Two novel aromatic glucosides,marylaurencinosides D and E,from the fresh flowers of Cymbidium Great Flower ‘Marylaurencin’

Two novel aromatic glucosides, named marylaurencinosides D (1) and E (2), were isolated from the fresh flowers of Cymbidium Great Flower ‘Marylaurencin’. In addition, eight known aromatic compounds (3–10) were isolated. These structures were determined on the basis of NMR experiments as well as chemical evidence.     

Furostanol glycosides from the rhizomes of Helleborus orientalis

Eight new furostanol glycosides (1–8), together with two known ones (9 and 10), have been isolated from a glycoside-enriched fraction prepared from the rhizomes of Helleborus orientalis (Ranunculaceae). The structures of 1–8 were determined on the basis of extensive spectroscopic analysis, including 2D NMR, and the results of hydrolytic cleavage. The isolated compounds were evaluated for their cytotoxic activity against HSC-2 cells.     

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.     

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.     

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.     

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.     

Eremophilane derivatives from Senecio dianthus

From the aerial parts of Senecio dianthus, five eremophilane glucosides (1, 2, 4–6) and one new eremophilenolide (7) were isolated, together with sixteen known compounds (3, 8–22). Their structures and relative configurations were elucidated on the basis of extensive spectroscopic analysis, including HR-ESI-MS, X-ray, CD, 1D- and 2D-NMR experiments.     

Design and evaluation of new hybrid pharmacophore quinazolino-tetrazoles as anticonvulsant strategy

The anticonvulsant study of 25 newly synthesized quinazolin-4(3H)-one substituted 1H and 2H-tetrazoles (6a–6d, 7a–7b, 8a–8i, 8a′–8i′) was executed. The study employing the maximal electroshock and subcutaneous pentylenetetrazole (scPTZ) screens, the ‘gold standards’ in the preliminary anticonvulsant breakthrough and the neurotoxicity study applying the rotorod test unveiled a triad of compounds 6c, 7b and 8i′ as the looms amongst the compendium of synthesized compounds. The quantification data of these compounds following oral administration in rats showcased 7b to endorse a remarkable position in the MES screen with a protective indice (PI) of >39.67 and 6c in the scPTZ delineating a PI > 3.10, respectively. All the potent compounds were destitute of toxicity.     

Five new sesquiterpene lactones from Inula hupehensis

Four new pseudoguaianolides (1–4), one new guaianolide (5), together with ten known compounds (6–15) were isolated from the aerial parts of Inula hupehensis. Their structures were elucidated mainly on the basis of 1D and 2D spectroscopic methods and circular dichroism analysis. In addition, compounds 1–10 and 13 were tested for their inhibitory effects against LPS-induced NO production in RAW264.7 macrophages. Compounds 2, 6, 8 and 9 exhibited significant inhibitory activities with IC₅₀ values in the range of 0.6–6.6 μM.     

Synthesis of β-amino carbonyl derivatives of coumarin and benzofuran and evaluation of their biological activity

A series of β-amino carbonyl compounds containing coumarin (4a–h) and benzofuran (6a–i) moieties was synthesized by a three component Mannich reaction of 3-acetyl-2H-chromen-2-one (1) or 1-(1-benzofuran-2-yl) ethanone (5) with p-substituted aromatic aldehydes (2a–g) and aromatic amines (3a–b) in the presence of cerric ammonium nitrate as a catalyst. The newly synthesized compounds were screened for antimicrobial and antioxidant activities. Compounds 4b, 4e, 4f, 6f, 6g, and 6i showed microbial inhibition with minimal inhibition concentration ranging between 0.040 and 0.500 mg/mL, compounds 4b, 4c, 6c, 6e, and 6i showed promising free radical scavenging activity and compounds 4b, 4f, 6c, 6d, and 6h showed good chelating ability with Fe²⁺ ions. The synthesized compounds were studied for docking on the enzyme, glucosamine-6-phosphate synthase to predict the binding affinity and orientation at the active site of the receptor.     

Synthesis and characterization of novel benzo[d][1,3]dioxole gathered pyrazole derivatives and their antimicrobial evaluation

Benzo[d][1,3]dioxole gathered pyrazole derivatives (4a–i) were synthesized by the reaction of chalcones with phenyl hydrazine in presence of absolute alcohol as a solvent. Chalcones were prepared by the Claisen-Schmidt reaction between 1-(benzo[d][1,3]dioxol-5-yl)ethanone (2) and substituted aromatic aldehydes. The synthesized compounds were characterized by spectral and elemental analysis data. Furthermore, Benzo[d][1,3]dioxole gathered pyrazole derivatives (4a–i) were evaluated for their in vitro antimicrobial activity. Among the newly synthesized compounds 4a, 4c, 4 g and 4 h showed the excellent antifungal activity and as well as 4a and 4d showed the excellent antibacterial activity when compared to other compounds.     

New diterpenoids with estrogen sulfotransferase inhibitory activity from Leonurus sibiricus L.

Four new diterpenoids (1–4), along with eight known diterpenoids (5–12) were isolated from the acetone extract of Leonurus herb (aerial parts of Leonurus sibiricus L.). The structures of the compounds were determined by spectroscopic methods. Among the isolated compounds, compounds 2, 3, 8, 9 and 10 showed inhibitory activity against human liver cytosol estrogen sulfotransferase (E-ST), which plays a key role in the maintenance of cellular estrogen levels. Compound 2 showed the strongest activity with an IC₅₀ value of 7.9 μM, which is comparable to the activity of the positive control, meclofenamic acid (IC₅₀ 5.4 μM).     

Anti-inflammatory and antioxidant activities of phenolic compounds from Desmodium caudatum leaves and stems

Four flavanonols (1–4), one xanthone (5), and three flavonoid glycosides (6–8), were isolated from the leaves and stems of Desmodium caudatum. Their structures were elucidated by comparing spectroscopic data with reported values. The anti-inflammatory activity of the isolated compounds was investigated in lipopolysaccharide (LPS)-stimulated bone marrow-derived dendritic cells. Among them, compounds 1 and 2 exhibited inhibitory effects on LPS-induced IL-6, IL-12 p40, and TNF-α production with IC₅₀ values ranging from 6.0 to 29.4 μM. Compound 5 exhibited 1,1-diphenyl-2-picrylhydrazyl radical and intracellular reactive oxygen species scavenging activity in human HaCaT keratinocytes. These results warrant further studies of the potential anti-inflammatory and antioxidant benefits of compounds from D. caudatum.     

Arginase II inhibitory activity of flavonoid compounds from Scutellaria indica

Arginase II has recently reported as a novel therapeutic target for the treatment of cardiovascular diseases such as atherosclerosis. In the course of screening plants used in natural medicines as arginase II inhibitory activity, a methanol extract of Scutellaria indica showed significant inhibitory effect. Further fractionation and repeated column chromatography led to the isolation of a new flavan-type (1), and seven known compounds (2–8). The chemical structures of isolated compounds were elucidated based on extensive 1D and 2D NMR spectroscopic data. The isolates 1–8 were investigated in vitro for their arginase II inhibitory activity using enzyme solution prepared from kidney of anesthetized C57BL/6 mice. Compounds 3 and 5 significantly inhibited arginase II activity with IC₅₀ values of 25.1 and 11.6 μM, respectively, whereas the other compounds were apparently inactive.     

Synthesis, characterization, and biological evaluation of some N-aryl hydrazones and their 2,3-disubstituted-4-thiazolidinone derivatives

A series of 2,3-disubstituted 4-thiazolidinones 6 and 8a-p have been prepared by the cyclo condensation reaction of various substituted N-aryl hydrazones 5 and 7a–p with mercapto acetic acid. The intermediate N-aryl hydrazones 5 and 7a–p were synthesized by the condensation of 2-bromo-5-methoxy benzohydrazide 4 with 2 or various substituted aromatic aldehydes. The new Naphthalene-2-carboxaldehyde 2 has been synthesized by Vilsmeier-Haack reaction of naphthalen-1(2H)-one 1. The key starting compound 2-bromo-5-methoxy benzohydrazide 4 was prepared from methyl 2-bromo-5-methoxybenzoate 3 by the reaction with hydrazine hydrate in alcoholic medium. The formulae of the compounds were confirmed by elemental analyses and their structures were determined based on IR, ¹H-NMR, ¹³C-NMR, ¹³C-NMR-DEPT, and mass spectral data. The newly synthesized compounds were evaluated for their antioxidant, anti-inflammatory, and analgesic activities. The antibacterial activities of the newly synthesized compounds against E. coli ATCC 8739, S. aureus ATCC 6538, P. aeruginosa ATCC 1539, and Bacillus cereus, while the antifungal activities of the compounds against Candida albicans were tested. The acute cytotoxicity data of compounds 7h and 8a are tested and are found to be nontoxic up to 2,500 mg/kg.     

Oleanane-type triterpenoid saponins from the roots of Pulsatilla koreana and their apoptosis-inducing effects on HL-60 human promyelocytic leukemia cells

Twenty-four oleanane-type triterpenoid saponins were isolated from a methanol extract of the Pulsatilla koreana roots. Their structures were elucidated by comparing spectroscopic data to published values. Among them, compounds 8–12 and 20–24 significantly diminished the proliferation of HL-60 human promyelocytic leukemia cells with IC₅₀ values from 0.3 to 4.2 μM, whereas compounds 7 and 19 showed moderate cytotoxic activity. Furthermore, apoptotic characteristics such as chromatin condensation and increase in the population of sub-G1 hypodiploid cells were observed after the HL-60 cells were treated with these compounds.     

Flavonoids from Millettia nitida var. hirsutissima with their anticoagulative activities and inhibitory effects on NO production

Two new compounds, (2R)-7,3′-dihydroxy-6,4′-methoxyflavan (1) and (3R)-7,4′-dihydroxy-2′-methoxyisoflavan (2), along with 12 known flavonoids (3–14), were isolated from the vine stems of Millettia nitida var. hirsutissima. The structures of the isolated compounds were elucidated based on spectroscopic analyses and comparison of literature data. All of the isolates were evaluated for their effects on in-vitro anticoagulative assay and on nitric oxide (NO) production in lipopolysaccharide (LPS)-activated RAW264.7 macrophages. As a result, all compounds showed weak antiplatelet aggregation activities and compounds 4, 5, 7, 8 and 9 demonstrated antithrombin activity with a good dose–effect relationship from 5 to 100 μg mL^?1 in rabbit plasma. Compounds 8, 9, 10 and 14 exhibited inhibitory effects on LPS-induced NO production in RAW264.7 macrophages with IC₅₀ values of 4.79 ± 0.20, 8.23 ± 0.35, 5.23 ± 0.11 and 6.30 ± 0.30 μg mL^?1, respectively.     

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.     

Synthesis, antitumor activity, and structure–activity relationship of some 4H-pyrano[3,2-h]quinoline and 7H-pyrimido[4′,5′:6,5]pyrano[3,2-h]quinoline derivatives

Several 4H-pyrano[3,2-h]quinoline (3a–d, 4a, 7a,b, 9a–c, 10a,b, 11a,b, and 13a–c) and 7H-pyrimido[4′,5′:6,5]pyrano[3,2-h]quinoline derivatives (8a–c) were obtained by treatment of 8-hydroxyquinoline (1a) and 8-hydroxy-2-methylquinoline (1b) with α-cyano-p-chloro/bromocinnamonitrile (2a,b) or 4H-pyrano[3,2-h]quinoline derivatives (3a,c,d) with different electrophilic reagents followed by nucleophilic reagents. Structures of these compounds were established on the basis of spectral data. The antitumor activity of the synthesized compounds was investigated in comparison with Vinblastine. Among them, compounds 3c,d, 4a, 8b, 9b,c, 11a,b, and 13a,c inhibited the growth of cancer cells compared to Vinblastine. The structure–activity relationships were discussed.     

Anti-Helicobacter pylori xanthones of Garcinia fusca

A new geranylated xanthone derivative, fuscaxanthone I (1), along with nine xanthones (2–9 and 11), a biphenyl (10) and three biflavonoids (12–14) were isolated from the roots of Garcinia fusca Pierre. Compounds 8, 10 and 11–14 were reported from this plant species for the first time. Their structures were elucidated by spectroscopic analyses, including 1D- and 2D-NMR and MS. The isolated compounds were evaluated for antibacterial activity against Helicobacter pylori. Cowaxanthone (5) and fukugiside (14) exhibited stronger inhibitory activity against H. pylori DMST reference strain at MICs 4.6 and 10.8 μM, respectively, than that of the control metronidazole. Isojacareubin (8) displayed the most potent activity against H. pylori HP40 clinical isolate with MIC 23.9 μM, which was approximately two times greater than that of the standard drug amoxicillin.