Studies on nepalese crude drugs. XXVI. Chemical constituents of Panch Aunle, the roots of Dactylorhiza hatagirea D. Don.

Abstract

From the dried roots of Dactylorhiza hatagirea, which are termed Panch Aunle in Nepal, five new compounds called dactylorhins A, B, C, D and E, and two new natural compounds named dactyloses A and B, have been isolated together with twelve known compounds. In addition to these compounds, two kinds of lipid mixture were also obtained. The structures of the new compounds have been determined by spectroscopic and chemical methods as follows: dactylorhin A, (2R)-2-β-D-glucopyranosyloxy-2-(2- methylpropyl)butanedioic acid bis(4-β-D-glucopyranosyloxybenzyl) ester; dactylorhin B, (2R,3S)-2-β-D-glucopyranosyloxy-3-hydroxy-2-(2- methylpropyl)butanedioic acid bis(4-β-D-glucopyranosyloxybenzyl) ester; dactylorhin C, (2R)-2-β-D-glucopyranosyloxy-2-(2-methylpropyl)butanedioic acid; dactylorhin D, (2R,3S)-2-β-D-glucopyranosyloxy-3-hydroxy-2-(2- methylpropyl)butanedioic acid 1(4-β-D-glucopyranosyloxybenzyl) ester; dactylorhin E, (2R)-2-β-D-glucopyranosyloxy-2-(2-methylpropyl)butanedioic acid 1-(4-β-D-glucopyranosyloxybenzyl) ester; dactylose A, 1-deoxy-1-(4- hydroxyphenyl)-L-sorbose; dactylose B, 1-deoxy-1-(4-hydroxyphenyl)-L- tagatose. Although a mixture of dactyloses A and B has been already synthesized, this is the first example of their isolation from natural resources. Dactyloses A and B were suggested to be biosynthesized from L- ascorbic acid and 4-hydroxybenzyl alcohol via 2-C-(4-hydroxybenzyl)-α-L- xylo-3-ketohexulofuranosono-1,4-lactone.