In vitro growth inhibitory efficacy of some target specific novel drug molecules against Theileria equi.

This research evaluates the effectiveness of certain drug molecules at inhibiting the growth of the parasite Theileria equi under laboratory conditions, concluding that two drug molecules, harmaline hydrochloride dihydrate (HHD) and hexadecyltrimethylammonium bromide (HDTAB), demonstrate significant potential to combat this parasite.

Methodology and Drugs of Study

• The study was conducted in vitro, i.e., outside a living organism, using a culture system known as a microaerophilic stationary-phase (MASP) to grow Theileria equi parasites.
• Focused on five drug molecules: harmaline hydrochloride dihydrate (HHD), hexadecyltrimethylammonium bromide (HDTAB), hesparidin methyl chalcone (HMC), andrographolide, and imidocarb dipropionate.

Results and Analysis

• Inhibitory power was measured using the 50% inhibitory concentration value (IC50) – the concentration of a drug required to inhibit half the growth of the parasite.
• All five drugs were tested, but andrographolide proved ineffective at inhibiting the growth of Theileria equi in this specific study.
• The IC50 values of HHD, HDTAB, HMC, and imidocarb dipropionate were found to be 17.42 μM, 14.00 μM, 246.34 μM, and 0.279 μM, respectively.
• Cytotoxicity (the quality of being toxic to cells) of each drug was also evaluated. Measurements were taken to ascertain the percentage of cytotoxicity on horse PBMC (peripheral blood mononuclear cells) when a 2000 μM concentration was used. Results were as follows: 8.34% for HHD, 46.44% for HDTAB, 58.53% for HMC, 31.06% for andrographolide, and 15.14% for imidocarb dipropionate. These numbers highlight that HHD caused the least amount of cell toxicity.

Conclusions

• Based on the IC50 values and cytotoxicity levels, HHD demonstrated less cell toxicity and a lower IC50 value compared to the reference drug, imidocarb dipropionate, making it the most promising drug in the study.
• HDTAB also exhibited a lower IC50 value, indicating effective inhibition of the parasite, but it had a higher level of cytotoxicity, which could affect its potential as a treatment.
• The final conclusion of the study is that HHD and HDTAB are potential drug molecules against Theileria equi because they selectively inhibit heat shock protein 90 (Hsp90) and the choline kinase pathway, mechanisms essential for the life cycle of the parasite.