Two unsymmetric tetracyclic triterpenoids from cissus quadrangularis

Two new unsymmetric tetracyclic triterpenoids onocer-7-ene-3α,21β-diol and onocer-7-ene-3β,21α-diol together with sitosterol, δ-amyrin and δ-amyrone have been isolated from Cissus quadrangularis. The structures of the new compounds were elucidated on the basis of ¹H NMR, mass spectral and chemical evidence.     

Triterpenoids of Salvia horminum,constitution of a new diol

Lupeol, lup-(20)29-ene-2α,3β-diol and a new triterpenic alcohol olean-(13)18-ene-2β,3β-diol were isolated from the petrol extract of air dried Salvia horminum and their structures were determined.     

Triterpenoids from Salvia pinnata

A new and four known triterpenoids have been isolated from the leaves of Salvia pinnata. The structures of these compounds have been established by spectral data and by some chemical reactions.     

Two new triterpenoids from Rhodomyrtus tomentosa

Repetition of an investigation of the petrol extracts of Rhodomyrtus tomentosa has led to the isolation of two new triterpenoids, R₄ from the leaves and R₅ from the stems besides R₁, R₂, R₃ and the other known compounds already reported. R₁ and R₄ were proved to be 21α$\text{H}$-hop-22(29)en-3β,30-diol and 3β-hydroxy-21α$\text{H}$-hop-22(29)-en-30-al respectively, and R₂, R₃ and R₅ are 3β-acetoxy-11α,12α-epoxyoleanan-28,13β-olide, 3β-acetoxy-12α-hydroxyoleanan-28, 13β-olide and 3β-acetoxy-12-oxo-oleanan-28,13β- olide respectively. The ethanol extract of the leaves contained betulinic, ursolic and aliphitolic acids and that of the stems betulonic, betulinic and oleanolic acids.     

Chemical Constituents from Fruits of Rosa davidii

From the fruit of Rosa davidii Crep., eleven compounds were isolated and identified by spectral evidence, viz. 2α,3β,19β-trihydroxyl-olean-12-en-28-oic acid (1), 2α,3β-dihydroxyl-urs-28(13)-lactone (2), arjunic acid (3), euscaphic acid (4), 2α,3β-dihydroxyl-urs-12-en-28-oic acid (5), oleanolic acid (6), kaempferol (7), tiliroside (8), quercetin (9), daucosterol (10) and β-sitosterol (11). Among them, 1 and 2 were new compounds.     

Studies on the Structures of Two New Triterpene Saponins C and D from Polygala japoni-ca Houtt

Two new triterpene saponins C and D have been isolated from the aerial parts of Polygala japonica Houtt. Their molecular formulas: C42H68O15 were structural isomers of each other. Acid hydrolysis of the two saponins all produced a sapogenin (2a, 3a, 24-trihydroxyo-lean-12-ene-28-oic acid) and D-glucoses. But only the saponin D could be hydrolyzed in the alkaline solution, the products were identical with those from acid hydrolysis. Their structures have been established by means of 1HNMR,13CNMR and MS as 3-O-[β-D-glucopyranosyl(l→2)β-D-glucopyranosyl] 2α, 3α, 24-trihydroxyolean-12-ene-28-oic acid, 28-O-[β-D-glucopy-ranosyl (1→2)-β-D-glucopyranosyl] 2α, 3α, 24-trihydroxyolean-12-ene-28-oic acid.     

Study on the Structure of a New Triterpene Saponin B from Polygala japoniea Houtt

A new triterpene saponin B has been isolated from the earial parts of Polygala japonica Houtt in folk-lore medicine. Its molecular: C48H78O20, m.p. 199–202℃, [α]D23+30.0 (C, 0.5, CH3OH). Acidic hydrolysis of this saponin gave a sapogenin (2α, 3α, 24-tri-hydroxyolean-12-ene-28-oic acid) and D-glucose. The structure of saponin B was elucidated as 28-O- [β-D-glucopyranosyl (1→2) -β-D-glucopyranosyl (1→2) -β-D-glucopy- ranosyl] 2α, 3α, 24-trihydroxyolean-12-ene-28-oic acid mainly by 13C-NMR, MS and some chemical transfomations.     

Anti-HIV-1 protease triterpenoids from Stauntonia obovatifoliola Hayata subsp. intermedia

Three triterpenoids, 16beta-hydroxy-2,3-seco-lup-20(29)-ene-2,3-dioic acid (1), 3beta,21beta,24-trihydroxy-30-noroleana-12,20(29)-dien-28-oic acid (2) and 16beta-hydroxylupane-1,20(29)-dien-3-one (3), along with eleven known triterpenes were isolated from stems of Stauntonia obovatifoliola Hayata subsp. intermedia (Y.C. Wu) T. Chen. Their structures were determined by analysis of HR-EI/FAB-MS and 1D and 2D NMR spectroscopic data and comparison with those in the literature. Ten of the compounds showed inhibitory activity against HIV-1 protease.     

Methoxylation of methyl 3α,7α-dihydroxychol-4-en-24-oate and its 3β-epimer. —a contribution to chenodeoxycholic acid biogenesis

By the conventional methods of gas liquid chromatography (GLC) as well as mass spectrometry, 3β,7α-dihydroxychol-5-en-24-oic acid (Δ⁵-acid), a key intermediate of chenodeoxycholic acid biogenesis and its metabolic by-product, 3α,7α-dihydroxychol-4-en-24-oic acid (Δ⁴-acid) have not yet been identified as such probably due to thermal decomposition. However, taking advantage of the observation that they are readily methoxylated in methanoi containing a trace of acids, their individual methoxy-compounds were easily prepared and proved to be useful for their identification, even though they are present in minimal amounts as was the case with the human or hen bile. The present paper reported physical as well as spectral properties of the methoxy-compounds derived from methyl 3α,7α-dihydroxychol-4-en-24-oate, compared with those of its 3β-epimer     

Carbon-carbon bond cleavage of fucosterol-24, 28-oxide by cell-free extracts of silkworm Bombyx mori.

The 1500 X g supernatant of the silkworm $\text{Bombyx mori}$ gut homogenate catalyzed the conversion of 24, 28-epoxystigmast-5-en-3β-ol(III) to cholesta-5, 24-dien-3β-ol(IV) which is a key step of stigmast-5-en-3β-ol(I) dealkylation in the insects. A structural analog 24, 28-imino-stigmast-5-en-3β-ol(VI) was a potent inhibitor of this conversion.     

Triterpenes of five euphorbiaceae species of Sri Lanka

Five endemic species of Euphorbiaceae have been investigated. Aleuritolic acid and its derivatives were isolated from P. thwaitesii. A. cardiosperma had friedelan derivatives. The Glochidion species contained the same triterpenes, viz. glochidonol, lup-20(29)-ene-3α,23-diol and glochidiol. The bark extractives of a new Glochidion species had, in addition, glochidone and probably lup-20(29)-ene-1α,3α,23-triol. The latter is a new natural product. Glochidone was isolated for the first time outside the genus Glochidion from Bridelia moonii.     

Cholinesterase inhibitory triterpenoids from the bark of Garcinia hombroniana

Abstract

Context: Garcinia hombroniana Pierre, known as manggis hutan in Malaysia is a rich source of xanthones and benzophenones.

Objectives: This study was aimed to isolate and characterize potential cholinesterase inhibitors from the extracts of G. hombroniana bark and investigate their interactions with the enzymes.

Materials and methods: The dichloromethane extract afforded five triterpenoids which were characterized by NMR and mass spectral techniques. Cholinesterase inhibitory assay and molecular docking were performed to get insight of the inhibitory activity and molecular interactions of the compounds. The compounds were also tested for their antioxidant capacity.

Results: The isolated triterpenoids were identified as: 2β-hydroxy-3α-O-caffeoyltaraxar-14-en-28-oic acid (1), taraxerol (2), taraxerone (3), betulin (4) and betulinic acid (5). Compound 1 was the most active dual inhibitor of both AChE and BChE. Compound 1 also showed good antioxidant activities.

Conclusion: Compound 1 had dual and moderate inhibitory activity on AChE and BChE worthy for further investigations.     

Triterpene constituents of Caltha palustris

The structure of a new triterpene lactone, palustrolide, has been elucidated as 3β,23-dihydroxylupan-13β→28 lactone on the basis of physico-chemical studies. In addition, sitosterol, its glucoside, hederagenin, 16,17-dihydroxykauran-19-oic acid and hederagenic acid have been characterized.     

Structure of terminic acid,a dihydroxytriterpene carboxylic acid from Terminalia arjuna

The structure of terminic acid, a new dihydroxytriterpene carboxylic acid isolated from the roots of Terminalia arjuna, has been established as 3β, 13β-dihydroxylup-20(29)-en-28-oic acid by a study of its chemical reactions and spectroscopic data. Terminic acid and its derivatives were found to undergo skeletal rearrangement under protonic conditions to yield oleanene lactone.     

3β-hydroxy-21β-e-cinnamoyloxyolean-12-en-28-oic acid,a triterpenoid from enterolobium contorstisiliquum

The triterpenes 3β-hydroxy-21β-E-cinnamoyloxyolean-12-en-20-oic acid, 3β,21β-dihydroxyolean-12-en-28-oic acid (machaerinic acid) and its lactone (3β-hydroxyolean-12-en-21β→28-lactone) were isolated from the fruits of Enterolobium contorstisiliquum. Methyl and ethyl esters of 3β,21β-dihydroxyolean-12-en-oic acid were isolated and characterized as artifacts. The structures of these triterpenes have been established by a study of their chemical and spectroscopic (IR, MS and NMR) data.     

Two triterpenoid carboxylic acids from Acanthopanax trifoliatus

Two new triterpenoid carboxylic acids have been isolated from leaves of Acanthopanax trifoliatus and their structures elucidated as 3α, 11α-dihydroxylup-20(29)-en-28-oic acid and 30α, 11α,23-trihydroxylup-20(29)-en-28-oic acid by physical data and chemical transformations.     

Three triterpenes and other terpenoids from Catha cassinoides

The investigation of stems and leaves of Catha cassinoides afforded, in addition to sitosterol, β-amyrin, ursolic acid, lup-20(29)-en-3β,30-diol and friedelin, three new pentacyclic triterpenes: 30-hydroxyfriedelan-3-one, 29-hydroxyfriedelan-3-one and 3-oxo-friedelan-29-oic acid. The structures ofthese were determined by spectral studies and correlations, and were confirmed by X-ray analysis of 29-hydroxyfriedelan-3-one acetate.