Synthesis of Vinyl-Containing Lupane- and a-Secolupane-Type Triterpene Esters

Two novel triterpene esters were isolated from the leaves of Ceriops decandra in addition to 16 known triterpenes: lupenone 3, lupeol 4, betulinaldehyde 5, 3β-Z-coumaroyllupeol 6, 3β-E-coumaroyllupeol 7, 3-epi-betulinic acid 8, betulin 9, betulinic acid 10, 3β-E-feruloylbetulin 11, 30-nor-lup-3β-ol-20-one 12, 3β-E-caffeoyllupeol 13, lup-20(29)-en-3β,30-diol 14, 3β-hydroxylupan-29-oic acid 15, 3β,20-dihydroxylupane 16, and a mixture of oleanolic and ursolic acid 17 and 18. The new compounds were determined by spectroscopic methods to be 3β-E-feruloyllupeol 1 and 3β-Z-feruloyllupeol 2. Compounds 3 and 5–16 were reported for the first time as metabolites of C. decandra.

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Triterpene Esters: Natural Products from Dorstenia arifolia (Moraceae)

Molecules ◽

10.3390/molecules18044247 ◽

2013 ◽

Vol 18 (4) ◽

pp. 4247-4256 ◽

Cited By ~ 19

Author(s):

Catharina Fingolo ◽

Thabata Santos ◽

Marcelo Filho ◽

Maria Kaplan

Keyword(s):

Natural Products ◽

Triterpene Esters

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Characterization of a Pentacyclic Triterpene Acetyltransferase Involved in the Biosynthesis of Taraxasterol and ψ-Taraxasterol Acetates in Lettuce

Frontiers in Plant Science ◽

10.3389/fpls.2021.788356 ◽

2022 ◽

Vol 12 ◽

Author(s):

Han Suk Choi ◽

Jung Yeon Han ◽

Eun Ju Cheong ◽

Yong Eui Choi

Keyword(s):

Amino Acid ◽

Ectopic Expression ◽

Fatty Acyl ◽

Amino Acid Sequences ◽

Acyl Donor ◽

Amino Acid Residues ◽

Pentacyclic Triterpene ◽

Free System ◽

Oxidosqualene Cyclase ◽

Triterpene Esters

Triterpenoids exist in a free state and/or in conjugated states, such as triterpene glycosides (saponins) or triterpene esters. There is no information on the enzyme participating in the production of triterpene esters from free triterpenes. Lettuce (Lactuca sativa) contains various pentacyclic triterpene acetates (taraxasterol acetates, ψ-taraxasterol acetates, taraxerol acetates, lupeol acetates, α-amyrin acetates, β-amyrin acetates, and germanicol acetate). In this study, we report a novel triterpene acetyltransferase (LsTAT1) in lettuce involved in the biosynthesis of pentacyclic triterpene acetates from free triterpenes. The deduced amino acid sequences of LsTAT1 showed a phylogenetic relationship (43% identity) with those of sterol O-acyltransferase (AtSAT1) of Arabidopsis thaliana and had catalytic amino acid residues (Asn and His) that are typically conserved in membrane-bound O-acyltransferase (MBOAT) family proteins. An analysis of LsTAT1 enzyme activity in a cell-free system revealed that the enzyme exhibited activity for the acetylation of taraxasterol, ψ-taraxasterol, β-amyrin, α-amyrin, lupeol, and taraxerol using acetyl-CoA as an acyl donor but no activity for triterpene acylation using a fatty acyl donor. Lettuce oxidosqualene cyclase (LsOSC1) is a triterpene synthase that produces ψ-taraxasterol, taraxasterol, β-amyrin and α-amyrin. The ectopic expression of both the LsOSC1 and LsTAT1 genes in yeast and tobacco could produce taraxasterol acetate, ψ-taraxasterol acetate, β-amyrin acetate, and α-amyrin acetate. However, expression of the LsTAT1 gene in tobacco was unable to induce the conversion of intrinsic sterols (campesterol, stigmasterol, and β-sitosterol) to sterol acetates. The results demonstrate that the LsTAT1 enzyme is a new class of acetyltransferase belong to the MBOAT family that have a particular role in the acetylation of pentacyclic triterpenes and are thus functionally different from sterol acyltransferase conjugating fatty acyl esters.

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New Anti-inflammatory Triterpene Esters and Glycosides from Alstonia scholaris

Anti-Inflammatory & Anti-Allergy Agents in Medicinal Chemistry ◽

10.2174/1871523018666190724122406 ◽

2020 ◽

Vol 19 (4) ◽

pp. 370-386

Author(s):

Nighat Sultana ◽

Muhammad Saleem Qazi ◽

Mustafa Kamal

Keyword(s):

Ethanolic Extract ◽

Two Dimensional ◽

1H And 13C Nmr ◽

Alstonia Scholaris ◽

Aerial Parts ◽

Nmr Data ◽

Lupeol Acetate ◽

Anti Inflammatory ◽

Phytochemical Studies ◽

Triterpene Esters

Background:: Phytochemical studies on the ethanolic extract of aerial parts of Alstonia scholaris lead to the isolation of two new triterpenoid of the lanostanetype, lanosta 5ene,24-ethyl-3-O-β-D-glucopyranoside (1), lanosta,5ene,24-ethyl-3-O-β-D-glucopyranosideester (2) and new ursane type triterpenoidmethylester, 12-ursene-2,3,18,19-tetrol,28 acetate (nighascholarene) (3), together with seven known triterpenes, betuline, triterpene of the lupane type, alstoprenyol (4), 3β-hydroxy-28-β-acetoxy-5-olea triterpene (5),α-amyrin acetate (6), α-amyrin (7), lupeol acetate (8), 3β-hydroxy-24-nor-urs-4,12,28-triene triterpene (9) and ursolic acid (l0). Methodology:: The triterpenoid structures of these colorless compounds were deduced from the 1H and 13C-NMR data, and in particular from the application of two-dimensional 1H, 13C correlation experiments as well as by comparison with reported literature data. Results and Conclusion: This study deals with isolation and structural elucidation of natural new triterpenoidesters and glycosides with anti-inflammatory activity.

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