Flavonolignans from Lannea acida A. Rich. as potential antileishmanial agents

Phytochemical investigation of the bark of Lannea acida led to the isolation of a new flavonolignan glycoside, mururin A-3-O-α-L-rhamnopyranoside (1), along with twenty-three known secondary metabolites compounds 2-24. The structures of these compounds were determined using spectroscopic methods, including NMR and mass spectroscopy. Compounds 1 and 2 displayed good inhibitory effects against LmPTR1 with IC₅₀ values of 56.43 ± 2.14 and 104.6 ± 3.30 μM, respectively, as compared to the positive control trimethoprim (IC₅₀ = 21.07 ± 0.6 μM). Molecular docking and molecular dynamics simulations were performed to explore the binding mechanisms and stability of PTR1-inhibitor complexes over the timeframe of 100 ns. Notably, all evaluated compounds demonstrated no significant cytotoxicity against the human normal fibroblast cell line (BJ). This study reveals the significant anti-parasitic effects of flavonolignans compounds 1 and 2 against Leishmania species, the parasites responsible for leishmaniasis - a group of clinically important tropical diseases.