Biosynthesis of Lignans. Part I. Biosynthesis of Arctiin (3) and Phillyrin (5)

Abstract

SummaryLignans constitute a class of naturally occuring phenolic compounds, widely distributed in higher plants. They are formally composed of two phenylpropanoid units, stercospecifically joined at the /f-carbon atoms of their side chains. Their biosynthesis has as yet not been investigated. To sec, if these plant phenolics originate from simple phenylpropancs, various radioactively labelled, putative precursors were fed to Forsythia shoots. Chemically synthezised arylpropane derivatives, such as Ή/ 1 'C-glucoferulic acid, -glucoferulic aldehyde, and -coniferin were incorporated into the lignans arctiin (3) and phillyrin (5) while 3 H-3,4-dimcthoxycinnamic acid was not incorporated. From these results it may be concluded that the hydroxylated compounds are direct precursors of these dimeric phenylpropanes and are incorporated through a dimerisation step without degrada tion of the Q-Q skeleton.

Biosynthesis of podophyllotoxin in Linum album cell cultures

“…This strongly suggests that methylenedioxy-substituted precursors can be incorporated intact into lignans and thus implies that dimerisation depends on: (i) the ability of the methylenedioxy-substituted precursor to generate a free-radical intermediate, or (ii) the existence of an alternative mechanism to phenoxy free-radical coupling. (Sto¨ckigt and Klischies 1977). It also correlates with the incorporation into the lignans syringaresinol and liriodendrin, observed on feeding [2-14 C]FA to Liriodendron tulipifera (Fujimoto and Higuchi 1977).…”

“…These findings are in agreement with the absence of incorporation into the lignans arctiin and phillyrin observed on feeding [4¢-OCH 2 3 H]DMCA to Forsythia suspensa var. fortunei (Sto¨ckigt and Klischies 1977). They also correlate with the absence of incorporation into PTOX and 4¢-demethylPTOX on feeding [2-14 C]TMCA and [2-14 C]SA to Podophyllum hexandrum (Jackson and Dewick 1984a).…”

Characterization of Polyneuridine Aldehyde Esterase, a Key Enzyme in the Biosynthesis of Sarpagine/Ajmaline Type Alkaloids

“…[C3H302C-]-substrates (ajmalicine, yohimbine, catharanthine, loganin) were obtained from the corresponding acids by methylation with 3H-diazomethane [14]. Esterase activities with unlabelled esters (e.g.…”

The isolation of eleutherococcus senticosus constituents by centrifugal partition chromatography and their quantitative determination by high performance liquid chromatography

“…Similarly, there has been no previous mention of the occurrence of coniferaldehyde glucoside (3), coniferin (5) (Podimuang et al, 1971) or 1,sdicaffeoylquinic acid (8) in the plant. Coniferaldehyde glucoside (3) has been synthesized for biosynthetic studies on lignans (Stockigt and Klischies, 1977).…”