A furan-2-carbonyl C-glucoside and an alkyl glucoside from the parasitic plant,Dendrophthoe pentandra

A new furan-2-carbonyl C-(6′-O-galloyl)-β-glucopyranoside (scleropentaside F, 1) and a new alkyl glucoside [butane-2,3-diol 2-(6′-O-galloyl)-O-β-glucopyranoside, 2] were isolated from the entire hemi-parasitic plant, Dendrophthoe pentandra growing on Tectona grandis together with ten known compounds including, benzyl-O-β-d-glucopyranoside (3), benzyl-O-α-l-rhamnopyranosyl-(1 → 6)-β-d-glucopyranoside (4), benzyl-O-β-d-apiofuranosyl-(1 → 6)-β-d-glucopyranoside (5), methyl gallate 3-O-β-d-glucopyranoside (6), methyl gallate 3-O-(6′-O-galloyl)-β-d-glucopyranoside (7), (+)-catechin (8), procyanidin B-1 (9) and procyanidin B-3 (10), bridelionoside A (11), and kiwiionoside (12). In addition, compounds 1, 3–9 were isolated from this species growing on the different host, Mangifera indica. The structure elucidations were based on physical data and spectroscopic evidence including 1D and 2D experiments.     

Chemical constituents from Saussurea cordifolia

Thirty-six naturally occurring compounds, including four C₁₀-acetylenic glycosides and a lignan, were isolated from the whole plants of Saussurea cordifolia. Their structures were elucidated by means of spectroscopic and chemical methods to be 4,6-decadiyne-1-O-β-d-apiofuranosyl-(1 → 6)-β-d-glucopyranoside (1), 4,6-decadiyne-1-O-α-l-rhamnopyranosyl-(1 → 6)-β-d-glucopyranoside (2), (8E)-decaene-4, 6-diyn-1-O-α-l-rhamnopyranosyl-(1 → 6)-β-d-glucopyranoside (3), (8Z)-decaene-4,6-diyn-1-O-β-d-apiofuranosyl-(1 → 6)-β-d-glucopyranoside (4), and (2R, 3S, 4S)-4-(4-hydroxy-3-methoxybenzyl)-2-(5-hydroxy-3-methoxyphenyl)-3-(hydroxymethyl)-tetrahydrofuran-3-ol (5).     

Glycosides from Breynia fruticosa and Breynia rostrata

Glycosides, 3-acetyl-(?)-epicatechin 7-O-β-glucopyranoside (1), 3-acetyl-(?)-epicatechin 7-O-(6-isobutanoyloxyl)-β-glucopyranoside (2), 3-acetyl-(?)-epicatechin 7-O-[6-(2-methyl-butanoyloxyl)]-β-glucopyranoside (3), (5Z)-6-[5-(2-hydroxypropan-2-yl)-2-methyl-tetrahydrofuran-2-yl]-3-methylhexa-1,5-dien-3-O-β-glucopyranoside (4), hydroquinone O-[6-(3-hydroxyisobutanoyl)]-β-galactopyranoside (5), 4-(4-O-β-glucopyranosyl-phenoxy)-1-O-β-glucopyranosyl-1,3-benzenediol (6), 7,8-erythro-dihydroxy-3,4,5-trimethoxy-phenyl-propane8-O-β-glucopyranoside (7), 6,7-dimethylbenzofuranol 5-O-β-xylopyranosyl-(1 → 6)-β-glucopyranoside (8), along with 30 known glycosides, were isolated from Breynia fruticosa and Breynia rostrata (Euphorbiaceae). Their structures were determined on the basis of spectroscopic analysis and chemical methods.     

Renoprotective chemical constituents from an edible mushroom,Pleurotus cornucopiae in cisplatin-induced nephrotoxicity

Pleurotus cornucopiae (Pleurotaceae) is an edible and medicinal mushroom widely distributed in Korea, China, and Japan. The MeOH extract of the fruiting bodies of P. cornucopiae showed renoprotective effects against cisplatin-induced kidney cell damage. Chemical investigation of the MeOH extract led to the isolation and identification of 12 compounds including noransine (1), uridine (2), uracil (3), (3β, 5α, 6β, 22E, 24S) -ergosta-7, 22-diene-3, 5, 6, 9-tetrol (4), (22E,24S)-ergosta-7,22-diene-3β,5α,6β-triol (5), (22E,24R)-ergosta-8(14),22-diene-3β,5α,6β,7α-tetrol (6), cerebroside B (7), (2R) -N- [(1S, 2R, 3E, 7E) -1- [(β-d-glucopyranosyloxy) methyl] -2-hydroxy-8-methyl-3, 7-heptadecadien-1-yl] -2-hydroxy-heptadecanamide (8), cerebroside D (9), nicotinamide (10), 1,2-bis(hydroxymethyl)-4,5-dimethoxybenzene (11), and benzoic acid (12). Among them, compounds 1 and 11 were isolated as naturally occurring products for the first time, though they were reported as synthetic products in previous papers. All of the compounds (except 8 and 11) abrogated cisplatin-induced LLC-PK1 cell damage in a dose-dependent manner. Of special note, compounds 2, 5, 6, and 12 ameliorated cisplatin-induced nephrotoxicity to 80% of the control value at 10 μM. The protective effects of compounds 2, 5, 6, and 12 were mediated via the deactivation of JNK-caspase 3 apoptotic cascade. This study is the first to demonstrate that the chemical constituents of P. cornucopiae display renoprotective effects against anticancer drug-induced damage in kidney cells.     

Cycloartane-type glycosides from Astragalus schottianus

Three new cycloartane-type triterpene glycosides were isolated from the roots of Astragalus schottianus Boiss. Their structures were established as 20(R),25-epoxy-3-O-β-d-xylopyranosyl-24-O-β-d-glucopyranosyl-3β,6α,16β,24α-tetrahydroxycycloartane (1), 20(R),25-epoxy-3-O-[β-d-glucopyranosyl(1 → 2)]-β-d-xylopyranosyl-24-O-β-d-glucopyranosyl-3β,6α,16β,24α-tetrahydroxycycloartane (2), 3-O-β-d-xylopyranosyl-3β,6α,16β,20(S),24(S),25-hexahydroxycycloartane (3) by the extensive use of 1D and 2D-NMR techniques and mass spectrometry.     

Phenylethanoid glycosides from the leaves of Magnolia hodgsonii

Three new phenylethanoid glycosides, 2-(3-hydroxy-4-methoxyphenyl)ethyl 1-O-β-d-allopyranoside (hodgsonialloside A, 1), 2-(3-hydroxy-4-methoxyphenyl)ethyl 1-O-β-d-glucopyranosyl-(1 → 4)-β-d-allopyranoside (hodgsonialloside B, 2) and 2-(3-methoxy-4-hydroxyphenyl)ethyl 1-O-β-d-allopyranoside (hodgsonialloside C, 3) were isolated from the leaves of Magnolia hodgsonii in addition to six known compounds, tyrosol 4-O-β-d-xylopyranosyl-(1 → 6)-β-d-glucopyranoside (4), kaempferol 3-O-neohesperidoside (5), kaempferol 3-O-rutinoside (6), kaempferol 3-O-α-l-rhamnopyranosyl-(1 → 2)-[α-l-rhamnopyranosyl-(1 → 6)]-β-d-glucopyranoside (7), (+)-syringaresinol O-β-d-glucopyranoside (8), and oblongionoside C (9). The structure elucidation of these compounds was based on analyses of physical and spectroscopic data including 1D and 2D NMR experiments.     

Synthesis of 2- (and 6-) -dithian-2-yluracil nucleosides and their conversion into nucleoside derivatives

Addition of 2,2′-anhydro-[1-(3-O-acetyl-5-O-trityl-β-D-arabinofuranosyl)uracil] (1) to excess 2-litho-1,3-dithiane (2)in oxolane at ?78° gave 2-(1,3-dithian-2-yl)-1-(5-O-trityl-β-D-arabinofuranosyl)-4(1H)pyrimidinone (3), O²,2′-anhydro-5,6-di-hydro-6-(S)-(1,3-dithian-2-yl)-5′-O-trityluridine (4), and 2-(1,4-dihydroxybutyl)-1,3-dithiane (5) in yields of 15, 30, and 10% respectively. The structure of 3 was proved by its hydrolysis in acid to give 2-(1,3-dithian-2-yl)-4-pyrimidinone (6) and arabinose, and by desulfurization with Raney nickel to yield the known 2-methyl-1-(5-O-trityl-β-D-arabinofuranosyl)-4(1H)-pyrimidinone (7). Detritylation of 3 without glycosidic cleavage could only be effected by prior acetylation to 1-(2,3-di-O-acetyl-5-O-trityl-β-D-arabinofuranosyl)-2-(1,3-dithian-2-yl)-4(1H)-pyrimidinone (8) which, after treatment with acetic acid at room temperature for 65 h followed by the action of sodium methoxide gave 2-(1,3-dithian-2-yl)-1-β-D-arabinofuranosyl-4(1H)-pyrimidinone (10) in 45% yield. Detritylation of 4 in boiling acetic acid gave 5,6-dihydro-6-(S)-(1,3-dithian-2-yl)-1-β-D-arabinofuranosyluracil (12) and 3-[(S)-1-(1,3-dithian-2-yl)]propionamido-(1,2-dideoxy-β-D-arabinofurano)-[1,2-d]-2-oxazolidinone (13) in 10 and 90% yields, respectively. When 12 was kept in water or methanol for 7 days, quantitative conversion into 13 occurred. Acid hydrolysis of 12 afforded arabinose and 5,6-di-hydro-6-(1,3-dithian-2-yl)uracil (14), which was desulfurized with Raney nickel to the known 5,6-dihydro-6-methyluracil (15). Treatment of 13 with trifluoroacetic anhydride-pyridine yielded 77% of the cyano derivative 17. Similar dehydration of 3-(R)-1-methylpropionamido-(1,2-dideoxy-β-D-arabinofurano)-[1,2-d]-2-oxalidinone (18), obtained by desulfurization of 13, gave 60% of the nitrile 19. Hydrogenation of 19 over platinum oxide in acetic anhydride gave the acetamide derivative 20 in 95% yield. Nitrobenzoylation of 13 gave 3-[(S)-1-(1,3-dithian-2-yl)]cyanomethyl-3,5-di-O-p-nitrobenzoyl-(1,2-dideoxy-β-D-arabinofurano)-[1,2-d]-2-oxazolidinone (22), which was converted in 37% yield by treatment with methyl iodide in dimethyl sulfoxide into the aldehyde 24, characterized as the semicarbazone 25. The purification of 5 and its characterization as 2-(1,4-di-O-p-nitrobenzoylbutyl)-1,3-dithiane (27) is described.     

A new phenylpropanoid and an alkylglycoside from Piper retrofractum leaves with their antioxidant and α-glucosidase inhibitory activity

Two new compounds, piperoside (1) and isoheptanol 2(S)-O-β-d-xylopyranosyl (1→6)-O-β-d-glucopyranoside (11), along with 10 known compounds 3,4-dihydroxyallylbenzene (2), 1,2-di-O-β-d-glucopyranosyl-4-allylbenzene (3), tachioside (4), benzyl-O-β-d-glucopyranoside (5), icariside F₂ (6), dihydrovomifoliol-3′-O-β-d-glucopyranoside (7), isopropyl O-β-d-glucopyranoside (8), isopropyl primeveroside (9), n-butyl O-β-d-glucopyranoside (10), isoheptanol 2(S)-O-β-d-apiofuranosyl-(1→6)-O-β-d-glucopyranoside (12), were isolated from the leaves of Piper retrofractum. Their structures were determined from 1D-NMR, 2D-NMR, and HR-ESI-MS spectral, a modified Mosher’s method, and comparisons with previous reports. All of the isolated compounds showed modest α-glucosidase inhibitory (4.60 ± 1.74% to 11.97 ± 3.30%) and antioxidant activities under the tested conditions.     

Two new glycosides and one new neolignan from the roots of Cynanchum stauntonii

Three new compounds including one C₂₁-steroidal glycoside, one methylglycoside, and one neolignan, named as Deoxyamplexicogenin A-3-O-yl-4-O-(4-O-α-l-cymaropyranosoyl-β-d-digitoxopyranosoyl)-β-d-canaropyranoside (1), Methyl-O-α-l-cymaropyranosoyl-(1 → 4)-β-D-digitoxopyranoside (2), and (+)-(7S, 8R, 7′E)-5-hydroxy-3, 5′-dimethoxy-4′, 7-epoxy-8, 3′-neolign-7′-ene-9, 9′-diol 9′-ethyl ether (3), respectively, were isolated from the roots of Cynanchum stauntonii. The structure elucidations were achieved by in-depth spectroscopic examination, mainly including the experiments and analyses of multiple 1D- and 2D-NMR and HRESIMS and CD analysis and qualitative chemical tests. Cytotoxicity activities of compounds 1–3 were evaluated against five tumor cell lines (HCT-8, Bel-7402, BGC-823, A549, and A2780) in cell based assays where they were found to be inactive.     

Gynostemosides A–E,megastigmane glycosides from Gynostemma pentaphyllum

Megastigmane glycosides (1–5) together with seven (6–12) related known compounds were isolated from the whole plants of Gynostemma pentaphyllum. The structures were elucidated by means of spectroscopic methods, including 2D NMR, HR-ESIMS, and circular dichroism (CD), as well as chemical transformations to be (3R, 4R, 5S, 6S, 7E)-3,4,6-trihydroxymegastigmane-7-en-9-one-3-O-β-d-glucopyranoside (gynostemoside A, 1), (3S, 4S, 5R, 6R, 7E, 9R)-3,4,6,9-tetrahydroxymegastigmane-7-en-3-O-β-d-glucopyranoside (gynostemoside B, 2), (3S, 4S, 5S, 6S, 7E, 9R)-3,4,9-trihydroxymegastigmane-7-en-9-O-β-d-glucopyranoside (gynostemoside C, 3), (3S, 4S, 5S, 6S, 7E, 9R)-3,4,9-trihydroxymegastigmane-7-en-3-O-β-d-glucopyranoside (gynostemoside D, 4), and (3S, 4S, 5S, 6S, 7E, 9R)-3,4,9-trihydroxymegastigmane-7-en-4-O-β-d-glucopyranoside (gynostemoside E, 5), respectively.     

Xanthine oxidase inhibitory terpenoids of Amentotaxus formosana protect cisplatin-induced cell death by reducing reactive oxygen species (ROS) in normal human urothelial and bladder cancer cells

The diterpenoids (+)-ferruginol (1), ent-kaur-16-en-15-one (2), ent-8(14),15-sandaracopimaradiene-2α,18-diol (3), 8(14),15-sandaracopimaradiene-2α,18,19-triol (4), and (+)-sugiol (5) and the triterpenoids 3β-methoxycycloartan-24(24¹)-ene (6), 3β,23β-dimethoxycycloartan-24(24¹)-ene (7), 3β,23β-dimethoxy-5α-lanosta-24(24¹)-ene (8), and 23(S)-23-methoxy-24-methylenelanosta-8-en-3-one (9), isolated from Amentotaxus formosana, showed inhibitory effects on xanthine oxidase (XO). Of the compounds tested, compound 5 was a potent inhibitor of XO activity, with an IC₅₀ value of 6.8 ± 0.4 μM, while displaying weak ABTS radical cation scavenging activity. Treatment of the bladder cancer cell line, NTUB1, with 3–10 μM of compound 5 and 10 μM cisplatin, and immortalized normal human urothelial cell line, SV-HUC1, with 0.3–1 μM and 10–50 μM of compound 5 and 10 μM cisplatin, respectively, resulted in increased viability of cells compared with cytotoxicity induced by cisplatin. Treatment of NTUB1 with 20 μM cisplatin and 10 or 30 μM of compound 5 resulted in decreased ROS production compared with ROS production induced by cisplatin. These results indicate that 10 or 30 μM of compound 5 in NTUB1 cells may mediate through the suppression of XO activity and reduction of reactive oxygen species (ROS) induced by compound 5 cotreated with 20 μM cisplatin and protection of subsequent cell death.     

Two new guaiane sesquiterpenes from Datura metel L. with anti-inflammatory activity

Chemical investigation of an acidic methanol extract of the whole plants of Datura metel resulted in the isolation of two new guainane sesquiterpenes, 1β,5α,7β-guaiane-4β,10α,11-triol (1) and 1α,5α,7α-11-guaiene-2α,3β,4α,10α,13-pentaol (2), along with eight known compounds: pterodontriol B (3), disciferitriol (4), scopolamine (5), kaempferol 3-O-β-d-glucosyl(1 → 2)-β-d-galactoside 7-O-β-d-glucoside (6), kaempferol 3-O-β-glucopyranosyl(1 → 2)-β-glucopyranoside-7-O-α-rhamnopyranoside (7), pinoresinol 4′′-O-β-d-glucopyranoside (8), (7R,8S,7′S,8′R)-4,9,4′,7′-tetrahydroxy-3,3′-dimethoxy-7,9′-epoxy-lignan-4-O-β-d-glucopyranoside (9), and (7S,8R,7′S,8′S)-4,9,4′,7′-tetrahydroxy-3,3′-dimethoxy-7,9′-epoxylignan-4-O-β-d-glucopyranoside (10). Their structures were elucidated by extensive spectroscopic methods, including 1D and 2D NMR and MS spectra. Compounds 2-4 and 6-10 were shown to have modest anti-inflammatory effects through inhibition of NO production in LPS-stimulated BV cells.     

Thiophenes,polyacetylenes and terpenes from the aerial parts of Eclipata prostrata

One new bithiophenes, 5-(but-3-yne-1,2-diol)-5′-hydroxy-methyl-2,2′-bithiophene (2), two new polyacetylenic glucosides, 3-O-β-d-glucopyranosyloxy-1-hydroxy-4E,6E-tetradecene-8,10,12-triyne (8), (5E)-trideca-1,5-dien-7,9,11-triyne-3,4-diol-4-O-β-d-glucopyranoside (9), six new terpenoid glycosides, rel-(1S,2S,3S,4R,6R)-1,6-epoxy-menthane-2,3-diol-3-O-β-d-glucopyranoside (10), rel-(1S,2S,3S,4R,6R)-3-O-(6-O-caffeoyl-β-d-glucopyranosyl)-1,6-epoxy menthane-2,3-diol (11), (2E,6E)-2,6,10-trimethyl-2,6,11-dodecatriene-1,10-diol-1-O-β-d-glucopyranoside (12), 3β,16β,29-trihydroxy oleanane-12-ene-3-O-β-d-glucopyranoside (13), 3,28-di-O-β-d-glucopyranosyl-3β,16β-dihydroxy oleanane-12-ene-28-oleanlic acid (14), 3-O-β-d-glucopyranosyl-(1→2)-β-d-glucopyranosyl oleanlic-18-ene acid-28-O-β-d-glucopyranoside (15), along with fifteen known compounds (1, 3–7, and 16–24), were isolated from the aerial parts of Eclipta prostrata. Their structures were established by analysis of the spectroscopic data. The isolated compounds 1–9 were tested for activities against dipeptidyl peptidase IV (DPP-IV), compound 7 showed significant antihyperglycemic activities by inhibitory effects on DPP-IV in human plasma in vitro, with IC₅₀ value of 0.51 μM. Compounds 10–24 were tested in vitro against NF-κB-luc 293 cell line induced by LPS. Compounds 12, 15, 16, 19, 21, and 23 exhibited moderate anti-inflammatory activities.     

Voulkensin C–E,new 11-oxocassane-type diterpenoids and a steroid glycoside from Caesalpinia volkensii stem bark and their antiplasmodial activities

A bioassay guided isolation of potential antimalarial molecules from the stem bark of Caesalpinia volkensii Harms (Fabaceae) achieved three new 11-oxocassane-type diterpenoids named voulkensin C (1), D (2) and E (3) together with one steroid glycoside named 3-O-[β-glucopyranosyl(1→2)-O-β-xylopyranosyl]-stigmasterol (4) and seven other known compounds including stigmasterol (5), β-sitosterol (6), oleanolic acid (7), 3-β-acetoxyolean-12-en-28-methyl ester (8), voucap-5-ol (9), caesadekarin C (10), deoxycaesaldekarin C (11). The structures of the new compounds were determined on the basis of extensive spectroscopic data (IR, MS, ¹H and ¹³C NMR and 2D NMR) analyses. The polar extracts revealed moderate to good antiplasmodial activities against chloquine-sensitive (D6) and -resistant strains (W2) of Plasmodium falciparum. Whereas the pure isolates exhibited limited to moderate antiplasmodial activities with compound 4 showing the highest antiplasmodial activities (IC₅₀ values of 4.44 ± 0.88 and 2.74 ± 1.10 μM against D6 and W2 strains, respectively). These results suggest a possible contribution of phytochemicals from C. volkensii stem bark towards inhibition of plasmodial parasites’ growth hence potential antimalarial.     

Synthesis and biological evaluation of novel propargyl amines as potential fluorine-18 labeled radioligands for detection of MAO-B activity

The aim of this project was to synthesize and evaluate three novel fluorine-18 labeled derivatives of propargyl amine as potential PET radioligands to visualize monoamine oxidase B (MAO-B) activity.The three fluorinated derivatives of propargyl amine ((S)-1-fluoro-N,4-dimethyl-N-(prop-2-ynyl)-pent-4-en-2-amine (5), (S)-N-(1-fluoro-3-(furan-2-yl)propan-2-yl)-N-methylprop-2-yn-1-amine (10) and (S)-1-fluoro-N,4-dimethyl-N-(prop-2-ynyl)pentan-2-amine (15)) were synthesized in multi-step organic syntheses. IC₅₀ values for inhibition were determined for compounds 5, 10 and 15 in order to determine their specificity for binding to MAO-B. Compound 5 inhibited MAO-B with an IC₅₀ of 664 ± 48.08 nM. No further investigation was carried out with this compound. Compound 10 inhibited MAO-B with an IC₅₀ of 208.5 ± 13.44 nM and compound 15 featured an IC₅₀ of 131.5 ± 0.71 nM for its MAO-B inhibitory activity. None of the compounds inhibited MAO-A activity (IC₅₀ > 2 μM).The fluorine-18 labeled analogues of the two higher binding affinity compounds (10 and 15) (S)-N-(1-[¹⁸F]fluoro-3-(furan-2-yl)propan-2-yl)-N-methylprop-2-yn-1-amine (16) and (S)-1-[¹⁸F]fluoro-N,4-dimethyl-N-(prop-2-ynyl)pentan-2-amine (18) were both prepared from the corresponding precursors 9A, 9B and 14A, 14B by a one-step fluorine-18 nucleophilic substitution reaction. Autoradiography experiments on human postmortem brain tissue sections were performed with 16 and 18. Only compound 18 demonstrated a high selectivity for MAO-B over MAO-A and was, therefore, chosen for further examination by PET in a cynomolgus monkey.The initial uptake of 18 in the monkey brain was 250% SUV at 4 min post injection. The highest uptake of radioactivity was observed in the striatum and thalamus, regions with high MAO-B activity, whereas lower levels of radioactivity were detected in the cortex and cerebellum. The percentage of unchanged radioligand 18 was 30% in plasma at 90 min post injection.In conclusion, compound 18 is a selective inhibitor of MAO-B in vitro and demonstrated a MAO-B specific binding pattern in vivo by PET in monkey. It can, therefore, be considered as a candidate for further investigation in human by PET.     

Three new dinormonoterpenoid glucosides from pericarps of Myriopteron extensum

Three new dinormonoterpenoid glucosides, rel-(3R,4R)-3-(1-hydroxypropan-2-yl)-3,4-epoxypentane-1,5-diol-1-O-β-d-glucopyranoside (1), rel-(3R,4S)-3-(1-hydroxypropan-2-yl)-3,4-epoxypentane-1,5-diol-1-O-β-d-glucopyranoside (2), and rel-(3R,4S)-3-(1-hydroxy-2-propen-2-yl)-3,4-epoxypentane-1,5-diol-1-O-β-d-glucopyranoside (3), were isolated from the edible pericarps of Myriopteron extensum (Wight & Arn.) K. Schum. (Asclepiadaceae). Their structures were elucidated by chemical and spectroscopic methods including HRESIMS, 1D and 2D NMR. Dinormonoterpenoid glucosides were reported from Asclepiadaceae for the first time. Compounds 1–3 were evaluated for their cytotoxicity against five human cancer cell lines HL-60, SMMC-7221, A-549, MCF-7, and SW-480, but they did not exhibit cytotoxicity on the tested cell lines.     

Cytotoxic quinazoline alkaloids from the seeds of Peganum harmala

Seventeen quinazoline alkaloids and derivatives, containing two pairs of new epimers, named as (S)- and (R)-1-(2-aminobenzyl)-3-hydroxypyrrolidin-2-one β-d-glucopyranosyl-(1?→?6)-β-d-glucopyranoside (1, 2), (S)- and (R)-vasicinone β-d-glucopyranosyl-(1?→?6)-β-d-glucopyranoside (3, 4), and a new enantiomer (12b), together with six known ones (5–8, 10, and 12a), and three pairs of known enantiomers (9, 11, and 13), were isolated from the ethanol extracts of the seeds of Peganum harmala L.. Their structures including the absolute configuration were elucidated by using 1D and 2D NMR, and ECD calculation approaches. The cytotoxic activities of all isolated compounds were evaluated. 11 showed moderate cytotoxicity against PC-3 cells with an IC₅₀ value of 15.41?μM.     

Cycloartane glycosides from Astragalus gombo

Six new cycloartane-type triterpene glycosides named 3-O-[β-d-glucopyranosyl(1 → 2)-β-d-xylopyranosyl]-3β,16β,23(R),24(R),25-pentahydroxycycloartane (1), 3-O-[β-d-glucopyranosyl(1 → 2)-β-d-xylopyranosyl]-3β,16β,23(R),24(R)-tetrahydroxy-25-dehydrocycloartane (2), 3-O-[β-d-xylopyranosyl]-6α-acetoxy-23α-methoxy-16β,23(R)-epoxy-24,25,26,27-tetranorcycloartane (3), 3-O-[β-d-xylopyranosyl]-6α-acetoxy-23α-butoxy-16β,23(R)-epoxy-24,25,26,27-tetranorcycloartane (4), 3-O-[β-d-glucopyranosyl(1 → 2)]-β-d-xylopyranosyl]-6α-acetoxy-23α-methoxy-16β,23(R)-epoxy-24,25,26,27-tetranorcycloartane (5), 3-O-[β-d-glucopyranosyl(1 → 2)]-β-d-xylopyranosyl]-23α-methoxy-16β,23(R)-epoxy-4,25,26,27-tetranorcycloartane (6), in addition to three known secondary metabolites consisting of another cycloartane triterpene glycoside and two flavonol glycosides, were isolated from the aerial parts of Astragalus gombo Coss. & Dur. (Fabaceae). The structures of the isolated compounds were established by spectroscopic methods, including 1D and 2D-NMR, mass spectrometry and comparison with literature data.     

Steroidal saponins from Tribulus terrestris

Five new steroidal saponins were isolated from the fruits of Tribulus terrestris. Their structures were fully established by spectroscopic and chemical analysis as (23S,25S)-5α-spirostane-24-one-3β,23-diol-3-O-{α-l-rhamnopyranosyl-(1 → 2)-O-[β-d-glucopyranosyl-(1 → 4)]-β-d-galactopyranoside} (1), (24S,25S)-5α-spirostane-3β,24-diol-3-O-{α-l-rhamnopyranosyl-(1 → 2)-O-[β-d-glucopyranosyl-(1 → 4)]-β-d-galactopyranoside} (2), 26-O-β-d-glucopyranosyl-(25R)-5α-furostan-2α,3β,22α,26-tetraol-3-O-{β-d-glucopyranosyl-(1 → 2)-O-β-d-glucopyranosyl-(1 → 4)-β-d-galactopyranoside} (3), 26-O-β-d-glucopyranosyl-(25R)-5α-furostan-20(22)-en-2α,3β,26-triol-3-O-{β-d-glucopyranosyl-(1 → 2)-O-β-d-glucopyranosyl-(1 → 4)-β-d-galactopyranoside} (4), and 26-O-β-d-glucopyranosyl-(25S)-5α-furostan-12-one-22-methoxy-3β,26-diol-3-O-{α-l-rhamnopyranosyl-(1 → 2)-O-[β-d-glucopyranosyl-(1 → 4)]-β-d-galactopyranoside} (5). The isolated compounds were evaluated for cytostatic activity against HL-60 cells.