Long-chain betulaprenol-type polyprenols from the leaves of Ginkgo biloba

Abstract

A long-chain betulaprenol-type polyprenol mixture was isolated from the leaves of Ginkgo biloba mainly as acetate. The structure was determined by mass spectroscopy, 1H-n.m.r. spectroscopy and 13C-n.m.r. spectroscopy. The mixture contained polyprenols-14-22, predominantly polyprenols-17, -18 and -19, and consisted of the dimethylallyl terminal unit (omega-terminal), two trans-isoprene residues, a sequence of 11-19 cis-isoprene residues and a terminal hydroxylated isoprene unit (alpha-terminal) aligned in that order. The concentration of these polyprenols in leaves increased from 0.04 to 2.0% of dry wt. with maturing of the leaves, though the content of total lipids was constant. The distribution of chain length in these polyprenols showed little variation throughout the whole life of the leaves.

Complete 1H and 13C signal assignment of prenol‐10 with 3D NMR spectroscopy

“…[10,23,41] The knowledge of polyisoprenoid structural features might permit the understanding of the function of dolichyl phosphates in glycoconjugate synthesis (requiring translocation of dolichol linked oligosaccharides through the membrane of the endoplasmic reticulum). On the other hand, quantitative analysis of the intensity of 13 C NMR signals is essential for more detailed studies on the biosynthesis of polyisoprenoid alcohols in plants. Recently presented spatial model of the biosynthesis of dolichol in plant cell [22] requires further verification, which is possible by application of the method described in this report.…”

“…[42,43] Final purification of prenol-10 was performed on a silica gel column. [44] All NMR experiments for prenol-10 in 80 mM solution in benzene (C 6 D 6 ) were recorded at 298 K on a Varian NMR System 700 spectrometer equipped with a Performa XYZ PFG unit and using the 5-mm 1 H, 13 C, 15 N-triple resonance probehead with high power 1 H and 13 C π /2 pulses of 6.2 and 13.0 µs, respectively. For 2D HSQC spectrum with band-selective homodecoupling presented in Fig.…”

Divergent pattern of polyisoprenoid alcohols in the tissues of Coluria geoides: A new electrospray lonization MS approach

“…Electron ionization mass spectra of dolichols up to 19 isoprene units published in the 1970s and more recently, after some modification of the method (45), demonstrated molecular peaks and substantial fragmentation, but the sensitivity of this method was not very high. More recently developed soft ionization techniques such as FABMS and field desorption (FD)-MS allowing estimation of polyisoprenoid alcohols require prederivatization to acetates (46) or phosphates (47) to increase the sensitivity. High hydrophobicity and nonvolatility of the polyisoprenoid alcohols caused technical difficulties that led us to test a new MS technique based on the ESI method (48).…”

Biflavone Glucosides from Ginkgo biloba Yellow Leaves

“…9,17) In this paper, we report the isolation and structural identification of new biflavone glucosides (1, 2) from the leaves of G. biloba collected in Korea.…”