Myrsinionosides A-E: megastigmane glycosides from the leaves of Myrsine seguinii Lev

Eight megastigmane glycosides were isolated from the leaves of Myrsine seguinii collected in Okinawa. Three of them were found to be known compounds, i.e., ampelopsisionoside, alangionoside J, and linarionoside A. The structures of the new megastigmane glycosides were elucidated from the spectroscopic data and their absolute stereochemistries were determined in detail using a modified Mosher's method.     

Staphylionosides A-K: megastigmane glucosides from the leaves of Staphylea bumalda DC

Chemical investigation of leaves of Staphylea bumalda DC., collected in the suburbs of Hiroshima City, afforded 11 new megastigmane glucosides, named staphylionosides A-K (3-13), along with two known megastigmane glucosides (1, 2). The relative structures were elucidated from spectroscopic evidence, and the absolute structures of the aglycones were determined by means of the combination of beta-D-glucosylation-induced shift-trends and the modified Mosher's method.     

Ellagic acid glycosides from Turpinia ternata

Bioassay-guided fractionation of the methanolic extract of Turpinia ternata stems, has led to the isolation of the new ellagic acid derivative 3,4'-di-O-methylellagic acid-4-O-alpha-L-arabinofuranoside (1), and the known compounds ellagic acid (2), 3-O-methyl ellagic acid (3), 3-O-methylellagic acid-3'-O-alpha-L-rhamnopyranoside (4), and 3,3'-di-O-methylellagic acid-4'-O-alpha-D-glucopyranoside (5). Their structures were elucidated by extensive spectroscopic methods. Compounds 1, 3, and 4 showed moderate antioxidant activity against DPPH free radical, whereas compound 1 was found to be moderately cytotoxic against Artemia salina larvae.     

Glochidionionosides A-D: megastigmane glucosides from leaves of Glochidion zeylanicum (Gaertn.) A. Juss

Five megastigmane glucosides were isolated from the leaves of Glochidion zeylanicum. One of them was a known compound, blumenol C O-beta-D-glucopyranoside (1), and the structures of the four new compounds, glochidionionosides A-D (2-5), were mainly elucidated by spectroscopic methods, including a modified Mosher's method. The absolute configurations of the six-membered ring of glochidionionoside D (5) were deduced by beta-D-glucopyranosylation-induced shift trends in the (13)C-NMR spectra and confirmed by X-ray analysis as its p-bromobenzoate (5b), and the axis chirality of C-7 was determined to be R.     

Cytotoxic phenylpropanoids and a new triterpene, turformosinic acid, from Turpinia formosana Nakai

One new phenylpropanoid, turformosin A (1), and one new triterpene, turformosinic acid (2), together with 16 known compounds, were isolated from the stems of Turpinia formosana Nakai. All structures were elucidated on the basis of spectroscopic analysis, including 1D- and 2D-NMR techniques and MS analysis. Selected isolated compounds were evaluated for in vitro cytotoxicity against four human cancer cell lines and antioxidant scavenging effects on DPPH. (-)-(7'S,8'S)-threo-carolignan X (3) exhibited cytotoxicity against Hep2, WiDr, Daoy, and MCF-7 cell lines with ED(50) values of 3.60, 4.45, 6.07, and 13.7 μg/mL, respectively. Turformosin A (1), (-)-(7'S,8'S)- threo-carolignan X (3), methoxyhydroquinone-4-β-D-glucopyranoside (5), and methoxy-hydroquinone-1-β-D-glucopyranoside (6), exhibited similar anti-oxidative activity. Hep2 cells treated with 10 μg/mL of 3 showed elevation of sub-G1 population (from 20% at 8 h to 60% at 48 h), and activation of caspase-9/caspase-3/PARP cascade. Compound 3 induced intrinsic apoptotic pathway in Hep2 cells with dose and time dependence (10 μg/mL for 8 h).     

New megastigmane glucosides from Excoecaria cochinchinensis LOUR. var. cochinchinensis

Two new megastigmane glucosides, called excoecariosides A and B were isolated from the leaves of a medicinal Vietnamese plant, Excoecaria cochinchinensis LOUR. var. cochinchinensis (Euphorbiaceae) together with seven known compounds. Their structures were elucidated by spectroscopic analyses and chemical reactions including the modified Mosher's method.     

New megastigmane and tetraketide from the leaves of Euscaphis japonica

New megastigmane (1) and tetraketide (2) were isolated from the leaves of Euscaphis japonica and the structures were elucidated by means of spectroscopic and chemical evidence.     

Tricalysionoside A, a megastigmane gentiobioside, sulfatricalysines A-F, and tricalysiosides X-Z, ent-kaurane glucosides, from the leaves of Tricalysia dubia

Further isolation work on the water-soluble fraction of a MeOH extract of Tricalysia dubia afforded one new megastigmane gentiobioside, named tricalysionoside A (1), and three sulfates, named sulfatricalysines A-C (2-4). Extensive isolation work on the 1-BuOH-soluble fraction of a MeOH extract of T. dubia yielded sulfatricalysines D-F (5-7) and three new ent-kaurane glucosides, named tricalysiosides X-Z (8-10). The structures of the new compounds were elucidated by analyses of one- and two-dimensional NMR spectroscopic data. The absolute stereochemistry of tricalysionoside A (1) was established by modified Mosher's method.     

Biflavone glucosides from Ginkgo biloba yellow leaves

Phytochemical investigation of Ginkgo biloba (Ginkgoaceae) has resulted in the isolation of two new biflavone glucosides, ginkgetin 7'-O-beta-D-glucopyranoside (1) and isoginkgetin 7-O-beta-D-glucopyranoside (2). The structures were determined on the basis of chemical and spectroscopic evidences.     

Radical-scavenging activities of new megastigmane glucosides from Macaranga tanarius (L.) MULL.-ARG

Four new megastigmane glucosides, named macarangiosides A-D (2-5), together with mallophenol B, lauroside E, methyl brevifolin carboxylate, and hyperin and isoquercitrin as a mixture were isolated from the leaves of Macaranga tanarius (L.) MULL.-ARG. (Euphorbiaceae). Their structures were elucidated by spectroscopic and chemical analyses. Macarangioside A-C (2-4) and mallophenol B were galloylated on glucose moiety and possessed the potent 2,2-diphenyl-picrylhydrazyl (DPPH) radical-scavenging activity.     

Two new megastigmane O-glucopyranosides from the leaves of Broussonetia papyrifera

Two new megastigmane O-glucopyranosides,named (2R,3R,5R,6S,9R)-3-hydroxy-5,6-epoxy-β-ionol-2-O-β-D-glucopyrano- side(1) and (2R,3R,5R,6S,9R)-3-hydroxyl-5,6-epoxy-acety-β-ionol-2-O-β-D-glucopyranoside(2) together with six known mega- stigmanes,were isolated from the leaves of Broussonetia papyrifera (Linn.) Vent.Their structures were established by chemical methods and spectroscopic techniques including 2D NMR.     

Two new cyanogenic glucosides from the leaves of Hydrangea macrophylla

Chemical investigation of the ethanol extract of the aerial parts of Hydrangea macrophylla collected in the Sichuan Province of China resulted in the isolation of two new cyanogenic glucosides. Their structures were elucidated as [(2R)-2-β-D-glucopyranosyloxy)-2-(3,4-dimethoxy-phenyl)] acetonitrile (1) and {(2R)-2-[α-D-glucopyranosyl(1-->6)β-D-glucopyranosyloxy]-2-(3-hydroxy-4-methoxy-phenyl)}acetonitrile (2) on the basis of extensive spectroscopic analysis (1D, 2D NMR and HRESIMS) and chemical studies.     

Tricalysiosides P-U: Ent-kaurane glucosides and a labdane glucoside from leaves of Tricalysia dubia OHWI

Further extensive isolation work on the 1-BuOH-soluble fraction of a MeOH extract of Tricalysia dubia afforded five new ent-kaurane glucosides (4-8) and one new labdane glucoside (9), together with a known megastigmane glucoside, sammangaoside B (1), and monoterpene glucosides (2, 3). The structures of the new compounds were elucidated by analyses of one- and two-dimensional NMR spectroscopic data. The absolute configuration of the 9-position of sammangaoside B was revised to S and its total stereochemistry was established by the modified Mosher's method.     

Schefflerins A-G, new triterpene glucosides from the leaves of Schefflera arboricola

From the 1-BuOH-soluble fraction of a MeOH extract of leaves of Schefflera arboricola, collected in Okinawa, six new lupane glucosides, named schefflerins A-F (1-6) and one new dammarane glucoside, named schefflerin G (7), were isolated together with three known compounds, citroside A (8), and oleanane saponins, oleanolic acid (9) and echinocystic acid (10) 3-O-α-L-rhamnopyranosyl(1→4')-O-β-D-glucuronopynosides. Their structures were elucidated through a combination of spectroscopic analyses and the structure of schefflerin F (6) was determined by X-ray crystallographic method using SPring-8 synchrotron radiation.     

Flavonoids from the leaves of Epimedium Koreanum Nakai and their potential cytotoxic activities

Abstract

Phytochemical studies on the leaves of Epimedium koreanum Nakai have resulted in the discovery of two new flavonol glycosides, koreanoside F (1) and koreanoside G (2), along with six known flavonoids. Their structures were elucidated on the basis of HRESIMS, UV, IR, 1?D NMR and 2?D NMR data. Absolute configurations of 1 and 2 was further determined by ¹³C-NMR spectra with gate decoupling (GD). All of the compounds were evaluated for cytotoxic activities by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazoliumbromide (MTT) assay. The results indicated that compounds 3, 5, 6, 7 and 8 inhibited the proliferation of A549 and NCI-292 cells with IC₅₀ values of 5.7–23.5?μM. Real-time monitoring in three kinds of lung cancer cells and a kind of human bronchial epithelial cells treated with compound 6 was also assessed.     

Glochidionolactones A-F: butenolide glucosides from leaves of Glochidion zeylanicum (GAERTN) A. JUSS

From the leaves of Glochidion zeylanicum, six new butenolide glucoside, named glochidionolactones A-F, were isolated along with a known related compound, phyllanthurinolactone. The structures of glochidionolactones A-D and F were elucidated mainly by spectroscopic analyses. The absolute stereochemistry of glochidionolactone E was established by X-ray crystallographic analysis.     

Cussosaponins A-E,triterpene saponins from the leaves of Cussonia racemosa,a Malagasy endemic plant

Five new triterpene saponins, cussosaponins A (2), B (3), C (4), D (5), and E (6), were isolated from the dried leaves of Cussonia racemosa BAKER. The structures of these new compounds were deduced on the basis of chemical and spectroscopic evidence.