In vitro growth inhibitory effect of selected 18β-glycyrrhetinic acid esters on Theileria annulata

Glycyrrhetinic acid (GA) is one of the important Pentacyclic Triterpenoids (PT) found in the roots of licorice. This study aimed to evaluate the in vitro growth inhibitory effect of 18β-GA (18β-Glycyrrhetinic acid) and C-30 esters against Theileria annulata, the causative agent of Tropical Bovine Theileriosis. C-30 esters of 18β-GA were synthesized and their structures were elucidated using spectroscopy. The pharmacodynamic properties of 18β-GA and its C-30 esters were predicted using DataWarrior and Swiss ADME tools. Cattle isolates of T. annulata schizont-infected bovine lymphoblastoid cells were cultured using standard conditions and the growth inhibitory effect of GA and its esters were evaluated using MTT assay. The isopropyl ester of 18β-GA (GI50- 1.638 μM; R2- 0.818) showed improved anti-theileriosis efficacy than other 18β-GA derivatives. The propyl (GI50 - 5.549 μM), ethyl (GI50 - 5.638 μM), and benzyl (GI50 - 7.431 μM) esters also showed considerable inhibitory effect. The GI50 value for 18β-GA was recorded as 6.829 μM. This study throws light on the usefulness of 18β-GA and its esters for the treatment of Tropical Bovine Theileriosis.