Evaluating the inhibitory effect of resveratrol on the multiplication of several Babesia species and Theileria equi on in vitro cultures, and Babesia microti in mice

Abstract

Introduction: Histone post-translational modification is one of the most studied factors influencing epigenetic regulation of protozoan parasite gene expression, which is mediated by histone deacetylases (KDACs) and acetyltransferases (KATs).Objective and methods: The present study investigated the role of resveratrol (RVT) as an activator of histone deacetylases in the control of various pathogenic Babesia sp. and Theileria equi in vitro, as well as B. microti infected mice in vivo using fluorescence assay. Its role in mitigating the side effects associated with the widely used antibabesial drugs diminazene aceturate (DA) and azithromycin (AZM) has also been investigated.Results: The in vitro growth of B. bovis, B. bigemina, B. divergens, B. caballi and Theileria equi (T. equi) was significantly inhibited (P < 0.05) by RVT treatments. The estimated IC50 values revealed that RVT has the greatest inhibitory effects on B. bovis growth in vitro, with an IC50 value of 29.51 ± 2.46 µM. Reverse transcription PCR assay showed that such inhibitory activity might be attributed to resveratrol’s stimulatory effect on B. bovis KDAC3 (BbKADC3) as well as its inhibitory effect on BbKATS. RVT causes a significant decrease (P < 0.05) in cardiac troponin T (cTnT) levels in heart tissue of B. microti- infected mice, thereby indicating that RVT may play a part in reducing the cardiotoxic effects of AZM. Resveratrol showed an additive effect with imidocarb dipropionate in vivo. Treatment of B. microti-infected mice with a combined 5 mg/kg RVT and 8.5 mg/kg ID resulted in an 81.55% inhibition at day 10 postinoculation (peak of parasitemia).Conclusion: Our data show that RVT is a promising antibabesial pharmacological candidate with therapeutic activities that could overcome the side effects of the currently used anti-Babesia medications.

Antiparasitic activity of FLLL-32 against four Babesia species, B. bovis, B. bigemina, B. divergens and B. caballi, and one Theileria species, Theileria equi in vitro, and Babesia microti in mice

“…On the fourth day of treatment, the viability assay was carried out by mixing 1.5 μL of the control or FLLL32-treated infected RBCs with 3.5 μL of parasite-free RBCs, suspending the mixture in fresh growth medium without the addition of drugs, and incubating the mixture at 37 °C for the following 4 days without changing the medium (Rizk et al, 2016). The IC 50 values of FLLL32 were calculated using the non-linear regression curve fit in GraphPad Prism 5.0 (GraphPad Software, Inc., San Diego, CA, United States) (Rizk et al, 2016;Rizk et al, 2017;Rizk et al, 2019;Rizk et al, 2021a;Rizk et al, 2021b;El-Sayed et al, 2023).…”

“…Reverse transcription-PCR (RT-PCR) was used to assess the effect of FLLL-32 treatment on the mRNA transcription of the target B. bovis genes including S-adenosylhomocysteine hydrolase (BbSAHH) and the Histone deacetylase (BbHDAC3) (El-Sayed et al, 2023). Babesia bovis was grown in bovine RBCs on 24-well culture plates (Nunc, Roskilde) as previously described and was treated for 8 h with FLLL-32 at the 99% inhibitory concentration (IC99) (18.94 μM) and 0.1% DMSO as a negative control.…”

“…After staining with ethidium bromide, the amplified products were electrophoresed on 2.0% (w/v) agarose gels and visualized with a UV transilluminator (Nippon Gene, Tokyo, Japan). Gel electrophoresis bands were analyzed using ImageJ software (Schadich et al, 2012;El-Sayed et al, 2023).…”