Co-reporter:Yoshinori Fujimoto, Izumi Maeda, Kiyoshi Ohyama, Juri Hikiba, Hiroshi Kataoka
Phytochemistry 2015 Volume 111() pp:59-64
Publication Date(Web):March 2015
DOI:10.1016/j.phytochem.2014.12.019
•An early-step intermediate after cholesterol in 20-hydroxyecdysone biosynthesis in Ajuga hairy roots was investigated.•3β-Hydroxy-5β-cholestan-6-one was characterized by HPLC–MS/MS analysis.•Cholesterol was converted to the ketone with migration of the hydrogen atom from C-6 to C-5.•The ketone was proposed to be an intermediate immediately after cholesterol in 20-hydroxyecdysone.3β-Hydroxy-5β-cholestan-6-one was identified in the EtOAc extract of Ajuga hairy roots by micro-analysis using LC–MS/MS in the multiple reaction mode (MRM). Furthermore, administration of (2,2,4,4,7,7-2H6)- and (2,2,4,4,6,7,7-2H7)-cholesterols to the hairy roots followed by LC–MS/MS analysis of the EtOAc extract of the hairy roots indicated that cholesterol was converted to the 5β-ketone with hydrogen migration from the C-6 to the C-5 position. These findings, in conjunction with the previous observation that the ketone was efficiently converted to 20-hydroxyecdysone, strongly suggest that the 5β-ketone is an intermediate immediately formed after cholesterol during 20-hydroxyecdysone biosynthesis in Ajuga sp. In addition, the mechanism of the 5β-ketone formation from cholesterol is discussed.3β-Hydroxy-5β-cholestan-6-one was characterized as an early-step intermediate for 20-hydroxyecdysone biosynthesis in Ajuga hairy roots. 2H-labeled cholesterol was converted to the ketone with migration of the hydrogen atom from C-6 to C-5. The ketone was suggested to be an intermediate immediately after cholesterol in this plant.
Co-reporter:Kiyoshi Ohyama, Akiko Okawa, Yoshinori Fujimoto
Bioorganic & Medicinal Chemistry Letters 2014 Volume 24(Issue 15) pp:3556-3558
Publication Date(Web):1 August 2014
DOI:10.1016/j.bmcl.2014.05.048
Co-reporter:Yui Hirayama, Keiko Okuzumi, Hironori Masubuti, Hidehiro Uekusa, Jean-Pierre Girault, and Yoshinori Fujimoto
The Journal of Organic Chemistry 2014 Volume 79(Issue 12) pp:5471-5477
Publication Date(Web):May 13, 2014
DOI:10.1021/jo5005108
A C29 phytoecdysteroid named amarasterone A (1) has been isolated from Cyathula capitata (Amaranthaceae), Leuzea carthamoides (Asteraceae), and Microsorum scolopendria (Polypodiaceae). We recently isolated amarasterone A from C. officinalis. Amarasterone A has been postulated as a biosynthetic intermediate of cyasterone in Cyathula sp. The stereochemistry at the C-24 and C-25 positions of these amarasterone A samples was investigated by comparing the NMR spectroscopic data with those of stereodefined model compounds, (24R,25S)-, (24R,25R)-, (24S,25S)-, and (24S,25R)-isomers of (20R,22R)-3β-methoxystigmast-5-ene-20,22,26-triol (2a–d), which were synthesized in the present study. Amarasterone A isolated from Cyathula officinalis was determined to be the (24R,25S)-isomer (1a), while amarasterone A from L. carthamoides was found to be the (24R,25R)-isomer (1b). Amarasterone A from M. scolopendria was found to be a mixture of 1a and 1b. The biosynthesis of cyasterone in Cyathula sp. is discussed on the basis of the identical C-24 configuration of sitosterol and amarasterone A.
Co-reporter:Poonam Khandelwal, Pahup Singh, Tohru Taniguchi, Kenji Monde, Kohei Johmoto, Hidehiro Uekusa, Hironori Masubuti, Yoshinori Fujimoto
Phytochemistry Letters 2014 10() pp: 224-229
Publication Date(Web):
DOI:10.1016/j.phytol.2014.10.004
Co-reporter:Hironori Masubuti, Yasuhisa Endo, Hiroshi Araya, Hidehiro Uekusa, and Yoshinori Fujimoto
Organic Letters 2013 Volume 15(Issue 9) pp:2076-2079
Publication Date(Web):April 15, 2013
DOI:10.1021/ol400595k
Sarcodonin ε (2), isolated from Sarcodon scabrosus, was treated with trimethylsilyldiazomethane to yield a crystalline methylated derivative 6. The structure of 6 was determined by X-ray analysis, which confirmed the presence of an unprecedented N(1b)-OMe group, the configuration at N(1b) and the 1,3,4-substituted phenyl ring structure of 2. More importantly, the structures of 6 and 2 have answered the intriguing problem of solving the core structure of the sarcodonin class of natural products, establishing that sarcodonins have a benzodioxazine core structure, rather than the recently proposed benzodioxane aminal core structure.
Co-reporter:Takaomi Sakai;Yuhei Tanemura;Satsuki Itoh
Chemistry & Biodiversity 2013 Volume 10( Issue 6) pp:
Publication Date(Web):
DOI:10.1002/cbdv.201200366
Abstract
Chemical investigation of the glandular trichome exudate of Erodium pelargoniflorum (Geraniaceae) led to the isolation of two dodecyl disaccharide derivatives, named pelargoside A1 and pelargoside B1 (1 and 2, resp.). The structures of 1 and 2 were determined as dodecyl 4-O-acetyl-α-L-rhamnopyranosyl-(12)-4-O-acetyl-β-D-fucopyranoside and dodecyl 3,4-di-O-acetyl-α-L-rhamnopyranosyl-(12)-4-O-acetyl-β-D-fucopyranoside, respectively, by spectroscopic studies, including 2D-NMR, and chemical transformations. In addition, undecyl, tridecyl, and tetradecyl homologs of 1 and 2, named pelargosides A2–A4 and pelargosides B2–B4, were also characterized as minor constituents of the exudate.
Co-reporter:Kiyoshi Ohyama, Akiko Okawa, Yuka Moriuchi, Yoshinori Fujimoto
Phytochemistry 2013 Volume 89() pp:26-31
Publication Date(Web):May 2013
DOI:10.1016/j.phytochem.2013.01.010
The C-26 amino group of steroidal alkaloids, such as tomatine, is introduced during an early step of their biosynthesis from cholesterol. In the present study, the mechanism of C-26 amination was reinvestigated by administering stable isotope labeled compounds, such as (26,26,26,27,27,27-2H6)cholesterol during biosynthesis of tomatine, solanine and solasonine. The chemical compositions of tomatine and solanine so obtained were analyzed by LC–MS after administering the d6-cholesterol to a tomato seedling and a potato shoot, respectively. The resulting spectra indicated that two deuterium atoms were eliminated from C-26 of cholesterol during biosynthesis. Furthermore, administration of (6-13C2H3)mevalonate in combination with lovastatin to an eggplant seedling, followed by GC–MS analysis of solasodine after TMS derivatization established that two deuterium atoms were eliminated from C-26 of cholesterol during solasonine biosynthesis. These findings are in contrast to an earlier observation that one hydrogen atom was lost from C-26 during tomatidine biosynthesis, and suggest that C-26 nitrogen atom addition involves an aldehyde intermediate. Thus, it is proposed that the C-26 amination reaction that occurs during steroidal alkaloid biosynthesis proceeds by way of a transamination mechanism.Graphical abstractElimination of two hydrogen atoms from C-26 of cholesterol during the biosynthesis of tomatine, solanine, chaconine and solasonine suggest a transamination mechanism for the C-26 amination.Highlights► Mechanism of C-26 amination during steroidal alkaloid biosynthesis was investigated. ► Deuterium labeled cholesterol and mevalonate were administered to Solanum lycopersicum, Solanum tuberosum and Solanum melongena. ► Two hydrogen atoms were eliminated from C-26 of cholesterol during steroidal alkaloid biosynthesis. ► It is proposed that the C-26 amination reaction proceeds via a transamination mechanism.
Co-reporter:Akiko Ohkawa;Takaomi Sakai;Kiyoshi Ohyama
Chemistry & Biodiversity 2012 Volume 9( Issue 8) pp:1611-1617
Publication Date(Web):
DOI:10.1002/cbdv.201200097
Abstract
Chemical investigation of the glandular trichome exudate from Ceratotheca triloba (Pedaliaceae) led to the identification of nine 1-O-acetyl-2-O-[(R)-3-acetyloxy-fatty acyl]-3-O-malonylglycerols. Among these, 1-O-acetyl-2-O-[(R)-3-acetyloxyicosanoyl]-3-O-malonylglycerol (7) was the most abundant constituent (41%), followed by 1-O-acetyl-2-O-[(R)-(3-acetyloxyoctadecanoyl)-3-O-malonylglycerol (2; 21%). Compounds having iso- and anteiso-type structures in the 3-acetyloxy-fatty acyl groups in the fatty acyl moiety were also characterized as minor constituents. This is the first report of the isolation of malonylated glycerolipids as natural products.
Co-reporter:Teigo Asai, Yuki Nakamura, Yui Hirayama, Kiyoshi Ohyama, Yoshinori Fujimoto
Phytochemistry 2012 Volume 82() pp:149-157
Publication Date(Web):October 2012
DOI:10.1016/j.phytochem.2012.07.001
Fourteen cyclic glycolipids, named glomerasides A–N, have been isolated from the glandular trichome exudate of Cerastium glomeratum (Caryophyllaceae). Their structures were determined by spectroscopic analysis of the glycolipids, as well as by application of the Ohrui–Akasaka method to the fatty acid methyl esters derived from the glycolipids and GCMS studies of trimethylsilyl ether derivatives of the methyl esters. The various glomerasides have a glycosidic linkage between the anomeric hydroxy group of the glucose and the C-11, C-10 or C-9 positions of the docosanoyl moiety. They also contained an ester linkage between the C-6 hydroxy group of the glucose ring and the carboxyl group of the oxygenated fatty acid to form their macrocyclic structures. The glucose moiety was optionally acetylated and/or malonylated at the C-2 or C-3 hydroxy groups. Among these compounds, the 1,6′-cyclic ester of 11(R)-(2-O-acetyl-β-d-glucopyranosyloxy)docosanoic acid (glomeraside D) was the most abundant (25%).Chemical investigation of glandular trichome exudates of Cerastium glomeratum (Caryophyllaceae) led to identification of fourteen 1,6′-cyclic ester derivatives of 9-, 10- and 11-glucopyranosyloxydocosanoic acids (glomerasides A–N).
Co-reporter:Teigo Asai, Yui Hirayama, Yoshinori Fujimoto
Phytochemistry Letters 2012 5(2) pp: 376-378
Publication Date(Web):
DOI:10.1016/j.phytol.2012.03.006
Co-reporter:Teigo Asai, Yoshinori Fujimoto
Phytochemistry Letters 2011 Volume 4(Issue 1) pp:38-42
Publication Date(Web):15 March 2011
DOI:10.1016/j.phytol.2010.11.001
A glycolipid, 2-acetyl-1-{3-[3,4-di-O-acetyl-β-d-glucopyranosyl-(1 → 3)-2-O-acetyl-α-l-rhamnopyranosyloxy]octadecanoyl}-sn-glycerol (1) and a dammarane triterpene, (2α,20S)-2,20-dihydroxydammar-24-en-3-one (2), along with known (20S)-20-hydroxydammar-24-en-3-one (3), were isolated from the exudates of the glandular trichome-like secretory organs in the young stipules and leaves of Cerasus yedoensis (Rosaceae).Graphical abstractCerasus yedoensis (Rosaceae) has glandular trichome-like organs at the edge of young stipules and leaves. Chemical investigation of the exudates from the secretory organs yielded 2-acetyl-1-{3-[3,4-di-O-diacetyl-β-d-glucopyranosyl-(1 → 3)-2-O-acetyl-α-l-rhamnopyranosyloxy]octadecanoyl}-sn-glycerol and (2α,20S)-2,20-dihydroxydammar-24-en-3-one.Research highlights▶ Glandular trichome-like organs in young stipules and leaves of Cerasus yedoensis. ▶ Isolation of a glycolipid and two dammarane triterpenes from the exudates. ▶ Structure determination of 2-acetyl-1-(3-glycosyloxy-octadecanoyl)-sn-glycerol. ▶ Structure determination of (2α,20S)-2,20-dihydroxydammar-24-en-3-one.
Co-reporter:Chitrasen Gupta;Subedar Prasad;Mahendra Sahai;Teigo Asai;Noriyuki Hara
Helvetica Chimica Acta 2010 Volume 93( Issue 10) pp:1925-1932
Publication Date(Web):
DOI:10.1002/hlca.201000102
Abstract
Six new lanostane triterpenes, artabotryols A, B, C1, C2, D, and E (1, 2, 3a, 3b, 4, and 5, resp.) have been isolated from the seeds of Artabotrys odoratissimus (Annonaceae). Their structures have been established as (3α,22S,25R)-3-hydroxy-22,26-epoxylanost-8-en-26-one (1), (3α,22S,25R)-22,26-epoxylanost-8-ene-3,26-diol (2), (3α,22S,25R,26R)-26-methoxy-22,26-epoxylanost-8-en-3-ol (3a), (3α,22S,25R, 26S)-26-methoxy-22,26-epoxylanost-8-en-3-ol (3b), (3α,22S,25R)-3,22-dihydroxylanost-8-en-26-oic acid (4) and (3α,7α,11α,22S,25R)-3,7,11-trihydroxy-22,26-epoxylanost-8-en-26-one (5) by spectroscopic studies and chemical correlations.
Co-reporter:Teigo Asai, Yoshinori Fujimoto
Phytochemistry 2010 Volume 71(11–12) pp:1410-1417
Publication Date(Web):August 2010
DOI:10.1016/j.phytochem.2010.05.008
Chemical investigation of the glandular trichome exudate from Silene gallica L. (Caryophyllaceae) resulted in isolation of 10 cyclic fatty acyl glycosides (gallicasides A–J). The cyclic structures were characterized by a glycosidic linkage of the glucose moiety to either the C-12 or the C-13 position of the octadecanoyl moiety, and by an ester linkage between the C-2 hydroxy group of the glucose moiety and the carboxyl group of the oxygenated octadecanoic acid. The structures of the cyclic fatty acyl glycosides were further distinguished from one another by acetylation and/or malonylation on the glucose moiety. Of these compounds, the 1,2′-cyclic ester of 12(R)-(6-O-acetyl-3-O-malonyl-β-d-glucopyranosyloxy)octadecanoic acid (gallicaside J) was the most abundant (30.7%). These secondary metabolites were found specifically in the glandular trichome exudate rather than in other aerial parts.Chemical investigation of the glandular trichome exudate on the calyx of Silene gallica (Caryophyllaceae) led to isolation of 10 cyclic ester derivatives of 12- and 13-glucosyloxy-octadecanoic acids.
Co-reporter:Teigo Asai, Noriyuki Hara, Yoshinori Fujimoto
Phytochemistry 2010 Volume 71(8–9) pp:877-894
Publication Date(Web):June 2010
DOI:10.1016/j.phytochem.2010.02.013
Ibicellalutea and Proboscidea louisiana, both of the Martyniaceae family, are known for rich glandular trichomes on their leaves and stems. Chemical investigations of the glandular trichome exudates on leaves of the two plants furnished three types of secondary metabolites, glycosylated fatty acids, glycerides (2-O-(3,6-diacetyloxyfattyacyl)glycerols and 2-O-(3-acetyloxyfattyacyl)glycerols) and dammarane triterpenes. The glycosylated fatty acids from I.lutea were determined to be 6(S)-(6-O-acetyl-β-d-glucopyranosyloxy)-octadecanoic acid (1A), -eicosanoic acid (1B) and -docosanoic acid (1C), as well as their respective deacetyl congeners (2A, 2B and 2C), whereas P. louisiana furnished 8(S)-(6-O-acetyl-β-d-glucopyranosyloxy)-eicosanoic acid (3A) and -docosanoic acid (3B) and their respective deacetyl congeners (4A and 4B), together with 2B. Both plants contained 12 identical 2-O-[(3R,6S)-3,6-diacetyloxyfattyacyl]glycerols (5A-L), in which the fatty acyl moieties contained between 17 and 21 carbon atoms. The corresponding mono-acetyloxy compounds, 2-O-[(3R)-3-acetyloxyfattyacyl]glycerols (6A–L) were detected in both plants. Among these glycerides, ten compounds (5A, 5C, 5F, 5H, 5K, 6A, 6C, 6F, 6H and 6K) had iso-fattyacyl structures and four (5E, 5J, 6E and 6J) had anteiso-fattyacyl structures. A previously unknown dammarane triterpene, betulatriterpene C 3-acetate (7), was isolated together with three known dammarane triterpenes, 24-epi-polacandrin 1,3-diacetate (8), betulatriterpene C (9) and 24-epi-polacandrin 3-acetate (10) from I.lutea, whereas 12 dammarane triterpenes, named probosciderols A–L (12–23), and the known compound betulafolienetriol (11) were isolated from P. louisiana. The structures of these compounds were elucidated by spectroscopic analysis including 2D-NMR techniques and chemical transformations. The 6-O-acetylglucosyloxy-fatty acids 1A–C (42%) and the dammarane triterpenes 7–10 (31%) were the two most abundant constituents in the glandular trichome exudate of I.lutea, whereas the dammarane triterpenes 11–23 (47%) and the glucosyloxy-fatty acids (4A, 4B and 2B) (38%) were the most abundant constituents in the glandular trichome exudate of P. louisiana.Forty-six secondary metabolites, which are classified into 6-O-acetylglucosyloxy-fatty acids, glucosyloxyfatty-acids, 2-(3,6-diacetyloxyfattyacyl)glycerols, 2-(3-acetyloxyfattyacyl)glycerols and dammarane triterpenes, were identified as components of glandular trichome exudates from the leaves of the two plant species.
Co-reporter:Teigo Asai;Noriyuki Hara;Sawa Kobayashi;Shiro Kohshima
Helvetica Chimica Acta 2009 Volume 92( Issue 8) pp:1473-1494
Publication Date(Web):
DOI:10.1002/hlca.200800456
Abstract
Chemical investigations of the glandular trichome exudates on the leaves of Paulownia tomentosa (Scrophulariaceae) led to the identification of the thirty acylglycerols (=glycerides) 1–30, including five known ones (2, 3, 6, 9, and 15) (Fig. 1). Spectroscopic analysis combined with GC/MS studies of the glycerides and the liberated fatty acids, in the form of trimethylsilyl ether derivatives and trimethylsilylated methyl esters, respectively, established that the constituents belonged to 1,3-di-O-acetyl-2-O-(fatty acyl)glycerols, 1-O-acetyl-2-O-(fatty acyl)-sn-glycerols, and 2-O-(fatty acyl)glycerols, wherein the fatty acyl moiety was either an eicosanoyl or an octadecanoyl group bearing OH and/or AcO groups at the 3-, 3,6-, 3,7-, 3,8-, or 3,9-positions. The 1-O-acetyl-2-O-[(3R,6S)-3-(acetyloxy)-6-hydroxyeicosanoyl]-sn-glycerol (12; 20% of the total glycerides), 2-O-[(3R,8R)-3,8-bis(acetyloxy)eicosanoyl]glycerol (17; 14%), 2-O-[(3R,9R)-3,9-bis(acetyloxy)eicosanoyl]glycerol (18; 12%), and 2-O-[(3R)-3-(acetyloxy)eicosanoyl]glycerol (10; 12%) were relatively abundant constituents. The configurations of the stereogenic centers of the fatty acyl moieties were determined by 1H-NMR analysis of the monoesters obtained from (R)- and (S)-2-(naphthalen-2-yl)-2-methoxyacetic acid ((R)- and (S)-2NMAOH and the hydroxy-substituted fatty acid methyl esters (Fig. 2). The configuration at C(2) of the glycerol moiety of the 1-O-acetyl-2-O-(fatty acyl)glycerols was determined to be (2S) by chemical conversion of, e.g., G-2 (=2/3 1 : 10) to (+)-3-O-[tert-butyl)diphenylsilyl]-sn glycerol of known absolute configuration.
Co-reporter:Teigo Asai, Noriyuki Hara, Sawa Kobayashi, Shiro Kohshima, Yoshinori Fujimoto
Phytochemistry 2008 Volume 69(Issue 5) pp:1234-1241
Publication Date(Web):March 2008
DOI:10.1016/j.phytochem.2007.11.011
Chemical investigation of the methanol extract of the viscous secretion on the surface of immature fruits of Paulownia tomentosa furnished nine geranylated flavanones, 6-geranyl-5,7-dihydroxy-3′,4′-dimethoxyflavanone (1), 6-geranyl-3′,5,7-trihydroxy-4′-methoxyflavanone (2), 6-geranyl-4′,5,7-trihydroxy-3′,5′-dimethoxyflavanone (3), 6-geranyl-4′,5,5′,7-tetrahydroxy-3′-methoxyflavanone (4), 6-geranyl-3,3′,5,7-tetrahydroxy-4′-methoxyflavanone (5), 4′,5,5′,7-tetrahydroxy-6-[6-hydroxy-3,7-dimethyl-2(E),7-octadienyl]-3′-methoxyflavanone (6), 3,3′,4′,5,7-pentahydroxy-6-[6-hydroxy-3,7-dimethyl-2(E),7-octadienyl]flavanone (7), 3,3′,4′,5,7-pentahydroxy-6-[7-hydroxy-3,7-dimethyl-2(E)-octenyl]flavanone (8), and 3,4′,5,5′,7-pentahydroxy-3′-methoxy-6-(3-methyl-2-butenyl)flavanone (9), along with six known geranylated flavanones. Among these, compounds 4, 6–9 and the known 6-geranyl-3′,4′,5,7-tetraahydroxyflavanone (diplacone), 6-geranyl-3,3′,4′,5,7-pentahydroxyflavanone (diplacol) and 3′,4′,5,7-pentahydroxy-6-[7-hydroxy-3,7-dimethyl-2(E)-octenyl]flavanone showed potent radical scavenging effects towards DPPH radicals.The viscous secretion on the surface of the immature fruits of Paulownia tomentosa yielded nine flavanones substituted with either a geranyl group, its oxidized forms, or a prenyl group at the C-6 position, along with six known flavanones. Some of these compounds showed more potent anti-oxidant activity than tocopherol towards DPPH radicals.
Co-reporter:Teigo Asai, Yui Hirayama, Yoshinori Fujimoto
Phytochemistry Letters (June 2012) Volume 5(Issue 2) pp:376-378
Publication Date(Web):1 June 2012
DOI:10.1016/j.phytol.2012.03.006
A new sesquiterpene glycoside, (−)-epi-α-bisabolol 6-deoxy-β-d-gulopyranodide (1), has been isolated from the glandular trichome exudate of Brillantaisia owariensis (Acanthaceae). The structure of compound 1 was determined by spectroscopic analysis as well as acidic hydrolysis of 1 leading to (−)-epi-α-bisabolol (2) and 6-deoxy-d-gulose (3). This is the first study to analyze secondary metabolites from glandular trichome exudates of plants belonging to the Acanthaceae family. 6-Deoxygulopyranoside is the first example of an epi-α-bisabolol glycoside of plant origin.Graphical abstractThe structure was elucidated by spectroscopic analysis and acidic hydrolysis leading to (−)-epi-α-bisabolol and 6-deoxy-d-gulose.Download full-size imageHighlights► Chemical investigation of the glandular trichome exudate from Brillantaisia owariensis was conducted. ► The structure determination of (−)-epi-α-bisabolol 6-deoxy-β-d-gulopyranoside was reported. ► This is the first report of the isolation of epi-α-bisabolol glycosides from plants.
![2BETA,3BETA,14ALPHA,22[R],25-PENTAHYDROXY-7-CHOLESTEN-6-ONE](http://img.cochemist.com/ccimg/3700/3604-87-3.png)
![2BETA,3BETA,14ALPHA,22[R],25-PENTAHYDROXY-7-CHOLESTEN-6-ONE](http://img.cochemist.com/ccimg/3700/3604-87-3_b.png)
