alpha-Glucosidase Inhibitors from Dendrobium tortile

From the whole plant of Dendrobium tortile, a new compound, namely 4-(2-hydroxypropyl)-2(5H)-furanone, was isolated, together with six known compounds, which included trans-tetracosylferulate (2), cis-docosylferulate (3), p-hydroxybenzaldehyde (4), 3,4-dihydroxy-3,4 ¢ -dimethoxybibenzyl (5), (2S)-eriodictyol (6) and dendrofalconerol A (7). The structures of these compounds were determined through analysis of 1-D and 2-D NMR and HR-ESI-MS data. All of the isolates were evaluated for their a -glucosidase inhibitory activity. Compound 7 showed strong a -glucosidase inhibitory activity when compared with the positive control acarbose, whereas compounds 5 and 6 exhibited appreciable effects. An enzyme kinetic study revealed that compound 7 is a non-competitive inhibitor of a -glucosidase. This is the first report of the chemical constituents with biological activity from D. tortile.