Herniarin

The enzyme that catalyses the conversion of DMAPP and umbelliferone into 6-dimethylallylumbelliferone, the first reaction specifically directed to the biosynthesis of linear furanocoumarins, has been isolated394 from suspension cultures and young leaves of Ruta graveolens. The particulate enzyme could utilize neither herniarin as a substitute for umbelliferone nor GPP in place of DMAPP. 8-Dimethylallylumbelliferone, which is an intermediate in the formation of the angular furanocoumarins, was not formed by these preparations. 

Umbelliferone is the pivotal metabolite in the pathways to substituted coumarins and furano- or pyranocoumarins. Its 7-0-methylation to herniarin (Fig. 4.3) or 0-prenylation and C-alkylation reactions are often observed in coumarin-producing higher plants where the prenylation at C-6 or C-8 mark the entry to the routes branching linear from angular furano- and pyranocoumarins (Fig. 4.5). In Ruta graveolens and Ammi rmjus, the prenylation reactions are catalysed by particulate enzymes (Hamerski et at, 1990), and... 

B KOH reagent intensifies the fluorescence of herniarin and scopoletin to a bright blue. Both compounds are detectable in samples (l)-(3). 

The lipophilic coumarins,. such as herniarin, migrate as blue fluorescent zones up to the solvent front. 

The reaction of 2-alkynoate esters and electron-rich phenols in the presence of formic acid and catalytic amounts of either Pd(OAc)2 or Pd2(dba)3 CHCl3 provides an efficient way to synthesize coumarins (Eq. 35) [76]. This chemistry has been utilized to synthesize the natural products fraxinol methyl ether, ayapin, herniarin, xanthoxyletin, and alloxanthoxyletin. The reaction appears to involve a Pd(0) catalyst and the formation of hydridopalladium intermediates. 

Chamomile has been indicated as an herb with the theoretical potential for interacting with warfarin due to the coumarin content of the herb (Heck et al. 2000). The cou-marin content, however, consists of the coumarin derivatives herniarin and umbelliferone. Herniarin has been shown to have hemostatic activity (Ahmad and Misra 1997) and umbelliferone has shown no evidence of anticoagulant activity (Egan et al. 1990 Feuer 1974 Pelkonen et al. 1997). The flavonoid apigenin has been shown to inhibit platelet aggregation in vitro (Landolfi et al. 1984 Teng et al. 1985). 

Rue oil contains varying amounts of 2-nonanone, 2-decanone, and 2-undecanone (methyl-n-nonyl ketone) as major components, with 2-undecanone about 90% in Algerian me oil.Other components include 2-heptanone, 2-octanone, 2-nonanol, 2-unde-canol, undecyl-2-acetate, anisic acid, phenol, guaiacol, small amounts of coumarins (bergapten, herniarin, and xanthotoxin), monoterpenes (cineole, a- and P-pinenes, limonene), and others (karrer jiangsu martindale). 

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