Abstract
Hairy roots of Ajuga reptans var. atropurpurea produce clerosterol, 22- dehydroclerosterol, and cholesterol as sterol constituents, and 20- hydroxyecdysone, cyasterone, isocyasterone, and 29-norcyasterone as ecdysteroid constituents. To better understand the biosynthesis of these steroidal compounds, we carried out feeding studies of variously 2H- and 13C-labeled sterol substrates with Ajuga hairy roots. In this article, we review our studies in this field. Feeding of labeled desmosterols, 24- methylenecholesterol, and 13C2-acetate established the mechanism of the biosynthesis of the two C29-sterols and a newly accumulated codisterol, including the metabolic correlation of C-26 and C-27 methyl groups. In Ajuga hairy roots, 3α-, 4α-, and 4β-hydrogens of cholesterol were all retained at their original positions after conversion into 20-hydroxyecdysone, in contrast to the observations in a fern and an insect. Furthermore, the origin of 5β-H of 20-hydroxyecdysone was found to be C-6 hydrogen of cholesterol exclusively, which is inconsistent with the results in the fern and the insect. These data strongly support the intermediacy of 7-dehydrocholesterol 5α,6α-epoxide. Moreover, 7-dehydrocholesterol, 3β-hydroxy-5β-cholest-7- en-6-one (5β-ketol), and 3β,14α-dihydroxy-5β-cholest-7-en-6-one (5β- ketodiol) were converted into 20-hydroxyecdysone. Thus, the pathway cholesterol → 7-dehydrocholesterol → 7-dehydrocholesterol 5α, 6α-epoxide → 5β-ketol → 5β-ketodiol is proposed for the early stages of 20- hydroxyecdysone biosynthesis. 3β-Hydroxy-5β-cholestan-6-one was also incorporated into 20-hydroxyecdysone, suggesting that the introduction of a 7-ene function is not necessarily next to cholesterol. C-25 Hydroxylation during 20-hydroxyecdysone biosynthesis was found to proceed with ca. 70% retention and 30% inversion. Finally, clerosterol was shown to be a precursor of cyasterone and isocyasterone.
| Original language | English |
|---|---|
| Pages (from-to) | 279-288 |
| Number of pages | 10 |
| Journal | Lipids |
| Volume | 35 |
| Issue number | 3 |
| Publication status | Published - 2000 |
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ASJC Scopus subject areas
- Medicine (miscellaneous)
- Biochemistry, Genetics and Molecular Biology(all)
- Food Science
- Biochemistry
Cite this
Biosynthesis of sterols and ecdysteroids in Ajuga hairy roots. / Fujimoto, Yoshinori; Ohyama, Kiyoshi; Nomura, Keiko; Hyodo, Ryo; Takahashi, Kyoko; Yamada, Junko; Morisaki, Masuo.
In: Lipids, Vol. 35, No. 3, 2000, p. 279-288.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Biosynthesis of sterols and ecdysteroids in Ajuga hairy roots
AU - Fujimoto, Yoshinori
AU - Ohyama, Kiyoshi
AU - Nomura, Keiko
AU - Hyodo, Ryo
AU - Takahashi, Kyoko
AU - Yamada, Junko
AU - Morisaki, Masuo
PY - 2000
Y1 - 2000
N2 - Hairy roots of Ajuga reptans var. atropurpurea produce clerosterol, 22- dehydroclerosterol, and cholesterol as sterol constituents, and 20- hydroxyecdysone, cyasterone, isocyasterone, and 29-norcyasterone as ecdysteroid constituents. To better understand the biosynthesis of these steroidal compounds, we carried out feeding studies of variously 2H- and 13C-labeled sterol substrates with Ajuga hairy roots. In this article, we review our studies in this field. Feeding of labeled desmosterols, 24- methylenecholesterol, and 13C2-acetate established the mechanism of the biosynthesis of the two C29-sterols and a newly accumulated codisterol, including the metabolic correlation of C-26 and C-27 methyl groups. In Ajuga hairy roots, 3α-, 4α-, and 4β-hydrogens of cholesterol were all retained at their original positions after conversion into 20-hydroxyecdysone, in contrast to the observations in a fern and an insect. Furthermore, the origin of 5β-H of 20-hydroxyecdysone was found to be C-6 hydrogen of cholesterol exclusively, which is inconsistent with the results in the fern and the insect. These data strongly support the intermediacy of 7-dehydrocholesterol 5α,6α-epoxide. Moreover, 7-dehydrocholesterol, 3β-hydroxy-5β-cholest-7- en-6-one (5β-ketol), and 3β,14α-dihydroxy-5β-cholest-7-en-6-one (5β- ketodiol) were converted into 20-hydroxyecdysone. Thus, the pathway cholesterol → 7-dehydrocholesterol → 7-dehydrocholesterol 5α, 6α-epoxide → 5β-ketol → 5β-ketodiol is proposed for the early stages of 20- hydroxyecdysone biosynthesis. 3β-Hydroxy-5β-cholestan-6-one was also incorporated into 20-hydroxyecdysone, suggesting that the introduction of a 7-ene function is not necessarily next to cholesterol. C-25 Hydroxylation during 20-hydroxyecdysone biosynthesis was found to proceed with ca. 70% retention and 30% inversion. Finally, clerosterol was shown to be a precursor of cyasterone and isocyasterone.
AB - Hairy roots of Ajuga reptans var. atropurpurea produce clerosterol, 22- dehydroclerosterol, and cholesterol as sterol constituents, and 20- hydroxyecdysone, cyasterone, isocyasterone, and 29-norcyasterone as ecdysteroid constituents. To better understand the biosynthesis of these steroidal compounds, we carried out feeding studies of variously 2H- and 13C-labeled sterol substrates with Ajuga hairy roots. In this article, we review our studies in this field. Feeding of labeled desmosterols, 24- methylenecholesterol, and 13C2-acetate established the mechanism of the biosynthesis of the two C29-sterols and a newly accumulated codisterol, including the metabolic correlation of C-26 and C-27 methyl groups. In Ajuga hairy roots, 3α-, 4α-, and 4β-hydrogens of cholesterol were all retained at their original positions after conversion into 20-hydroxyecdysone, in contrast to the observations in a fern and an insect. Furthermore, the origin of 5β-H of 20-hydroxyecdysone was found to be C-6 hydrogen of cholesterol exclusively, which is inconsistent with the results in the fern and the insect. These data strongly support the intermediacy of 7-dehydrocholesterol 5α,6α-epoxide. Moreover, 7-dehydrocholesterol, 3β-hydroxy-5β-cholest-7- en-6-one (5β-ketol), and 3β,14α-dihydroxy-5β-cholest-7-en-6-one (5β- ketodiol) were converted into 20-hydroxyecdysone. Thus, the pathway cholesterol → 7-dehydrocholesterol → 7-dehydrocholesterol 5α, 6α-epoxide → 5β-ketol → 5β-ketodiol is proposed for the early stages of 20- hydroxyecdysone biosynthesis. 3β-Hydroxy-5β-cholestan-6-one was also incorporated into 20-hydroxyecdysone, suggesting that the introduction of a 7-ene function is not necessarily next to cholesterol. C-25 Hydroxylation during 20-hydroxyecdysone biosynthesis was found to proceed with ca. 70% retention and 30% inversion. Finally, clerosterol was shown to be a precursor of cyasterone and isocyasterone.
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UR - http://www.scopus.com/inward/citedby.url?scp=0034075686&partnerID=8YFLogxK
M3 - Article
C2 - 10783005
AN - SCOPUS:0034075686
VL - 35
SP - 279
EP - 288
JO - Lipids
JF - Lipids
SN - 0024-4201
IS - 3
ER -