Dolichandroside A, a new alpha-glucosidase inhibitor and DPPH free-radical scavenger from Dolichandrone falcata seem.

A new phenylpropanoid glycoside, dolichandroside-A, together with seven known compounds alpha-lapachone, lapachol, aloesaponarin II, 8-hydroxydehydroiso-alpha-lapachone, beta-sitosterol, 3,8-dihydroxydehydroiso-alpha-lapachone and verbascoside were isolated from the active ethyl acetate soluble extract of heartwood of Dolichandrone falcata. All except for dolichandroside-A are known compounds, but have been isolated for the first time from this plant. The structure of all these compounds was determined on the basis of 1D- and 2D-NMR spectral data. All the isolates were tested for alpha-glucosidase inhibitory and DPPH radical scavenging activity. This is the first report identifying DPPH scavenging activity and alpha-glucosidase inhibitory activity in D. falcata. Furthermore, along with a new compound, dolichandroside-A, this study also assigns for the first time alpha-glucosidase inhibitory activity to verbascoside and aloe saponarin-II.