Compounds from the leaves of Celtis mildbraedii Engl. (Cannabaceae) and evaluation of their activity against adult and immature stage of Schistosoma mansoni.

A new sphingolipid derivative, mildbramide 1, was isolated from the EtOH/H2O extract of the leaves of Celtis mildbraedii along with seven known compounds including friedelin 2, betulin 3, β-friedelinol 4, a β-sitosterol 5 and stigmasterol 6 mixture, β-sitosterol 3-O-β-D-glucoside 7 and trans-N coumaroyltyramine 8. Their chemical structures were elucidated by analysing their NMR and MS data. Notably, all the isolated compounds 1-8 are reported for the first time from this species and compound 4 was isolated for the first time from the genus Celtis. The extract, fractions and isolated secondary metabolites were evaluated for their cytotoxicity and antischistosomal activity against adult and immature stages of Schistosoma mansoni. The new compound 1 showed moderate antischistosomal activity against schistosomula with EC50 value of 135.6 ± 6.7 µg/mL and a selectivity indice (SI) of > 3.6. The druggability of compounds 1-8 was assessed in silico where their pharmacokinetic, physicochemical properties and drug-likeness were examined.