Michiho Ito

Sedative effects of vapor inhalation of agarwood oil and spikenard extract and identification of their active components.

Agarwood oil and spikenard extract were examined for their sedative activity using a spontaneous vapor administration system. It was shown that inhalation of agarwood oil vapor sedated mice. The main volatile constituents of the oil were found to be benzylacetone [agarwood oil from a Hong Kong market (1)], or α-gurjunene and (+)-calarene [agarwood oil made in Vietnam (2)]. A hexane extract of spikenard contained a lot of calarene, and its vapor inhalation had a sedative effect on mice. Individual principles benzylacetone, calarene, and α-gurjunene were administered to mice, which reproduced the result of the corresponding oil or extract. However, the most effective dose of the compounds was lower than their original content in the oil and extract (benzylacetone 0.1%, calarene 0.17%, α-gurjunene 1.5%).

Characterization of δ-Guaiene Synthases from Cultured Cells of Aquilaria, Responsible for the Formation of the Sesquiterpenes in Agarwood

The resinous portions of Aquilaria plants, called agarwood, have been used as medicines and incenses. Agarwood contains a great variety of sesquiterpenes, and a study using cultured cells of Aquilaria showed the production of sesquiterpenes (α-guaiene, α-humulene, and δ-guaiene) to be induced by treatment with methyl jasmonate (MJ). In this study, the accumulation and production of sesquiterpenes were quantified. The amounts accumulated and produced reached a maximum at 12 h, and the most abundant product was α-humulene at 6 h and δ-guaiene after 12 h. However, a headspace analysis of the cells revealed that α-humulene is likely to be volatilized; so overall, the most abundant sesquiterpene in the cells was δ-guaiene. A cDNA library from RNA isolated from MJ-treated cells was screened using PCR methodologies to isolate five clones with very similar amino acid sequences. These clones were expressed in Escherichia coli, and enzymatic reactions using farnesyl pyrophosphate revealed that three of the clones yielded the same compounds as extracted from MJ-treated cells, the major product being δ-guaiene. These genes and their encoded enzymes are the first sesquiterpene synthases yielding guaiane-type sesquiterpenes as their major products to be reported. Expression of a fourth terpene synthase gene in bacteria resulted in the accumulation of the protein in insoluble forms. Site-directed mutagenesis of the inactive clone and three-dimensional homology modeling suggested that the structure of the N-terminal domain was important in facilitating proper folding of the protein to form a catalytically active structure.

Coumarins and γ-pyrone derivatives from Prangos pabularia: antibacterial activity and inhibition of cytokine release

The n-hexane and ethyl acetate extracts of the stems and the ethyl acetate extracts of roots from Prangos pabularia afforded an gamma-pyrone derivative and furanocoumarin derivatives with three glucose and gamma-pyrone (pabularin A, B and C), along with 26 previously known compounds (18 coumarins, six terpenoids and two glycosides). Their structures were established on the basis of spectroscopic studies. Of these, 16 coumarin derivatives isolated from P. pabularia were tested for antibacterial activity and inhibition of cytokine release.

Engineering of cyanobacteria for the photosynthetic production of limonene from CO2

Isoprenoids, major secondary metabolites in many organisms, are utilized in various applications. We constructed a model photosynthetic production system for limonene, a volatile isoprenoid, using a unicellular cyanobacterium that expresses the plant limonene synthase. This system produces limonene photosynthetically at a nearly constant rate and that can be efficiently recovered using a gas-stripping method. This production does not affect the growth of the cyanobacteria and is markedly enhanced by overexpression of three enzymes in the intrinsic pathway to provide the precursor of limonene, geranyl pyrophosphate. The photosynthetic production of limonene in our system is more or less sustained from the linear to stationary phase of cyanobacterial growth for up to 1 month.

Sesquiterpenoids from the fruits of Ferula kuhistanica and antibacterial activity of the constituents of F. kuhistanica

Ethyl acetate extracts of the air-dried fruits of Ferula kuhistanica afforded three daucane esters: kuhistanicaol H, I and J, together with nine other known compounds. Their structures were established on the basis of spectroscopic evidence. Isolated compounds in this paper and previously reported compounds from the roots and stems of F. kuhistanica were tested for antibacterial activity. Some of them were selectively toxic against Gram-positive bacteria, including methicillin-sensitive and methicillin-resistant Staphylococcus aureus (MSSA and MRSA).

Induction of Sesquiterpenoid Production by Methyl Jasmonate in Aquilaria sinensis Cell Suspension Culture

Abstract A suspension cell culture was established from Aquilaria sinensis, a timber species producing fragrant woody material called “Agarwood.” Methyl jasmonate was added to this culture in order to induce production of fragrant compounds. Cells were harvested after seven days of incubation and subjected to solid phase micro-extraction to produce an extract that was analyzed by GC/MS. Three peaks appeared on GC and were identifi ed as α-guaiene, γ-guaiene (= 1(10),11-guaiadiene), and α-humulene based on their mass fragmentation patterns and 13C-NMR data. The production of the guaiene derivatives and α-humulene showed different kinetics, which may mean they are the products of different induced biosynthetic enzymes.

A New Type of Essential Oil from Perilla frutescens from Thailand

Abstract A new type of oil from Perilla frutescens, the piperitenone type, was discovered in Thailand. GC/MS analysis of steam-distilled oil showed that it contained piperitenone (36.3%) and limonene (23.7%). Crossing experiments between the piperitenone-type and the principal types of perilla suggested the presence of one dominant gene regarding the regulation of oil types between the piperitenone-type and the perillaldehyde-type.

Phenylbutanoids and stilbene derivatives of Rheum maximowiczii.

The methanol extract of the dried roots of Rheum maximowiczii afforded four phenylbutanoid and two stilbene derivatives. Their structures were established on the basis of chemical and spectroscopic studies.

Evaluation of volatile components from spikenard : valerena-4,7(11)-diene is a highly active sedative compound

Valerena-4,7(11)-diene and β-maaliene were isolated from spikenard for the first time, and the effects of inhaling these compounds were investigated. Both compounds reduced the locomotor activity of mice dose-dependently, even at a low dose. Valerena-4,7(11)-diene had a particularly profound effect, with the strongest sedative activity observed at a dose of 0.06%. Caffeine-treated mice that showed an area under the curve (AUC) for locomotor activity that was double that of controls were calmed to normal levels by administration of valerena-4,7(11)-diene. The continuous sleep time of pentobarbital-treated mice was prolonged by about 2.7 times with valerena-4,7(11)-diene, an effect similar to that of chlorpromazine administered orally.

Anticarcinogenic compounds in the Uzbek medicinal plant, Helichrysum maracandicum

An ethanol extract of Helichrysum maracandicum showed antiproliferative activity against cultured cells of SENCAR mouse in an in vitro assay, and activity-guided fractionation of the extract resulted in the isolation of isosalipurposide as an active substance. Naringenin chalcone, the aglycone of isosalipurposide, also showed strong antiproliferative activity. An in vivo assay of two-stage carcinogenesis on mouse skin revealed that epidermal application of isosalipurposide resulted in delayed formation of papillomas. Western blot analysis showed that the expression of p38 mitogen-activated protein kinase was suppressed by the administration of naringenin chalcone or isosalipurposide, which might be related to the anticarcinogenic activity.