Ursane-type triterpenoid saponins from Elsholtzia bodinieri

Investigation of the n-BuOH extract of the aerial parts of Elsholtzia bodinieri led to the isolation of two new ursane-type triterpenoid saponins, bodiniosides O (1) and P (2), along with five known saponins, rotungenoside (3), 3,28-O-bis-β-d-glucopyranosides of 19α-hydroxyarjunolic acid (4), oblonganosides I (5), rotungenic acid 28-O-α-L-rhamnopyranosyl-(1→2)-β-d-glucopyranoside (6), and bodinioside M (7) isolated from the species. The structures of compounds 1 and 2 were characterized by spectroscopic data as well as acid hydrolysis and GC analysis as 3-O-β-d-xylopyranosyl-23-acetoxy-urs-12(13)-en-28-oic acid 28-O-β-d-xylopyranosyl-(1→6)-[β-d-glucopyranosyl-(1→4)-α-L-rhamnopyranosyl-(1→2)]-β-d-glucopyranoside and 3-O-β-d-xylopyranosyl-23-hydroxy-urs-12(13)-en-28-oic acid 28-O-β-d-glucopyranosyl-(1→6)-β-d-glucopyranoside. Compounds 1 and 2 exhibited potent anti-HCV activities in vitro with a selective index of 30.63 and 9.08, respectively.     

Structural determination of two new acacic acid-type saponins from the stem barks of Albizia zygia (DC.) J. F. Macbr

As a continuation of our interest in the study of triterpenoid saponins from Albizia zygia, phytochemical investigation of its stem barks led to the isolation of two new oleanane-type saponins, named zygiaosides C–D (1–2). Their structures were established on the basis of extensive analysis of 1D and 2D NMR (1H-, 13C NMR, DEPT, COSY, TOCSY, ROESY, HSQC and HMBC) experiments, HRESIMS studies, and by chemical evidence as, 3-O-[ β-d-glucopyranosyl-(1→2)-[α-l-arabinopyranosyl-(1→6)]-β-d-glucopyranosyl]-21-O-[(2E,6S)-2,6-dimethyl-6-O-(β-d-quinovopyranosyl) octa-2,7-dienoyl]acacic acid 28-O-α-l-arabinofuranosyl-(1→4)-[β-d-glucopyranosyl-(1→3)]-α-l-rhamnopyranosyl-(1→2)-β-d-glucopyranosyl ester (1) and 3- O-[β-d-glucopyranosyl-(1→2) -[ β-d-fucopyranosyl-(1→6)]-β-d-glucopyranosyl]-21-O-[(2E,6S)-2,6-dimethyl-6-O-(β-D-quinovopyranosyl) octa-2,7-dienoyl]acacic acid 28-O-α-l-arabinofuranosyl-(1→4)-[β-d-glucopyranosyl-(1→3)]-α-l-rhamnopyranosyl-(1→2)-β-d-glucopyranosyl ester (2).     

Lebbeckoside C,a new triterpenoid saponin from the stem barks of Albizia lebbeck inhibits the growth of human glioblastoma cells

One new acacic acid-type saponin, named lebbeckoside C (1), was isolated from the stem barks of Albizia lebbeck. Its structure was established on the basis of extensive analysis of 1D and 2D NMR (¹H, ¹³C NMR, DEPT, COSY, TOCSY, ROESY, HSQC and HMBC) experiments, HRESIMS studies, and by chemical evidence as 3-O-[β-d-xylopyranosyl-(l→2)-β-d-fucopyranosyl-(1→6)-[β-d-glucopyranosyl(1→2)]-β-d-glucopyranosyl]-21-O-{(2E,6S)-6-O-{4-O-[(2E,6S)-2,6-dimethyl-6-O-(β-d-quinovopyranosyl)octa-2,7-dienoyl]-4-O-[(2E,6S)-2,6-dimethyl-6-O-(β-d-quinovopyranosyl)octa-2,7-dienoyl]-β-d-quinovopyranosyl}-2,6-dimethylocta-2,7-dienoyl}acacic acid 28 O-[β-d-quinovopyranosyl-(l→3)-[α-l-arabinofuranosyl-(l→4)]-α-l-rhamnopyranosyl-(l→2)-β-d-glucopyranosyl] ester. The isolated saponin (1) displayed significant cytotoxic activity against the human glioblastoma cell line U-87 MG and TG1 stem-like glioma cells isolated from a patient tumor with IC₅₀ values of 1.69 and 1.44 μM, respectively.     

A new flavonol glycoside and other flavonoids from the aerial parts of Taverniera aegyptiaca

Isolation of flavonoids from the aerial parts of Taverniera aegyptiaca Bioss. (Fabaceae) led to identification of one new flavonol glycoside, isorhamnetin-3-O-α-l-rhamnopyranosyl-(1→2)-α-l-arabinopyranoside (1), along with eleven compounds, which previously have not been isolated from this plant quercetin-3-O-α-l-rhamnopyranosyl-(1→2)-[α-l-rhamnopyranosyl-(1→6)-β-d-galactopyranoside] (2), isorhamnetin-3-O-α-l-arabinopyranoside (3), quercetin-3-O-α-l-rhamnopyranosyl-(1→6)-β-d-glucopyranoside (4), isorhamnetin-3-O-α-l-rhamnopyranosyl-(1→6)-β-d-glucopyranoside (7), isorhamnetin 3-O-α-l-rhamnopyranosyl-(1→2)-[α-l-rhamnopyranosyl-(1→6)-β-d-galactopyranoside] (8), isorhamnetin 3-O-α-l-rhamnopyranosyl-(1→2)-[α-l-rhamnopyranosyl-(1→6)-β-d-glucopyranoside] (9), kaempferol 3-O-α-l-rhamnopyranosyl-(1→2)-[α-l-rhamnopyranosyl-(1→6)-β-d-galactopyranoside] (10), isorhamnetin (11), 4,4′-dihydroxy-2′-methoxychalcone (12), formononetin (13) and calycosin (15)] and some compounds already known from this plant [quercetin-3-O-robinobioside (5), isorhamnetin-3-O-robinobioside (6), afrormosin (14) and odoratin (16)].     

A new isoflavane-4-ol derivative from Melilotus officinalis (L.) Pall.

A new isoflavane derivative, melilofficinaside together with seven other metabolites including coumarin, uridine, methyl-α-d-fructofuranoside, and flavonoid glucosides were isolated from the aerial parts of Melilotus officinalis (L.) Pall.     

Enzymatic synthesis of novel quercetin sialyllactoside derivatives

Quercetin and its derivatives are important flavonols that show diverse biological activity, such as antioxidant, anticarcinogenic, anti-inflammatory, and antiviral activities. Adding different substituents to quercetin may change the biochemical activity and bioavailability of molecules, when compared to the aglycone. Here, we have synthesised two novel derivatives of quercetin, quercetin-3-O-β-d-glucopyranosyl, 4′′-O-d-galactopyranosyl 3′′′-O-α-N-acetyl neuraminic acid i.e. 3′-sialyllactosyl quercetin (3′SL-Q) and quercetin-3-O-β-d-glucopyranosyl, 4′′-O-β-d-galactopyranosyl 6′′′-O-α-N-acetyl neuraminic acid i.e. 6′-sialyllactosyl quercetin (6′SL-Q) with the use of glycosyltransferases and sialyltransferases enzymes. These derivatives of quercetin were characterised by high-resolution quadrupole-time-of-flight electrospray ionisation mass spectrometry (HR-QTOF-ESI/MS) and ¹H and ¹³C nuclear magnetic resonance (NMR) analyses.     

Two new triterpenoids from Nauclea officinalis

Two new triterpenoids and three 27-nor-triterpenoids were isolated from the stems (with bark) of Nauclea officinalis. Their structures were identified to be 2β,3β,19α,23-tetrahydroxy-urs-12-en-28-oic acid (1), 2β,3β,19α,23-tetrahydroxy-urs-12-en-28-O-[β-d-glucopyranosyl (1-2)-β-d-glucopyranosyl] ester (2), pyrocincholic acid 3β-O-α-l-rhamnopyranoside (3), pyrocincholic acid 3β-O-α-l-rhamnopyranosy1-28-O-β-d-glucopyranosyl ester (4), pyrocincholic acid 3β-O-α-l-rhamnopyranosy1-28-O-β-d-glucopyranosyl-(1-6)-β-d-glucopyranosyl ester (5) by spectroscopic methods including 1D, 2D NMR and HR-MS analyses. The cytotoxic activity of 1–5 against lung cancer A-549 cells was also investigated.     

Chemical constituents of Genista numidica Spach aerial parts and their antimicrobial,antioxidant and antityrosinase activities

A previously undescribed triterpenoid saponin, 3-O-[α-l-rhamnopyranosyl-(1→2)-{β-d-glucopyranosyl-(1→6)-}β-d-galactopyranosyl-(1→2)-β-d-glucuronopyranosyl]-sophoradiol (1), in addition to twenty-nine known constituents (2–30) were isolated from the aerial parts of Genista numidica Spach. Structures elucidation was performed by comprehensive 1D- and 2D-NMR analyses and HRESIMS. The extracts, fractions and isolated compounds were evaluated for their antibacterial, antioxidant and tyrosinase inhibitory activities. The experimental findings indicated that genistin (16), isosalipurpol (27), and koaburaside (29) have moderate to low antibacterial activity against E. faecalis, S. aureus, S. epidermidis and P. aeruginosa bacteria with MICs ranging from 31.2 to 125 μg/mL. Compounds 19 and 27 exhibited a good antiradical activity potential (IC₅₀ 11.8 and 11.1 μg/mL, respectively). Only compounds 23, 27 and 28 exhibited low inhibitory effect against mushroom tyrosinase (IC₅₀ from 90.2 to 225.6 μg/mL).     

Three new triterpenoid saponins from the roots of Ardisia crenata and their cytotoxic activities

Three new triterpenoid saponins, ardisicrenoside O (1), ardisicrenoside P (2) and ardisicrenoside Q (3) together with three known compounds, 3β,16α-dihydroxy-30-methoxy-28, 30-epoxy-olean-12-en, cyclamiretin A 3-O-β-d-glucopyranosyl-(1→2) -α-l-arabinopyranoside and cyclamiretin A 3-O-β-d-glucopyranosyl-(1→4) -α-l-arabinopyranoside were isolated from the roots of Ardisia crenata Sims. Their structures were determined by one- and two-dimensional NMR techniques, including HSQC, HMBC and TOCSY experiments, as well as acid hydrolysis and GC analysis. All isolates were evaluated for the cytotoxic activities on two human cancer cell lines and compounds 3, 5 and 6 showed significant cytotoxicity.     

Insecticidal and α-glucosidase inhibitory activities of chemical constituents from Viburnum fordiae Hance

The ethanolic extract of the stems of Viburnum fordiae Hance showed insecticidal and α-glucosidase inhibitory activities and then was fractionated by bioactivity-guided fractionation to obtain a rare C₁₃-norisoprenoid (1), together with a new phenolic glycoside (2), and seven known compounds, alangionoside C (3), pisumionoside (4), koaburaside (5), 3,5-dimethoxy-benzyl alcohol 4-O-β-d-glucopyranoside (6), 3,4,5-trimethoxybenzyl-β-d-glucopyranoside (7), arbutin (8), and salidroside (9). The previously undescribed compounds were elucidated as (3R,9R)-3-hydroxy-7,8-didehydro-β-ionyl 9-O-α-d-arabinopyranosyl-(1→6)-β-d-glucopyranoside (1) and 2-(4-O-β-d-glucopyranosyl)syringylpropane-1,3-diol (2) by spectroscopic data (¹H and ¹³C NMR, HSQC, HMBC, ¹H-¹H COSY, HSQC-TOCSY, HRESIMS, IR and ORD) and chemical methods. Compound 1 showed potent insecticidal effect against Mythimna separata with LD₅₀ value of 140 μg g^?1. Compounds 2, 5, 6, 8 and 9 showed varying α-glucosidase inhibitory activity with IC₅₀ values ranging from 148.2 to 230.9 μM.     

A new triterpenoid saponin from Clinopodium chinense (Benth.) O. Kuntze

A new triterpene saponin, 3β,16β,23α,28β,30β-pentahydroxyl-olean-11,13(18)-dien-3β-yl-[β-d-glucopyranosyl-(1→2)]-[β-d-glucopyranosyl-(1→3)]-β-d-fucopyranoside, was named Clinoposaponin D (1), together with six known triterpene saponins, buddlejasaponin IVb (2), buddlejasaponin IVa (3), buddlejasaponin IV (4), clinopodisides D (5), 11α,16β,23,28-Tetrahydroxyolean-12-en-3β-yl-[β-d-glucopyranosyl-(1→2)]-[β-d-glucopyranosyl-(1→3)]-β-d-fucopyranoside (6) and prosaikogenin A (7), and two known triterpenes, saikogenin A (8) and saikogenin F (9) were isolated from Clinopodium chinense (Benth.) O. Kuntze. Their structures were elucidated on the basis of 1D, 2D NMR and MS analysis. Meanwhile, the effects of all compounds on rabbit platelet aggregation and thrombin time (TT) were investigated in vitro. Compounds 4 and 7 had significant promoting effects on platelet aggregation with EC₅₀ value at 53.4 and 12.2 μM, respectively. In addition, the highest concentration (200 μM) of compounds 2 and 9 shortened TT by 20.6 and 25.1%, respectively.     

Heptyl vicianoside and methyl caramboside from sour star fruit

Two new alkyl glycosides, heptyl vicianoside (1) and methyl 2-O-β-d-fucopyranosyl-α-l-arabinofuranoside (methyl caramboside, 4), were isolated from the sour fruit of Averrhoa carambola L. (Oxalidaceae), along with octyl vicianoside (2), cis-3-hexenyl rutinoside (3), and methyl α-d-fructofuranoside (5). Their structures were determined by spectroscopic and chemical methods. Compounds 2, 3, and 5 were obtained from the genus Averrhoa for the first time. All the compounds were evaluated for in vitro α-glucosidase, pancreatic lipase, and acetylcholinesterase inhibitory activities, but none of them were potent.     

Chemical constituents of Silene montbretiana

A new steroidal glycoside, 3-O-β-d-glucopyranosyl-3β,25-dihydroxy-5β-cholest-7-en-6-one 25-O-β-d-glucopyranoside (1), together with six known steroidal derivatives (2-7), one cerebroside (8) and one flavonoid (9) were isolated from Silene montbretiana Boiss (Caryophyllaceae), a perennial herb growing mainly in the Middle and East Anatolia, Azerbaijan, Iran, and Turkey. Their structures were established by the extensive use of 1D and 2D NMR experiments along with ESI-MS analyses. The cytotoxicity against the cancer A549 (human alveolar basal carcinoma) and Hela (human epitheloid cervix carcinoma) cell lines has been evaluated. None of the tested compounds, in a range of concentrations between 12.5 and 100 μM, caused a significant reduction of the cell number.     

Synthesis of Non-glucosamino Glucan Oligosaccharides Related to Heparin and Heparan Sulphate

Abstract

A series of three oligosaccharides, α-d-Glc-(1→4)-β-d-GlcA-1ωe, β-d-GlcA-(1→4)-α-d-Glc-(1→4)-β-d-GlcA-lωe and α-d-Glc-(1→4)-β-d-GlcA-(1→4)-α-d-Glc-(1→4)-β-d-GlcA-1ωe was prepared by a short synthetic route, using maltose and glucuronic acid derivatives as starting materials. The oligosaccharides contain glucose residues instead of glucosamines, and have a less complicated structure than the corresponding unsulphated structures found in native heparin and heparan sulphate. This simplification in structure has diminished the number of synthetic steps and raised the total yield compared to the preparation of the corresponding heparin/heparan sulphate structures which have been found to bind acidic and basic FGF.     

Antitumor triterpene saponins from Anemone flaccida

A new triterpenoid saponin, 3-O-[（6′-butyryl）-β-D-glucopyranosyl]-28-O-[α-L-rhamnopyranosyl-（1→4）-β-D-glucopyranosyl-（1→6）-β-D-glucopyranosyl] oleanolic acid, as well as three known triterpenoid saponins were isolated from the rhizomes of Anemone flaccida. Their structures were elucidated by spectroscopic methods. These compounds showed significant antitumor activities.     

Two new compounds from the fruit of Ailanthus altissima

A new phenolic derivative, 4-hydroxyphenol-1-O-[6-O-(E)-feruloyl-β-d-glucopyranosyl]-(1→6)-β-d-glucopyranoside (1), and a new terpenylated coumarin, named altissimacoumarin H (2) were identified from the fruit of Ailanthus altissima (Mill.) Swingle (Simaroubaceae), together with ten known compounds (3–12), including two coumarins and eight phenylpropanoids. Their structures were determined on the basis of chemical method and spectroscopic data. Antiviral effect against Tobacco mosaic virus (TMV) of all the compounds obtained were evaluated using leaf-disc method.     

Mimics of the Structural Elements of Type III Group B Streptococcus Capsular Polysaccharide. Part I: Synthesis of a Carboxylate-Containing Pentasaccharide

Abstract

A carboxylate-containing pentasaccharide, methyl O-(β-d-galactopyranosyl)-(1→4)-O-(β-d-glucopyranosyl)-(1→6)-O-{3-O-[(S)-1-carboxyethyl]-β-d-galactopyranosyl-(1→4)-O}-(2-acetamido-2-deoxy-β-d-glucopyranosyl)-(1→3)-β-d-galactopyranoside (27) was synthesized by block condensation of suitably protected donors and acceptors. Phenyl 3-O-benzyl-4,6-di-O-chloroacetyl-2-deoxy-2-phthalimido-1-thio-β-d-glucopyranoside (17) was condensed with methyl 2,4,6-tri-O-benzyl-β-d-galactopyranoside (4) to afford a disaccharide, methyl O-(3-O-benzyl-4,6-di-O-chloroacetyl-2-deoxy-2-phthalimido-β-d-glucopyranosyl)-(1→3)-2,4,6-tri-O-benzyl-β-d-galactopyranoside (18). Removal of chloroacetyl groups gave 4,6-diol, methyl 0-(3-O-benzyl-2-deoxy-2-phthalimido-β-d-glucopyranosyl)-(1→3)-2,4,6-tri-O-benzyl-β-d-galactopyranoside (19), in which the primary hydroxy group (6-OH) was then selectively chloroacetylated to give methyl O-(3-O-benzyl-6-O-chloroacetyl-2-deoxy-2-phthalimido-β-d-glucopyranosyl)-(1→3)-2,4,6-tri-O-benzyl-β-d-galactopyranoside (20). This acceptor was then coupled with 2,4,6-tri-O-acetyl-3-O-[(S)-1-(methoxycarbonyl)ethyl]-α-d-galactopyranosyl trichloroacetimidate (14) to afford a trisaccharide, methyl O-{2,4,6-tri-O-acetyl-3-O-[(S)-l-(methoxycarbonyl)ethyl]-β-d-galactopyranosyl}-(1→4)-O-(3-O-benzyl-6-O-chloroacetyl-2-deoxy-2-phthalimido-β-d-glucopyranosyl)-(1→3)-2,4,6-tri-O-benzyl-β-d-galactopyranoside (21). Removal of the 6-O-chloroacetyl group in 21 gave 22, which was coupled with 4-O-(2,3,4,6-tetra-O-acetyl-β-d-galactopyranosyl)-2,3,6-tri-O-acetyl-α-d-glucopyranosyl trichloroacetimidate (23) to yield protected pentasaccharide 24. Standard procedures were used to remove acetyl groups and the phthalimido group, followed by N-acetylation, and debenzylation to yield pentasaccharide 27 and a hydrazide by-product (28) in a 5:1 ratio, respectively. Compound 27 contains a complete repeating unit of the capsular polysaccharide of type III group B Streptococcus in which terminal sialic acid is replaced by an (S)-1-carboxyethyl group.     

Structural Elucidation of an Elicitor-Active Oligosaccharide,LN-3, Prepared from Algal Laminaran

Abstract

The primary structure of an elicitor-active oligosaccharide, LN-3, prepared from partially hydrolyzed algal laminaran was determined by means of the analyses of glycosyl-linkage, fragments by acetolysis, and glycosyl-sequence. The elicitor-active oligosaccharide, LN-3, is a pyridylaminated hepta-β-d-glucoside which was shown to have the following linear structure: β-d-Glcp(1→6)-β-d-Glcp(1→3)-β-d-Glcp(1→3)-β-d-Glcp(1→3)-β-d-Glcp(1→6)-β-d-Glcp(1→3)-Glc-PA.     

A new furostanol saponin from Dendrobium chrysanthum Lindl. with cytotoxic activity

A new furostanol saponin, (25R)-26-O-(α-d-glucopyranosyl)-(1→2)-α-l-rhamnopyranosyl-furost-5-ene-3β, 22α, 26-triol-3-O-α-d-glucopyranoside (1), together with four known compounds 2–5 were isolated from the ethanolic extract of the stems of Dendrobium chrysanthum Lindl. The structures of these new compounds were identified by extensive spectroscopic analysis including 1D and 2D NMR and HR-ESI-MS, as well as chemical methods. Compounds 1–3 were isolated from D. chrysanthum for the first time. Furthermore, the inhibitory effects of the compounds on tumor cells were evaluated, and compounds 1–2 exhibited significant cytotoxic activities potentially against SPC-A1, MCF-7 and HeLa human cancer cell lines. Compounds 3–5 showed inhibitory activity against the SPC-A1 and MCF-7.