A guaianolide and other constituents from Lychnophora species

A new guaianolide, 11 β,13-dihydroeremanthine, together with a caryophyllene derivative and pentacyclic triterpenes, has been isolated from Lychnophora species.     

5-Formylfurfuryl esters from Duabanga grandiflora

5-Formylfurfuryl esters, duabanganals A–D, together with sixteen known compounds, a known 5-formylfurfuryl ester, latifolinal, eight pentacyclic triterpenes, a benzofuran derivative, an ellagic acid derivative, vanillin, β-sitosterol, β-sitosterol glucoside, 3-hydroxy-4-methoxycinnamaldehyde, and 5-formylfurfurol, were isolated from the stem bark of Duabanga grandiflora. The structures of these compounds were elucidated on the basis of spectroscopic analysis. Several of these metabolites were evaluated for cytotoxic activities against six cancer cell lines.     

Triterpenes and a triterpene glucoside from Dysoxylum cumingianum

Six triterpenes and a triterpene glucoside were isolated from the MeOH extract of the leaves of Dysoxylum cumingianum together with three known triterpenes. Their structures were elucidated by extensive spectroscopic analyses. In cytotoxicity assays against three human cancer cell lines, including a multi-drug resistant cancer cell line (KB-C2), compounds 1, 2 and 5 demonstrated significantly enhanced cytotoxicity against KB-C2 cells in the presence of 2.5 μM colchicine, as compared with those in the absence of colchicine. This result suggested that these triterpenes might show some MDR-reversing effects.     

Triterpenes from Angelica cartilagino-marginata var. foliata Yuan et Shan and their significance as chemosystematic characters

One new and three known triterpenes were isolated from roots of Angelica cartilagino-marginata var. foliata Yuan et Shan. The structures of the new compounds were determined by modern spectroscopic techniques, including 2D NMR experiments. These triterpenes are important characters in chemosystematics of Umbelliferae.     

Chemical constituents from Salacia amplifolia

The present phytochemical investigation on Salacia amplifolia led to the isolations of 13 triterpenes, including quinonemethides, friedelanes, oleananes and ursanes triterpenes, three simple phenolics, one polyol and one chromanone. All of them were isolated from this plant for the first time. The presences of quinonemethide triterpenoids might be employed as the common characteristic constituents of both Hippocrateaceae and Celastraceae families.     

Composition of epicuticular wax layer of two species of Mandevilla (Apocynoideae,Apocynaceae) from Rio de Janeiro,Brazil

The chemical composition of epicuticular waxes of Mandevilla guanabarica and Mandevilla moricandiana was comparatively analyzed by extraction in n-hexane and chloroform. The mean wax content per unit of leaf area in the n-hexane extract was about 13–30 μg cm⁻² for M. guanabarica, containing 20–28% n-alkanes and 55–63% triterpenes; for M. mori-candiana, the mean content was 19 μg cm⁻², containing 73% n-alkanes and 14% triterpenes. In the chloroform extract, the wax yield was 40–80 μg cm⁻² for M. guanabarica, with about 9–11% n-alkanes and 75–82% triterpenes; while for M. moricandiana, the wax yield was 110 μg cm⁻², with 52% n-alkanes and 14% triterpenes. The major compounds identified were lupeol, pentacyclic triterpenes of the α- and β-amyrin class, and n-alkanes such as nonacosane, hentriacontane and tritriacontane. These results indicate that the quantitative chemical profiles of epicuticular waxes of M. guanabarica and M. moricandiana are distinct and could be used as an additional feature in taxonomic identification.     

Silvaglins and related 2,3-secodammarane derivatives - unusual types of triterpenes from Aglaia silvestris

Lipophilic crude extracts of leaves, stem and root bark of six different provenances of Aglaia silvestris were compared to determine species-specific chemical trends as well as infraspecific variability. 3,4-Secodammarane triterpenes formed the basic chemical equipment accompanied by the 2,3-seco derivative aglasilvinic acid, probably representing the precursor of the silvaglin A and isosilvaglin A characterised by a five membered ring A. In addition, the pregnane steroid pregnacetal was isolated and identified together with the known sesquiterpenes α-muurolene and viridiflorol, and the bisamide pyramidatin. Depending on the collection site all major triterpenes showed two different stereochemical trends either towards 20R or 20S configuration, giving rise to isolation and identification of the two isomers methylisofoveolate B (20S,24R) and methylfoveolate B (20R,24S) as well as the known derivatives shoreic acid (20S,24R), isoeichlerianic acid (20R,24S), and methylisoeichleriate (20R,24S). The structures were elucidated by 2D-NMR experiments and silvaglin A additionally by X-ray diffraction. The structural diversity and distribution of triterpenoids within the genus Aglaia is highlighted with respect to chemotaxonomic implications.     

Three hydroxy ellagic acid methyl ethers,chrysophanol and scopoletin from Shorea worthingtonii and Vatica obscura

Extraction of the bark and timber of Shorea worthingtonii and Vatica obscura gave three new natural products: hexamethylcoruleoellagic acid, pentamethylflavellagic acid, tetramethylflavellagic acid, together with tetramethylellagic acid, scopoletin and chrysophanol. The above are reported for the first time in the family. Several triterpenes, already described from this family, were also isolated.     

A new triterpene,betulafolienpentaol, from Betula platyphylla

A new triterpene, betulafolienpentaol, 3α,12β,17,20,25-pentahydroxy dammar-23-trans-ene and two other known triterpenes were isolated from Betula platyphylla. The latter compounds were identified as betulafolientetraol and betulafolientetraol-A, respectively.     

Hopane triterpenes as chemotaxonomic markers for the scale insect pathogens Hypocrella s. lat. and Aschersonia

The scale insect pathogens Hypocrella s. lat. and their Aschersonia anamorphs, collected at various locations in Thailand, were surveyed for their productivity of three hopane triterpenes, zeorin (6α,22-dihydroxyhopane), dustanin (15α,22-dihydroxyhopane), and 3β-acetoxy-15α,22-dihydroxyhopane, when cultured in a liquid medium (potato-dextrose broth) under static conditions. Among 53 strains of Aschersonia species, 48 strains (91 %) produced at least one of these compounds. Hypocrella and Moelleriella species (43 strains) also frequently produced these triterpenoids; only two strains lacked all of these triterpenes. The results demonstrate that hopane triterpenes may be suitable for use as chemotaxonomic markers for Hypocrella and Moelleriella species and their Aschersonia anamorphs.     

Naphthoquinones and triterpenes from african Diospyros species

Investigation of the bark and/or wood of seventeen African species of Diospyros has revealed the presence of a number of triterpenes and naphthoquinones. The triterpenes lupeol, betulin and betulinic acid were detected in all samples but three other triterpenes were each found in only one species; betulinaldehyde in D. canaliculata, cerin in D. iturensis, and glutinol in D. zenkeri. Naphthoquinones were detected in fourteen of the seventeen species and the common dimeric compounds diospyrin, isodiospyrin and diosindigo-A were isolated. D. canaliculata differed from all other species in producing derivatives of plumbagin including its reduced form, isoshinanolone (1R,2R) and a novel stereoisomer which was given the trivial name epiisoshinanolone (1S,2R).     

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.     

Triterpenes and neolignans from the roots of Nannoglottis carpesioides

Seven oleanane-type triterpenes and two 8-O-4′-neolignans, along with five known compounds (three 28-noroleanane-type triterpenes, one sarratane triterpene, and one neolignan), were isolated from roots of Nannoglottis carpesioides. Their structures were elucidated by spectroscopic methods, including 1D and 2D NMR, HRMS, and CD. The absolute configurations of two triterpenes were determined by experimental and calculated circular dichroism (CD) and optical rotation values. Ten compounds were evaluated for their cytotoxicity against human promyelocytic leukaemia (HL-60) and human hepatoma (Hep-G2) cells using the MTT assay. The antioxidant activities of these compounds were assessed by ABTS radical-scavenging assays. Among the tested compounds, three compounds exhibited moderate radical-scavenging activity against ABTS⁺, with IC₅₀ values of 22.4, 17.4, and 23.2 μM, respectively.     

The pentacyclic triterpene Esters and the free,esterified and glycosylated sterols of Sorghum vulgare grain

The free, esterified and glycosylated sterols and triterpene esters of Sorghum vulgare grains were analysed by GLC. 4-Demethylsterols were found free, esterified and glycosidated. 4-Monomethyl-sterols were found completely free whilst the triterpenes were completely esterified. Three quarters of the total sterols in the grain were located in the embryo whilst the triterpenes were equally distributed between the embryo and endosperm.     

Triterpenes of Lithocarpus species

The triterpenes of the five Lithocarpus species examined comprised members of the friedo- and unrearranged oleanane groups, viz. friedelin, friedelan-3β-ol, taraxerol and β-amyrin. Glutinol was also present, except in L. harlandi where friedelan-2α,3β-diol was found. In addition, three new cycloartane triterpenes, lithocarpolone (21,24-epoxy-24-hydroxymethyl-cycloartan-3-one), lithocarpdiol (21,24-epoxy-24-hydroxymethyl-cycloartan-3β-ol). and 24-methylenecycloartan-3β,21-diol were found in L. polystachya, and their structures determined.     

Varietal similarities and differences in the polycyclic isopentenoid composition of sorghum

The intraspecific similarities and differences among the various polycyclic isopentenoids (sterols and pentacyclic triterpenes) which occur in leaf tissue and surface wax from three varieties of flowering Sorghum bicolor; G499 GBR, BOK 8 and IS 809, have been determined. The three varieties exhibited differences in phenotypic characters (e.g. shoot height) and pest resistance. While sterol and pentacyclic amyroid compositions were similar in the three varieties, significant differences were evident in the qualitative distribution of the migrated hopanoids. One variety, IS 809, which is phenotypically short and resistant, contained a single migrated hopanoid, sorghumol Alternatively, the other two varieties, both phenotypically tall and one-G 499 GBR-resistant, the other-BOK 8-susceptible, contained a mixture of four Δ⁹⁽¹¹⁾-migrated hopanoids, i.e. sorghumol and three of its stereoisomers, and the Δ⁵⁽⁶⁾-migrated hopanoid simiarenol. While ketones corresponding to the Δ⁹⁽¹¹⁾-migrated hopanoids were detected in the three varieties, the ketone of the Δ⁵⁽⁶⁾-migrated hopanoid was apparently absent. In contrast to other graminaceous plants, the predominant C-3 derivatives did not include the C-3 methyl ethers, but did include esters and polar conjugates. Significant differences apparent in amounts of pentacyclic triterpenes were not apparent in the total amount of sterols extracted from the leaves (including surface wax) of the three varieties. Since S. bicolor varietal differences occurred only among the migrated hopanoids (found in mature leaves) it would appear that pentacyclic triterpenes, unlike sterols, have greater applicability as chemotaxonomic indices for intraspecific relationships in sorghum.     

Triterpenes from Euonymus revolutus

Fourteen pentacyclic triterpenes, which included ten D:A-friedooleananes, three lup-20(29)-enes and 2α,3α-dihydroxy-olean-12-en-28-oic acid, were isolated from the stem bark extract of Euonymus revolutus.     

Biosynthesis of sterols and triterpenes in Pelargonium hortorum

Although all parts of the geranium plant (Pelargonium hortorum) are capable of synthesizing sterols and triterpenes and their esters in vitro from mevalonic acid-[2-¹⁴C], the aerial portions are more active than other tissues. All plant parts were shown to incorporate mevalonic acid-[2-¹⁴C] into isoprenoids for at least 3 days. The leaves and petioles had the greatest incorporation on a wet weight basis. Chopped preparations showed comparable incorporations of mevalonate whereby rootlets incorporated about one half as much as most parts; the flower petals incorporated five times the average amount. In leaves the principal sterol synthesized was sitosterol. Metabolic studies with isolated leaves indicated a fairly rapid conversion of free tetracyclic triterpenes to 4-desmethyl-sterols, while β-amyrin was synthesized at a different rate than α-amyrin. Esterified tetracyclic triterpenes exhibited only a slight amount of conversion to 4-desmethylsterols.     

Neue labdan-derivate aus Gutierrezia-arten

The aerial parts of Gutierrezia lucida afforded three new diterpenic acids, all closely related to agathic acid and those of G. mandonii also three diterpenic acids, which again are labdane derivatives. The structures were elucidated by spectroscopic methods and some chemical transformations. The roots of these species and of a further one only contain triterpenes and no acetylenes. The chemotaxonomic situation is briefly discussed.     

Chemical constituents from the roots of cultivated Ilex pubescens

Phytochemical study of butanol extract from the roots of cultivated Ilex pubescens Hook. et Arn. obtained nine ursane triterpenes (1–9), two oleanane triterpenes (10–11) and three phenylpropanoids (12–14). All of the compounds were determined on the basis of MS and NMR and comparison with literature. Among them, compounds 2 and 13 were isolated from I. pubescens for the first time, of which 13 was a new finding in the Aquifoliaceae family. Our present study exhibited the taxonomic relationships between I. pubescens and other species in genus Ilex and those between Aquifoliaceae and other families. Furthermore, the study suggested the cultivated I. pubescens may be as an alternative for those wild resource collected freshly from mountain.