaila, Mohamad Alaa Terkawi, Thillaiampalam Sivakumar, Madoka Ichikawa, Batdorj Davaasuren, Tserendorj Nyamjargal, Naoaki Yokoyama, Ikuo Igarashi. Inhibitory effects of pepstatin A and mefloquine on the growth of Babesia parasites. The American journal of tropical medicine and hygiene. 2012 Oct;87(4):681-8