Rothmanniamide and other constituents from the leaves of Rothmannia hispida (K.Schum.) fagerl. (Rubiaceae) and their chemophenetic significance

The chemical investigation of the CH2Cl2/MeOH (1:1) extract of the leaves of Rothmannia hispida (K. Schum.) Fagerl. (Rubiaceae) led to the isolation of a new ceramide rothmanniamide (1) and a naturally isolated alkyl cinnamate derivative n-heptadecyl-4-hydroxy-trans-cinnamate (2), along with fifteen known compounds including lupeol palmitate (3), lupeol (4), a mixture of uvaol (5) and erythrodiol (6), ursolic acid (7), 30-nor2 alpha,3 beta-dihydroxyurs-12-ene (8), hederagenin (9), stigmast-22-en-3-ol (10), a mixture of beta-sitosterol (11) and stigmasterol (12), stigmast-4,22-dien-3-ol (13), stigmasterol 3-O-beta-D-glucoside (14), triacontan-1-ol (15), kaempferol 3-O-beta-D-glucopyranoside (16) and D-mannitol (17). Their structures were elucidated with the help of MS and NMR data. Compounds 8, 10 and 15 were isolated for the first time from the Rubiaceae family. The crude extract and the isolates were assessed in vitro for their antileishmanial activity against Leishmania donovani 1 S (MHOM/SD/62/1 S) promastigotes and cytotoxicity on RAW 264.7 macrophage cells. Compounds 7 and 8 exhibited a highly potent antileishmanial activity with IC50 values of 0.88 and 1.75 mu g/mL, respectively, with good selectivity indexes (SI > 57). The chemophenetic significance of these compounds is also discussed.