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Oriental Beauty, which is made from tea leaves infested by the tea green leafhopper (Jacobiasca formosana) in Taiwan, has a unique aroma like ripe fruits and honey. To determine what occurs in the tea leaves during the oolong tea manufacturing process, the gene expression profiles and the chemical profiles were investigated. Tea samples were prepared from Camellia sinensis var. sinensis cv. Chin-shin Dah-pang while the tea leaves were attacked by the insect. The main volatile compounds, such as linalool-oxides, benzyl alcohol, 2-phenylethanol, and 2,6-dimethylocta-3,7-diene-2,6-diol, increased during manufacture. The gene expression profiles during manufacture were analyzed by differential screening between fresh leaves and tea leaves of the first turn over. Many up-regulated transcripts were found to encode various proteins homologous to stress response proteins. Accordingly, the endogenous contents of abscisic acid and raffinose increased during manufacture. Thus the traditional manufacturing method is a unique process that utilizes plant defense responses to elevate the production of volatile compounds and other metabolites.

Odour threshold concentrations, determined in agueous-ethanol solution, and odour qualities are reported for 18 enantiomeric and diastereomeric pairs of citronellyl derivatives [13 linear monoterpene compounds and five monocyclic α-damascone and α-ionone-related compounds (trans-2,2,6-trimethylcyclohexyl derivatives)] (98%ee). Fairly large differences in both odour strength and odour qualities were found between the monocyclic diastereomeric pairs. In four of the five cyclic compounds, the (1R, 6S)-form was found to be stronger and more sensorily active than the antipode. On the other hand, the linear enantiomeric pairs showed only small differences in both odour strength (half of them showed the same threshold values) and odour character. However, all the (3S)-forms showed milder, cleaner and a much preferable top note than the (3R)-forms except for citronellyl nitrile and the diester (citronellyl ethyl oxalate), whose (3R)-form showed a characteristic floral musk odour, although the (3S)-form showed a rose floral odour. Copyright © 2004 John Wiley & Sons, Ltd.

人々の清潔志向を背景に, 腋臭を中心とした体臭のデオドラントニーズは年々高まっている。われわれは, 官能評価および機器分析を用いてヒトの腋臭について研究した結果, 新たな臭気原因成分としてビニルケトン類 (1-octen-3-one, cis-1,5-octadien-3-one) を発見した。これらビニルケトン類のにおい閾値は非常に低く強烈な金属臭を有し, 腋臭に大きく寄与していることが示唆された。これら臭気は, 人体代謝物中の不飽和脂肪酸と鉄が接触して生成する酸化物であることをモデル実験によりつきとめ, におい発生のメカニズムを解明した。また, 植物抽出エキスの抗酸化作用により, ビニルケトン類の生成を抑制する方法をin vitro系にて検討し, 『クワエキス』に優れた生成抑制効果を見出した。

Enantiomeric 2-n-hexyl- and 2-n-heptylcyclopentanones ( 3 ) and ( 4 ) have been synthesized by asymmetric hydrogenation of 2-n-hexylidene and 2-n-heptylidenecyclopentanones ( 1 ) and ( 2 ) with Ru2Cl4[p-tolyl-binap]2NEt3 complexes. The differences in odor qualities between enantiomeric pairs of the ketones 3 and 4 have been found to be small, and the same odor threshold values have been observed between the enantiomeric pairs, although the corresponding δ-undeca- and δ-dodecalactones ( 6 ) and ( 7 ), synthesized by Baeyer–Villiger oxidation of the chiral ketones 3 and 4 , showed a fairly large difference in the threshold values between the enantiomeric pairs.

A novel and practical synthesis of (R)- and (S)-muscones by the asymmetric hydrogenation of (E)- and (Z)-3-methyl-2-cyclopentadecen-1-ones catalyzed by p-tolyl-BINAP-Ru(II) complexes has been achieved in nearly complete enantioselectivity.

Substrate recognition mechanism of soybean lipoxygenase-1 (L -1) was studied by using an entire series of (ω3Z,ω6Z,ω9Z)-C12~C22-trienoic acids and -trienols. The maximum activity of L-1 was obtained with C20-trienoic acid of all the substrates used. Among trienols, the maximum activity was obtained with C15-trienol. Analysis of the products obtained by the reaction of these substrates with L-1 revealed that trienoic acids were oxygenated mostly at ω6 position independently on the chain length. The hydroperoxy group at ω6 was introduced at (S)-configuration with over 98% enantioselectivity. Although the products formed from most trienols were also selectively oxygenated at ω6 position, only C15-trienol was oxygenated at both ω6 and ω10 positions in the ratio of ω6/ω10 = 48/52.