Ref: eugenol related synthesis
Biosynthesis of estragole and methyl-eugenol in sweet basil (Ocimum basilicum L). Developmental and chemotypic
association of allylphenol O-methyltransferase activities
Efraim Lewinsohn a,*, Iris Ziv-Raz a,b, Nativ Dudai a, Yaacov Tadmor a, Elena Lastochkin a, Olga Larkov a, David Chaimovitsh a, Uzi Ravid a, Eli
Putievsky a, Eran Pichersky c, Yuval Shoham b
Plant Science 160 (2000) 27–35
Abstract
Sweet basil (Ocimum basilicum L., Lamiaceae) is a common herb, used for culinary and medicinal purposes. The essential oils of different sweet basil
chemotypes contain various proportions of the allyl phenol derivatives estragole (methyl chavicol), eugenol, and methyl eugenol, as well as the
monoterpene alcohol linalool. To monitor the developmental regulation of estragole biosynthesis in sweet basil, an enzymatic assay for S
adenosyl-L-methionine (SAM):chavicol O methyltransferase activity was developed. Young leaves display high levels of chavicol O-methyltransferase
activity, but the activity was negligible in older leaves, indicating that the O-methylation of chavicol primarily occurs early during leaf
development. The O methyltransferase activities detected in different sweet basil genotypes differed in their substrate specificities towards the
methyl acceptor substrate. In the high-estragole-containing chemotype R3, the O methyltransferase activity was highly specific for chavicol, while
eugenol was virtually not O-methylated. In contrast, chemotype 147:97, that contains equal levels of estragole and methyl eugenol, displayed
O-methyltransferase activities that accepted both chavicol and eugenol as substrates, generating estragole and methyl eugenol, respectively. Chemotype
SW that contains high levels of eugenol, but lacks both estragole and methyl eugenol, had apparently no allylphenol dependent O-methyltransferase
activities. These results indicate the presence of at least two types of allylphenol-specific O-methyltransferase activities in sweet basil
chemotypes, one highly specific for chavicol; and a different one that can accept eugenol as a substrate. The relative availability and substrate
specificities of these O-methyltransferase activities biochemically rationalizes the variation in the composition of the essential oils of these
chemotypes.
Keywords : Ocimum basilicum L.; Lamiaceae; Sweet basil; Essential oils; Estragole; Methyl eugenol; O-methyltransferase
Attachment: Biosynthesis of estragole and methyl-eugenol in sweet basil Ocimum basilicum L). Developmental and chemotypic associatio (98kB)
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