External flavones in sweet basil, Ocimum basilicum, and related taxa

Grayer, Renée J.; Bryan, Sarah E.; Veitch, Nigel C.; Goldstone, Fiona J.; Paton, Alan; Wollenweber, Eckhard

doi:10.1016/s0031-9422(96)00430-x

Cited by 87 publications

(41 citation statements)

References 7 publications

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“…Extracts from four standard sweet basil lines (EMX-1, Sweet Dani [SD], SW, and MC; Gang et al, 2001;Iijima et al, 2004;Kapteyn et al, 2007;Xie et al, 2008) contained the major flavonoids known in this species (Grayer et al, 1996(Grayer et al, , 2001, with SALV and nevadensin (NEV; Fig. 1) being most abundant.…”

Section: Choice Of Basil Lines For An Investigation Of Flavone Biosynmentioning

confidence: 99%

“…The volatile compounds defining the flavor of basil are produced by the secretory cells and then stored in the oil cavity under the elevated cuticle of the peltate glandular trichomes on the leaf surface (Werker et al, 1993;Gang et al, 2001). Basil also produces PMFs, whose occurrence and distribution in a number of basil cultivars have been studied in detail (Xaasan et al, 1980;Grayer et al, 1996Grayer et al, , 2000Grayer et al, , 2001Vieira et al, 2003). Whereas the total PMF amount is probably controlled by the activity of early phenylpropanoid-acetate pathway enzymes, the relative amounts of compounds differing from each other by a methyl or a methoxyl group depend on the late, "decorative" steps, such as 6-, 7-, 8-, 39-, or 49-methylations and 6-, 8-, or 39-hydroxylations. Nothing is known about the flavonoid 6-and 8-hydroxylases in the Lamiaceae, while flavonoid O-methyltransferases (FOMTs) from this plant family have received some attention.…”

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confidence: 99%

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A Set of Regioselective O-Methyltransferases Gives Rise to the Complex Pattern of Methoxylated Flavones in Sweet Basil

2012

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Polymethoxylated flavonoids occur in a number of plant families, including the Lamiaceae. To date, the metabolic pathways giving rise to the diversity of these compounds have not been studied. Analysis of our expressed sequence tag database for four sweet basil (Ocimum basilicum) lines afforded identification of candidate flavonoid O-methyltransferase genes. Recombinant proteins displayed distinct substrate preferences and product specificities that can account for all detected 7-/6-/49-methylated, 8-unsubstituted flavones. Their biochemical specialization revealed only certain metabolic routes to be highly favorable and therefore likely in vivo. Flavonoid O-methyltransferases catalyzing 49-and 6-O-methylations shared high identity (approximately 90%), indicating that subtle sequence changes led to functional differentiation. Structure homology modeling suggested the involvement of several amino acid residues in defining the proteins' stringent regioselectivities. The roles of these individual residues were confirmed by site-directed mutagenesis, revealing two discrete mechanisms as a basis for the switch between 6-and 49-O-methylation of two different substrates. These findings delineate major pathways in a large segment of the flavone metabolic network and provide a foundation for its further elucidation.

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Section: Choice Of Basil Lines For An Investigation Of Flavone Biosynmentioning

confidence: 99%

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confidence: 99%

A Set of Regioselective O-Methyltransferases Gives Rise to the Complex Pattern of Methoxylated Flavones in Sweet Basil

2012

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“…Basil oils from different geographical origins have been classified. [3][4][5][6][7][8][9][10][11][12][13] According to the chemical composition and geographical origin, Lawrence in 1980 and Boniface in 1987 classified them into three large groups: European type, Exotic or Reunion type and African type. 14 On the basis of more than 200 analyses of oils extracted from O. basilicum, Lawrence 8 established four essential oil chemotypes (methyl chavicol, linalool, methyl eugenol and methyl cinnamate) and also numerous subtypes.…”

Section: Introductionmentioning

confidence: 99%

Essential oil composition from twelve varieties of basil (Ocimum spp) grown in Colombia

Viña¹,

Murillo²

2003

J. Braz. Chem. Soc.

133

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Foi analizada a composição do óleo esencial das partes aéreas de doze variedades de alfavaca (Ocimum spp). A análise foi feita por cromatografía gasosa-espectrometria de massas (CG-EM) e encontrou-se que dez das amostras foram caracterizadas pela presença de uma alta porcentagem de cinamato de metila (35-80%), o qual define o químiotipo destas variedades. Somente uma das variedades apresentou o químiotipo cariofileno e mais uma o químiotipo linalol. As variedades "crespa morada", "virgen pequeña", e "virgen morada" apresentam o subtipo cinamato > linalol. A "blanca compacta" e a "crespa blanca" têm o subtipo cinamato de metila > linalol > 1,8-cineol. A "castilla morada" têm o subtipo cinamato de metila > metil eugenol. O subtipo linalol > cinamato de metila foi apresentado pela "verde de folhas grandes". Cariofileno > metil eugenol foi o subtipo da alfavaca "clavo". Cinamato de metila (constituindo mais do 62% do total do óleo esencial) foi o químiotipo para as outras variedades: "canela", "querendona morada", "dulce de castilla" e "zancona morada".Essential oil compositions of aerial parts from twelve basil cultivars (Ocimum spp) were analysed by gas chromatography-mass spectrometry (GC-MS). Ten of them were characterized by the presence of a high percentage of methyl cinnamate (35-80%), which defined the chemotype for these varieties. Only one presented the caryophyllene chemotype and another, the linalool chemotype. Three of the basils, "purple ruffles", "little virgin" and "purple virgin" exhibited the methyl cinnamate > linalool subtype. "White compact" and "white ruffles" showed the methyl cinnamate > linalool > 1,8-cineole subtype. Methyl cinnamate > methyl eugenol was the subtype for "purple castle". The variety "large green leaves" exhibited the linalool > methyl cinnamate subtype. Caryophyllene > methyl eugenol subtype was determined for "clove basil". The rest of the basils "cinnamon", "purple lovingly", "sweet castle" and "purple long-legged", belonged to the methyl cinnamate chemotype in which methyl cinnamate constituted more than 62% of the total essential oil content.

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“…In addition to volatiles, basil produces specific lipophilic flavones, such as nevadensin (NEV), salvigenin (SALV), and gardenin B (GARD B) ( Fig. 1) as characteristic compounds (11). We recently found that flavone biosynthesis and accumulation are also largely peltate trichome-specific (12).…”

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confidence: 99%

“…A cytochrome P450-dependent monooxygenase from soybean was most active with liquiritigenin, a 7,4Ј-dihydroxyflavanone, and is likely to contribute to accumulation of 6-substituted isoflavonoids (14). In contrast, a 2-oxoglutarate-dependent dioxygenase (ODD) from Chrysosplenium americanum preferred methylated flavonols as substrates and is involved in biosynthesis of polymethoxylated flavonols (15,16) that are similar to methoxylated flavones in sweet basil (11). In addition, P450-dependent 6-hydroxylase activity was detected in protein extracts from Tagetes species, yet the molecular basis was not elucidated (17).…”

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confidence: 99%

The Roles of a Flavone-6-Hydroxylase and 7-O-Demethylation in the Flavone Biosynthetic Network of Sweet Basil

Berim

Gang

2013

Journal of Biological Chemistry

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Background: Late steps of lipophilic flavone biosynthesis in mints are unknown. Results: CYP82D monooxygenases catalyze 6-hydroxylation of 7-O-methylated precursor, whose 7-methyl group is subsequently removed by demethylation in basil but not in peppermint. Conclusion: Flavone biosynthesis in basil involves an unusual loop. Significance: Novel mechanisms elucidated in basil suggest a new hypothesis for similar metabolic networks in other plants.

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External flavones in sweet basil, Ocimum basilicum, and related taxa

Cited by 87 publications

References 7 publications

A Set of Regioselective O-Methyltransferases Gives Rise to the Complex Pattern of Methoxylated Flavones in Sweet Basil

A Set of Regioselective O-Methyltransferases Gives Rise to the Complex Pattern of Methoxylated Flavones in Sweet Basil

Essential oil composition from twelve varieties of basil (Ocimum spp) grown in Colombia

The Roles of a Flavone-6-Hydroxylase and 7-O-Demethylation in the Flavone Biosynthetic Network of Sweet Basil

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