Antiallergic agents from natural sources. 3. Structures and inhibitory effects on nitric oxide production and histamine release of five novel polyacetylene glucosides from Bidens parviflora WILLD

In Vitro and In Silico Investigation of Polyacetylenes from Launaea capitata (Spreng.) Dandy as Potential COX-2, 5-LOX, and BchE Inhibitors

Diverse secondary metabolites are biosynthesized by plants via various enzymatic cascades. These have the capacity to interact with various human receptors, particularly enzymes implicated in the etiology of several diseases. The n-hexane fraction of the whole plant extract of the wild edible plant, Launaea capitata (Spreng.) Dandy was purified by column chromatography. Five polyacetylene derivatives were identified, including (3S,8E)-deca-8-en-4,6-diyne-1,3-diol (1A), (3S)-deca-4,6,8-triyne-1,3-diol (1B), (3S)-(6E,12E)-tetradecadiene-8,10-diyne-1,3-diol (2), bidensyneoside (3), and (3S)-(6E,12E)-tetradecadiene-8,10-diyne-1-ol-3-O-β-D-glucopyranoside (4). These compounds were investigated for their in vitro inhibitory activity against enzymes involved in neuroinflammatory disorders, including cyclooxygenase-2 (COX-2), 5-lipoxygenase (5-LOX), and butyrylcholinesterase (BchE) enzymes. All isolates recorded weak-moderate activities against COX-2. However, the polyacetylene glycoside (4) showed dual inhibition against BchE (IC₅₀ 14.77 ± 1.55 μM) and 5-LOX (IC₅₀ 34.59 ± 4.26 μM). Molecular docking experiments were conducted to explain these results, which showed that compound 4 exhibited greater binding affinity to 5-LOX (-8.132 kcal/mol) compared to the cocrystallized ligand (-6.218 kcal/mol). Similarly, 4 showed a good binding affinity to BchE (-7.305 kcal/mol), which was comparable to the cocrystallized ligand (-8.049 kcal/mol). Simultaneous docking was used to study the combinatorial affinity of the unresolved mixture 1A/1B to the active sites of the tested enzymes. Generally, the individual molecules showed lower docking scores against all the investigated targets compared to their combination, which was consistent with the in vitro results. This study demonstrated that the presence of a sugar moiety (in 3 and 4) resulted in dual inhibition of 5-LOX and BchE enzymes compared to their free polyacetylenes analogs. Thus, polyacetylene glycosides could be suggested as potential leads for developing new inhibitors against the enzymes involved in neuroinflammation.

A new dihydroflavone and a new polyacetylene glucoside from Bidens parviflora

A new dihydroflavone, 2(S)-isookanin-4'-methoxy-8-O-β-D-glucopyranoside (1), and a new polyacetylene glucoside, (10S)-tridecane-2E-ene-4,6,8-triyne-1-ol-10-O-β-D-glucopyranoside (2), along with seven known compounds (3-9), were isolated from the herb of Bidens parviflora Willd. The structures of all the extracted compounds were elucidated by HR-ESI-MS, 1 D and 2 D NMR spectra, as well as circular dichroism (CD).

Polyacetylene Glycosides: Isolation, Biological Activities and Synthesis

Polyacetylene glycosides (PAGs) constitute a relatively small class of secondary metabolites characterized by the presence of a sugar unit anomerically connected to a polyacetylene. These compounds are found in fungi, seaweed, and more often in plants. PAGs exhibit a wide range of biological and pharmacological activities and, as a result, the literature of these compounds has grown exponentially in recent years.

Anticancer Properties of Lobetyolin, an Essential Component of Radix Codonopsis (Dangshen)

Lobetyolin (LBT) is a polyacetylene glycoside found in diverse medicinal plants but mainly isolated from the roots of Codonopsis pilosula, known as Radix Codonopsis or Dangshen. Twelve traditional Chinese medicinal preparations containing Radix Codonopsis were identified; they are generally used to tonify spleen and lung Qi and occasionally to treat cancer. Here we have reviewed the anticancer properties of Codonopsis extracts, LBT and structural analogs. Lobetyolin and lobetyolinin are the mono- and bis-glucosylated forms of the polyacetylenic compound lobetyol. Lobetyol and LBT have shown activities against several types of cancer (notably gastric cancer) and we examined the molecular basis of their activity. A down-regulation of glutamine metabolism by LBT has been evidenced, contributing to drug-induced apoptosis and tumor growth inhibition. LBT markedly reduces both mRNA and protein expression of the amino acid transporter Alanine-Serine-Cysteine Transporter 2 (ASCT2). Other potential targets are proposed here, based on the structural analogy with other anticancer compounds. LBT and related polyacetylene glycosides should be further considered as potential anticancer agents, but more work is needed to evaluate their efficacy, toxicity, and risk-benefit ratio.

Three new polyacetylene glycosides (PAGs) from the aerial part of Launaea capitata (Asteraceae) with anti-biofilm activity against Staphylococcus aureus

Four polyacetylenic glycosides, three of which are new, together with two known flavonoids were isolated from the methanol extract of the aerial parts of Launaea capitate, designated bidensyneoside A1 (1), 6´-O-acetyl-bidensyneoside A1 (2), bidensyneoside E (3), bidensyneoside F (4), luteolin (5) and luteolin-7-glucoside (6) also known as cynaroside. Their structures were elucidated by comprehensive analysis of 1D, 2D-NMR and HR-MS data. The absolute configuration of the bidensyneosides was determined by Mosher ester analysis and the optical rotation values. The isolated compounds were tested against biofilm formation of Staphylococcus aureus as well as against several pathogens including Gram-positive bacteria, Gram-negative bacteria, fungi and yeasts. Furthermore, they were tested for their cytotoxicity against two cancer cell lines L929 and KB-3-1. Compound 4 showed moderate inhibition of S. aureus biofilm formation with 30% and 25% at 256 and 128 μg/mL, respectively, while compounds 1 and 5 showed weak inhibition with 20% at 256 μg/mL. Compound 5 showed moderate cytotoxicity against both cell lines L929 and KB-3-1, with IC₅₀ values of 18 μg/mL.

Four new polyynes from Codonopsis pilosula collected in Yunnan province, China

Choushenpilosulynes D-G (1-4): four new polyynes were isolated from the roots of Codonopsis pilosula (Campanulaceae) cultivated in Yunnan province, China. Their structures were identified by spectroscopic methods. Bioactive evaluation showed that choushenpilosulynes E (2) and F (3) demonstrated potent inhibitory effect on lipid formation induced by 100 μM oleic acid stimulation. In addition, choushenpilosulyne F (3) uncovered inhibitory activity against the expression of human 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) and squalene monooxygenase (SQLE) gene transcript in HepG2 cells.

Chemical Compounds in Natural Medicines That Affect Macropharges and Adipocyte Cells

Macrophages play major roles in inflammation, immunity and host defense mechanisms. Once activated they produce and release cytokines, oxygen and nitrogen species, and eicosanoids. The best characterized stimuli to induce the transcription of genes encoding pro-inflammatory proteins in macrophages in vitro is bacterial lipopolysaccharide (LPS). LPS could be used alone or in combination with recombinant mouse interferon-γ (IFN-γ). Such stimulation results in cytokine release and the synthesis of enzymes such as cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS). The nitric oxide (NO) radical is known to play a central role in inflammatory and immune reactions for self-protection. However, the excessive production of NO may lead to tissue damage. In inflammatory diseases such as rheumatoid arthritis, excessive NO production by activated macrophages has been observed. Adipose tissue is composed of various cell types such as mature adipocytes, preadipocytes, fibroblasts, endothelial cells, vascular cells, and macrophages. Recent studies indicate that obesity is associated with low-grade chronic inflammation of adipose tissues, and that such inflammation is one of the potential mechanisms leading to the insulin resistance. It has been demonstrated that obese adipose tissue is characterized by the increased infiltration of macrophages. Therefore, we attempted to identify natural anti-inflammatory compounds that not only inhibit the secretion of NO from RAW 264.7 cells, but also inhibit triglyceride accumulation in 3T3-L1 adipocytes. This review describes the NO prpduction inhibitory activity or the TG accumulation inhibitory activity of the compounds obtained from 18 plants and a fungi that have been used as traditional medicines.

Isolation, characterization and antimicrobial activities of polyacetylene glycosides from Coreopsis tinctoria Nutt

Polyacetylene glycosides, (6Z, 12E)-tetradecadiene-8,10-diyne-1-ol-3(R)-O-β-D-glucopyranoside (trivially named coreoside E) and (6Z, 12E)-tetradecadiene-8,10-diyne-1-ol-3(R)-O-β-L-arabinopyranosyl-(1 → 2)-β-D-glucopyranoside (trivially named coreoside F), were isolated from buds of Coreopsis tinctoria Nutt., together with one known compound, coreoside B. Their chemical structures were elucidated by extensive spectroscopic analysis and on the basis of their chemical reactivities. Coreoside E exhibited high levels of antimicrobial activity against Staphylococcus aureus and Bacillus anthracis with minimum inhibitory concentrations of 27 ± 0.27 and 18 ± 0.40 μM, respectively, whereas coreoside F and coreoside B showed weak antimicrobial activity against S. aureus and B. anthracis.

New ursane-type triterpene with NO production suppressing activity from Nauclea officinalis

Two new ursane-type triterpenes, named as 3β, 19α, 23, 24-tetrahydroxyurs-12-en-28-oic acid (1) and 2β, 3β, 19α, 24-tetrahydroxyurs-12-en-28-oic acid (2), together with two known triterpenoids, 3-oxo-urs-12-ene-27, 28-dioic acid (3) and quinovic acid-3-β-rhamnopyranoside (4), were isolated from the stems (with barks) of Nauclea officinalis. The structures of 1 and 2 were determined by the combined use of single-crystal X-ray diffraction and spectroscopic data analysis. The inhibitory activities on nitric oxide (NO) production induced by lipopolysaccharide in mouse macrophage RAW 264.7 cells were examined, and compound 1 was found to inhibit NO production, with the IC(50) value of 4.8 μM.

A review on herbal antiasthmatics

In traditional systems of medicine, many plants have been documented to be useful for the treatment of various respiratory disorders including asthma. In the last two decades the use of medicinal plants and natural products has been increased dramatically all over the world. Current synthetic drugs used in pharmacotherapy of asthma are unable to act at all the stages and targets of asthma. However some herbal alternatives employed in asthma are proven to provide symptomatic relief and assist in the inhibition of disease progression also. The herbs have shown interesting results in various target specific biological activities such as bronchodilation, mast cell stabilization, anti-anaphylactic, anti-inflammatory, anti-spasmodic, anti-allergic, immunomodulatory and inhibition of mediators such as leukotrienes, lipoxygenase, cyclooxygenase, platelet activating, phosphodiesterase and cytokine, in the treatment of asthma. This paper is an attempt to classify these pharmacological and clinical findings based on their possible mechanism of action reported. It also signifies the need for development of polyherbal formulations containing various herbs acting at particular sites of the pathophysiological cascade of asthma for prophylaxis as well as for the treatment of asthma.

A C14-polyacetylenic glucoside with an alpha-pyrone moiety and four C10-polyacetylenic glucosides from Mediasia macrophylla

Polyacetylenic glucosides (1-5) were isolated from the MeOH extract of Mediasia macrophylla, and their structures were established by spectroscopic analyses. Compounds 2-4 were the first examples of C(10)-polyacetylenic glucosides found in the family Umbelliferae, while compound 1 was a unique polyacetylenic glucoside possessing an alpha-pyrone moiety.

DOSY NMR applied to analysis of flavonoid glycosides from Bidens sulphurea

2D DOSY 1H NMR has proved to be a useful technique in the identification of the molecular skeleton of the four major compounds of ethyl acetate extract of aerial parts of Bidens sulphurea (Asteraceae). The combination of this technique with HPLC, mass spectrometry and other NMR techniques enabled the identification of four flavonoid glycosides: quercetin-3-O-beta-D-galactopyranoside, quercetin-3-O-beta-D-glycopyranoside, quercetin-3-O-alpha-L-arabinofuranoside and quercetin-3-O-beta-D-rhamnopyranoside.

Naturally occurring and synthetic polyyne glycosides

Polyyne glycosides are a class of natural products that have been found in terrestrial plants, fungi, and marine algae. Many display interesting and potentially useful biological activities, which in some cases has initiated synthetic efforts toward their formation. This review provides a comprehensive report of polyyne glycosides isolated from natural sources, as well as the synthesis of these molecules and their analogues.

Flavonoids and a new polyacetylene from Bidens parviflora Willd

Fifteen flavonoids, 1-7 and 9-16, and a polyacetylene, 8, were isolated from the ethanol extract of the dried whole plant of Bidens parviflora Willd. by various chromatographic techniques. Their structures have been elucidated on the basis of spectroscopic analyses and chemical studies. Compound 8 is new and was identified as 3-(R),8(E)-decene-4,6-diyne-1,3,10-triol. All the flavonoid compounds were isolated for the first time from this plant species.

Cytopiloyne, a novel polyacetylenic glucoside from Bidens pilosa, functions as a T helper cell modulator

An extract of Bidens pilosa, an anti-diabetic Asteraceae plant, has recently been reported to modulate T cell differentiation and prevent the development of non-obese diabetes (NOD) in NOD mice. In this paper, a novel bioactive polyacetylenic glucoside, cytopiloyne (1), was identified from the Bidens pilosa extract using ex vivo T cell differentiation assays based on a bioactivity-guided fractionation and isolation procedure. Its structure was elucidated as 2beta-D-glucopyranosyloxy-1-hydroxytrideca-5,7,9,11-tetrayne by various spectroscopic methods. Functional studies showed that cytopiloyne was able to inhibit the differentiation of naïve T helper (Th0) cells into type I T helper (Th1) cells but to promote the differentiation of Th0 cells into type II T helper (Th2) cell. Accordingly, cytopiloyne also suppressed IFN-gamma expression and promoted IL-4 expression in mouse splenocytes ex vivo. These results suggest that cytopiloyne functions as a T cell modulator that may directly contribute to the ethnopharmacological effect of Bidens pilosa extract on preventing diabetes. Moreover, cytopiloyne can serve as an index compound for quality control of lot-to-lot extract preparations of Bidens pilosa.

Two new monoterpene glycosides and a new (+)-jasmololone glucoside from Bidens parviflora Willd

Two new monoterpene glycosides named bidensmenthosides A, B and a new (+)-jasmololone glucoside, were isolated from the air-dried whole plant of Bidens parviflora Willd. Their structures were determined as (1S, 3S, 4R)-3-hydroxy-p-menth-6-one 3-O-beta-D-glucopyranoside (1), (3R, 4R)-3-hydroxy-p-menth-1 (2)-en-6-one 3-O-beta-D-glucopyranoside (2) and (4R)-hydroxy-3-methyl-2-(2 Z-pentenyl)-cyclopent-2-enone 4-O-beta-D-glucopyranoside (3) based on spectroscopic analysis and physiochemical properties, respectively. The bidensmenthosides A, B and aglycone of 3 were found to reduce 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radicals.

Two neolignan glucosides and antihistamine release activities from Bidens parviflora WILLD

Two new neolignan glucosides, bidenlignasides A (1) and B (2), were isolated from the whole plant of Bidens parviflora WILLD. The structures of the two new compounds 1 and 2 established to be 3-hydroxy-1-(4-hydroxy-3-methoxyphenyl)-3-[5E-(3-hydroxypropenyl)-3-methoxy-2-O-beta-D-glucosyl)phenyl] propan-1-one and 3-{3-[1,3-dihydroxy-3-(4-hydroxy-3-methoxyphenyl)propyl]-4-hydroxy-5-methoxyphenyl}-allyl-O-beta-D-glucuside, respectively, on the basis of spectral and chemical evidence. Compounds 1 and 2 were found to inhibit histamine release from peritoneal exudate mast cells induced by antigen-antibody reaction.

Isolation and structure elucidation of cytotoxic polyacetylenes and polyenes from Echinacea pallida

Bioassay-guided fractionation of n-hexane extracts of Echinacea pallida (Asteraceae) roots led to the isolation and structure elucidation of two polyacetylenes (1, 3) and three polyenes (2, 4, 5). Two are known hydroxylated compounds, namely 8-hydroxy-pentadeca-(9E)-ene-11,13-diyn-2-one (1) and 8-hydroxy-pentadeca-(9E,13Z)-dien-11-yn-2-one (2). Two dicarbonylic constituents, namely pentadeca-(9E)-ene-11,13-diyne-2,8-dione (3) and pentadeca-(9E,13Z)-dien-11-yne-2,8-dione (4), were isolated and characterized for the first time. Furthermore, the structure elucidation of pentadeca-(8Z,13Z)-dien-11-yn-2-one (5) is described. The structure of the compounds isolated was determined on the basis of UV, IR, NMR (including 1D and 2D NMR experiments, such as 1H-1H gCOSY, gHSQC-DEPT, gHMBC, gNOESY) and MS spectroscopic data. The cytotoxic activity of the isolated constituents against MIA PaCa-2 human pancreatic adenocarcinoma cells was evaluated in the concentration range 1-100 microg/ml. Results show that the hydroxylated compounds (1, 2) have low cytotoxicity, while the more hydrophobic polyacetylenes (3) and polyenes (4, 5) displayed moderate activity.

Synthesis of Naturally Occurring Polyynes

Over the past fifty years, hundreds of polyyne compounds have been isolated from nature. These often unstable molecules are found in sources as common as garden vegetables and as obscure as bacterial cultures. Naturally occurring polyynes feature a wide range of structural diversity and display an equally broad array of biological properties. Early synthetic efforts relied primarily on Cu-catalyzed, oxidative acetylenic homo- and heterocoupling reactions to assemble the polyyne framework. The past 25 years, however, have witnessed a renaissance in the field of polyyne natural product synthesis: transition-metal-catalyzed alkynylation reactions and asymmetric transformations have combined to substantially expand access to natural polyynes. This Review recounts these synthetic achievements and also highlights both the natural source(s) and biological relevance for many of these compounds.

New Acetylenic Glucosides from Carthamus tinctorius

Two new acetylenic glucosides, 4',6'-acetonide-8Z-decaene-4,6-diyne-1-O-beta-D-glucopyranoside named carthamoside A(1) (1) and 4,6-decadiyne-1-O-beta-D-glucopyranoside named carthamoside A(2) (2), along with one known acetylenic glucoside, 8Z-decaene-4,6-diyne-1-O-beta-D-glucopyranoside (3), have been isolated from the air-dried flower of Carthamus tinctorius, these structures have been identified on the basis of spectroscopic methods.

Astonishing diversity of natural surfactants: 1. Glycosides of fatty acids and alcohols

Alkyl and fatty acid glycosides have become of great commercial interest in general and specifically for the pharmaceutical, cosmetic, and food industries. Natural surfactants are good sources for future chemical preparation of these glycosides. This review article shows an astonishing diversity of natural surfactants that could be used in laboratories and industry. More than 250 natural surfactants, including their chemical structures and biological activities, are described in this review article.

Bioactive sucrose esters from Bidens parviflora

An investigation on Bidens parviflora led to the isolation of three sucrose esters and a substituted truxillate. Their structures were elucidated as (6-O-(E)-p-coumaroyl)-beta-D-fructofuranosyl-(2-->1)-alpha-D-glucopyranoside, (6-O-(E)-p-coumaroyl)-beta-D-fructofuranosyl-(2-->1)-(6-O-(E)-p-coumaroyl)-alpha-D-glucopyranoside II, 6,6'-sucrose ester of (1alpha,2alpha,3beta,4beta)-3,4-bis(4-hydroxyphenyl)-1,2-cyclobutanedicarboxylic acid, dimethyl ester of (1alpha,2alpha,3alpha,4alpha)-2,4-bis(3,4-dihydroxyphenyl)-1,3-cyclobutanedicarboxylic acid on the basis of spectral and chemical evidence. These compounds were subjected to the following bioassays: the histamine release inhibition of rat mast cells induced by antigen-antibody reaction and the inhibitory activity of PGE(2) production by macrophages.

Anti-allergic agents from natural sources (4): anti-allergic activity of new phloroglucinol derivatives from Mallotus philippensis (Euphorbiaceae)

Two new phloroglucinol derivatives, mallotophilippen A (1). and B (2). were isolated from the fruits of Mallotus philippensis. These compounds were identified, using chemical and spectral data, as 1-[5,7-dihydroxy-2,2-dimethyl-6-(2,4,6-trihydroxy-3-isobutyryl-5-methyl-benzyl)-2H-chromen-8-yl]-2-methyl-butan-1-one and 1-[6-(3-Acetyl-2,4,6-trihydroxy-5-methyl-benzyl)-5,7-dihydroxy-2,2-dimethyl-2H-chromen-8-yl]-2-methyl-butan-1-one, respectively. They inhibited nitric oxide (NO) production and inducible NO synthase (iNOS) gene expression by a murine macrophage-like cell line (RAW 264.7), which was activated by lipopolysaccharide (LPS) and recombinant mouse interferon-gamma (IFN-gamma). Furthermore, they inhibited histamine release from rat peritoneal mast cells induced by Compound 48/80. These results suggest that the novel phloroglucinol derivatives have anti-inflammatory effects.