Xanthones isolated from Gentianella acuta and their protective effects against H2O2-induced myocardial cell injury

In the present study, two new xanthones, (5′S,8′S)-1,3,5,8-tetrahydroxyxanthone(7→2′)-1,3,5,8-tetrahydroxy-5′,6′,7′,8′-tetrahydroxanthone (1), 5-hydroxy-3,4,6-trimethoxyxanthone-1-O-β-D-glucopyranoside (2), and eight known xanthones (3–10) were isolated from the whole plants of Gentianella acuta. Their structures were identified by the spectroscopic analyses (HR-ESI-MS, and 1D and 2D NMR). Meanwhile, cell-protective effects against H₂O₂-induced H9c2 cardiomyocyte injury and cytotoxic activities of compounds 1–10 were also determined.     

A new caffeic acid tetramer from the Dracocephalum moldavica L.

A new caffeic acid tetramer compound, named (+) methyl rabdosiin (4), together with seven known caffeic acid multimers (1–3, 5–8) and one caffeic acid monomer (9), were isolated from the aerial parts of Dracocephalum moldavica L. The structures of these compounds were assigned on the basis of 1D and 2D NMR spectroscopic and mass spectrometry analyses. The protective effects of compounds 2–4 against hydrogen peroxide (H₂O₂)-induced apoptosis were evaluated in primary cardiomyocytes of SD neonatal rats in vitro by the MTT method. Three compounds exhibited potent protective activities at 12.5 μg/mL.     

A new antiviral pregnane from a gorgonian-derived Cladosporium sp. fungus

A new pregnane, 3α-hydroxy-7-ene-6,20-dione (1), and five known steroids (2–6), along with one known steroidal glycoside (7) were obtained from the fungus Cladosporium sp. WZ-2008-0042 cultured from a gorgonian Dichotella gemmacea collected from the South China Sea. The structure and absolute configuration of the new compound (1) were elucidated by comprehensive spectroscopic data and X-ray diffraction data. The compound has a rare configuration of 3α-OH that is different from most of pregnanes. All of the isolated compounds were evaluated for their antiviral activities against respiratory syncytial virus (RSV). Among them, 1 exhibited potential antiviral activity with the IC₅₀ value of 0.12 mM.     

A new fatty acid ester from Nigella sativa var. hispidula Boiss showing potent anti-protein tyrosine phosphatase 1B activity

A new fatty acid ester (1) and seven known phenolic compounds, i.e. salfredin B₁₁ (2), nigephenol C (3), nigephenol B (4), acetovanillion (5), p-hydroxybenzoic acid (6), p-hydroxy-acetophenone (7) and p-hydroxybenzaldehyde (8), were isolated from the seeds of Nigella sativa var. hispidula. Among them, compounds 5, 7 and 8 were isolated from Nigella for the first time. Their structures were elucidated with HR-ESI-MS, 1D and 2D NMR spectra. Evaluation of the isolated compounds on protein tyrosine phosphatase (PTP1B) assay indicated that although compounds 2–8 show no promising anti-PTP1B activities, compound 1 possess anti-PTP1B activity with an IC₅₀ value of 7.38 ± 0.14 μM in vitro.     

Bioactive furanocoumarins from the stems and leaves of Clausena hainanensis

A new furanocoumarin, clauhainanin A (1), together with seven known furanocoumarins (2–8), were isolated from the stems and leaves of Clausena hainanensis. The structure of 1 was elucidated by extensive spectroscopic methods and the known compounds were identified by comparisons with data reported in the literature. All known compounds (2–8) were isolated from C. hainanensis for the first time. All isolated compounds were evaluated for their cytotoxicities against five human cancer cell lines: HL-60, SMMC-7721, A-549, MCF-7 and SW480 in vitro. Compounds 1–8 exhibited significant inhibitory effects with IC₅₀ values ranging from 1.36 to 18.96 μM.     

Two new benzolactones from the leaves of Nicotiana tabacum and their anti-tobacco mosaic virus activities

Two new benzolactones, 5-methyl-6-prenyl-isobenzofuran-1(3H)-one (1), 5-hydroxymethyl-6-prenyl-isobenzofuran-1(3H)-one (2), together with four known phenolic compounds (3–6), were isolated from the leaves of Nicotiana tabacum. Their structures were elucidated by spectroscopic methods, including extensive 1D and 2D NMR techniques. Compounds 1–6 were evaluated for their anti-tobacco mosaic virus (anti-TMV) activities. The results showed that compounds 1–6 exhibited high anti-TMV activities with inhibition rates in the range of 16.9–26.2%, respectively.     

Chemical constituents and biological activities of Viburnum macrocephalum f. keteleeri

Three new compounds (1–3) and seven known compounds (4–10) have been isolated from the ethanolic extract of Viburnum macrocephalum f. keteleeri using bioactivity-guided fractionation and identified as methyl (2-α-L-rhamnopyranosyloxy)acetate (1), methyl (2R-3-α-L-rhamnopyranosyloxy)glycerate (2), methyl (3R-4-α-L-rhamnopyranosyloxy-3-hydroxy)butanoate (3), bridelionoside B (4), (6S,7E,9R)-roseoside (5), linarionoside A (6), 3,7,11-trimethyl-1,6-dodecadien-3,10,11-triol (7), (+)-8-hydroxylinalool (8), β-sitosterol (9) and daucosterol (10). The structures of 1–3, including absolute configurations, were determined by spectroscopic data (¹H and ¹³C NMR, HSQC, HMBC and ORD) and chemical methods. In addition, compounds 1–8 were assayed for their insecticidal and antimicrobial activities. Compounds 7 and 8 exhibited moderately insecticidal effects against Mythimna separata with LD₅₀ values of 180 and 230 μg g^?1, respectively. Compounds 2, 3, 7 and 8 showed varying antimicrobial activities with IC₅₀ values ranging from 125 to 529 μM.     

A new phenylethanoid glycoside from Orobanche cernua Loefling

A novel phenylethanoid glycoside, 3′-O-methyl isocrenatoside (1), along with two known compounds, methyl caffeate (2) and protocatechuic aldehyde (3), were isolated from the fresh whole plant of Orobanche cernua Loefling. All the isolated compounds (1–3) were elucidated on the basis of spectroscopic analysis including IR, MS and NMR data. The cytotoxic activities of these compounds were evaluated. Results showed that 3′-O-methyl isocrenatoside (1) and methyl caffeate (2) exhibited significant cytotoxicity, with IC₅₀ values of 71.89, 36.97 μg/mL and 32.32, 34.58 μg/mL against the B16F10 murine melanoma and Lewis lung carcinoma cell lines, respectively.     

Secondary metabolites from marine-derived Streptomyces antibioticus strain H74-21

A new secondary metabolite, (2S,3R)-l-threonine, N-[3-(formylamino)-2-hydroxybenzoyl]-ethyl ester (streptomyceamide C, 1), together with four known compounds 1, 4-dimethyl-3-isopropyl-2,5-piperidinedione (2), cyclo-((S)-Pro-8- hydroxy-(R)-Ile (3), cyclo-((S)-Pro-(R)-Leu (4), and seco-((S)-Pro-(R)-Val) (5), were isolated from the EtOH extract of the fermented mycelium of the marine-derived streptomycete strain H74-21, which was isolated from sea sediment in a mangrove site. The structure of the new compound was established on the basis of its spectroscopic data, including 1D and 2D NMR, HR-TOF-MS. Their antifungal activities against Candida albicans and cytotoxicities against human breast adenocarcinoma cell line MCF-7, human glioblastoma cell line SF-268 and human lung cancer cell line NCI-H460 were tested. Compounds 1 only displayed cytotoxicity against human breast adenocarcinoma cell line MCF-7 with the IC₅₀ value of 27.0 μg/mL. However, compounds 1–5 do not show antifungal activities at the test concentration of 1 mg/mL, and 2–5 have no cytotoxicities at the test concentration of 50 μg/mL.     

Phenolic compounds isolated from Morus nigra and their α-glucosidase inhibitory activities

Abstract

A novel benzofuranone unprecedentedly with a prenyl group at C-3, nigranol A (1), a new flavonol, nigranol B (2), and three known compounds, sanggenon M (3), nigrasin C (4), and nigrasin A (5) were isolated from the twigs of Morus nigra Linn. Their structures were elucidated on the basis of the analysis of multiple spectroscopic data. All of the compounds, along with eight previously isolated ones (6–13) were investigated for their α-glucosidase inhibitory activities. The result showed that compounds 1–13 except 4 exhibited prominent inhibitory activities against α-glucosidase. Among them, compounds 2 and 7 were the best α-glucosidase inhibitory candidates with IC₅₀ values at 1.63 and 1.43?μM, respectively. Furthermore, the structure-activity relationships of the sanggenon-type flavanones were summarized.     

A new aldehyde compound from the fruit of Pandanus tectorius Parkinson ex Du Roi

From the fruit of Pandanus tectorius Parkinson ex Du Roi, one new (1) and six known aldehyde compounds (2–7) were isolated by various chromatography methods. Based on their spectroscopic data, these compounds were identified as (Z)-4-hydroxy-3-(4-hydroxy-3-methylbut-2-en-1-yl) benzaldehyde (1), p-hydroxybenzaldehyde (2), syringaldehyde (3), (E)-ferulaldehyde (4), (E)-sinapinaldehyde (5), vanillin (6) and 5-hydroxymethylfurfual (7). The α-glucosidase inhibitory activity of all compounds was measured. The isolated compounds (1–6) showed better α-glucosidase inhibitory activity (IC₅₀ values ranging from 36.5 to 192.4 μM) than the standard drug acarbose (IC₅₀ = 214.5 μM).     

Two new compounds from cultures of the basidiomycete Antrodiella albocinnamomea

A new linear triterpene (1), and a new sesquiterpene (2), together with a known compound methyl indole-3-carboxylate (3) were isolated from the crude extract of Antrodiella albocinnamomea. The structures of the new compounds 1–2 were determined by comprehensive spectroscopic analysis. Compound 1 exhibited signi?cant inhibitory activities against protein tyrosine phosphatase 1B (PTP1B) with IC₅₀ value of 1.0 μg/mL.     

Antiangiogenic phenylpropanoid glycosides from Gynura cusimbua

A new phenylpropanoid glycoside, named α-L-rhamnopyranosyl-(1?2)-β-D-[4″-(8E)-7-(3,4-dihydroxyphenyl)-8-propenoate, 1″-O-(7S)-7-(3,4-dihydroxyphenyl)-7-methoxy-ethyl]-glucopyranoside (1), together with nine known compounds (2–10) were isolated from the active fraction (n-Butanol fraction) of Gynura cusimbua for the first time. The known compounds (2–10) were identified as phenylpropanoid glycosides on the basis of extensive spectral data and references. The antiangiogenic activities of compounds (1–10) were evaluated by MTT assay on HUVECs and wild-type zebrafish in vivo model assay. As a result, compounds 1, 6, 7, 8 and 10 exhibited certain antiangiogenic activities.     

Secondary metabolites from Antarctic marine-derived fungus Penicillium crustosum HDN153086

A new polyene compound (1) and a new diketopiperazine (2), as well as three known compounds (3–5), were isolated from the Antarctic marine-derived fungus Penicillium crustosum HDN153086. The structures of 1–5 were deduced based on MS, NMR and TD-DFT calculations of specific ECD spectra. These compounds were evaluated for their cytotoxic activities against K562 cell line and only compound 2 exhibited cytotoxicity against K562 cell, with IC₅₀ value of 12.7 μM.     

Dhasingreoside: new flavonoid from the stems and leaves of Gaultheria fragrantissima

A new flavonoid, dhasingreoside (1) and seven known compounds, quercetin 3-O-β-d-galacturonopyranoside (2), quercetin 3-O-β-d-galactopyranoside (3), quercetin 3-O-β-d-glucuronopyranoside (4), quercetin 3-O-α-l-rhamnopyranoside (5), (–)-epicatechin (6), salicylic acid (7) and gaultherin (8), have been isolated from the shade-dried stems and leaves of Gaultheria fragrantissima, commonly known as ‘Dhasingre’ in Nepal. The structures were elucidated on the basis of physical, chemical and spectroscopic methods. Among known compounds, five compounds (3–6 and 8) were isolated for the first time from G. fragrantissima. In vitro antioxidant activity of all the isolated compounds was evaluated by 1,1-diphenyl-2-picrylhydrazyl free radical-scavenging assay. Dhasingreoside (1) and other compounds (2–6) showed significant free radical-scavenging activity.     

A new dihydrochalcone glycoside from the stems of Homalium stenophyllum

A new dihydrochalcone glycoside, phloretin-4-O-β-D-glucopyranoside (1), together with seven known flavonoids (2–8), were isolated from the stems of Homalium stenophyllum. The structure of 1 was elucidated by extensive spectroscopic methods and the known compounds were identified by comparisons with data reported in the literature. The known compounds (2–8) were isolated from the genus Homalium for the first time. All compounds were evaluated for their antibacterial activities against six pathogenic bacteria in vitro.     

A new dihydrofurocoumarin from the fruits of Pandanus tectorius Parkinson ex Du Roi

From the fruit of Pandanus tectorius Parkinson ex Du Roi, one new dihydrofurocoumarin, named pandanusin A (1) and 15 known compounds, including one furanocoumarin (2), two coumarins (3, 4), four lignans (5–8), one neolignan (9), two flavonoids (10, 11), three phenolics (12–14), one monoglyceride (15) and one monosaccharide (16) were isolated by various chromatography methods. Among them, compounds (3–5) were obtained from the Pandanus genus for the first time and compounds (9–14, 16) were reported from this species for the first time. Their structures were elucidated by HR–ESI–MS, NMR 1D and 2D experiments and comparison with previous reported data. The α-glucosidase inhibitory activity of all compounds was measured. The isolated compounds (1–12, 14) showed better α-glucosidase inhibitory activity (IC₅₀ = 42.2, 36.5, 84.7, 73.2, 40.8, 26.7, 76.5, 33.8, 68.1, 14.4, 22.1, 81.5, 43.8 μM, respectively) than the standard drug acarbose (IC₅₀ = 214.5 μM).     

A new tigliane-type diterpene from Euphorbia dracunculoides Lam

One new tigliane-type diterpene, 4-deoxy-4(β)H-8-hydroperoxyphorbol-12-benzoate-13-isobutyrate (1), together with two known diterpenoids, 3-acetyl-5,8-dibenzoyl-14α-propanoyl-13,17-epoxy-7-myrsinaone diterpene with C9–C10 cyclised to form an additional lactone ring (2), Euphodendriane A (3) have been isolated from the whole plants of Euphorbia dracunculoides Lam. Their structures were elucidated by means of extensive spectroscopic analysis (NMR and HR-ESI-MS) and comparison with data reported in the literature. This is the first isolation of 8-hydroperoxy tigliane diterpene (1) from the genus of Euphorbia. All compounds were evaluated for their antifungal activities.     

A new phenanthropyran and a new biphenanthrene from the rhizomes of Dioscorea septemloba and their antioxidant activities

Abstract

A new phenanthropyran, dioscorone B (1), and a new phenanthrene (2), together with seven known compounds (3–9), were isolated from the 75% ethanol extract of Dioscorea septemloba rhizomes. The chemical structures of these compounds were elucidated by comprehensive spectroscopic methods including NMR, HRESIMS, IR, and UV spectra. Compounds 1–5 were first isolated from genus Dioscorea. The proton and carbon chemical shifts of compounds 1–9 were unambiguously assigned based on the 1D-NMR and 2D-NMR data. Compounds 1–5 and 8–9 were first tested for their antioxidant activities. Compounds 1 and 2 showed excellent activities with IC₅₀ values of 0.07?±?0.10?μM and 0.13?±?0.09?μM, respectively.     

Two new secondary metabolites from a mangrove-derived fungus Cladosporium sp. JJM22

Two new compounds (1 and 2), together with six known compounds (3–8), were obtained from the Cladosporium sp. JJM22, an endophytic fungus isolated from the stem bark of the mangrove plant Ceriops tagal collected in South China Sea. Their structures were elucidated on the basis of detailed spectroscopic analysis. The absolute configurations of 1 and 2 were confirmed by the comparison of optical rotation and the CD data with those of known compounds. The inhibitory activities of the isolated compounds against six terrestrial pathogenic bacteria and human cervical carcinoma Hela cell line were evaluated. Compound 3 exhibited a broad spectrum of antibacterial activities.