Discovery of Novel Flavonoids From Paeonia × suffruticosa Andr. and Their Acetylcholinesterase Inhibitory Activity

Three previously undescribed flavonoids, mudanpi A-C (1-3), and a new tetralin glycoside, suffruticoside M (4), along with 12 known compounds (5-16), were isolated from the dried root bark of Paeonia × suffruticosa Andr. Their structures were identified by spectroscopic analyses and computational methods. Given that studies have shown the therapeutic potential of Paeonia × suffruticosa Andr. extract against Alzheimer's disease, we evaluated the acetylcholinesterase inhibitory activity of its isolated compounds. Notably, compounds 2, 6, and 10 exhibited interesting acetylcholinesterase (AChE) inhibitory properties in vitro assays with the IC₅₀ values of 8.95 ± 0.86, 7.69 ± 1.01, and 8.62 ± 0.12 µM, respectively.