Kyoto, Japan
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Hasegawa T.,Saitama University | Izumi H.,Saitama University | Tajima Y.,Saitama University | Yamada H.,Yamada matsu Co.
Molecules | Year: 2012

(Z)-α-Santalol, which has a unique woody odor, is a main constituent of sandalwood essential oil. We investigated the structure-odor relationship of (Z)-α-santalol and its derivatives, focusing on the relationship between the structure of the side chain and the odor of the compounds. Various α-santalol derivatives (aldehydes, formates, and acetates) were synthesized from (Z)- and (E)-α-santalol, which were prepared from (+)-3-bromocamphor through modifications of a reported synthetic route. The Z- and E-isomers of α-santalols have different double-bond configurations in the side chain. Analogues with saturated side chains were also prepared from the corresponding α-santalols, and the odors of the all the prepared compounds were evaluated. We found that the odors of the Z-isomers (woody) were similar to those of the corresponding saturated compounds, but clearly different from the odors of the corresponding E-isomers (odorless, fresh, or fatty). These results indicate that the relative configuration of the side chain with respect to the santalane frame plays an important role in the odor of α-santalol. E-configuration in the side chain eliminates the woody odor character of α-santalol and its examined derivatives, whereas the Z-configuration or saturation of the carbon side chain does not.

Hasegawa T.,Saitama University | Izumi H.,Saitama University | Yamada H.,Yamada matsu Co.
Natural Product Communications | Year: 2013

α-Santalol is a sesquiterpene that is a major constituent of sandalwood (Santalum album L.), and is responsible for its distinctive woody odor. We replaced the polycyclic moiety and hydroxyl group of α-santalol with other moieties, and we compared the odors of the E/Z-isomers and their saturated analogues. Our previous study of the structure-odor relationships of α-santalols bearing hydroxyl, formyl, formyloxy, and acetoxy functional groups showed there was a similarity in odor between the Z-isomer and its saturated analogue. We synthesized α-santalols with a benzyl group in place of the hydroxyl group, because many benzyl compounds have strong characteristic odors. We found similar odors for the E-isomer and its saturated analogue. In contrast, the odors of the α- santalol derivatives with a hydroxyl, formyl, formyloxy, or acetoxy group were different. We also replaced the bulky polycyclic moiety with a linear alkyl chain. The polycyclic moiety was the most important structural factor in the characteristic sandalwood odor. The synthesis of derivatives and the evaluation of their odor allowed us to identify the key structural factors in the odor of α-santalol.

Satou T.,Toho University | Miyagawa M.,Toho University | Seimiya H.,Saitama University | Yamada H.,Yamada matsu Co. | And 2 more authors.
Flavour and Fragrance Journal | Year: 2014

The fragrance of Santalum album L. (sandalwood) has been used as a sedative. However, few reports have investigated the anxiolytic activity of sandalwood fragrance. Therefore, in this study, we examined the anxiolytic-like activity of hexane-extracted sandalwood oil (SAO). Male ICR mice, aged 5weeks at the start of each experiment, were used. To mimic its clinical use, the effect of SAO after stress loading was investigated. Mice were individually housed in cages for 1week and subjected to loaded water-immersion stress for 24h. Next, SAO inhalation (i.h.) was initiated 90min prior to the elevated plus maze (EPM) test. As a result, significant anxiolytic-like activity was observed at 4μl/l air SAO i.h. In contrast, anxiolytic-like activity was not observed in non-stressed control mice. Additionally, mice were subjected to SAO i.h prior to water-immersion stress for 24h in order to investigate its prolonged effect. As a result, significant anxiolytic-like activity was observed at 4μl/l air SAO i.h. In contrast, anxiolytic-like activity was not observed in non-stressed control mice. The above results indicate that the anxiolytic-like activity of SAO i.h. is revealed under stress conditions and is prolonged for at least 24h. Since the main components of SAO are (Z)-α-santalol (51.1%) and (Z)-β-santalol (28.5%), it is proposed that they are involved in mediating the characteristic anxiolytic-like activity of SAO. © 2013 John Wiley & Sons, Ltd.

Hasegawa T.,Saitama University | Toriyama T.,Saitama University | Ohshima N.,Saitama University | Tajima Y.,Saitama University | And 4 more authors.
Flavour and Fragrance Journal | Year: 2011

Sandalwood (Santalum album L.) is a traditional incense, and its essential oil is used in fragrances. The hexane extract from Indian sandalwood chips had a sandalwood odour similar to sandalwood chips, but it clearly differed from that of commercial essential oil. By fractional distillation of the extract under reduced pressure, a fraction was obtained that had a sandalwood-like odour and contained several unknown formyl compounds as the main constituents. Santalyl formates were isolated as new components from this fraction by chromatography and characterized by 1H- and 13C-NMR spectroscopy. These constituents were less abundant in the commercial essential oil than in the hexane extract. Santalyl formates were synthesized from the corresponding alcohols. Copyright © 2010 John Wiley & Sons, Ltd.

Miyagawa M.,Toho University | Satou T.,Toho University | Yukimune C.,Toho University | Ishibashi A.,Toho University | And 4 more authors.
Phytotherapy Research | Year: 2014

The fruit of Illicium verum Hook. f. (star anise) is used by many as a spice. The fragrance of I. verum fruit is characteristically anise-like. In this study, hexane-extracted I. verum fruit oil (IVO), trans-anethole as the main component, and related compounds (propiophenone, 4′-methoxy-propiophenone, trans-β-methylstyrene) were analyzed in order to clarify the emotional effect of inhaling the fragrance of I. verumfruit.As a result, although 4 μL/L air IVO did not exhibit an anxiolytic-like effect, 1 μL/L air trans-anethole exhibited a significant effect (p<0.05). Moreover, the anxiolytic-like effect of 1 μL/L air trans-anethole was significantly greater than 1 μL/L air propiophenone and 1 μL/L air 4′-methoxy-propiophenone (p<0.05). Thus, the anxiolytic-like effect of transanethole was confirmed, and it is proposed that the methoxyl group and 1-propenyl group in the para position of the benzene ring are necessary for the effect. Copyright © 2014 John Wiley & Sons, Ltd.

Hasegawa T.,Saitama University | Kikuchi A.,Saitama University | Saitoh H.,Saitama University | Yamada H.,Yamada matsu Co.
Journal of Essential Oil Research | Year: 2012

Frankincense has a unique odor and is an important fragrance material for Japanese incense. The constituents of frankincense vary according to the species of tree from which the resin is derived. The aroma profile of the frankincense used in Japanese incense showed that the important odor components were diterpenes, and incensole and its derivatives. These compounds have not been previously recognized as important odor compounds, and the relative stereochemistry of the diterpenes has not been assigned. We investigated the stereochemical structures of these compounds through synthetic studies with respect to 2. Incensole epoxide was isolated as pure crystals, and its structure was determined by single-crystal X-ray diffraction. The stereochemistry of the diterpenes was assigned by synthetic methods. Incensole and incensole acetate in the hexane extracts gradually oxidized to their epoxides, although this was not observed in the isolated pure compounds. These results indicate that incensole epoxides are not primary constituents of frankincense, but secondary products. © 2012 Taylor & Francis.

Hasegawa T.,Saitama University | Seimiya H.,Saitama University | Fujihara T.,Saitama University | Fujiwara N.,Saitama University | Yamada H.,Yamada matsu Co.
Natural Product Communications | Year: 2014

Star anise is an important fragrance material that has a characteristic anise-like odor. Although the main component of star anise is (E)-anethole, which accounts for over 90% of the constituents, the odor of (E)-anethole is different from that of the material itself. Here, we examined the aroma profile of star anise. GC-MS analysis of star anise extracts showed that it contains many compounds with structures similar to (E)-anethole. Our results indicate that (E)-anethole is the key compound in the odor of star anise, but structurally similar compounds play an important role in creating its odor. We examined the structure-odor relationship of (E)-anethole, focusing on the methoxy and 1-propenyl substituents. Altering the 1-propenyl group changed the odors of all the anethole derivatives. Replacing the methoxy group with a hydrogen atom created compounds with similar fatty odors. This shows that the methoxy group is important for the characteristic odor of anethole. We synthesized anethole derivatives where the methoxy group was replaced with a methyl group. In both methoxy- and methyl-substituted anethole derivatives, altering the 1-propenyl group changed the odors of the derivatives. Therefore, the methoxy and methyl benzene moieties are important structural features for the odor of star anise. The structural characteristics of anethole are closely related to its odor expression.

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