Oploxynes A and B, polyacetylenes from the stems of Oplopanax elatus

A new C22 polyacetylene and seven isoprenylated pterocarpans from Erythrina subumbrans

A new C22 polyacetylene, erysectol A (1), and seven isoprenylated pterocarpans, phaseollin (2), phaseollidin (3), cristacarpin (4), (3'R)-erythribyssin D/(3'S)-erythribyssin D (5a/5b) and dolichina A/dolichina B (6a/6b) were isolated from the twigs and leaves of Erythrina subumbrans. Their structures were determined based on their NMR spectral data. Except for 2-4, all the other compounds were isolated from this plant for the first time. Erysectol A was the first reported C22 polyacetylene from plants. Polyacetylene was isolated from Erythrina plants for the first time.

Azolium Aurates as Pre-Catalysts for the Oxidative Coupling of Terminal Alkynes under Mild Conditions

A simple and efficient method for the oxidative coupling of terminal alkynes is reported for the first time, making use of imidazol(in)ium aurates as pre-catalysts. This approach displays high functional group tolerance and leads to a broad range of 1,3-diyne compounds in moderate to excellent yields using low catalyst loading and is performed in air under mild and sustainable conditions.

Chemical profiling of root bark extract from Oplopanax elatus and its in vitro biotransformation by human intestinal microbiota

Oplopanax elatus (Nakai) Nakai, in the Araliaceae family, has been used in traditional Chinese medicine (TCM) to treat diseases as an adaptogen for thousands of years. This study established an ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UPLC-Q-TOF/MS) method to identify chemical components and biotransformation metabolites of root bark extract from O. elatus. A total of 18 compounds were characterized in O. elatus extract, and 62 metabolites by human intestinal microbiota were detected. Two polyynes, falcarindiol and oplopandiol were recognized as the main components of O. elatus, whose metabolites are further illustrated. Several metabolic pathways were proposed to generate the detected metabolites, including methylation, hydrogenation, demethylation, dehydroxylation, and hydroxylation. These findings indicated that intestinal microbiota might play an essential role in mediating the bioactivity of O. elatus.

The phenolic acids from Oplopanax elatus Nakai stems and their potential photo-damage prevention activity

25 phenolic acids, including four new isolates, eurylophenosides A-D (1-4) and 21 known ones (5-25) were isolated and identified from the stems of Oplopanax elatus Nakai. Among the known compounds 5-9, 11-13, 16, 18-25 were isolated from the genus for the first time; 17 was first obtained from the plant; and the NMR data of 22 was reported here first. Meanwhile, the UVB-induced photodamage model of HaCaT cells was used to study the prevent-photodamage abilities of compounds 1-2, 4-8, 11-13 and 15-25 with a nontoxic concentration at 50 μM. Moreover, a dose-dependent experiment was conducted for active compounds at the concentration of 10, 25, and 50 µM, respectively. Consequently, pretreatment with compounds 1, 16, 17, 19, 20, 22, 24 and 25 could suppress the cell viability decreasing induced by UVB irradiation in a concentration-dependent manner. These results indicated that phenolic acids were one kind of material basis with prevent-photodamage activity of O. elatus.

Bioactive C17 and C18 Acetylenic Oxylipins from Terrestrial Plants as Potential Lead Compounds for Anticancer Drug Development

Bioactive C₁₇ and C₁₈ acetylenic oxylipins have shown to contribute to the cytotoxic, anti-inflammatory, and potential anticancer properties of terrestrial plants. These acetylenic oxylipins are widely distributed in plants belonging to the families Apiaceae, Araliaceae, and Asteraceae, and have shown to induce cell cycle arrest and/or apoptosis of cancer cells in vitro and to exert a chemopreventive effect on cancer development in vivo. The triple bond functionality of these oxylipins transform them into highly alkylating compounds being reactive to proteins and other biomolecules. This enables them to induce the formation of anti-inflammatory and cytoprotective phase 2 enzymes via activation of the Keap1–Nrf2 signaling pathway, inhibition of proinflammatory peptides and proteins, and/or induction of endoplasmic reticulum stress, which, to some extent, may explain their chemopreventive effects. In addition, these acetylenic oxylipins have shown to act as ligands for the nuclear receptor PPARγ, which play a central role in growth, differentiation, and apoptosis of cancer cells. Bioactive C₁₇ and C₁₈ acetylenic oxylipins appear, therefore, to constitute a group of promising lead compounds for the development of anticancer drugs. In this review, the cytotoxic, anti-inflammatory and anticancer effects of C₁₇ and C₁₈ acetylenic oxylipins from terrestrial plants are presented and their possible mechanisms of action and structural requirements for optimal cytotoxicity are discussed.

Diastereoselective Synthesis of 1,3-Diyne-Tethered Trifluoromethylcyclopropanes through a Sulfur Ylide Mediated Cyclopropanation/DBU-Mediated Epimerization Sequence

A one-pot synthesis of 1,3-diyne-tethered trifluoromethylcyclopropanes starting from 2-CF₃-3,5-diyne-1-enes and sulfur ylides via a sulfur ylide mediated cyclopropanation and a DBU-mediated epimerization sequence is described in this work. This process is highly diastereoselective with broad substrate scope. Moreover, a series of synthetic transformations based on the diyne moieties were conducted smoothly, affording cyclopropanes featuring trifluoromethyl-substituted all-carbon quaternary centers.

Inhibitory Mechanisms of Water Extract of Oplopanax elatus on Lipopolysaccharide-Induced Inflammatory Responses in RAW 264.7 Murine Macrophage Cells

OBJECTIVE

To study the anti-inflammatory action and cellular mechanism of Oplopanax elatus.

METHODS

A hot water extract of OE (WOE) was prepared and a major constituent, syringin, was successfully isolated. Its content in WOE was found to be 214.0 µg/g dried plant (w/w). Their anti-inflammatory activities were examined using RAW 264.7 macrophages and a mouse model of croton oil-induced ear edema.

RESULTS

In lipopolysaccharide (LPS)-treated RAW 264.7 cells, a mouse macrophage cell line, WOE was found to significantly and strongly inhibit cyclooxygenase-2 (COX-2)-induced prostaglandin E₂ (PGE₂) production [half maximal inhibitory concentration (IC₅₀)=135.2 µg/mL] and inducible nitric oxide synthase (iNOS)-induced NO production (IC₅₀=242.9 µg/mL). In the same condition, WOE was revealed to inhibit NO production by down-regulating iNOS expression, mainly by interrupting mitogen activated protein kinases (MAPKs)/activator protein-1 (AP-1) pathway. The activation of all three major MAPKs, p38 MAPK, extracellular signal-regulated kinase (ERK), and c-Jun N-terminal kinase, was inhibited by WOE (50-300 µg/mL). On the other hand, WOE reduced PGE₂ production by inhibiting COX-2 enzyme activity, but did not affect COX-2 expression levels. In addition, WOE inhibited the production of proinflammatory cytokines such as interleukin-6 and tumor necrosis factor-α. In croton oil-induced ear edema in mice, oral administration of WOE (50-300 mg/kg) dose-dependently inhibited edematic inflammation.

CONCLUSION

Water extract of OE exhibited multiple anti-inflammatory action mechanisms and may have potential for treating inflammatory disorders.

Synthesis of chiral propargyl alcohols following the base-induced elimination protocol: application in the total synthesis of natural products

Synthesis of enantiomerically pure propargyl alcohols is one of the most important tools in organic synthesis and “base-induced elimination of β-alkoxy chlorides” could offer the enantiomerically pure propargyl alcohols.

Crystal structure of 4-methoxyphenyl-3-phenylpropiolate, C16H12O3

C16H12O3, orthorhombic, Pbca (no. 19), a = 3.9935(16) Å, b = 16.629(7) Å, c = 19.406(8) Å, V = 1288.7(9) Å3, Z = 4, Rgt(F) = 0.0387, wRref(F2) = 0.1084, T = 296(2) K.

Chemo-Preventive Potential of Falcarindiol-Enriched Fraction from Oplopanax elatus on Colorectal Cancer Interfered by Human Gut Microbiota

Oplopanax elatus (Nakai) Nakai is an oriental herb, the polyyne-enriched fraction of which (PEFO) showed anticolorectal cancer (anti-CRC) effects. Other concomitant components, which are inevitably bio-transformed by gut microbiota after oral administration, might be interfere with the pharmacodynamics of polyynes. However, the influence of human gut microbiota on molecules from O. elatus possessing anticancer activity are yet unknown. In this study, the compounds in PEFO and PEFO incubated with human gut microbiota were analyzed and tentatively identified by HPLC-DAD-QTOF-MS. Two main polyynes ((3[Formula: see text]8[Formula: see text]-falcarindiol and oplopandiol) were not significantly decomposed, but some new unknown molecules were discovered during incubation. However, the antiproliferative effects of PEFO incubated with human gut microbiota for 72 h (PEFO I) were much lower than that of PEFO on HCT-116, SW-480, and HT-29 cells. Furthermore, PEFO possessed better anti-CRC activity in vivo, and significantly induced apoptosis of the CRC cells, which was associated with activation of caspase-3 according to the Western-blot results ([Formula: see text]). These results suggest anticolorectal cancer activity of polyynes might be antagonized by some bio-converted metabolites after incubation with human gut microbiota. Therefore, it might be better for CRC prevention if the polyynes could be orally administrated as purified compounds.

Adventitious root cultures of Oplopanax elatus inhibit LPS-induced inflammation via suppressing MAPK and NF-κB signaling pathways

Bioreactor-cultured adventitious roots (ARs) of the endangered medicinal plant Oplopanax elatus Nakai is a novel alternative plant material. To utilize ARs in the product production, the present study investigated the anti-inflammatory effect of O. elatus ARs. In the in vivo experiment, lipopolysaccharide (LPS)-induced acute lung injury disease model was established and several inflammatory indexes were determined. For the LPS-stimulated mice, after pretreatment of AR crude extract (200 mg/kg), cell infiltration in lungs was decreased, the production of proinflammatory mediators, including nitric oxide (NO), tumor necrosis factor (TNF)-α, and interleukin (IL)-6, and 1β in the bronchoalveolar lavage fluid was evidently reduced, which indicated that O. elatus ARs had an anti-inflammatory effect. In the in vitro experiment, ethyl acetate (EtOAc) fractions (12.5, 25, and 50 μg/mL) were used to treat LPS-induced peritoneal macrophages (PMs) of mice. The production of NO, prostaglandin E₂, TNF-α, IL-6, and IL-1β in LPS-stimulated PMs was obviously inhibited (p < 0.05) after pretreatment with EtOAc fractions, and the expression of the inducible nitric oxide synthase and cyclooxygenase were also suppressed. To clarify the anti-inflammatory mechanism, effects of EtOAc fraction on changes of proteins related to the pathways of mitogen-activated protein kinases (MAPKs) and nuclear factor-kappa B (NF-κB) were investigated. The phosphorylation of extracellular regulated protein kinases, c-jun n-terminal kinase, and p38 MAPK in LPS-induced PMs was inhibited after pretreatment of EtOAc fractions. In addition, EtOAc fractions enhanced inhibitor of nuclear factor-kappa B-α expression and decreased nuclear translocation of p65 NF-κB. Thus, EtOAc from O. elatus ARs is involved in regulating MAKP and NF-κB signaling pathways to inhibit LPS-induced inflammation.

Oxygenated C17 polyacetylene metabolites from Algerian Eryngium tricuspidatum L. roots: Structure and biological activity

The secondary metabolite pattern of Eryngium tricuspidatum has been found to be dominated by C₁₇ acetylene oxylipins, according to the chemistry reported in the literature for the genus Eryngium. Two new oxylipins, 11-acetoxy-falcarindiol (4) and 1,2-dihydro-11-acetoxy-falcarindiol (5) have been isolated, along with main related polyacetylenes 1-3 and the already known monoterpene aldehydes 6-10, from the petroleum ether extract of roots. The structure and the absolute configuration of compounds 4 and 5 have been determined by spectroscopic methods as well as by comparison with related known compounds. Polyacetylenes 1-4 inhibited significantly the in vitro growth of a series of cancer cell lines, ranging from 0.3 to 29 μM, whereas 5 was inactive.

Polyacetylenes from the Roots of Swietenia macrophylla King

A phytochemical investigation of the roots of Swietenia macrophylla led to the isolation of seven polyacetylenes, including five new compounds (1-5) and two known ones (6-7). Their structures were elucidated by extensive spectroscopic analysis and detailed comparison with reported data. All the isolates were tested for their cytotoxicity against the human hepatocellular carcinoma cell line BEL-7402, human myeloid leukemia cell line K562, and human gastric carcinoma cell line SGC-7901. Compounds 1 and 6 showed moderate cytotoxicity against the above three human cancer cell lines with IC50 values ranging from 14.3 to 45.4 μM. Compound 4 displayed cytotoxicity against the K562 and SGC-7901 cancer cell lines with IC50 values of 26.2 ± 0.4 and 21.9 ± 0.3 μM, respectively.

Synergetic Inhibition of Human Colorectal Cancer Cells by Combining Polyyne-Enriched Fraction from Oplopanax elatus and Irinotecan

Although irinotecan is an important anticancer drug for treating colorectal cancer, its dose-dependent side effects limited its clinical application. Thus, it's important to develop low-toxic candidates to enhance the efficacy of irinotecan. Polyynes from genus Oplopanax were reported to possess potential anticancer effects on colorectal cancer. Hereby, we evaluated the synergetic inhibition of human colorectal cancer cells by combining polyyne-enriched fraction from Oplopanax elatus (the dichloromethane fraction of Oplopanax elatus, OED) and irinotecan. The results showed that 5 μg/ml of OED combined with 40 μM of irinotecan possessed significant synergetic inhibition on SW-480 cells with a combination index (CI) of 0.56. Besides, the percentage of apoptotic cells was significantly increased from 69.57% (40 μM of irinotecan) or 72.7% (5 μg/ml of OED) to 95.6% after treatment of OED combined with irinotecan (OCI), suggesting OED and irinotecan possess the synergistic apoptotic effect (P < 0.01). Furthermore, Caspase-3 was significantly activated in OCI group (P < 0.05). Besides, the percentage of apoptotic cells of OED or/and irinotecan significantly decreased after inhibition of caspase-3. These data indicated that OED could enhance antiproliferative effects of irinotecan on colorectal cancer cells, which was related with induction of apoptosis and regulations of activity of caspase-3.

Determination of six polyynes in Oplopanax horridus and Oplopanax elatus using polyethylene glycol modified reversed migration microemulsion electrokinetic chromatography

A PEG-modified reversed migration MEEKC method was developed for simultaneous determination of six polyynes, including oplopandiol, falcarindiol, oplopandiol acetate, (11S, 16S, 9Z)-9,17-octadecadiene-12,14-diyne-1,11,16-triol,1-acetate, oplopantriol B, and oplopantriol A, in Oplopanax horridus and Oplopanax elatus. The running buffer containing 0.8% v/v ethyl acetate, 3.8% w/v SDS, 6.6% v/v n-butanol in 20 mM phosphate buffer (pH 2.5), followed by mixing with propan-2-ol at 30% v/v and PEG-1000 at 15% w/v, was applied in the analysis. The proposed method was successfully applied to determine the six polyynes in five samples of Oplopanax horridus and one of O. elatus. The result showed that the types and amounts of polyynes present were obviously different when comparing the two herbs. Besides, the developed PEG-modified reversed MEEKC method might be suitable for the analysis of hydrophobic analytes in herbal medicines.

Oplopanax elatus (Nakai) Nakai: chemistry, traditional use and pharmacology

Oplopanax elatus (Nakai) Nakai, a member of the ancient angiosperm plant family Araliaceae, is used for the treatment of different disorders in the medicine systems of China, Russia, and Korea, and was designated in Russia as a classical adaptogen. Despite extensive studies of classical adaptogens, there are comparatively few reports concerning the chemical composition and pharmacological effects of O. elatus in English. The plant is a potential source of saponins, flavonoids, anthraquinones, terpenes, and other active compounds. Experimental studies and clinical applications have indicated that O. elatus possesses a number of pharmacological activities, including adaptogenic, anti-convulsant, anti-diabetic, anti-fungal, anti-inflammatory, anti-oxidant, blood pressure modulating, and reproductive function effects. In this review, the chemistry, safety, and therapeutic potential of O. elatus are summarized and highlighted to encourage the further development of this plant.

Bioactivity-guided isolation of polyacetylenes with inhibitory activity against NO production in LPS-activated RAW264.7 macrophages from the rhizomes of Atractylodes macrocephala

ETHNOPHARMACOLOGICAL RELEVANCE

The rhizome of Atractylodes macrocephala (Compositae) is one of the most well-known traditional Chinese medicine in China, Japan and Korea, which has a long history of use for the treatment of splenic asthenia, edema, anorexia, and excessive perspiration, etc. As active compounds of anti-inflammatory activity of this medicinal plant have not been fully elucidated, the aim of this study was to isolate and identify the active constituents inhibiting nitric oxide (NO) production from the rhizomes of A. macrocephala.

MATERIALS AND METHODS

Inhibitory activity against NO production in lipopolysaccharide-activated RAW264.7 macrophages was evaluated by Griess reaction. Fifteen polyacetylenes were isolated from the active ethyl acetate extract using activity-guided screening. The structures of all compounds were elucidated by spectroscopic methods and comparison with published data. The compounds were further tested for their inhibitory activity against NO production.

RESULTS

Seven new polyacetylenes, named atractylodemaynes A-G (1-7), along with eight known ones (8-15) were isolated. Compound 14 was isolated for the first time from the rhizomes of A. macrocephala. The study showed that the tested compounds exhibited inhibitory activity against NO production in a dose-dependent manner. Among them, compounds 10, 11 and 12 had relatively stronger inhibitory effect with IC50 values of 28, 23 and 19μM, respectively.

CONCLUSION

The results demonstrated that the polyacetylenes might greatly contribute to the anti-inflammatory activity of the rhizomes of A. macrocephala.

Polyacetylenes from the leaves of Vernonia scorpioides (Asteraceae) and their antiproliferative and antiherpetic activities

Polyacetylenes constitute an underexplored and unstable class of compounds that are found mainly in the Apiaceae, Araliaceae and Asteraceae families. Vernonia scorpioides (Lam.) Pers., Asteraceae is a lianous neotropical herb that usually grows in soils that have been deforested and are of poor quality. It is used in folk medicine for the treatment of several skin conditions. This study addresses the characterisation of eight polyacetylenes isolated from the leaves of V. scorpioides. Their structures were established on the basis of 1D and 2D NMR spectroscopy and MS analysis. Ab initio calculations including solvent effects were employed to aid the elucidation of the absolute configurations of the compounds. The in vitro antiproliferative and anti-herpetic activities of the polyacetylenes were determined. The isolated compounds presented no inhibitory effect against a human cell line of non-small cell lung cancer, but presented a mild non-selective in vitro antiviral activity, although their corresponding glycosides were inactive.

Bioactive acetylenic metabolites

This article focuses on anticancer, and other biological activities of acetylenic metabolites obtained from plants and fungi. Acetylenic compounds belong to a class of molecules containing triple bond(s). Naturally occurring acetylenics are of particular interest since many of them display important biological activities and possess antitumor, antibacterial, antimicrobial, antifungal, and immunosuppressive properties. There are of great interest for medicine, pharmacology, medicinal chemistry, and pharmaceutical industries. This review presents structures and describes cytotoxic activities of more than 100 acetylenic metabolites, including fatty alcohols, ketones, and acids, acetylenic cyclohexanoids, spiroketal enol ethers, and carotenoids isolated from fungi and plants.

Absolute Configuration of Falcarinol (9Z-heptadeca-1,9-diene-4,6-diyn-3-ol) from Pastinaca Sativa

Falcarinol (9 Z-heptadeca-1,9-diene-4,6-diyn-3-ol; (1) is a polyacetylene commonly found in several plant families. The absolute configuration of naturally occurring 1 is not clear and contradictory results have been reported in the literature. Determination of the absolute configuration of 1 from Pastinaca sativa L. was carried out. Isolation of 95% pure 1 was performed via successive fractionation and preparative-HPLC. A racemic mixture comprised of 3 R-1 and 3 S-1 was synthesized in order to confirm the absolute configuration of the isolated natural product using chiral HPLC. Based on a combination of chiral HPLC and specific rotation, 1 present in P. sativa was found to have a 3 R absolute configuration (i.e. (3 R, 9 Z)-heptadeca-1,9-diene-4,6-diyn-3-ol).

Chemical and pharmacological studies of Oplopanax horridus, a North American botanical

Oplopanax horridus (OH), or Devil's club, is an ethnobotanical used by the indigenous people native to the Pacific Northwest of North America. There are three species in the genus Oplopanax, and OH is the only species that is distributed in North America. Compared with the extensive research on OH's "cousin," American ginseng, there is comparatively little reported about the chemical makeup and pharmacological effects of OH. Nevertheless, there has been some research over the past few years that shows promise for the future usage perspectives of OH. To date, 17 compounds were isolated and elucidated, including polyynes, glycosides, lignans, and polyenes, with most of the attention being paid to the polyynes. Gas chromatography (GC) and high-performance liquid chromatography (HPLC) were used to determine the contents of volatile compounds and polyynes in the essential oil and extracts of OH. For the pharmacological studies, antibacterial and antidiabetes effects of polyynes were reported. Our recent study has focused more on the anticancer effects of OH and the involved mechanisms of action. In this review, we will summarize the research status in the botany, phytochemistry, and pharmacology of OH.

The relevance of higher plants in lead compound discovery programs

Along with compounds from terrestrial microorganisms, the constituents of higher plants have provided a substantial number of the natural product-derived drugs used currently in Western medicine. Interest in the elucidation of new structures of the secondary metabolite constituents of plants has remained high among the natural products community over the first decade of the 21st century, particularly of species that are used in systems of traditional medicine or are utilized as botanical dietary supplements. In this review, progress made in the senior author's laboratory in research work on naturally occurring sweeteners and other taste-modifying substances and on potential anticancer agents from tropical plants will be described.

Isolation and analysis of ginseng: advances and challenges

Ginseng occupies a prominent position in the list of best-selling natural products in the world. Because of its complex constituents, multidisciplinary techniques are needed to validate the analytical methods that support ginseng's use worldwide. In the past decade, rapid development of technology has advanced many aspects of ginseng research. The aim of this review is to illustrate the recent advances in the isolation and analysis of ginseng, and to highlight new applications and challenges. Emphasis is placed on recent trends and emerging techniques.