Continuation of the phytochemical investigation of the aerial parts of Tephrosia purpurea subsp. dunensis resulted in the isolation and structural elucidation of a new prenylated flavonoid demeapollinin (1), glabratephrinol (2) and a mixture (3) of tephroapollin G (3a) and epi-tephroapollin G (3b). The neuroprotective activity of compounds (1-3) besides the previously isolated compounds; dunensin (4), pseudosemiglabrin (6), glabratephrin (7), apollinin (5), kampferol 3, 7-O-α-L-dirhamnoside (8) and quercetin 3, 7-O-α-L-dirhamnoside (9) was examined. Molecular docking, acetylcholine esterase inhibitory assay and protection against both H2O2 and induced neurotoxicity were used to evaluate their neuroprotective effect. Compound 2 showed the highest acetylcholine esterase inhibitory activity (IC50 4.31 ± 0.75 µM) compared to galantamine (IC50 1.64 ± 0.32 µM), compounds 4 and 3 exhibited potent protective effect against induced neurotoxicity (IC50 7.70 ± 5.23 and 10.91 ± 6.27 µM, respectively) compared to standard epigallocatechin gallate (IC50 18.36 ± 6.22 µM).
Keywords: Tephrosia purpurea; molecular docking; neuroprotective; prenylated flavonoids.