C₁₄-Polyacetylene glucosides from Codonopsis pilosula

Abstract

Seven new C₁₄-polyacetylene glucosides codonopilodiynosides A–G (1–7) were isolated from an aqueous extract of the Codonopsis pilosula roots. Their structures were determined by spectroscopic and chemical methods as (–)-(5S,6E,12E)-tetradeca-6,12-dien-8,10-diyn-1,5,14-triol 5-O-β-d-glucopyranoside (1), (–)-(5S,6E,12E)-tetradeca-6,12-dien-8,10-diyn-1,5,14-triol 5-O-β-d-glucopyranosyl-(1″ → 2′)-β-d-glucopyranoside (2), (–)-(5S,6E,12E)-tetradeca-6,12-dien-8,10-diyn-1,5,14-triol 5,14-di-O-β-d-glucopyranoside (3), (–)-(5S,6E)-tetradeca-6-en-8,10-diyn-1,5,14-triol 5-O-β-d-glucopyranoside (4), (–)-(5S,6E,12E)-tetradeca-6,12-dien-8,10-diyn-1,5-diol 5-O-β-d-glucopyranosyl-(1″ → 2′)-β-d-glucopyranoside (5), (–)-(6S,4E,12E)-tetradeca-4,12-dien-8,10-diyn-1,6-diol 6-O-β-d-glucopyranosyl-(1″ → 2′)-β-d-glucopyranoside (6), and (–)-(5S,6E)-tetradeca-6-en-1,5-epoxy-8,10-diyn-14-ol 14-O-β-d-glucopyranosyl-(1″ → 2′)-β-d-glucopyranoside (7), respectively. The absolute configurations of 1–7 were assigned by enzymatic hydrolysis followed by isolation of glucose and aglycones (1a and 4a–7a), and subsequent comparison of specific rotation, TLC, and ¹H NMR data of the glucose with an authentic sugar sample and application of modified Mosher's method based on the MPA determination rule of Δδ^RS values for 1a and 4a, and Δδ^S values for 6a. The configuration of 7 was assigned by electronic circular dichroism calculations based on the quantum-mechanical time-dependent density functional theory.

Keywords::

• Campanulaceae
• Codonopsis pilosula
• codonopilodiynosides A–G
• C₁₄-polyacetylene glucosides
• absolute configuration

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplemental data

The supplemental data for this article can be accessed at http://dx.doi.org/10.1080/10286020.2015.1041932

Notes

We dedicate this paper to Prof. Xin-Sheng Yao on the occasion of his 80th birthday.

Additional information

Funding

Financial support from the National Natural Sciences Foundation of China [grant number 30825044], [grant number 21132009]; the Program for Changjiang Scholars and Innovative Research Team in University [grant number IRT1007]; and the National Science and Technology Project of China [grant number 2012ZX09301002-002], [grant number 2011ZX0 9307-002-01] is acknowledged.