Lanosterol glycosides

Triterpenes. The triterpenes (30 carbon atoms) are widely found in nature, especially plants, both in the free state and as esters or glycosides. A smaller but important group, including lanosterol [79-63-0] (114), occurs in animals. The triterpene hydrocarbon, squalene [111-02-4] (115), occurs in the hver oils of certain fish, especially those of sharks. 

Holotoxin Ai inhibits the RNA biosynthesis in Candida albicans and Saccharomyces carlsbergensis, as indicated by the decrease in incorporation of C-uridine to the acid-insoluble fraction of the cells. Similar results were obtained for glycoside fractions of 14 species of Pacific sea cucumbers [132]. Apparently the inhibition of RNA biosynthesis in Saccharomyces carlsbergensis is related to nucleotide loss from yeast cells after treatment with glycosides. Holotoxin Ai also inhibits biosyntheses of squalene, lanosterol and ergosterol in S. carlsbergensis [133]. Mitosis is arrested and DNA synthesis inhibited in onion root bulbs by crude holothurin [134]. 

Cueurbitacins tetracyclic triterpenes found as their glycosides in the Cucurbitaceae and Cruciferae. These toxic, bitter compounds are structurally related to the parent hydrocarbon, cucurbitane [19(10-9P)-abeo-5p-lanostane], which differs from lanostane (see Lanosterol) in the formal shift of the 10-methyl group to the 9p-position. Cucurbitacin E was formerly known as elaterin. C. have a laxative action some serve as insect attractants, and a few have antineo-plastic and antigibberellin activity. 

Sterols are substituted with an isoprenoid side chain at C-17 (Fig. 120). In plants they may be glycosylated (steryl glycosides) or acylated by fatty acids (steryl esters) at the C-3 hydroxy group. Acylated steryl glycosides, e.g., 6-0-palmitoyl-/8-D-glucosyl-sitosterol, also occur in plants. Sterols are grouped according to the pattern of methylation into 4,4-dimethylsterols, e.g., lanosterol and cycloartenol, 4a-methylsterols, e.g., obtusifoliol, and 4-demethylsterols, e.g., cholesterol. 

Ori K, Koroda M, Mimaki Y, Sakagami H, Sashida Y (2003) Lanosterol and tetranorla-nosterol glycosides from the bulbs of Muscari paradoxum. Phytochemistry 64 1351-1359... 

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