New benzoyl glucosides and cytotoxic pterosin sesquiterpenes from Pteris ensiformis burm.

Three new compounds: 2R, 3R- pterosin L 3-O-beta-D-glucopyranoside ( 1), beta-D-xylopyranosyl( 1 -> 2)-7-O-benzoyl-beta-D-glucopyranoside ( 2) and 4-O-benzoyl-beta-D-xylopyranosyl(1 -> 2)-7-O-benzoyl-beta-D-glucopyranoside ( 3), together with nine known compounds, were isolated from the ethyl acetate extract of Pteris ensiformis. 5-[2-Hydroxyethylidene]- 2(5H)-furanone ( 4), which had been synthesized, was isolated from natural sources for the first time. The structures of all isolated compounds were determined on the basis of mass and spectroscopic evidence. Compound 1 and pterosin B ( 5) show cytotoxicity against HL 60 cells ( human leukemia) with the IC50 values of 3.7 and 8.7 mu g/mL, respectively.