Search

The monoterpene D-limonene shows cancer preventative and cancer therapeutic activities in vitro and in vivo. Unlike plants, animals are unable to synthesize limonene de novo and obtain limonene through dietary sources. In the present study we established transgenic mouse embryonic NIH 3T3 fibroblast cells that produce limonene by introducing the D-limonene synthase gene obtained from Japanese catnip (Schizonepeta tenuifolia). Apoptosis was not observed in the limonene-producing cells. A concomitant increase in the level of apoptosis-related protein Bcl-2 (B-cell lymphoma protein 2) and decreases in the levels of Bad (Bcl-2 antagonist of cell death) and phosphorylated JNK (c-Jun N-terminal kinase) were observed in limonene-producing cells. Limonene-producing cells may provide a useful new system to investigate the in vivo function of this monoterpene.

Geraniol synthases were isolated from five pure strains of Perilla citriodora and Perilla frutescens which vary in essential oil type, the main compounds of which were citral, elsholtziaketone, perillaketone, and perillene, respectively. This result supports the putative biosynthetic pathways of these three furylalkenes which are all produced by way of citral. Nucleotide sequences of geraniol synthases from three oil types of P. citriodora were identical, and almost the same as the sequence from P. frutescens, a species with twice the chromosome number of P. citriodora. This identity in sequence between P. citriodora and P. frutescens, together with other previous results, indicates that P. frutescens was formed as an amphidiploid of P. citriodora and an unknown wild species.

From an EtOAc extract of Dracocephalum subcapitatum, five flavonoids, calycopterin, xanthomicrol, isokaempferide, luteolin and apigenin, together with five terpenoids, oleanolic acid, ursolic acid, geranial, neral and limonene-10-al, were isolated. Among them, citral and limonene-10-al were the most effective components against epimastigotes of Trypanosoma cruzi, the parasitic agent of Chagas disease.

From the whole plant of Dracocephalum kotschyi BOISS., two new monoterpene glycosides (9, 10), together with seven known terpenoids and a phytosterol (1-8), were isolated. Their structures were determined to be limonen-10-al (1), geranial (2), neral (3), beta-sitosterol (4), oleanolic acid (5), ursolic acid (6), p-mentha-8-en-1,2-diol (7), colosolic acid (8), limonen-10-ol 10-O-beta-D-glucopyranoside (9), and limonen-10-ol 10-O-beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranoside (10). Compounds 1 (3.1 microM), 2 (3.1 microM), 3 (3.1 microM), 5 (6.2 microM), 6 (6.2 microM), and 8 (6.2 microM) were effective against epimastigotes of Trypanosoma cruzi.

Trypanocidal constituents of dried leaves of Laurus nobilis L. (Lauraceae) were examined. Activity-guided fractionation of the methanol extract resulted in the isolation of two guaianolides, dehydrocostus lactone (1) and zaluzanin D (2), and a new p-menthane hydroperoxide, (1R,4S)-1-hydroperoxy-p-menth-2-en-8-ol acetate (3). The minimum lethal concentrations of these compounds against epimastigotes of Trypanosoma cruzi were 6.3, 2.5, and 1.4 microM, respectively.

Four monoterpene hydroperoxides were isolated from aerial parts of Chenopodium ambrosioides along with ascaridole (1), the anthelmintic principle of this plant, as anti-trypanosomal compounds. The structures of these monoterpenes were determined to be (-)-(2S,4S)- and (-)-(2R,4S)-p-mentha-1(7),8-dien-2-hydroperoxide (2a and 3a) and (-)-(1R,4S)- and (-)-(1S,4S)-p-mentha-2,8-dien-1-hydroperoxide (4a and 5a) on the basis of spectroscopic methods and chemical correlations. In vitro trypanocidal activities of ascaridole (1) and these hydroperoxides (2a-5a) against epimastigotes of Trypanosoma cruzi were 23, 1.2, 1.6, 3.1, and 0.8 microM, respectively. Fresh leaves of C. ambrosioides also contained isomeric hydroperoxides 6a and 7a, and the content ratio of 2a-7a suggested that these hydroperoxides were formed through the singlet-oxygen oxidation of limonene.

Abstract: Trypanocidal constituents of Dracocephalum komarovi were investigated. Under guidance of the in vitro trypanocidal activity against epimastigotes of Trypanosoma cruzi, the causative agent of Chagas'' disease, two new diterpenes, dracocequinones A ( 1 ) and B ( 2 ), and two known triterpene acids, ursonic acid and ursolic acid, were isolated as trypanocidal constituents, in addition to previously reported diterpenes, cyclocoulterone ( 4 ), komaroviquinone ( 5 ), dracocephalone A ( 6 ) and komarovispirone ( 7 ). Furthermore a new diterpene, komarovinone A ( 3 ), was isolated, together with four known terpenes. Among these compounds, komaroviquinone ( 5 ) showed the most potent activity with minimum lethal concentration of 0.4μM. Structure elucidation of the new diterpenes 1–3 was described. [Copyright &y& Elsevier]

A new diterpene, komarovispirone () with a spiro-octahydroindene skeleton, was isolated from Dracocephalum komarovi. The structure was elucidated by extensive analyses of spectral data. Komarovispirone () showed trypanocidal activity against epimastigote of Trypanosoma cruzi, the causative agent of American trypanosomiasis, with a minimum lethal concentration of 23 μM. [Copyright &y& Elsevier]