Scillapersicene: a new homoisoflavonoid with cytotoxic activity from the bulbs of Scilla persica HAUSSKN.

The phytochemical investigation of Scilla persica HAUSSKN bulbs led to the isolation of a novel homoisoflavonoid that named Scillapersicene (1) and identified as 3-(3',4'-dihydroxybenzylidene)-8-hydroxy-5,7-dimethoxychroman-4-one along with five known homoisoflavonoids 2-6, whose structures were elucidated using HRFAB-MS, 1D and 2D NMR spectroscopic data. The known compounds were identified as 3-(3',4'-dihydroxybenzyl)-5,8-dihydroxy-7-methoxychroman-4-one (2), 3,9-dihydro-autumnalin (3), autumnalin (4), 3-(3',4'-dihydroxybenzylidene)-5,8-dihydroxy-7-methoxychroman-4-one (5) and scillapersicone (6). All compounds obtained, expect 2 and 4, showed strong cytotoxic activity against AGS cell line. The toxicity on AGS cell line was measured by 1, 3, 5 and 6 with IC50 values of 8.4, 30.5, 10.7 and 24.2 μM, respectively. In addition, the physico-chemical properties of these natural compounds were optimised using density functional method (B3LYP) with standard 6-311+G* basis set. These natural products have low-energy gaps between the first ionisation potentials and highest occupied molecular orbital. In conclusion, the low-energy gap could cause reason for cytotoxic activity of homoisoflavonoids.