Category:TP3
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===Biosynthesis=== | ===Biosynthesis=== | ||
Revision as of 19:18, 31 July 2010
Contents |
Triterpene (C30) Biosynthesis
Triterpenes are formed by joining two FPPs tail-to-tail. The precursor compound of cholesterol (C27) is lanosterol (C30) for animals. For plants, fungi and algae, it is almost cycloartenol with a trace of lanosterol-derived sterols[1].
Steroid
Ring configuration
The basic steroid structure is 4 carbon rings, cyclopenta[a]phenanthrene, gonane, or sterane.
The rings B/C are always trans in all natural steroids. If the rings C/D are trans, it is called gonane. If its stereochemistry is unspecified, it is called sterane.
Most steroids take gonane form, but in cardenolides and bufadienolides, the rings C/D are cis.
The majority of steroids have methyl groups sticking out from the bridgehead positions C-10 and C-13.
When these methyl groups (or hydrogens) stand above the plane, they are called β-configuration.
Those below the plane are called α-configuration.
By default, hydrogen atoms or substituents at the positions C-8, 9, 10, 13, and 14 are assumed to be
8β, 9α, 10β, 13β, and 14α configurations. C-5 is a special position, because there are as many 5α steroids as 5β are. If the configuration at any site is unknown, it is indicated as ξ (Greek Xi).
 |
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| Cyclopenta[a]phenanthrene | Gonane |
Biosynthesis
 2,3-Oxidosqualene |
|
 ダンマラン (dammarane) 型 |
| ||
 Cholestane-type |
|
 Lanostane-type |
|
| ||
 Pregnane-type |
|
  Androstane- and Estrane-type |
Phytosterols
Most common phytosterols are campesterol, β-sitosterol, and stigmasterol. Soybean (Glycine max, Fabaceae) is a rich source of phytosterols (about 0.1% of its weight), and is used for semi-synthesis of medicinal steroids [2]. Since dietary phytosterols reduce cholesterol levels, they are used as food additives such as for margarine [3]. Vitamin D is a family of sterol metabolites generated photochemically in our skin by UV irradiation.
Saponins
Saponins are surfactant glycosides, i.e., they produce foams in aqueous solution and therefore are called ‘sapo’ (a Latin for soap). Plant-based crude drugs are still actively prescribed in Eastern Asia, and many of their active components are attributed to saponins. Well known examples of saponin and its aglycone include glycyrrhizin from liquorice (Glycyrrhiza uralensis/glabra, Category:Fabaceae) used in European confectionery and Asian medicine; ginsenosides from ginseng (Panax ginseng, Araliaceae) for tonic, especially in Korea; diosgenin from wild yam (Dioscorea spp., Dioscoreaceae) for hormone replacement therapy.
| 2,3-Oxidosqualene |
|
ダンマラン (dammarane) 型 |
| ring rearrangement
| ||
 Lupane-type |
|
 Baccharane-type |
|
| ||
 Oleanane-type |
|
 Taraxastane-type |
Design of Tri-terpene ID numbers ID番号の設計
12-DIGIT
| T | P | 3 | x | y | y | r | h | g | n | c | c |
- x ... species information
| Symbol at x | Kingdom | Phyla | Examples |
|---|---|---|---|
| I | Animalia | Arthropoda (Insects, crabs) | ecdysteroids |
| V | Chordate (Vertebrates) | sex steroids, corticosteroids, anabolic steroids | |
| O | Others | marine steroids | |
| P | Plantae | Phytosterols | lanosterols, cholesterols, brassinolides |
| S | Saponins | saponins | |
| F | Fungi | ergosterols | ergosterols |
| B | Bacteria | bacterial sterols | hopanoids |
- y ... backbone structure (母核構造)
|
|
- r ... number of major rings (環構造数)
Click above categories to see details.
- h ... hydroxylation pattern (水酸基数)
Click above categories to see details.
- g ... glycosylation pattern(糖修飾パターン)
Click above categories to see details.
- n ... number of sugars (修飾糖数)
Click above categories to see details.
- c ... serial number (通し番号)
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