Flavonoids from the flower buds of Mesua ferrea Linn with CYP1 enzymes inhibitory activity

The chemical constituents of the 95% ethanol extract from Mesua ferrea Linn were isolated and purified by silica gel, Sephadex LH-20, open ODS, semi preparative HPLC column chromatography and other separation methods. The structure of the compounds were elucidated by NMR spectroscopy and MS data. 25 flavonoid compounds were isolated and identified, including apigenin (1), luteolin (2), chrysoeriol (3), isovitexin (4), vitexin (5), luteolin-3′-O-β-xylopyranoside (6), kaempferol (7), quercetin (8), quercetin-3-O-rhamnoside (9), quercetin-3-O-β-D-glucoside (10), kaempferol-3-O-α-rhamnopyranoside (11), aromadendrin (12), rhusflavone (13), rhusflavanone (14), 2,5-dihydroxyxanthone (15), 5-hydroxy-1-methoxy xanthone (16), 2,5-dihydroxy-1-methoxylxanthone (17), 5-hydroxy-1,3-dimethoxyxanthone (18), 1,3,5-trihydroxyxanthone (19), 2-hydroxyxanthone (20), 4-hydroxyxanthone (21), 1,7-dihydroxyxanthone (22), 1,3,7-trihydroxyxanthone (23), 1,5,6-trihydroxyxanthone (24), 5,6-dihydroxy-1-methoxyxanthone (25). Compounds 3, 7, 10, 12, 15, 22, 23 and 25 were isolated from this plant for the first time. In addition, CYP1A1/CYP1A2/CYP1B1 enzyme activity inhibition assay was performed on compounds 1−5, 7−13 and 15, and the results showed that compound 4 could target CYP1A1 enzyme with an inhibition rate of (28.40±8.83)%; compound 12 could target CYP1A2 enzyme with an inhibition rate of (44.15±2.16)%; Compounds 11 and 13 were able to target the CYP1B1 enzyme with inhibition rates of (90.52±2.79)% and (75.72±26.78)%, respectively. Molecular docking techniques revealed that compounds 4, 11−13 were able to bind well to the corresponding receptor proteases of the CYP1 family through hydrogen bonding, with binding energies less than −34.00 kJ/mol.