alpha-Glucosidase inhibitory pentacyclic triterpenes from the stem bark of Fagara tessmannii (Rutaceae)

In addition to fatty acids, a mixture of sterols (beta-sitosterol, stigmasterol, campesterol and stigmastanol), lupeol, arctigenin methylether, sesamin, vanillic acid (1), 2,6-dimethoxy-1,4-benzoquinone (2), betulinic acid and two pentacyclic triterpene acetates were isolated from Fagara tessmannii Engl. They were identified as 3beta-acetoxy-16beta-hydroxybetulinic acid (3a) and 3beta,16beta-diacetoxybetulinic acid (3b), and their structures were established using 1 and 2D NMR spectra and by comparison with published data. Two derivatives of the compounds were prepared. Some isolated compounds were evaluated for their antifungal and antibacterial activities. Compounds 1 and 3a showed significant inhibition of alpha-glucosidase.     

Phenolic and terpenoid compounds from Chione venosa (sw.) urban var. venosa (Bois Bandé)

The Caribbean island of Grenada furnishes the popular aphrodisiac drug Bois Bandé, which consists of the stem bark and the roots of Chione venosa (sw.) URBAN var. venosa (Rubiaceae), a native tree growing in the islands' rain forest. The phytochemical investigation of dichloromethane and methanolic-aqueous extracts of the bark and the roots yielded three acetophenone derivatives described for the first time in plants - ortho-hydroxy-acetophenone-azine (1), acetophenone-2-O-[beta-D-apiofuranosyl-(1'-->6')-O-beta-D-glucopyranoside] (2) and acetophenone-2-O-beta-D-glucopyranoside (3) - along with five known compounds, alpha-morroniside (4), sweroside (5), diderroside (6), daucosterol (7) and beta-sitosterol (8). Their structures were elucidated by 1D and 2D NMR analysis, UV-Vis and ESI-MS.     

Withanolides from Withania somnifera roots

Two new and seven known withanolides along with beta-sitosterol, stigmasterol, beta-sitosterol glucoside, stigmasterol glucoside, alpha+beta glucose were isolated from the roots of Withania somnifera. Among the known compounds, Viscosa lactone B, stigmasterol, stigmasterol glucoside and alpha+beta glucose are being reported from the roots of W. somnifera for the first time. One of the new compounds contained the rare 16beta-acetoxy-17(20)-ene the other contained unusual 6alpha-hydroxy-5,7alpha-epoxy functional groups in the withasteroid skeleton. The structures were elucidated by spectroscopic methods and chemical transformations.     

Cycloartane type triterpenoids from the rhizomes of Polygonum bistorta

Two new compounds, 24(E)-ethylidenecycloartanone (1) and 24(E)-ethylidenecycloartan-3alpha-ol (2) were isolated from the rhizomes of Polygonum bistorta, together with seven known compounds viz., cycloartane-3,24-dione (3), 24-methylenecycloartanone (4), gamma-sitosterol (5), beta-sitosterol (6), beta-sitosterone (7), friedelin (8) and 3beta-friedelinol (9). All the cycloartane type triterpenoids, compounds 7 and 8 are reported for the first time from this plant. A combination of 1D and 2D NMR spectroscopy and MS were mainly used to elucidate the structures of the new compounds 1 and 2.     

Cladocalol, a pentacyclic 28-nor-triterpene from Eucalyptus cladocalyx with cytotoxic activity

A formylated triterpene named cladocalol has been isolated from the leaves of Eucalyptus cladocalyx, together with ursulolactone acetate, ursolic acid, 3 beta-acetate-12,20(29)-lupadien-28-oic acid, beta-sitosterol and the known flavonoid eucalyptine. Their structures were mainly established by extensive NMR studies (1H NMR, 13C NMR, DEPT, 1H-1H COSY, HSQC, HMBC) and mass spectroscopy as well as by X-ray crystallographic analysis. In this paper, we report on the cytotoxic effect induced by cladocalol and its derivatives on the myeloid leukemia cell line HL-60.     

Antioxidant constituents of Nymphaea caerulea flowers

As part of an ongoing search for antioxidants from medicinal plants, 20 constituents were isolated from the Nymphaea caerulea flowers, including two 2S,3S,4S-trihydroxypentanoic acid (1), and myricetin 3-O-(3'-O-acetyl)-alpha-L-rhamnoside (2), along with the known myricetin 3-O-alpha-L-rhamnoside (3), myricetin 3-O-beta-D-glucoside (4), quercetin 3-O-(3'-O-acetyl)-alpha-L-rhamnoside (5), quercetin 3-O-alpha-L-rhamnoside (6), quercetin 3-O-beta-D-glucoside (7), kaempferol 3-O-(3'-O-acetyl)-alpha-L-rhamnoside (8), kaempferol 3-O-beta-D-glucoside (9), naringenin (10), (S)-naringenin 5-O-beta-D-glucoside (11), isosalipurposide (12), beta-sitosterol (13), beta-sitosterol palmitate (14), 24-methylenecholesterol palmitate (15), 4alpha-methyl-5alpha-ergosta-7,24(28)-diene-3beta,4beta-diol (16), ethyl gallate (17), gallic acid (18), p-coumaric acid (19), and 4-methoxybenzoic acid (20). The structures were determined by spectroscopic means. Compounds were tested for antioxidant activity and nine compounds 2-7, 11, 12 and 18 were considered active with IC(50) of 1.16, 4.1, 0.75, 1.7, 1.0, 0.34, 11.0, 1.7 and 0.95 microg/ml, respectively, while 1 was marginally active (IC(50)>31.25 microg/ml). The most promising activity was found in the EtOAc fraction (IC(50) 0.2 microg/ml). This can be attributed to the synergistic effect of the compounds present in it.     

Steroidal saponins from roots of Asparagus officinalis

Sarsasapogenin M (1) and sarsasapogenin N (2), two new oligospirostanosides with a unique aglycone moiety, (25S)-5beta-spirostan-3beta, 17alpha-diol, along with seven known compounds (25S)-5beta-spirostan-3beta-ol-3-O-beta-d-glucopyranosyl-(1,2)-[beta-d-xylopyranosyl-(1,4)]-beta-d-glucopyranoside (3), (25S)-5beta-spirostan-3beta-ol-3-O-beta-d-glucopyranosyl-(1,2)-beta-d-glucopyranoside (4), (25S)-5beta-spirostan-3beta-ol-3-O-alpha-l-rhamnopyranosyl-(1,2)-[alpha-l-rhamnopyranosyl-(1,4)]-beta-d-glucopyranoside (5), (25S)26-O-beta-d-glucopyranosyl-5beta-furost-20 (22)-ene-3beta,26-diol-3-O-beta-d-glucopyranosyl-(1,2)-beta-d-glucopyranoside (6), yamogenin (7), beta-sitosterol (8), and sitosterol-beta-d-glucoside (9) were isolated from the roots of Asparagus officinalis L. Their structures were determined by spectral analysis, including extensive 1D and 2D NMR experiments.     

Sphingolipids from Conyza canadensis

Sphingolipid 1 and its corresponding beta-D-glucopyranoside derivative 2 have been isolated from the ethylacetate fraction of Conyza canadensis along with beta-sitosterol 3, stigmasterol 4, beta-sitosterol 3-O-beta-D-glucoside 5 and harmine 6, reported for the first time from this species. The structures of 1 and 2 were elucidated through spectroscopy including two-dimensional NMR.     

Pregnene derivatives from Solenostemma argel leaves

Two new pregnene derivatives 14beta-15alpha-dihydroxy-delta4pregnene-3,20 dione and 3beta-14beta,15alpha-16alpha hydroxy-20-oxo-delta5pregnene-tetra-ol, in addition to alpha- and beta-amyrin and beta-sitosterol, were isolated from Solenostemma argel leaves. The structures were established by extensive spectral analysis as well as comparison with reference materials.     

Diterpenoids and triterpenoids from Euphorbia guyoniana

Two new compounds with tigliane and cycloartane skeletons: 4,12-dideoxy(4alpha)phorbol-13-hexadecanoate (1) and 24-methylenecycloartane-3,28-diol (2), respectively, in addition of four known diterpenoids and 13 triterpenoids: 3-benzoyloxy-5,15-diacetoxy-9,14-dioxojatropha-6(17),11-diene (4), ent-abieta-8(14),13(15)-dien-16,12-olide (5), ent-8alpha,14alpha-epoxyabieta-11,13(15)-dien-16,12-olide (6), ent-3-hydroxyatis-16(17)-ene-2,14-dione (7), 3beta-hydroxytaraxer-14-en-28-oic acid (8), beta-sitosteryl-3beta-glucopyranoside-6'-O-palmitate (9), multiflorenyl acetate (10), multiflorenyl palmitate (11), peplusol (12), 24-methylenecycloartanol (3), lanosterol (13), euferol (14), butyrospermol (15), cycloartenol (16), obtusifoliol (17), cycloeucalenol (18) and beta-sitosterol (19), were isolated from the roots of Euphorbia guyoniana. Their structures were established on the basis of physical and spectroscopic analysis, including 1D and 2D homo- and heteronuclear NMR experiments (COSY, HSQC, HMBC and NOESY) and by comparison with the literature data.     

Diterpenes from the leaves of Croton zambesicus

Two new trachylobane- and one isopimarane-type diterpenoids: ent-18-hydroxy-trachyloban-3-one; ent-trachyloban-3-one; isopimara-7,15-dien-3beta-ol, were isolated from the leaves of Croton zambesicus, together with trans-phytol, beta-sitosterol, alpha-amyrin and stigmasterol. The structures were determined by extensive NMR techniques and X-ray analysis. The cytotoxicity of these compounds has been evaluated on cancer and non-cancer cell-lines.     

Constituents of the stems of Macrococculus pomiferus and their inhibitory activities against cyclooxygenases-1 and -2

As part of our program directed towards the discovery of new cancer chemopreventive agents from plants, the EtOAc-soluble extract of the stems of M. pomiferus was found to inhibit the enzyme cyclooxygenase-2 (COX-2). Bioassay-directed fractionation of this extract led to the isolation of two dibenzylbutyrolactone lignans, (8R,8'R)-3'-O-demethyl-5-hydroxymatairesinol (1) and (8R,8'R)-3'-O-demethyl-5-methoxymatairesinol (2), as well as seven known compounds, (-)-5'-methoxyyatein (3), blumenol A, (-)-deoxypodophyllotoxin (anthricin), (-)-deoxypodorhizone, 2,6-dimethoxyhydroquinone, 4-hydroxybenzaldehyde, and beta-sitosterol glucoside. The structures of compounds 1 and 2 were determined using spectroscopic data (1D and 2D NMR, and HREIMS), and the 8R and 8'R absolute stereochemistry was established for both 1 and 2 on the basis of their CD spectra. All isolates obtained in the present study were evaluated for their inhibitory effects with both COX-1 and -2. Of these, only 5'-methoxyyatein (3) showed weak activity against COX-2, while all other compounds isolated were inactive. The COX-2 inhibitory activity of the EtOAc extract was also traced to the presence of several common fatty acids by LC-MS.     

Sesquiterpene coumarins from Ferula szowitsiana and in vitro antileishmanial activity of 7-prenyloxycoumarins against promastigotes

Two new sesquiterpene coumarins, named szowitsiacoumarin A (1) and szowitsiacoumarin B (2), and a phenylpropanoid derivative, 2-epihelmanticine (3), together with nine known compounds, auraptene (4), umbelliprenin (5), galbanic acid (6), methyl galbanate (7), farnesiferol B (8), farnesiferol C (9), persicasulfide A (10), beta-sitosterol and stigmasterol were isolated from the roots of Ferula szowitsiana. The structures of these compounds were elucidated by extensive spectroscopic methods including 1D-((1)H and (13)C) and 2D-NMR experiments (DQF-COSY, HSQC, HMBC, and ROESY) as well as HR-MALDI-MS analysis. Since the configuration of 2-epihelmanticine was previously only partly determined, a relative configurational analysis of its four stereocenters was carried out on the basis of the recently reported J-based method. The inhibiting activity of prenylated coumarins, auraptene (4) and umbelliprenin (5), in addition to galbanic acid (6), as major component, and of the Me(2)CO extract of Ferula szowitsiana (Apiaceae) roots has been evaluated against promastigotes of Leishmania major. Umbelliprenin and auraptene showed significant activity with IC(50) values of 4.9microg/ml (13.3microM) and 5.1microg/ml (17.1microM) after 48h incubation, respectively.     

Chalcones and other constituents of Dorstenia prorepens and Dorstenia zenkeri

The twigs of Dorstenia prorepens furnished the digeranylated chalcone, 5,3'-(3,7-dimethyl-2,6-octadienyl)-3,4, 2',4'-tetrahydroxychalcone while Dorstenia zenkeri yielded the 3',4'-(3-hydroxy-2,2-dimethyldihydropyrano)-4,2'-dihydroxychalcone and a bichalcone. 4-Hydroxylonchocarpin was found in both plants. D. prorepens also yielded the known compounds: psoralen, bergapten, beta-sitosterol and its D-glucopyranosyl derivative. D. zenkeri yielded p-hydroxybenzaldehyde, dorsmanin A, 4,2',4'-trihydroxychalcone and 4,2',4'-trihydroxy-3'-prenylchalcone. Structures of the new compounds were established by UV, IR, MS and 2-D NMR analysis.     

A sugar ester and an iridoid glycoside from Scrophularia ningpoensis

From cytotoxic extracts of the roots of Scrophularia ningpoensis Hemsl. (Scrophulariaceae) a new sugar ester, ningposide D (3-O-acetyl-2-O-p-methoxycinnamoyl-alpha(beta)-L-rhamnopyranose) (1) and a new iridoid glycoside, scrophuloside B4 (6-O-(2'-O-acetyl-3'-O-cinnamoyl-4'-O-p-methoxycinnamoyl-alpha-L-rhamnopyranosyl) catalpol) (2) along with known compounds: oleanonic acid (3), ursolonic acid (4), cinnamic acid (5), 3-hydroxy-4-methoxy benzoic acid (6), 5-(hydroxymethyl)-2-furfural (7) and beta-sitosterol (8) were isolated. The structures of the new compounds were elucidated by spectral data (1, 2D NMR, EI, HRESI-MS and MS/MS). Oleanonic acid (3) and ursolonic acid (4) were found to be cytotoxic against a series of human cancer cell lines with IC50=4.6, 15.5 microM on MCF7; 4.2, 14.5 microM on K562; 14.8, 44.4 microM on Bowes; 24.9, 43.6 microM on T24S; 61.3, 151.5 microM on A549, respectively. Beta-sitosterol (8) inhibited Bowes cells growth at IC50=36.5 microM. Scrophuloside B4 (2) showed activity on K562 and Bowes cells at IC50=44.6, 90.2 microM, respectively.     

Phenolic glycosides from Symplocos racemosa: natural inhibitors of phosphodiesterase I

One new phenolic glycoside named benzoylsalireposide (1) along with one known phenolic glycoside named salireposide (2) have been isolated from Symplocos racemosa. Four other known compounds i.e. beta-amyrin (3), oleonolic acid (4), beta-sitosterol (5) and beta-sitosterol glycoside (6) were also isolated from this plant. The structure elucidation of the isolated compounds was based primarily on 1D- and 2D-NMR analysis, including COSY, HMQC, and HMBC correlations. The compound 1 and 2 showed inhibitory activity against snake venom phosphodiesterase I.     

Feeding stimulative activity of steroidal and secoiridoid glucosides and their hydrolysed derivatives toward the olive weevil (Dyscerus perforatus)

Beta-sitosteryl-D-glucoside and oleuropein isolated from the olive tree (Olea europaea) and their hydrolysed derivatives were tested by a feeding stimulative activity bioassay using the olive weevil (Dyscerus perforatus). Although the steroidal glucoside showed potent feeding stimulative activity, the activity of the aglycone (beta-sitosterol) was significantly lower than that of the glucoside. On the other hand, the difference in the activity between oleuropein, a secoiridoid glucoside, and the hydrolysed derivatives was not significant.     

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.     

A benzil and isoflavone from Iris tenuifolia

Two compounds, tenuifodione (1) and tenuifone (2), and 12 known compounds, izalpinin (3), alpinone (4), arborinone (5), irilin B (6), irisone A (7), irisone B (8), betavulgarin (9), beta-sitosterol (10), 5,7-dihydroxy-2',6-dimethoxyisoflavone (11), 2',5-dihdroxy-6,7-methylenedioxy flavanone (12), irisoid A (13) and ethyl-beta-d-glucopyranoside (14) were isolated from the whole plant of Iris tenuifolia Pall. All compounds, except 12, were isolated for the first time from this plant. Compounds 2, 3 and 11 have shown a considerable DPPH radical scavenging activity. Structures of these compounds were identified on the basis of spectroscopic techniques, including 2D NMR. Compounds 3, 5 and 7 were also subjected to single-crystal X-ray diffraction analysis and their structures were unambiguously deduced.     

Enhancement of beta-sitosterol transformation in Mycobacterium vaccae with increased cell wall permeability.

Mycobacterium vaccae exposed to compounds which are known to disorganise the cell wall composition and architecture (protamine, glycine) showed increased specific activity in beta-sitosterol biotransformation to androstene derivatives, intennediates in the production of most medical steroids. GC/MS analysis of free lipid fatty acids revealed higher content of unsaturated compounds, mainly C16:1 and C18:1 in protamine- and glycine-treated cells than that in control cells, which seems to change the permeability features of the cell wall barrier, facilitating hydrophobic beta-sitosterol diffusion.