Potential anthelmintics: polyphenols from the tea plant <Emphasis Type="Italic">Camellia sinensis</Emphasis> L. are lethally toxic to <Emphasis Type="Italic">Caenorhabditis elegans</Emphasis>

A novel gallate of tannin, (−)-epigallocatechin-(2β→O→7′,4β→8′)-epicatechin-3′-O-gallate (8), together with (−)-epicatechin-3-O-gallate (4), (−)-epigallocatechin (5), (−)-epigallocatechin-3-O-gallate (6), and (+)-gallocatechin-(4α→8′)-epigallocatechin (7), were isolated from the tea plant Camellia sinensis (L.) O. Kuntze var. sinensis (cv., Yabukita). The structure of 8, including stereochemistry, was elucidated by spectroscopic methods and hydrolysis. The compounds, along with commercially available pyrogallol (1), (+)-catechin (2), and (−)-epicatechin (3), were examined for toxicity towards egg-bearing adults of Caenorhabditis elegans. The anthelmintic mebendazole (9) was used as a positive control. Neither 2 nor 3 were toxic but the other compounds were toxic in the descending order 8, 7 ≈ 6, 9, 4, 5, 1. The LC₅₀ (96 h) values of 8 and 9 were evaluated as 49 and 334 μmol L⁻¹, respectively. These data show that many green tea polyphenols may be potential anthelmintics.     

Phenolic constituents of <Emphasis Type="Italic">Acorus gramineus</Emphasis>

The purification of a MeOH extract from the rhizome of Acorus gramineus (Araceae) using column chromatography furnished two new stereoisomers of phenylpropanoid, acoraminol A (1) and acoraimol B (2). It also furnished 17 known phenolic compounds, β-asarone (3), asaraldehyde (4), isoacoramone (5), propioveratrone (6), (1′R,2′S)-1′,2′-dihydroxyasarone (7), (1′S,2′S)-1′,2′-dihydroxyasarone (8), 3′,4′-dimethoxycinnamyl alcohol (9), 3′,4′,5′-trimethoxycinnamyl alcohol (10), kaempferol 3-methyl ether (11), 2-[4-(3-hydroxypropyl)-2-methoxyphenoxy]-1,3-propanediol (12), hydroxytyrosol (13), tyrosol (14), (2S,5S)-diveratryl-(3R,4S)-dimethyltetrahydrofuran (15), (7S,8R)-dihydrodehydrodiconiferyl alcohol (16), 7S,8S-threo-4,7,9,9′-tetrahydroxy-3,3′-dimethoxy-8-O-4′-neolignan (17), 7S,8R-erythro-4,7,9,9′-tetrahydroxy-3,3′-dimethoxy-8-O-4′-neolignan (18), and dihydroyashsbushiketol (19). The structures of the new compounds were elucidated by analysis of spectroscopic data including 1D and 2D NMR data. The absolute configurations of 1 and 2 were determined using the convenient Mosher ester procedure. Compounds 5–19 were isolated for the first time from this plant source. The isolated compounds were tested for cytotoxicity against four human tumor cell lines in vitro using a Sulforhodamine B (SRB) bioassay.     

Two new neolignan glycosides from leaves of <Emphasis Type="Italic">Osmanthus heterophyllus</Emphasis>

Two new neolignan glycosides, (7R, 8R)-threo-guaiacylglycerol-8-O-4′-sinapyl ether 7-O-β-d-glucopyranoside (1) and (7S, 8R)-5-methoxydehydrodiconiferyl alcohol 4-O-β-d-glucopyranoside (2), and four known ones (3–6), were isolated from the leaves of Osmanthus heterophyllus. The structures of compounds 1–6 were established on the basis of spectral and chemical data.     

Iridoid glucoside, (3<Emphasis Type="Italic">R</Emphasis>)-oct-1-en-3-ol glycosides,and phenylethanoid from the aerial parts of <Emphasis Type="Italic">Caryopteris incana</Emphasis>

Eleven compounds of interest were isolated from the aerial parts of Caryopteris incana, specifically a new acyl derivative (3) of 8-O-acetylharpagide, two new (3R)-oct-1-en-3-ol glycosides (5, 6), and 6-O-caffeoylphlinoside A (11) along with seven known compounds, 8-O-acetylharpagide (1), 6′-O-p-coumaroyl-8-O-acetylharpagide (2), (3R)-oct-1-en-3-ol (matsutake alcohol) O-α-l-arabinopyranosyl-(1″ → 6′)-O-β-d-glucopyranoside (4), apigenin 7-O-neohesperidinoside (7), 6′-O-caffeoylarbutin (8), and two phenylethanoids, leucosceptoside A (9) and phlinoside A (10). This paper deals with structural elucidation of the new compounds.     

Chemical and biologically active constituents of <Emphasis Type="Italic">Pteris multifida</Emphasis>

A new compound, 4-caffeoyl quinic acid 5-O-methyl ether (2), together with 12 known compounds—identified as (2R,3R)-pterosin L 3-O-β-d-glucopyrannoside (3), β-sitosterol β-d-glucopyranoside (4), apigenin 7-Ο-β-d-glucopyranoside (5), luteolin 7-Ο-β-d-glucopyranoside (6), sucrose (7), caffeic acid (8), pterosin C 3-Ο-β-d-glucopyranoside (9), pteroside C (10), 4,5-dicaffeoyl quinic acid (11), pteroside A (12), wallichoside (13) and (2S)-5,7,3′,5′-tetrahydroxyflavanone (14)—were isolated from Pteris multifida. The structure of the new compound was determined by means of physical, chemical and spectroscopic evidence. Compounds 5 and 6 were the main constituents of the plant, with yields of 0.19% and 0.16%, respectively. The cytotoxic activities of 2, 3, and 9–13 were evaluated against a human cell line (KB cells). Among the isolated compounds, pterosin C 3-Ο-β-d-glucopyrannoside (9) and 4,5-dicaffeoylquinic acid (11) showed a significant selective cytotoxicity (IC₅₀ 2.35 and 5.38, respectively), while moderate activity was observed for compound 2 (IC₅₀ 12.3). The chemosystematics of Pteris species is also discussed.     

A new phenolic glycoside syringate from the bark of <Emphasis Type="Italic">Juglans mandshurica</Emphasis> MAXIM. var. <Emphasis Type="Italic">sieboldiana</Emphasis> MAKINO

A new phenolic glycoside syringate, 4′-hydroxy-2′,6′-dimethoxyphenol 1-O-β-d-(6-O-syringoyl) glucopyranoside (1), together with two known ones, 2′-hydroxy-4′-methoxyphenol 1-O-β-d-(6-O-syringoyl) glucopyranoside (2) and 4′-hydroxy-2′-methoxyphenol 1-O-β-d-(6-O-syringoyl) glucopyranoside (3), were isolated from the bark of Juglans mandshurica MAXIM. var. sieboldiana MAKINO. Their structures were established on the basis of spectral and chemical data.     

A new flavonol glycoside from <Emphasis Type="Italic">Hylomecon vernalis</Emphasis>

Purification of a MeOH extract from the aerial parts of Hylomecon vernalis Maxim. (Papaveraceae) using column chromatography furnished a new acetylated flavonol glycoside (1), together with twenty known phenolic compounds (2–21). Structural elucidation of 1 was based on 1D- and 2D-NMR spectroscopy data analysis to be quercetin 3-O-[4‴-O-acetyl-α-L-arabinopyranosyl]-(1‴→6″)-β-D-galactopyranoside (1). The structures of compounds 2–21 were elucidated by spectroscopy and confirmed by comparison with reported data; quercetin 3-O-[2‴-O-acetyl-α-L-arabinopyranosyl]-(1‴→6″)-β -D-galactopyranoside (2), quercetin 3-O-α-L-arabinopyranosyl-(1‴→6″)-β-D-galactopyranoside (3), quercetin 3-O-β -D-galactopyranoside (4), kaempferol 3,7-O-α-L-dirhamnopyranoside (5), diosmetin 7-O-β -D-glucopyranoside (6), diosmetin 7-O-β -D-xylopyranosyl-(1‴→6″)-β-D-glucopyranoside (7), p-hydroxybenzoic acid (8), protocatechuic acid (9), caffeic acid (10), 6-hydroxy-3,4-dihydro-1-oxo-β -carboline (11), (Z)-3-hexenyl-β -D-glucopyranoside (12), (E)-2-hexenyl-β -D-glucopyranoside (13), (Z)-3-hexenyl-α-Larabinopyranosyl-(1″→6′)-β-D-glucopyranoside (14), oct-1-en-3-yl-α-L-arabinopyranosyl-(1″→6′)-β-D-glucopyranoside (15), benzyl-β-D-apiofuranosyl-(1″→6′)-β-D-glucopyranoside (16), benzyl-α-L-arabinopyranosyl-(1″→6′)-β-D-glucopyranoside (17), benzyl-β-D-xylopyranosyl-(1″→6′)-β-Dglucopyranoside (18), 2-phenylethyl-α-L-arabinopyranosyl-(1″→6′)-β-D-glucopyranoside (19), 2-phenylethyl-β-D-apiofuranosyl-(1″→6′)-β-D-glucopyranoside (20), and aryl-β-D-glucopyranoside (21). Compounds 2-21 were isolated for the first time from this plant. The isolated compounds were tested for cytotoxicity against four human tumor cell lines in vitro using a Sulforhodamin B bioassay.     

A dimeric triterpenoid glycoside and flavonoid glycosides with free radical-scavenging activity isolated from <Emphasis Type="Italic">Rubus rigidus</Emphasis> var. <Emphasis Type="Italic">camerunensis</Emphasis>

The aerial part of Rubus rigidus var. camerunensis (Rosaceae) is used to treat respiratory and cardiovascular disorders in the Cameroonian traditional medicine. The ethanol extract exhibited more potent antioxidant activity (E_maxs of 119% and 229% activity on DPPH and β-carotene test) than aqueous extract. Bioactivity-guided fractionation of the ethanol extract based on free radical-scavenging assay (DPPH assay) afforded five flavonoid glycosides (four flavonol glycosides and an anthocyanin) and three glucosides of 19α-hydroxyursane-type triterpenoid (two monomeric and one dimeric triterpenoids). The flavonoids were identified as kaempferol 3-O-(2″-O-E-p-coumaroyl)-β-D-glucopyranoside (1), kaempferol-3-O-β-D-glucopyranoside (astragalin, 2), kaempferol-3-O-α-L-arabinofuranoside (juglanin, 3), quercetin-3-O-β-D-glucopyranoside (isoquercitrin, 4), pelargonidin-3-O-β-D-glucopyranoside (callistephin, 5). The three triterpenoids were 2α, 3β, 19α, 23-tetrahydroxyurs-12-ene-28-O-β-D-glucopyranosyl ester (nigaichigoside F₁, 6), 2α, 3β, 19α-trihydroxyurs-12-ene-23-carboxyl-28-O-β-D-glucopyranosyl ester (suavissimoside R₁, 7) as monomeric triterpenoids and coreanoside F₁ (8) as a dimeric triterpenoid. The flavonoids exhibited potent antioxidant activities (66 to 93.56% against DPPH radical) and they were also active on β-carotene test. Coreanoside F₁ exhibited a 63% antioxidant activity, meanwhile the other two triterpenoids showed a weak activity. Three important facts on structure-activity relationship were observed: Compound 8, a dimeric triterpenoid glycoside, strongly enhanced antioxidant activity of its monomers, compound 3 with 3-O-α-L-arabinofuranyl has much more potent activity than compound 2 with 3-O-β-D-glucopyranosyl, and antocyanin (5) is more potent than its corresponding flavonol glycosides.     

Two new phenolic glycosides from <Emphasis Type="Italic">Syringa reticulata</Emphasis>

Two new phenolic glycosides—3′-O-β-d-glucopyranosysalidroside (1) and cis-echinacoside (2)—together with four known ones—forsythoside B (3), decaffeoylacteoside (4), osmanthuside F (5) and (−)-olivil-4′-O-β-d-glucopyranoside (6)—were isolated from the leaves of Syringa reticulata. Their structures were established on the basis of spectral and chemical data.     

Cytotoxic phenolic compounds from <Emphasis Type="Italic">Chionanthus retusus</Emphasis>

Cytotoxicity-guided fractionation and purification of MeOH extract from Chionanthus retusus Lindl. et Paxton resulted in the isolation of compounds. Fourteen phenolic compounds were isolated from the EtOAc soluble fraction, and their structures were determined by spectroscopic analysis. Isolated compounds were identified as phillygenin (1), scopoletin (2), pinoresinol (3), kaempferol (4), aromadendrin (5), 2-(4-hydroxyphenyl)ethanol (6), 3,3′,5,5′,7-pentahydroxyflavanone (7), luteolin (8), quercetin (9), apigenin (10), chrysoeriol (11), phillyrin (12), oleuropein (13), (7R,8R)-guaiacylglycerol (14). All compounds except for 12 and 13 were isolated for the first time from this plant and genus Chionanthus. Anti-proliferative effect of isolated compounds were evaluated by the sulforhodamin B assay against four human tumor cell lines (A549, SK-OV-3, SK-MEL-2, and HCT15). Compounds 4 and 8–10 were significantly active with ED50 values of 1.84–6.35 μg/mL. Also, compounds 1, 3, 5 and 7 revealed cytotoxic effects at concentrations below 30 μg/mL.     

A new lignan glycoside from <Emphasis Type="Italic">Juniperus rigida</Emphasis>

A new lignan glycoside, named juniperigiside (1) was isolated from the CHCl₃ soluble fraction of the MeOH extract of stems and leaves of Juniperus rigida S.et Z. Compound 1 was identified by 1D- and 2D-NMR spectroscopy as well as CD analysis as (2R,3S)-2,3-dihydro-7-methoxy-2-(4′-hydroxy-3′-methoxyphenyl)-3-hydroxymethyl-5-benzofuranpropanol 4′-O-(3-O-methyl)-α-L-rhamnopyranoside. Five known lignans, icariside E4 (2), desoxypodophyllotoxin (3), savinin (4), thujastandin (5), and (−)-nortrachelogenin (6) in addition to five known labdane diterpenes including trans-communic acid (7), 13-epi-torulosal (8), 13-epi-cupressic acid (9), imbricatoric acid (10), and isocupressic acid (11) were also isolated and their structures were characterized by comparing their spectroscopic data with those in the literature. All compounds were isolated for the first time from this plant, and 5 and 6 were first reported from the genus Juniperus. The isolated compounds were tested for cytotoxicity against four human tumor cell lines in vitro using a Sulforhodamin B bioassay. Compounds 3, 4, 7, and 8 showed considerable cytotoxicity against four human cancer cell lines in vitro.     

A new phenylpropane glycoside from the rhizome of <Emphasis Type="Italic">Sparganium stoloniferum</Emphasis>

The purification of the MeOH extract from the rhizome of Sparganium stoloniferum Buch.-Hamil. (Sparganiaceae) using column chromatography furnished one new phenylpropanoid glycoside (7) and known phenolic compounds (1–6, and 8–13). The structural elucidation of 7 was based on 1D- and 2D-NMR spectroscopic data analysis to be β-d-(6-O-trans-feruloyl) fructofuranosyl-α-d-O-glucopyranoside. Compounds 1–6, and 8–13 were elucidated by spectroscopy and confirmed by comparison with reported data; 24-methylenecycloartanol (1), p-hydroxybenzaldehyde (2), ferulic acid (3), p-coumaric acid (4), vanillic acid (5), β-d-(1-O-acetyl-3-O-trans-feruloyl)fructofuranosy-α-d-2′,4′,6′.-O-triacetyglucopyranoisde (6), β-d-(1-O-acetyl-3,6-O-trans-diferuloyl)fructofuranosyl-β-d-2′,4′,6′.-O-triacetylglucopyranoisde (8), hydroxytyrosol acetate (9), hydroxytyrosol (10), isorhamnetin-3-O-rutinoside (11), n-butyl-α-d-fructofuranoside (12), and n-butyl-β-d-fructopyranoside (13). Compounds 3 and 9–13 were isolated for the first time from this plant. The isolated compounds were tested for cytotoxicity against four human tumor cell lines in vitro using a Sulforhodamin B bioassay.     

New glycosides from <Emphasis Type="Italic">Dracocephalum tanguticum</Emphasis> maxim

Four new glycosides, luteolin-7-methoxy-3′-O-(3″-O-acetyl)-β-D-gluco pyranuronic acid-6″-methyl ester (1), benzyl-6-[(2E)-2-butenoate]-β-D-glucopyranoside (2), 2-methoxy-4-(2-propen-1-yl)penyl-6-acetate-β-D-glucopyranoside (3), and 2-methoxy-4-(2-propen-1-yl)penyl-6-[(2E)-2-butenoate]-β-D-glucopyranoside (4), along with benzyl-β-D-glucopyranoside (5), 2-methoxy-4-(2-propen-1-yl)penyl-β-D-glucopyranoside (6), and pectolarigenin (7), were isolated from the whole plant of Dracocephalum tanguticum Maxim. The structures of 1-4 were elucidated by detailed spectroscopic analyses, including HR-ESI-MS and 2D NMR spectroscopic data. The inhibitory effects against nitric oxide production in LPS-stimulated RAW264.7 cells of all seven compounds were also evaluated.     

<Emphasis Type="Italic">In vitro</Emphasis> Na<Superscript>+</Superscript>/K<Superscript>+</Superscript>-ATPase inhibitory activity and antimicrobial activity of sesquiterpenes isolated from <Emphasis Type="Italic">Thujopsis dolabrata</Emphasis>

A series of sesquiterpenes and hinokitiol-related compounds (1–15) was isolated from the essential oil of Thujopsis dolabrata Sieb. et Zucc. var. hondai Makino, and their structures were determined by combined spectroscopic analyses. The inhibitory effects of these compounds on microbial cell growth and Na⁺/K⁺-ATPase were evaluated in vitro. It was found that (−)-elema-1,3,11(13)-trien-12-ol (5), α,β,γ-costol (8), and chamigrenol (11) inhibit the activities of Na⁺/K⁺-ATPase, with IC₅₀ values of 11.2 ± 0.11, 12.2 ± 0.09, and 15.9 ± 0.54 μg/mL, respectively. Thujopsene (1), cedrol (9), γ-cuparenol (10), and chamigrenol (11) showed potent antibacterial activity, with MIC values in the range of 25–50 μg/mL, and β-thujaplicin (12) exhibited a broad spectrum of antibacterial and antifungal activity. These results indicate that these isolated compounds are promising candidates for the development of potent Na⁺/K⁺ ATPase inhibitors and antimicrobial agents.     

Inhibitory effects of phenolic compounds from needles of <Emphasis Type="Italic">Pinus densiflora</Emphasis> on nitric oxide and PGE<Subscript>2</Subscript> production

The needles of Pinus densiflora Siebold et Zuccarini, a representative Pinus species that grows in Korea, have been used in oriental traditional medicine as remedies for rheumatitis, hemorrhage, cancer, etc. Phytochemical examination of the needles of Pinus densiflora Siebold et Zuccarini led to the isolation of four lignans, one flavan-3-ol, two flavonols and one organic acid. They were identified as icariside E₄ (1), cupressoside A (2), schizandriside (3), (+)-isolariciresinol (4), (+)-catechin (5), quercetin 3-O-β-D-glucopyranoside (6), 5,7,8,4′-tetrahydroxy-3-methoxy-6-methylflavone 8-O-β-D-glucopyranoside (7) and (−)-shikimic acid (8). In order to evaluate the anti-inflammatory effects of these compounds, their inhibitory activities against nitric oxide and prostaglandin E₂ production in IFN-γ- and lipopolysaccharide-stimulated RAW 264.7 cells were examined.     

Cholinesterase inhibitors from <Emphasis Type="Italic">Cleistocalyx operculatus</Emphasis> buds

Five flavonoids, myricetin-3′-methylether 3-O-β-d-galactopyranoside (1), myricetin-3′,5′-dimethylether 3-O-β-d-galactopyranoside (2), quercetin (3), kaempferol (4), and tamarixetin (5) were isolated from the buds of Cleistocalyx operculatus (Myrtaceae). The chemical structures of these compounds were determined on the basis of spectroscopic analyses, including 2D NMR. Their anti-Alzheimer effects were evaluated via acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activity assays. All five compounds 1–5 showed potential inhibitory activities against AChE with IC₅₀ values of 19.9, 37.8, 25.9, 30.4 and 22.3 μM, respectively, while compounds 1, 3, 4 and 5 also possessed BChE inhibitory activity with IC₅₀ values of 152.5, 177.8, 62.5, and 160.6 μM, respectively.     

Biologically active <Emphasis Type="Italic">C</Emphasis>-alkylated flavonoids from <Emphasis Type="Italic">Dodonaea viscosa</Emphasis>

A new C-alkylated flavonoid (5,7-dihydroxy-3′-(4″-acetoxy-3″-methylbutyl)-3,6,4′-trimethoxyflavone (1), along with two known C-alkylated flavonoids (5,7-dihydroxy-3′-(3-hydroxymethylbutyl)-3,6,4′-trimethoxyflavone (2), 5,7,4′-trihydroxy-3′-(3-hyroxymethylbutyl)-3,6-dimethoxyflavone (3) and two new source C-alkylated flavonoids (5,7-dihydroxy-3′-(2-hydroxy-3-methyl-3-butenyl)-3,6,4′-trimethoxyflavone (4), 5,7,4′-trihydroxy-3,6-dimethoxy-3′-isoprenyl-flavone (5) were isolated from the aerial parts of Dodonaea viscosa. The structures of all compounds were established on the basis of 1D and 2D NMR spectroscopy and mass spectrometry. The isolated compounds were evaluated for their inhibitory effect on urease and α-chymotrypsin enzyme. All the compounds (1–5) exhibited mild inhibition against urease but remained recessive in case of α-chymotrypsin.     

Lignan glycosides from the leaves of <Emphasis Type="Italic">Osmanthus heterophyllus</Emphasis>

Seven known lignan glycosides were isolated from the leaves of Osmanthus heterophyllus: (+)-syringaresinol 4-O-β-d-glucopyranoside, (+)-syringaresinol 4, 4′-O-di-β-d-glucopyranoside, (+)-medioresinol 4, 4′-O-di-β-d-glucopyranoside, (+)-medioresinol 4-O-β-d-glucopyranoside, (+)-pinoresinol 4, 4′-O-β-d-glucopyranoside, (+)-epipinoresinol 4-O-β-d-glucopyranoside and phillyrin. Their structures were determined on the basis of spectral data.     

Constituents of the root of <Emphasis Type="Italic">Anemone tomentosa</Emphasis>

A new diterpene glycoside, tomentoside I (1), along with eleven known compounds, including the four coumarins, 4,5-dimethoxyl-7-methylcoumarin (2), 4,7-dimethoxyl-5-methylcoumarin (3), isofraxidin (4) and fraxidin (5) as well as the seven triterpenoids, oleanolic acid (6), oleanolic acid 3-O-α-L-arabinopyranoside (7), oleanolic acid 3-O-β-D-galactopyranosyl-(1→3)-β-D-glucopyranoside (8), hederagenin 3-O-α-L-arabinopyranoside (9), betulinic acid (10), 18-hydroxyursolic acid (11) and 2α,3β,23-trihydroxyurs-12-en-28-oic acid (12) were isolated from the ethanolic extract of the root of Anemone tomentosa and their chemical structures were elucidated by spectroscopic methods. The antimicrobial activities of compounds 1–12 were measured using the agar disc-diffusion method. Also, their antioxidant activities against 1,1-diphenyl-2-picrylhydrazyl (DPPH) were evaluated.     

Immunosuppressive effects of new cyclolanostane triterpene diglycosides from the aerial part of <Emphasis Type="Italic">Cimicifuga foetida</Emphasis>

Two new cyclolanostane diglycosides, cimifoetiside A (1) and cimifoetiside B (2), were isolated from an 80% ethanolic extract of the aerial part of Cimicifuga foetida L. (Ranuculaceae). Using spectral data and chemical analysis, the structures of 1 and 2 were identified as (23R, 24S) cimicigenol 3-O-β-D-glucopyranosyl-(1″→3′)-β-D-xylopyranoside and (23R, 24S) cimicigenol 3-O-β-D-glucopyranosyl-(1″→2′)-β-D-xylopyranoside, respectively. The in vitro immunosuppressive effects of the two new compounds 1 and 2, as well as four other known cyclolanostane saponins 3–6 on T cells were evaluated. All the agents tested effectively inhibited the proliferation of murine splenocytes induced by Concanavalin A (ConA), with IC₅₀ values ranging from 12.7 nM to 33.3 nM.