Antioxidant phenolic and quinonemethide triterpenes from Cheiloclinium cognatum

The triterpenes, 22beta-hydroxypristimerin and cognatine, were isolated together with the known compounds pristimerin, maytenin, 20alpha-hydroxymaytenin, 22beta-hydroxymaytenin, netzahualcoyol, netzahualcoyondiol and netzahualcoyone from root bark of Cheiloclinium cognatum. The structures of the isolated compounds were elucidated by interpretation of their spectral data, including gHMQC and gHMBC experiments.The isolates were investigated for their radical scavenging abilities through a spectrophotometric assay involving reduction of 2,2-diphenyl-picryl hydrazyl (DPPH).     

Biosynthesis of friedelane and quinonemethide triterpenoids is compartmentalized in Maytenus aquifolium and Salacia campestris

Maytenus aquifolium (Celastraceae) and Salacia campestris (Hippocrateaceae) species accumulate friedelane and quinonemethide triterpenoids in their leaves and root bark, respectively. Enzymatic extracts obtained from leaves displayed cyclase activity with conversion of the substrate oxidosqualene to the triterpenes, 3beta-friedelanol and friedelin. In addition, administration of (+/-)5-(3)H mevalonolactone in leaves of M. aquifolium seedlings produced radio labelled friedelin in the leaves, twigs and stems, while the root bark accumulated labelled maytenin and pristimerin. These experiments indicated that the triterpenes once biosynthesized in the leaves are translocated to the root bark and further transformed to the antitumoral quinonemethide triterpenoids.     

Root cultures of Monteverdia floribunda (Reissek) Biral grown in air sparging systems are sources of quinonemethide triterpenes

Plant Cell, Tissue and Organ Culture (PCTOC) - Quinonemethide triterpenes (QMTs) are chemotaxonomic markers of the family Celastraceae that are known to possess anti-inflammatory, antioxidant and...     

Pentacyclic triterpenes from Euphorbia stygiana

Two pentacyclic triterpenes, D-friedomadeir-14-en-3beta-yl acetate and D:C-friedomadeir-7-en-3beta-yl acetate, named madeiranyl acetate and isomadeiranyl acetate, respectively, were isolated from leaves of Euphorbia stygiana, together with the two known madeiranes, D-friedomadeir-14-en-3-one and D:C-friedomadeir-7-en-3-one, which were obtained from the stem bark. In addition, four known lupane and taraxerane-type triterpenes, namely lupenyl acetate, lupenone, taraxeryl acetate and taraxerone, were also isolated from the same source. Structures were elucidated by physical, chemical and spectroscopic methods (1H NMR, 13C NMR, IR and mass spectra) and by comparison with literature data, and in the case of D:C-friedomadeir-7-en-3beta-yl acetate by X-ray analysis as well.     

Tirucallane-type triterpenes from Juliania adstringens

Five tirucallane-type triterpenes were isolated along with nine known triterpenes from the bark of Juliania adstringens. The structures of the five triterpenes were determined by analysis of their 1H and 13C NMR and mass spectral data, and each compound exhibited growth inhibitory activity against leukemia cells (L-1210).     

Minor triterpenes from Orthopterygium huancuy

Two new triterpenes, 3-oxo-20-hydroxy-lupan-28-oic and 3β,6β-dihydroxy-olean-18-en-28-oic acids, along with oleanonic, morolic and sumaresinolic acids have been isolated from Orthopterygium huancuy. The structure of the first new terpene was determined by single crystal X-ray analysis.     

Pentacyclic triterpenes from Chuquiraga ulicina

Four taraxastane triterpenes, 3 beta-acetoxy-6 beta-hydroxytaraxasta-20-ene, 6 beta-hydroxytaraxasta-20-en-3-one, 6 beta-hydroxytaraxasta-20-ene 3 beta-palmitate and 3 beta,6 beta-dihydroxytaraxasta-20-ene were isolated from the dichloromethane-methanol extract of Chuquiraga ulicina ssp. ulicina together with the known triterpenes lupeol, lupenyl acetate, lupenone, friedelinol, 3 beta-acetoxy-30-nor-lupan-20-one, and 30-nor-lupan-3 beta-ol-20-one.     

Two triterpenes from Davidsonia pruriens

Two new triterpenoids, methyl 3-oxo-bauer-7-en-28-oate and 3β-hydroxy-bauer-7-en-28-oic acid, were isolated from the stem bark of Davidsonia pruriens and their structures were established by chemical and spectroscopic means.     

Three triterpenes from Astraeus hygrometricus

Three new triterpenes, as well as two known steroids, were isolated fromAstraeus hygrometricus. The structures of the new triterpenes were established by chemical and spectroscopic means.     

Tetracyclic triterpenes from Parthenium fruticosum

The shrub Parthenium fruticosum was shown to contain the three isomeric tetracyclic triterpenes fruticin A, fruticin B and the known incanilin. Fruticins A and B are new substances with lanostane and cycloartane skeletons, respectively. Their structures were determined by chemical and spectroscopic methods. The stereochemistry of fruticin B was established by X-ray diffraction analysis.     

Trypanocidal activity of quinonemethide triterpenoids from Cheiloclinium cognatum (Hippocrateaceae)

We report the trypanocidal activity of quinonemethide triterpenoids isolated from root extracts of Cheiloclinium cognatum, a plant of the Hippocrateaceae family, collected in the Cerrado Reserve at Universidade Federal de Goiás, Brazil. The trypanocidal activity assays showed an effect on the blood trypomastigote forms of the Y strain of Trypanosoma cruzi where tingenone and tingenol demonstrated activity on the parasite. Their structures were elucidated on the basis of spectral data, particularly COSY, HMQC and HMBC experiments, and chemical transformations.     

Two new pyrrole derivatives isolated from Salacia amplifolia Merr

Two new pyrrole derivatives Salaciamole (1), Salaciaglycoside A (2), long with one known compound 1H-pyrrole-3-carboxylic acid (3) were isolated from the roots of Salacia amplifolia Merr (Hippocrateaceae). The structures of the new compounds were deduced from their comprehensive spectroscopic analysis including IR, HR-EI-MS, ¹H NMR, ¹³C NMR, DEPT, COSY, HMBC and HMQC. And the structure of the known compound was identified by comparison of their spectral data with those reported in the literature.     

Two pentacyclic triterpenes from Rubia cordifolia

Rubicoumaric acid and rubifolic acid isolated from Rubia cordifolia have been shown to be 30-hydroxy-3β-p-hydroxycoumaryloxy-urs-12-ene-28-oic acid and 3β,30-dihydroxy-urs-12-ene-28-oic acid(30-hydroxyursolic acid) respectively on the basis of ¹H NMR, ¹³C NMR and mass spectral and chemical evidence.     

21beta-Hydroxy-oleanane-type triterpenes from Hippocratea excelsa

Stem bark of Hippocratea excelsa afforded six pentacyclic triterpenes, five oleanane and one ursane types. They were identified as 11beta,21beta-dihydroxy-olean-12-ene-3-one (2), 3alpha,11alpha,21beta-trihydroxy-olean-12-ene (3), 3alpha,21beta-dihydroxy-11alpha-methoxy-olean-12-ene (4), 3alpha,21beta-dihydroxy-olean-9(11),12-diene (5), 3alpha,21beta-dihydroxy-olean-12-ene (6) and 3alpha,21beta-dihydroxy-11alpha-methoxy-urs-12-ene, isolated as its diacetate derivative (7), as well as 3alpha,21beta-dihydroxy-olean-12-ene (1) previously isolated from the root bark. The known alpha- and beta-amyrin, oleanoic and ursolic acids, trans-polyisoprene, and the ubiquitous beta-sitosterol were also isolated. Structures were elucidated on the basis of spectroscopic analyses, including homo- and heteronuclear correlation NMR experiments (COSY, ROESY, HSQC and HMBC) and comparison with literature data. The antigiardial activity of compounds 2-5 was not significant.     

Antimitotic quinoid triterpenes from Maytenus chuchuhuasca

Four cytotoxic quinoid triterpenes, tingenone (1), 22 beta-hydroxytingenone (2), pristimerin (3), and celastrol (4), isolated from Maytenus chuchuhuasca, potently inhibit the polymerization of tubulin.