Three New Myrsinol Diterpenes from <em>Euphorbia prolifera</em> and Their Neuroprotective Activities

Three new myrsinol diterpenes were isolated from the roots of Euphorbia prolifera. Their structures were elucidated as 2α-O-isobutyryl-3β,5α,7β,10,15β-penta-O-acetyl-14α-O-benzoyl-10,18-dihydromyrsinol (1), 2α-O-isobutyryl-3β-O-propion-yl-5α,7β,10,15β-tetra-O-acetyl-10,18-dihydromyrsinol (2), and 2α,14α-di-O-benzoyl-3β,5α,7β,10,15β-penta-O-acetyl-10,18-dihydromyrsinol (3) on the basis of spectroscopic data analyses (IR, ESI-MS, HR-ESI-MS, and 1D and 2D NMR). Their neuroprotective activities were evaluated and compounds 1 and 2 showed neuroprotective effects against MPP⁺-induced neuronal cell death in SH-SY5Y cells.     

Synthesis, Antigenicity Against Human Sera and Structure-Activity Relationships of Carbohydrate Moieties from <em>Toxocara</em> larvae and Their Analogues

Stereocontrolled syntheses of biotin-labeled oligosaccharide portions containing the Galβ1-3GalNAc core of the TES-glycoprotein antigen obtained from larvae of the parasite Toxocara and their analogues have been accomplished. Trisaccharides Fuc2Meα1-2Gal4Meβ1-3GalNAcα1-OR (A), Fucα1-2Gal4Meβ1-3GalNAcα1-OR (B), Fuc2Meα1-2Galβ1-3GalNAcα1-OR (C), Fucα1-2Galβ1-3GalNAcα1-OR (D) and a disaccharide Fuc2Meα1-2Gal4Meβ1-OR (E) (R = biotinylated probe) were synthesized by block synthesis using 5-(methoxycarbonyl)pentyl-2,3,4,6-tetra-O-acetyl-β-D-galactopyranosyl-(1?3)-2-azide-4-O-benzyl-2-deoxy-α-D-galactopyranoside as a common glycosyl acceptor. We examined the antigenicity of these five oligosaccharides by enzyme linked immunosorbent assay (ELISA). Our results demonstrate that the O-methyl groups in these oligosaccharides are important for their antigenicity and the biotinylated oligosaccharides A, B, C and E have high serodiagnostic potential to detect infections caused by Toxocara larvae.     

Nephroprotective and antioxidant activities of ethyl acetate fraction of Euphorbia geniculata Ortega family Euphorbiaceae

In continuation of our work on genus Euphorbia, the phytochemical investigation of ethyl acetate fraction of the aerial parts of Euphorbia geniculata Ortega (Eg) family Euphorbiaceae revealed the isolation and identification of eight polyphenolic compounds; gallic acid (1), ellagic acid (2), quercetin-3-O-rutinoside) (rutin) (3), quercetin-3-O-glucopyranoside-7-O-rhamnoside (4), quercetin-3-O-rhamnoside (5), quercetin-3-O-β-D- glucopyranoside (6), and quercetin-3-O-β-D-arabinoside (7) and quercetin (8) using spectrophotometric and physicochemical analysis. Quantitative estimation of total flavonoids and phenolics contents were carried out for total methanolic extract. Biological activities of ethyl acetate fraction including nephroprotective and antioxidant activities were evaluated for the first time. The nephroprotective potential of Eg was evaluated in male rats with thioacetamide induced kidney injury. Antioxidant activity was evaluated using DPPH method.Results; Quantitative estimation of total phenolics and flavonoids content in the total methanolic extract of Eg revealed high phenolics content (285.4 mg GAE /gm extract) in comparison with flavonoids content (36.9 mg RE /gm extract). Isolation and characterization of eight polyphenolic compounds. The nephroprotictive activity was studied using thioacetamide as nephrotoxicant agent resulted in marked nephrotoxicity. While pretreatment of rats with ethyl acetate fraction of Eg significantly attenuated the nephrotoxicity through alteration of kidney biomarkers, improving the redox status of the tissue and so brought the serum biochemical parameters nearly toward the normal levels. The study revealed significant antioxidant activity of Eg in comparison with ascorbic acid. Conclusion; The results suggested that E. geniculata Ortega ethyl acetate fraction could be used in future therapy as nephroprotective and antioxidant drugs of natural source.     

Steroidal and Phenolic Glycosides from the Bulbs of <em>Lilium pumilum</em> DC and Their Potential Na⁺/K⁺ ATPase Inhibitory Activity

A new steroidal saponin, named pumilum A (1), and a new phenolic glycoside, threo-1-(4'-hydroxy-2'-methoxyphenyl)-2-(2',4'-dihydroxyphenyl)-1,3-propanediol-4'-O-β-D-glucopyranoside (7) were isolated from the methanolic extract of the bulbs of Lilium pumilum DC, along with five known steroidal saponins. Their chemical structures were elucidated on the basis of detailed spectroscopic analysis, including 1D and 2D NMR techniques and chemical methods. In addition, the inhibitory activity of all the isolates on Na⁺/K⁺ ATPase was evaluated.     

Two New Compounds Isolated from<em> Liriope muscari</em>

Two new compounds, (2S,3R)-methyl 7-hydroxy-2-(4-hydroxy-3-methoxy-phenyl)-3-(hydroxymethyl)-2,3-dihydrobenzofuran-5-carboxylate (1) and (4R,5S)-5-(3-hydroxy-2,6-dimethylphenyl)-4-isopropyldihydrofuran-2-one (2), tentatively named norcurlignan and limlactone, respectively, were isolated from Liriope muscari, together with the known compound (-)-pinoresinol (3). The structures of these compounds were elucidated and characterized on the basis of 1D NMR, 2D NMR, CD and MS data. The in vitro antioxidant activities of compounds 1-3 were assessed by the DPPH and ABTS scavenging methods.     

Cytotoxic Podophyllotoxin Type-Lignans from the Steam Bark of <em>Bursera fagaroides </em>var. <em>fagaroides</em>

The hydroalcoholic extract of the steam bark of B. fagaroides var. fagaroides displayed potent cytotoxic activity against four cancer cell lines, namely KB (ED₅₀ = 9.6 × 10^-2 μg/mL), PC-3 (ED₅₀ = 2.5 × 10^-1 μg/mL), MCF-7 (ED₅₀ = 6.6 μg/mL), and HF-6 (ED₅₀ = 7.1 × 10^-3 μg/mL). This extract also showed anti-tumour activity when assayed on mice inoculated with L5178Y lymphoma cells. Bioactivity-directed isolation of this extract, afforded seven podophyllotoxin-type lignans identified as podophyllotoxin (1), β-peltatin-A-methylether (2), 5'-desmethoxy-β-peltatin-A-methylether (3), desmethoxy-yatein (4), desoxypodophyllotoxin (5), burseranin (6), and acetyl podophyllotoxin (7) by 1D and 2DNMR and FAB-MS analyses, and comparison with reported values. All the isolated compounds showed potent cytotoxic activity in the cell lines tested, especially compound 3, which exhibited greater activity than camptothecin and podophyllotoxin against PC-3 (ED₅₀ = 1.0 × 10^-5 μg/mL), and KB (ED₅₀ = 1.0 × 10^-5 μg/mL). This is the first report of the isolation of podophyllotoxin and its acetate in a Bursera species.     

Four new constituents from Taraxacum mongolicum

Two new flavone glycosides,isoetin-7-O-β-D-glucopyranosyl-2′-O-α-L-arabinopyranoside (1) and isoetin-7-O-β-D-glucopyr- anosyl-2′-O-α-D-glucopyranoside (2),a new lignan,mongolicumin A (3),and a new guaianolide,mongolicumin B (4) were isolated from the aerial part of Taraxacum mongolicum.Their structures were elucidated mainly by spectral analyses.     

Phenolic Antioxidants Isolated from the Flowers of <em>Osmanthus fragrans</em>

O. fragrans has slightly less antioxidative activity than green tea. Five phenolic compounds, tyrosyl acetate (1), (+)-phillygenin (2), (8E)-ligustroside (3), rutin (4), and verbascoside (5), were isolated from the CHCl₃ sub-extract of O. fragrans. The structures were elucidated by interpreting their spectral data. Evaluation of the antioxidative property of the isolated (+)-phillygenin (2), rutin (4), and verbascoside (5) revealed strong DPPH radical scavenging activity, with IC₅₀ values of 19.1, 10.3, and 6.2 μM, respectively. These isolates also exhibited an H₂O₂ scavenging ability, with IC₅₀ values of 10.5, 23.4, and 13.4 μM, respectively.     

Biphenyl quinolizidine lactone alkaloids from “sinicuichi” (Heimia salicifolia)

Six new biphenyl quinolizidine lactone alkaloids: 14α-hydroxydecodine (1), 14β-hydroxydecodine (2), 4″-O-demethylheimidine (3), 4″-O-demethyl-9β-hydroxyvertine (4), 4″-O-demethylvertine N-oxide (5), and 4″-O-demethyl-9β-hydroxyvertine N-oxide (6) were isolated from so-called “sinicuichi” (origin: Heimia salicifolia) together with 18 known alkaloids. Their structures were determined by spectroscopic analyses and chemical conversions.     

A new triterpene and a saponin from Centella asiatica

A new triterpene and a saponin,named 2α,3β,23-trihydroxyurs-20-en-28-oic acid(1)and 2α,3β,23-trihydroxyurs-20-en-28-oic acid O-α-L-rhamnopyranosyl-(1→4)-O-β-D-glucopyranosyl-(1→6)-O-β-D-glucopyranosyl ester(2),have been isolated from the aerial part of Centella asiatica.Their structures were elucidated by spectral methods,including 2D-NMR spectra.     

The microbiological transformation of steroidal saponins by Curvularia lunata

The microbiological transformation of polyphyllin I (compound I), polyphyllin III (compound II), polyphyllin V (compound III) and polyphyllin VI (compound IV) by Curvularia lunata into their corresponding subsaponins, for example, diosgenin-3-O-α-l-arabinofuranosyl (1→4)-β-d-glucopyranoside (compound V), diosgenin-3-O-α-l-rhamnopyranosyl (1→4)-β-d-glucopyranoside (compound VI), diosgenin-3-O-β-d-glucopyranoside (compound VII) and pennogenin-3-O-β-d-glucopyranoside (compound VIII), were studied in this paper. Curvularia lunata is able to hydrolyze terminal rhamnosyls that are linked by 1→2 C- bond to sugar residues of steroidal saponins at C-3 position with high activity and regioselectivity.     

A new eudesmane sesquiterpene glycoside from Parepigynum funingense

A new eudesmane sesquiterpene glycoside,1α,6β-dihydroxy-5,10-bis-epi-eudesm-4(15)-ene-6-O-β-D-glucopyranoside(2), together with a known analogue compound,1α,6β-dihydroxy-5,10-bis-epi-eudesm-3-ene-6-O-β-D-glucopyranoside(1),were isolated from the roots of Parepigynumfuningense.The structure of 2 was determined by 1D and 2D NMR spectroscopy.Compound 1 was isolated from this plant for the first time.     

Screening and Analysis of the Potential Bioactive Components in Rabbit Plasma after Oral Administration of Hot-Water Extracts from Leaves of <em>B</em><em>ambusa </em><em>textilis </em>McClure

Bambusa textilis McClure is a traditional Chinese medicinal plant belonging to the Bambusoideae subfamily and used to treat chronic fever and infectious diseases. To investigate the bioactive compounds absorbed in the rabbit blood after oral administration of hot-water extracts from the leaves of B. textilis McClure, a validated chromatographic fingerprint method was established using LC-Q-TOF-MS. Twenty compounds in bamboo leaves and three potential bioactive compounds in rabbit plasma were detected. Of the twenty detected compounds in vitro, fifteen of which were tentatively identified either by comparing the retention time and mass spectrometry data with that of reference compounds or by reviewing the literature. Three potential bioactive compounds, including (E)-p-coumaric acid, (Z)-p-coumaric acid, and apigenin-8-C-β-D-(2"-O-α-L-rhamnosyl)-gluco-pyranoside, were detected in both the leaves of B. textilis McClure and rabbit plasma. Of the three compounds, apigenin-8-C-β-D-(2"-O-α-L-rhamnosyl)glucopyranoside was identified based on its UV, MS, and NMR spectra. This study provides helpful chemical information for further pharmacology and active mechanism research on B. textilis McClure.     

Furostanol saponins with inhibitory action against COX-2 production from Tupistra chinensis rhizomes

Two furostanol saponins were obtained from the n-butanol fraction of methanol extract from Tupistra chinensis rhizomes,a folk medicine of Shennongjia Forest District of Hubei Province.Their structures were determined as (25S)-26-O-(β-D-glucopyranosyl)- furost-1β,3β,22α,26-tetrol-3-O-β-D-glucopyranosyl-(1→4)-β-D-glucopyranosyl-(1→2)-β-D-glucopyranoside (1) and (25R)- 26-O-(β-D-glucopyranosyl)-furost-1β,3β22α,26-tetrol 3-O-β-D-glucopyranosyl-(1→4)-β-D-glucopyranosyl-(1→2)-β-D-glu- copyranoside (2),on basis of chemical and spectroscopic evidences.1 and 2 displayed marked inhibitory action towards COX-2 production in macrophages of the rat abdomen induced by LPS at 20μg/mL.     

Two New Daucane Sesquiterpenoids from <em>Daphne aurantiaca</em>

Two new daucane sesquiterpenoids 1β,2β-epoxy-10(H)α-dauca-11(12)-ene-7α,14-diol (1) and 1α,2α-epoxy-10(H)α-dauca-11(12)-ene-7α,14-diol (2) were isolated from the plateau medicinal plant Daphne aurantiaca Diels. (Thymelaeceae). Their structures were elucidated by 1D and 2D NMR spectroscopy, as well as HR-ESI-MS data.     

Montamine, a unique dimeric indole alkaloid, from the seeds of Centaurea montana (Asteraceae), and its in vitro cytotoxic activity against the CaCo2 colon cancer cells

Reversed-phase HPLC analysis of the methanol extract of the seeds of Centaurea montana afforded a flavanone, montanoside (4), six epoxylignans, berchemol (7), berchemol 4′-O-β-d-glucoside (5), pinoresinol (10), pinoresinol 4-O-β-d-glucoside (8), pinoresinol 4,4′-di-O-β-d-glucoside (6), pinoresinol 4-O-apiose-(1→2)-β-d-glucoside (9), two quinic acid derivatives, trans-3-O-p-coumaroylquinic acid (1), cis-3-O-p-coumaroylquinic acid (2), and eight indole alkaloids, tryptamine (3), N-(4-hydroxycinnamoyl)-5-hydroxytryptamine (11), cis-N-(4-hydroxycinnamoyl)-5-hydroxytryptamine (12), centcyamine (16), cis-centcyamine (17), moschamine (13), cis-moschamine (14) and a dimeric indole alkaloid, montamine (15). While the structures of two new compounds, montanoside (4) and montamine (15), were established unequivocally by UV, IR, MS and a series of 1D and 2D NMR analyses, all known compounds were identified by comparison of their spectroscopic data with literature data. The antioxidant properties of these compounds were assessed by the DPPH assay, and their toxicity towards brine shrimps and cytotoxicity against CaCo-2 colon cancer cells were evaluated by the brine shrimp lethality and the MTT cytotoxicity assays, respectively. The novel dimer, montamine (15), showed significant in vitro anticolon cancer activity (IC₅₀=43.9 μM) while that of the monomer, moschamine (13), was of a moderate level (IC₅₀=81.0 μM).     

First synthesis of 5,6-branched galacto-hexasaccharide,the dimer of the trisaccharide repeating unit of the cell-wall galactans of Bifidobacterium catenulatum YIT 4016

α-d-Galactopyranosyl-(1→6)-[β-d-galactofuranosyl-(1→5)]-β-d-galactofuranosyl-(1→6)-β-d-galactofuranosyl-(1→5)-[α-d-galactopyranosyl-(1→6)]-β-d-galactofuranose, the dimer of the trisaccharide repeating unit of the cell-wall galactans of Bifidobacterium catenulatum YIT 4016, has been synthesized as its dodecyl glycoside 2 by coupling of 2,3,4,6-tetra-O-benzyl-α-d-galactopyranosyl-(1→6)-[6-O-acetyl-2,3,5-tri-O-benzoyl-β-d-galactofuranosyl-(1→5)]-2-O-acetyl-3-O-benzyl-β-d-galactofuranosyl trichloroacetimidate 14 with dodecyl 2,3,4,6-tetra-O-benzyl-α-d-galactopyranosyl-(1→6)-[2,3,5-tri-O-benzoyl-β-d-galactofuranosyl-(1→5)]-2-O-acetyl-3-O-benzyl-β-d-galactofuranoside 16. The trisaccharide trichloroacetimidate donor 14 and trisaccharide acceptor 16 were regiospecifically prepared by employing 3-O-benzyl-1,2-O-isopropylidene-α-d-galactofuranose 4 as the glycosyl acceptor, and isopropyl 2,3,4,6-tetra-O-benzyl-1-thio-β-d-galactopyranoside 5 and 6-O-acetyl-2,3,5-tri-O-benzoyl-β-d-galactofuranosyl trichloroacetimidate 9 as glycosyl donors.     

Two xanthones and two rotameric (3⟶8) biflavonoids from the Cameroonian medicinal plant Allanblackia floribunda Oliv. (Guttiferae)

Two xanthones, 2-(3-hydroxy-3,3-dimethyldihydroallyl)-dihydro-6-deoxyisojacareubin (1) and dihydro-6-deoxyjacareubin (2), and two 3 ⟶ 8 rotameric biflavonoids, (2R,3S)-volkensiflavone-7-O-β-acetylglucopyranoside (3) and (2S,3S)-morelloflavone-7-O-β-acetylglucopyranoside (4), together with fifteen known compounds, were isolated from a dichloromethane/methanol (1:1, v/v) extract of the bark of the plant Allanblackia floribunda. The structures of the new compounds were elucidated by NMR spectroscopy and mass spectroscopic techniques and those of the known ones were deduced by comparison with data reported in the literature. The isolated biflavonoids were obtained as mixtures of conformers exhibiting duplicate NMR signals in solution at 25 °C and their respective absolute configurations were assigned using circular dichroism spectroscopy. Selected isolated compounds were assessed for their antibacterial and antioxidant properties.     

Alkaloids Isolated from the Lateral Root of <em>Aconitum carmichaelii</em>

Two new alkaloids, aconicarmine (1) and aconicaramide (5), were isolated from the EtOH extract of the lateral roots of Aconitum carmichaelii, together with five known compounds: fuziline (2), neoline (3), N-ethylhokbusine B (4), 5-hydroxymethylpyrrole-2-carbaldehyde (6), and oleracein E (7). Their structures were elucidated by physical and NMR analysis. Pyrrole alkaloids were isolated from A. carmichaelii for the first time. In the in vitro assays, compounds 2 and 3 showed activity against pentobarbital sodium-induced cardiomyocytes damage by obviously recovering beating rhythm and increasing the cell viability, while compounds 5 and 7 showed moderate antibacterial activity.     

Marine sterols—II : Asterosterol,a new C26 sterol from Asterias amurensis lütken

Asterosterol, a new marine C₂₆ sterol, was isolated from the asteroid, A. amurensis, and its structure was characterized as 22-trans-24-nor-5α-cholesta-7,22-dien-3β-ol (1). Episterol (9), 22-trans-(24R)-24-methylcholesta-7,22-dien-3β-ol (stellasterol, 3) and 22-trans-cholesta-7,22-dien-3β-ol (7) were also isolated and their structures were confirmed.