Linalool: a review on a key odorant molecule with valuable biological properties : Linalool: a key odorant molecule

Chemical composition, antioxidant and antimicrobial activities of the essential oils from aerial parts of basil (Ocimum basilicum L.) as affected by four seasonal, namely summer, autumn, winter and spring growing variation were investigated. The hydro-distilled essential oils content ranged from 0.5% to 0.8%, the maximum amounts were observed in winter while minimum in summer. The essential oils consisted of linalool as the most abundant component (56.7-60.6%), followed by epi-α-cadinol (8.6-11.4%), α-bergamotene (7.4-9.2%) and γ-cadinene (3.2-5.4%). Samples collected in winter were found to be richer in oxygenated monoterpenes (68.9%), while those of summer were higher in sesquiterpene hydrocarbons (24.3%). The contents of most of the chemical constituents varied significantly (p<0.05) with different seasons. The essential oils investigated, exhibited good antioxidant activity as measurements by DPPH free radical-scavenging ability, bleaching β-carotene in linoleic acid system and inhibition of linoleic acid oxidation. Evaluation of antimicrobial activity of the essential oils and linalool, the most abundant component, against bacterial strains: Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Pasteurella multocida and pathogenic fungi Aspergillus niger, Mucor mucedo, Fusarium solani, Botryodiplodia theobromae, Rhizopus solani was assessed by disc diffusion method and measurement of determination of minimum inhibitory concentration. The results of antimicrobial assays indicated that all the tested microorganisms were affected. Both the antioxidant and antimicrobial activities of the oils varied significantly (p<0.05), as seasons changed.

Volatile terpenoids released from different plant parts play crucial roles in pollinator attraction, plant defense, and interaction with the surrounding environment. Two distinct pathways localized in different subcellular compartments are responsible for the biosynthesis of these compounds. Recent advances in the characterization of genes and enzymes responsible for substrate and end product biosynthesis as well as efforts in metabolic engineering have revealed new aspects of volatile terpenoid biosynthesis. This review summarizes recent progress in the characterization of volatile terpenoid biosynthetic genes, their spatio-temporal expression patterns and subcellular localization of corresponding proteins. In addition, recent information obtained from metabolic engineering is discussed. Copyright 2010 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.