A new triterpenoid from Alisma orientale and their antibacterial effect

A new triterpenoid, named alisol Q 23-acetate, as well as fourteen known terpenes, alisol B 23-acetate (2), alisol B (3), alismol (4), 10-O-methyl-alismoxide (5), alismoxide (6), 11-deoxyalisol C (7), 13??,17??-epoxyalisol B 23-acetate (8), 4??,12-dihydroxyguaian-6,10-diene (9), alisol C 23-acetate (10), alisolide (11), 16??-methoxyalisol B monoacetate (12), alisol A (13), 16??-hydroxyalisol B 23-acetate (14), alisol A 24-acetate (15) were isolated from the rhizomes of Alisma orientale. The structures of compounds (1?C15) were identified based on 1D and 2D NMR, including ¹H-¹H COSY, HSQC, HMBC and NOESY spectroscopic analyses. Among these isolates, antibacterial effect of compounds 2, 3, 10, and 15, major constituents of A. orientale was examined. The MIC values of compounds 2, 10, and 15 were 5?C10 ??g/mL against eight antibiotic resistant strains, which were lower than those from the positive controls (MICs of chloramphenicol and ampicillin were 5?C80 ??g/mL). Therefore, compounds 2, 10 and 15 exhibited the potent antibacterial activity.     

Inhibition of DNA topoisomerases I and II and cytotoxicity by lignans from Saururus chinensis

Thirteen lignans, erythro-austrobailignan-6 (1), meso-dihydroguaiaretic acid (2), sauchinone (3), 1′-epi-sauchinone (4), saucerneol D (5), manassantin B (6), manassantin A (7), nectandrin B (8), machilin D (9), saucerneol F (10), saucerneol G (11), saucerneol H (12) and saucerneol I (13), were isolated from the ethyl acetate extract of the roots of Saururus chinensis. Among these compounds, 5 showed potent inhibitory activities against DNA topoisomerase I and II, and 5, 6, 7 and 10 showed mild cytotoxicities against HT-29 (IC₅₀ values; 13, 12, 11, and 10 µM, respectively) and HepG2 cell lines (IC₅₀ values; 16, 11, 12, and 11 µM, respectively).     

Phenylpropanoids and lignanoids from Euonymus acanthocarpus

A new phenylpropanoid derivative (1), along with five phenylpropanoids (2–6), two monoepoxy lignans (8–9), one bisepoxy lignan (10), two cyclolignans (11–12), six neolignans (7, 13–17), two mixed lignan-neolignans (18–19), two lignan glycosides (20–21), and four flavonolignans (22–25), were isolated from the stems and twigs of Euonymus acanthocarpus. Compounds 2–3, 6–8, 12, and 14–25 were obtained from Celastraceae family for the first time, and compounds 5 and 9 were isolated from Euonymus genus for the first time. All the compounds were tested for cytotoxicity against SK-OV-3 and MCG-803 human tumor cell lines. Compounds 3, 10, 12, and 18 showed weak cytotoxicity against SK-OV-3 cell line, and compounds 3–4, 10–13, and 19 showed weak cytotoxicity against MCG-803 cell line.     

Lupeol-3-O-decanoate, a new triterpene ester from Cadaba farinosa Forssk. growing in Saudi Arabia

A new triterpene ester (1) together with eight known compounds (2–9) were isolated from the leaves of Cadaba farinosa Forssk. Their chemical structures were established on the basis of physical, chemical, and spectroscopic methods (IR, 1D and 2D NMR, and mass spectral analyses) to be: lupeol-3-O-decanoate (1), lupeol (2), β-sitosterol (3), ursolic acid (4), 12-aminododecanoic (5), dillenetin-3-O-β-d-glucopyranoside (6), stachydrine (7), 3-hydroxy-stachydrine (8), and quercetin-3-O-β-d-glucopyranoside (9). That is the first report for the isolation of compound 5 from a plant source. Compounds 5, 6, and 9 were evaluated for their antioxidant activity.     

Antibacterial substances from Albizia myriophylla wood against cariogenic Streptococcus mutans

Albizia myriophylla has been used for long by Thai traditional healers as an important ingredient herb in Thai herbal formulas for caries. In this study, three flavonoids lupinifolin (6), 8-methoxy-7,3′,4′-trihydroxyflavone (7), and 7,8,3′,4′-tetrahydroxyflavone (8), a triterpenoid lupeol (3) as well as four sterols β-sitosterone (1), stigmasta-5,22-dien-3-one (2), β-sitosterol (4), and stigmasterol (5) were isolated from A. myriophylla wood. The antibacterial activity of these compounds against Streptococcus mutans ATCC 25175 was performed using broth microdilution method. All compounds exhibited antibacterial activity against S. mutans with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) ranging from 1–256 and 2–256 μg/ml, respectively. Among the isolated compounds, lupinifolin (6) was found to be the most potent with MIC and MBC of 1 and 2 μg/ml, respectively. Lupinifolin (6) also showed a strong activity against ten clinical isolates of S. mutans with MIC and MBC ranging from 0.25–2 and 0.5–8 μg/ml, respectively. These results reported the bioactive ingredients of A. myriophylla which support its ethnomedical claims as well. Lupinifolin (6) may have a potential to be a natural anticariogenic agent.     

Vasorelaxant activity of indole alkaloids from Tabernaemontana dichotoma

The aim of this study was to search for bioactive natural products from medicinal plants targeting vasorelaxant activity and we found the methanol extract from bark of Tabernaemontana dichotoma showed vasorelaxant activity on rat aorta. We isolated eight indole alkaloids including 10-methoxyalstonerine (1), a new macroline type indole alkaloid, from bark of T. dichotoma. These were respectively identified as 10-methoxyaffinisine (2), lochnerine (3), cathafoline (4), (?)-alstonerine (5), 19,20-dehydro-10-methoxytalcarpine (6), alstonisine (7), and alstonal (8) based on spectroscopic analysis. Among them, sarpagine type (2 and 3), akuammiline type (4), and macroline oxindole type (7 and 8) showed potent vasorelaxant activity. Mechanism of action on vasorelaxant activity of 10-methoxyaffinisine (2), cathafoline (4), and alstonisine (7) was clarified. Effects of 10-methoxyaffinisine (2), cathafoline (4), and alstonisine (7) were partially mediated the NO release from endothelial cells. Furthermore, 10-methoxyaffinisine (2) and alstonisine (7) attribute to the inhibitory effect of VDC and ROC, and cathafoline (4) have inhibitory effect on Ca²⁺ influx via ROC. In addition, 10-methoxyaffinisine (2) as a major compound from bark of T. dichotoma showed hypotensive effect on normotensive rats in vivo.     

Phenylethanoid and flavone glycosides from Ruellia tuberosa L.

A new phenylethanoid glycoside, isocassifolioside (8), and two new flavone glycosides, hispidulin 7-O-α-l-rhamnopyranosyl-(1′″ → 2″)-O-β-d-glucuronopyranoside (11) and pectolinaringenin 7-O-α-l-rhamnopyranosyl-(1′″ → 2″)-O-β-d-glucuronopyranoside (12) were isolated from the aerial portions of Ruellia tuberosa L., together with verbascoside (1), isoverbascoside (2), nuomioside (3), isonuomioside (4), forsythoside B (5), paucifloside (6), cassifolioside (7), hispidulin 7-O-β-d-glucuronopyranoside (9) and comanthoside B (10). The structure elucidations were based on analyses of chemical and spectroscopic data including 1D- and 2D-NMR. The isolated compounds 1–12 exhibited radical scavenging activity using ORAC assay.     

Two new steroidal saponins from the tubers ofLiriope spicata

Two novel steroidal saponins designated as spicatosidesA(1) andB(2) were isolated from the tubers ofLiriope spicata and their structures were clucidated as 25(S)-ruscogenin-1-O-β-D-glucopyranosyl (1→2)-[β-D-xylopyranosyl (1→3)]-β-D-fucopyranoside (1) and 26-O-β-D-glucopyranosyl 25(S)-22-O-methyl-furost-5-en-1β, 3β, 26-triol 1-O-β-D-glucopyranosyl (1→2)-[β-D-xylopyranosyl (1→3)]-β-D-fucopyranoside (2), respectively.     

Flavonoids from Astragalus membranaceus and their inhibitory effects on LPS-stimulated pro-inflammatory cytokine production in bone marrow-derived dendritic cells

Radix Astragali (Astragalus membranaceus) is an important traditional Chinese medicine that is widely used as a tonic to enhance the body’s natural defense mechanisms. In this phytochemical study, 12 flavonoids, isoliquiritigenin (1), liquiritigenin (2), calycosin (3), calycosin 7-O-β-d-glucoside (4), formononetin (5), formononetin 7-O-β-d-glucoside (6), daidzein (7), daidzein 7-O-β-d-glucoside (8), methylnissolin (9), methylnissolin 3-O-β-d-glucoside (10), isomucronulatol (11), and isomucronulatol 7-O-β-d-glucoside (12), were isolated from the roots of A. membranaceus. Their structures were elucidated by comparing spectroscopic data with reported values. The effects of the isolated compounds on lipopolysaccharide (LPS)-stimulated bone marrow-derived dendritic cells were investigated. Compounds 1 and 2 exhibited significant inhibitory effects on LPS-induced IL-6 and IL-12 p40 production, with IC₅₀ values ranging from 2.7 to 6.1 μM. Compound 1 also showed a moderate inhibitory effect on LPS-stimulated production of TNF-α with an IC₅₀ value of 20.1 μM. Further studies of the potential anti-inflammatory effects and benefits of flavonoids from A. membranaceus are warranted.     

A new neolignan and lignans from the stems of Lindera obtusiloba Blume and their anti-allergic inflammatory effects

A new neolignan, linderin A (1), together with six known lignans, (+)-xanthoxyol (2), pluviatilol (3), actiforin (4), (+)-syringaresinol (5), (+)-(7S,8R,8′R)-acuminatolide (6), and (+)-9′-O-trans-feruloyl-5,5′-dimethoxylariciresinol (7) were isolated from the stems of Lindera obtusiloba Blume (Lauraceae). Their chemical structures were elucidated by a combination of spectroscopic analysis and chemical reaction, and the absolute configuration of 1 was determined by Mosher’s esterification. The effect of compounds 1–7 on tumor necrosis factor (TNF)-α, interleukin(IL)-6, and their inhibitory activity of histamine release were examined using human mast cells. Among the lignans tested, compounds 1, 3, 4, 6, and 7 inhibited release of histamine from mast cells. Especially, compounds 1 and 4 suppressed the gene expressions of pro-inflammatory cytokines, TNF-α, and IL-6 in human mast cells. Our findings suggest that the lignan constituents in L. obtusiloba may contribute to its anti-allergic inflammatory effects.     

Two new natural products from the fruits of Alpinia oxyphylla with inhibitory effects on nitric oxide production in lipopolysaccharide-activated RAW264.7 macrophage cells

Chemical investigation of the fruits of Alpinia oxyphylla led to an isolation of the two new natural products, 9-hydroxy epinootkatol (1) and (S)-2-pentanol-2-O-β-D-glucopyranoside (2), in addition to the nine known compounds, pinocembrin (3), tectochrysin (4), izalpinin (5), nookatone (6), yakuchinone A (7), protocatechuic acid (8), β-sitosterol (9), daucosterol (10) and β-sitosterol palmitate (11). Their structures were elucidated on the basis of physicochemical constants and NMR spectral data analysis. The effects of the isolated components on nitric oxide production in LPS-induced RAW 264.7 macrophages were examined. The two new natural compounds showed inhibitory activities with IC₅₀ values of 21.8 and 32.8 μg/mL, respectively.     

Collagenase inhibitors from Viola yedoensis

Fractionation of acetone and methanol extracts of Viola yedoensis, under the guidance of inhibition against Clostridium histolyticum collagenase (ChC), resulted in the isolation of esculetin (1) (IC₅₀ 12 μM) and scopoletin (2) (IC₅₀ 1.8 μM) as the active constituents, together with trans-p-coumaric acid (3), cis-p-coumaric acid (4), 3-O-β-d-glucosyl-7-O-α-L-rhamnosylkaempferol (5), rutin (6), isovitexin (7), isoorientin (8), vicenin-2 (9), isoscoparin (10), vanillic acid (11) and adenosine (12). Modification of phenolic hydroxy groups of 1 showed that small O-alkyl groups largely increased the activity, whereas larger O-alkyl groups decreased the activity, and 6,7-dimethoxycoumarin (scoparone 13) potently inhibited ChC (IC₅₀ 24 nM).     

A new isoflavone from Blepharis ciliaris of an Egyptian origin

A phytochemical study of the aerial parts of Blepharis ciliaris (L.) B.L. Burtt. led to the isolation of one new isoflavone glycoside caffeic acid ester: genistein-7-O-(6″-O-E-caffeoyl-β-d-glucopyranoside) (4), along with seven known compounds: methyl veratrate (1), methyl vanillate (2), protocatechuic acid (3), naringenin-7-O-(3″-acetyl-6″-E-p-coumaroyl-β-d-glucopyranoside) (5), naringenin-7-O-(6″-E-p-coumaroyl-β-d-glucopyranoside) (6), apigenin-7-O-(6″-E-p-coumaroyl-β-d-glucopyranoside) (7), and acteoside (8). Their structures were established on the basis of detailed analyses of physical, chemical, and spectral data. Compounds 1, 2, 3, 6, and 8 were isolated for the first time from this plant. The antioxidant activity of the different extracts as well as for some of the isolated compounds was evaluated.     

Naphthoquinones from Catalpa ovata and their inhibitory effects on the production of nitric oxide

Bioassay-guided fractionation of a CH2Cl2-soluble fraction of the stems of Catalpa ovata led to isolation of a new naphthoquinone, 4-hydroxy-2-(2-methoxy-3-hydroxy-3-methyl-but-1-enyl)-4-hydro-1H-naphthalen-1-one (10), together with nine known compounds, catalponol (1), catalponone (2), catalpalactone (3), α-lapachone (4), 9-hydroxy-α-lapachone (5), 4,9-dihydroxy-α-lapachone (6), 9-methoxy-α-lapachone (7), 4-oxo-α-lapachone (8), and 9-methoxy-4-oxo-α-lapachone (9). The structures were elucidated on the basis of spectroscopic analyses. The inhibitory effects of these isolates on lipopolysaccharide-induced NO synthesis in RAW 264.7 cells were evaluated. Among them, catapalactone (3), 9-hydroxy-α-lapachone (5) and 4,9-dihydroxy-α-lapachone (6) exhibited potent inhibitory effects, with IC₅₀ values of 9.80, 4.64 and 2.73 μM, respectively.     

Bioactive anthraquinones from endophytic fungus Aspergillus versicolor isolated from red sea algae

The marine fungus Aspergillus versicolor was isolated from the inner tissue of the Red Sea green alga Halimeda opuntia. The fungus was identified by its morphology and 18s rDNA. Cultivation of this fungal strain led to a new metabolite named isorhodoptilometrin-1-methyl ether (1) along with the known compounds emodin (2), 1-methyl emodin (3), evariquinone (4), 7-hydroxyemodin 6,8-methyl ether (5), siderin (6), arugosin C (7), and variculanol (8). The structures were elucidated on the basis of NMR spectroscopic analysis and mass spectrometry. The biological properties of ethyl acetate extract and compounds 1–3 and 6–8 were explored for antimicrobial activity, anti-cancer activity and inhibition of Hepatitis C virus (HCV) protease.     

Two new c-glucosyl benzoic acids and flavonoids from Mallotus nanus and their antioxidant activity

Two new 2-C-β-D-glucopyranosyl benzoic acid derivatives named mallonanosides A (1) and B (2) were isolated from the methanolic extract of the leaves of Mallotus nanus along with five known flavonoids, kaempferin (3), juglanin (4), quercitrin (5), myricitrin (6), and rhoifolin (7). Their structures were established on the basis of spectral and chemical evidence. Their antioxidant activities were shown to depend on the number of hydroxyl groups, and the location and species of sugar moiety.     

Eco-friendly synthesis and antimicrobial activities of substituted-5-(1H-indol-3-yl)methylene)-2,2-dimethyl-1,3-dioxane-4,6-dione derivatives

l-Tyrosine is an efficient catalyst for the condensation of substituted indole-3-aldehydes 1(a–d), N-methyl indole-3-aldehydes 4(a–d), and N-ethyl indole-3-aldehydes 6(a–d) with meldrum’s acid (2) containing a cyclic active methylene group to produce 3(a–d), 5(a–d), and 7(a–d), respectively, in water at room temperature for 30 min. The antimicrobial activities of 3(a–d), 5(a–d), and 7(a–d) have been studied.     

Anticandidiasis agents from a Tanzanian plant, Combretum zeyheri

Combretum zeyheri Sond (Combretaceae) has been reported to exhibit anticandida activity against Candida kruzei, C. albicans, and C. parapsilosis; however, the active constituents have not been isolated so far. A bioactivity-guided fractionation of MeOH extract of C. zeyheri resulted in the isolation of triterpenoids, ursolic acid (1.1), oleanolic acid (1.2), maslinic acid (2.1), 2α,3β-dihydroxyurs-12-en-28-oic acid (2.2), 6β-hydroxymaslinic acid (3), and terminolic acid (4). These compounds were characterized on the basis of their 1D, 2D NMR, ESI-MS and FT-IR spectroscopic data. All the isolated compounds, 1.2, 2.1, 2.2, 3, and 4 except ursolic acid (1.1) are being reported for the first time from C. zeyheri. Later, the isolated triterpenoids (1–4) were evaluated for their anticandida activity against the three strains of C. albicans and all compounds showed anticandida activity of which terminolic acid (4) was most active. Furthermore, structure–activity relationship of isolated triterpenoids (1–4) was studied, which showed that triterpenoids of oleanane and ursane having 2α,3β,23-trihydroxyl group are more active.     

Phenolic compounds with IL-6 inhibitory activity from Aster yomena

A new biflavonoid, named asteryomenin (1), as well as six known phenolic compounds, esculetin (2), 4-O-β-d-glucopyranoside-3-hydroxy methyl benzoate (3), caffeic acid (4), isoquercitrin (5), isorhamnetin-3-O-glucoside (6), and apigenin (7) were isolated from the aerial parts of Aster yomena. The structures of compounds (1–7) were identified based on 1D and 2D NMR, including ¹H–¹H COSY, HSQC, HMBC and NOESY spectroscopic analyses. Compounds 2–7 were isolated from this plant for the first time. For these isolates, the inhibitory activity of IL-6 production in the TNF-α stimulated MG-63 cell was examined. Among these isolates, compounds 4 and 7 appeared to have potent inhibitory activity of IL-6 production in the TNF-α stimulated MG-63 cell, while compounds 1–3 and 5–6 showed moderate activity.     

Cytotoxic and anti-inflammatory constituents from the seeds of Descurainia sophia

A new sinapoyl glycoside, 1,3-di-O-sinapoyl-β-d-glucopyranose (1) along with 13 known compounds, including, sinapoyl glycosides (2 and 3), cardenolide glycoside (4), flavonoids (5–10), lignan (11), phenolic acids (12 and 13), and phytosterol (14), were isolated from the seeds of Descurainia sophia by chromatographic separation methods. The structures of 1–14 were determined by the interpretation of spectroscopic data as well as by comparison of that data with previously reported values. Compounds 2, 3, 5, 6, and 11 were identified in and isolated from this plant for the first time in this study. All isolates were evaluated for in vitro cytotoxic activities against seven human cancer cell lines and for in vitro anti-inflammatory potential using LPS-stimulated RAW264.7 murine macrophages. Compound 4 showed potent cytotoxicity (IC₅₀ values ranging from 0.034 to 0.596 μM) against all human cancer cell lines tested and was identified as the main active cytotoxic constituent of this plant. Compound 8 (ED₅₀ = 5.45 μM) and 11 (ED₅₀ = 10.02 μM) exerted dose-dependent inhibitory effects on NO production in LPS-stimulated RAW264.7 cells.