אסיף מאגר המחקר החקלאי

Biosynthesis of estragole and methyl-eugenol in sweet basil (Ocimum basilicum L). Developmental and chemotypic association of allylphenol O-methyltransferase activities

Year:

2000

Source of publication :

Authors :

Volume :

160

Co-Authors:

Lewinsohn, E., Newe ya'Ar Research Center, Agricultural Research Organization, P.O. Box 1021, Ramat Yishay 30095, Israel
Ziv-Raz, I., Newe ya'Ar Research Center, Agricultural Research Organization, P.O. Box 1021, Ramat Yishay 30095, Israel, Department of Food Engineering and Biotechnology, Technion-Israel Institute of Technology, Haifa 32000, Israel
Dudai, N., Newe ya'Ar Research Center, Agricultural Research Organization, P.O. Box 1021, Ramat Yishay 30095, Israel
Tadmor, Y., Newe ya'Ar Research Center, Agricultural Research Organization, P.O. Box 1021, Ramat Yishay 30095, Israel
Lastochkin, E., Newe ya'Ar Research Center, Agricultural Research Organization, P.O. Box 1021, Ramat Yishay 30095, Israel
Larkov, O., Newe ya'Ar Research Center, Agricultural Research Organization, P.O. Box 1021, Ramat Yishay 30095, Israel
Chaimovitsh, D., Newe ya'Ar Research Center, Agricultural Research Organization, P.O. Box 1021, Ramat Yishay 30095, Israel
Ravid, U., Newe ya'Ar Research Center, Agricultural Research Organization, P.O. Box 1021, Ramat Yishay 30095, Israel
Putievsky, E., Newe ya'Ar Research Center, Agricultural Research Organization, P.O. Box 1021, Ramat Yishay 30095, Israel
Pichersky, E., Department of Biology, University of Michigan, Ann Arbor, MI 48109-1048, United States
Shoham, Y., Department of Food Engineering and Biotechnology, Technion-Israel Institute of Technology, Haifa 32000, Israel

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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. © 2000 Elsevier Science Ireland Ltd.

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