Four lignans from Portulaca oleracea L. and its antioxidant activities

Abstract

A new lignan, named oleralignan (1) and three known componds (+)-syringaresinol (2), (+)-lirioresinol A (3) and monomethyl 3,3′,4,4′-tetrahydroxy-δ-truxinate (4) were isolated from the P. oleracea for the first time. The compound (1) were identified by 1D, 2D NMR spectroscopic methods and high resolution electrospray ionization time-of-flight mass spectrometry. In addition, it was found that the four lignans presented the scavenging activities in 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical quenching assay more than that of hydroxyl anisole (BHA).

     

Prenylated isoflavones with potential antiproliferative activities from Mappianthus iodoides

Abstract

A phytochemical investigation on the stems of Mappianthus iodoides led to the isolation of a new naturally occurring prenylated isoflavone, mappianthone A (1), together with seven known analogues (2?8). The structure of 1 was elucidated by extensive spectroscopic methods and the known compounds were identified by comparison with data reported in the literature. All isolated compounds were evaluated for their antiproliferative activities against five human cancer cell lines: HL-60, SMMC-7721, A-549, MCF-7 and SW480 in vitro. Compounds 1?8 showed significant antiproliferative effects against several human cancer cell lines with IC₅₀ values ranging from 0.16 to 12.68?μM.

     

Isolation and characterization of flavonoids from the roots of medicinal plant Tadehagi triquetrum (L.) H.Ohashi

Abstract

Three flavonoid compounds were isolated from the roots of medicinal plant Tadehagi triquetrum (L.) H.Ohashi, also known as Desmodium triquetrum (Fabaceae). On the basis of the chemical and spectral analysis, the compounds were identified as baicalein (Flavone), naringin and neohesperidin (Flavonone). To the best of our knowledge and based on the literature survey all three compounds were first time reported from this medicinal plant.

     

α-Tetralone glycosides from the green walnut husks of Juglans mandshurica Maxim. and their cytotoxic activities

Abstract

Five new α-tetralone glycosides, juglanbiosides A-E (1–5), together with an α-tetralone derivative (15) and nine known 1,4-naphthoquinones (6–14) were isolated from the 95% EtOH extract of green walnut husks of Juglans mandshurica Maxim. Their structures were elucidated by comprehensive spectroscopic methods (¹H, ¹³C NMR, DEPT, HSQC, HMBC, CD, HR-ESI-MS). In vitro cytotoxicities of all the isolated compounds were evaluated against BGC-823, HCT-15 and K562 cancer cell lines.

     

A immunosuppressive triterpenoid saponin from the stems of Epigynum griffithianum

Abstract

Chemical investigation of the stems of Epigunum griffithianum led to the isolation and identification of a new triterpenoid saponin (1) and two known compounds (epigynosides A (2) and B (3)). These structures were elucidated by means of spectroscopic analysis (1D and 2D NMR, MS, UV, IR) as well as comparison with the reported data. Compound 1 was evaluated in vitro for the immunosuppressive activities on proliferation of mice splenocyte and displayed significant immunosuppressive activities compared to the positive control (dexamethasone) with the concentration at 25?μM.     

A rare diketopiperazine glycoside from marine-sourced Streptomyces sp. ZZ446

Abstract

Two diketopiperazines were isolated from a culture of the marine-derived actinomycete Streptomyces sp. ZZ446. Their structures were elucidated as maculosin (1) and maculosin-O-α-L-rhamnopyranoside (2) based on their NMR and HRESIMS data, specific rotation, and chemical degradation. Maculosin-O-α-L-rhamnopyranoside (2) is a new diketopiperazine glycoside, a structural class not reported previously from the natural sources. Both compounds showed antimicrobial activity against methicillin-resistant Staphylococcus aureus, Escherichia coli, and Candida albicans with MIC values in a range from 26.0 to 37.0?μg/mL.

     

Cytotoxic naphthoquinones from Arnebia densiflora (Nordm.) Ledeb and determining new apoptosis inducers

Abstract

In this study, phytochemical composition of Arnebia densiflora (AD) was determined and cytotoxic effects of the n-hexane extract and compounds isolated from this species on various cell lines were investigated. By means of serial chromatographic studies, 6 naphthoquinone derivatives were yielded, which are isovalerylalkannin, α-methyl-n-butyl alkannin, acetylalkannin, β-acetoxy isovalerylalkannin, alkannin and a new compound: 4-hydroxy 4-methyl valeryl alkannin. Structures of the isolated compounds were elucidated using UV, IR, 1D-2D NMR, MS and CD methods. Cytotoxic effects of the extract and isolated alkannins were investigated on L929, HeLa, HEp-2 cells. AD and the isolated compounds demonstrated moderate to strong cytotoxic effects (IC₅₀ range: 4.92-172.35?µg/ml). The results of DNA fragmentation and caspase-3 activity studies on HeLa cells exhibited that AD and the naphthoquinones isolated from it caused cytotoxicity through induction of apoptosis.

     

Isolation,characterization, and xanthine oxidase inhibitory activities of flavonoids from the leaves of Perilla frutescens

Abstract

Phytochemical investigation of the water extract from the leaves of Perilla frutescens (Lamiaceae) led to the isolation of a new flavanone, a new chalcone, and a new aurone, namely, (2S)-5,7-dimethoxy-8,4'-dihydroxyflavanone (1), 2',4'-dimethoxy-4,5',6'-trihydroxychalcone (2), and (Z)-4,6-dimethoxy-7,4'-dihydroxyaurone (3), respectively. The structures were unambiguously elucidated on the basis of spectroscopic data. And the absolute configuration of 1 was determined by analysis of electronic circular dichroism spectrum. The isolated compounds were evaluated for their inhibitory effects on xanthine oxidase in vitro. Among them, 2 showed more potent activity than the positive control allopurinol, a well-known XO inhibitor clinically used for treatment of gout. Lineweaver-Burk transformation of the inhibition kinetics data demonstrated that it was a mixed-type inhibitor.

     

Two new triterpenoids from Gardenia jasminoides fruits

A new cycloartane triterpenoid, named gardenolic acid C (1), a new ursane triterpenoid, named 3β,16β,21β,23,24-pentahydroxy urs-12,18,20-trien-28-oic acid γ-lactone (2), together with three know triterpenoids, gardenolic acid A (3), gardenolic acid B (4), and 3α,16β,23,24-tetrahydroxy-28-nor-ursane-12,17,19,21-tetraen (5) were isolated from the fruits of Gardenia jasminoides Ellis. The structures of these compounds were elucidated by analyses of spectroscopic data. All isolates were evaluated for their neuroprotective effects in vitro.

     

Synthesis and structure anti-inflammatory activity relationships studies of andrographolide derivatives

Abstract

Andrographolide is a main bioactive diterpene lactone in A. paniculata with anti-inflammatory activity. In this study, a series of andrographolide derivatives were synthesized and evaluated for their structure-anti-inflammatory activity relationships in vivo. Among all compounds, isoandrographolide and 14-deoxyandrographolide showed stronger anti-inflammatory activity than andrographolide. The results indicated that the introduction of tetrahydrofuran ring and cyclic olefinic bond plays an important role in enhancing the anti-inflammatory activity of andrographolide derivatives. Isoandrographolide and 14-deoxyandrographolide are potent inhibitor of inflammation.

     

Quassinoids from seeds of Brucea Javanica and their anticomplement activities

Abstract

An investigation on seeds of Brucea javanica led to the acquisition of a new quassinoid, 20-hydroxyyadanzigan (1), along with five known quassinoids (2–6). The structure of the new compound was elucidated on the basis of extensive spectral analysis. All of the compounds were assayed for their anticomplement activities through classical and alternative pathways. Compounds 1–6 exhibited potent anticomplement activity with CH₅₀ and AP₅₀ values of 0.032–0.075?mg/mL and 0.061–0.118?mg/mL, respectively. Moreover, the structure-activity relationships of these compounds are discussed.

     

Neuroprotective terpenoids from the leaves of Viburnum odoratissimum

Abstract

As a part of our ongoing search for neuroprotective compounds from natural products, two new iridoid glycosides, vibsansuspenside A-B (1-2), along with five known terpenoids (3-7), were isolated from the dry leaves of Viburnum odoratissimum. Their chemical structures were well determined by means of NMR spectroscopic data as well as HRESIMS analysis. All compounds were detected for their neuroprotective effects against H₂O₂-induced damage in human dopaminergic neuroblastoma cells (SH-SY5Y). Among them, compound 3 displayed the most potent neuroprotective ability, and further investigation by Annexin V/PI and Western blot analysis demonstrated that compound 3 could protect SH-SY5Y cells from oxidative damage through inhibiting cell apoptosis.

     

Chemical composition,UV/vis absorptivity,and antioxidant activity of essential oils from bark and leaf of phoebe zhennan S. K. Lee & F. N. Wei

Abstract

The chemical composition of essential oils (EO) from bark and leaf of P. zhennan was identified by GC-MS. The compounds of α-calacorene, τ-cadinol, β-eudesmol and d-cadinene were found in the essential oils from both bark and leaf. The UV-Vis spectra results indicated the EO could completely absorbed the UV light at the wavelength range of 200-370?nm, revealing that EO had great potential as additives for manufacturing UV light blocking products. The radical DPPH scavenging activity assay showed that both the bark and leaf EO possessed strong DPPH radical scavenging activity of 90.25% and 82.10% respectively, which provides an important theoretical guiding in exploiting the value of P. zhennan bark and leaf.

     

Microbial transformation of isocoronarin D by Cunninghamella echinulata NRRL 1386

The diterpene isocoronarin D (1) is a bioactive major constituent of labdane diterpene from the aerial parts of Curcuma comosa Roxb. (Zingiberaceae), the Thai medicinal plant. Microbial transformation of 1 was performed by the fungus Cunninghamella echinulata NRRL 1386 to yield three new metabolites, 3β-hydroxyisocoronarin D (2), 6α-hydroxyisocoronarin D (3) and 3β,7α-dihydroxyisocoronarin D (4). The structures of the new compounds were elucidated by spectroscopic techniques.

     

The absolute configuration of anti-Vibrio citrinin dimeric derivative by VCD,ECD and NMR methods

Citrinin dimeric derivatives are bioactive polyketides previously reported from Penicillium, Aspergillus and Monascus fungi species. Due to the large distance between the stereogenic centers of the two monomer units, it was difficult to determine the absolute configuration of the whole molecule (1). In previous work, the absolute configuration of 1 was just proposed by biogenetic considerations. To address this problem, the experimental VCD of 1 was compared with the corresponding DFT calculations for two diastereomers (1a and 1b). Also, the experimental ECD and NMR spectra of 1 were combined for analysis with the corresponding theoretical predictions for different diastereomers. Additionally, compound 1 showed promising anti-Vibrio activity against pathogenic Vibrio spp. with MIC values ranging from 0.4 to 0.8?μM.

     

Silychristin derivatives conjugated with coniferylalcohols from silymarin and their pancreatic α-amylase inhibitory activity

Abstract

Silymarin is a mixture of flavonolignans extracted from the fruit of Silybum marianum (milk thistle). The latter is used as a medicinal plant to treat liver and gallbladder disorders. Recently, silymarin has been investigated for its effects against diabetes mellitus, and shown to reduce serum levels of glucose in model animals and in clinical trials. This effect can be explained mainly by the protective effect of silymarin against pancreatic beta-cells, but the involvement of other mechanisms is possible. We demonstrated the α-amylase inhibitory activity of silymarin and investigated the components responsible for this effect. Two major flavonolignans, silibinin and silychristin, did not show inhibition against α-amylase, but two novel silychristin derivatives conjugated with dehydrodiconiferyl alcohol were isolated as the mildly inhibiting components of silymarin. Further analyses indicated the presence of various silychristin derivatives in silymarin that may act synergistically to show α-amylase inhibitory activity.

     

A new 5α,8α-epidioxysterol with immunosuppressive activity from the South China Sea soft coral Sinularia sp.

Abstract

A new 5α,8α-epidioxysterol, namely yalongsterol A (1), along with two known related steroids 5α,8α-epidioxy-24-methyl-cholesta-6,24(28)-dien-3β-ol (2) and (22E,24S)-5α,8α-epidioxy-24-methyl-cholesta-6,22-dien-3β-ol (3), were isolated from the South China Sea soft coral Sinularia sp. Their structures were established by extensive spectroscopic analyses and comparisons of the spectral data with those reported in the literature. In bioassay, compounds 1–3 showed moderate immunosuppressive activities against T and/or B lymphocyte cells with IC₅₀ values ranging from 19.30 to 59.49 μM, and low cytotoxicity on murine splenocytes with CC₅₀ values ranging from 40.88 to 62.29 μM.

     

Volatiles composition and antioxidant activity Inula oculus-christi L. from Serbia

Abstract

The chemical composition of the essential oil and the volatiles obtained by static headspace (HS) of Inula oculus-christi L. is presented. The GC-MS analysis of the hydrodistilled oil resulted in the identification of 90 components, representing 92.7% of the oil. The most abundant compounds were: caryophyllene oxide (9.8%), trans-longipinocarveol (9.2%), eucalyptol (7.3%) and intermedeol (6.2%). The major constituent of I. oculus-christi L. HS volatiles was eucalyptol (87.4%). The antioxidant activity was evaluated by four different methods: 2,2-diphenyl-1-picryl-hydrazylhydrate free radical assay (DPPH), 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) method, total reducing power (TRP), ferric reducing antioxidant power (FRAP), and cupric reducing antioxidant capacity (CUPRAC). Total phenolic content in (TPC) examined oil was 177.95?µg GAE/mg oil. Radical scavenging potential of the oil was promising RSC-DPPH was 57.4% and RSC-ABTS was 82.7%.

     

Antimicrobial secondary metabolites of an endolichenic Aspergillus niger isolated from lichen thallus of Parmotrema ravum

Abstract

A new 6-benzyl-γ-pyrone (1), named aspergyllone was isolated from the culture filtrates of an endolichenic fungus Aspergillus niger Tiegh, obtained from lichen thallus Parmotrema ravum (Krog & Swinscow) Serus, collected in India. 1 was isolated for the first time from an endolichenic fungus together with six other known metabolites identified as aurasperones A (2) and D (3), asperpyrone A (4), fonsecinone A (5), carbonarone A (6) and pyrophen (7). The compounds were tested against a panel of human, plant, food borne and fish pathogens. Aspergyllone showed strong selective antifungal activity against Candida parapsilosis (Ashford) Langeron & Talice, with an IC₅₀ of 52?µg/mL. Aurasperone A and pyrophen showed moderate to strong antimicrobial activity inhibiting seven different test pathogens, being pyrophen active with IC₅₀ ranging from 35 to 97?µg/mL.

     

Influence of new effective allelochemicals on the distribution of Cleome arabica L. community in nature

Abstract

New allelochemicals were identified through bio-guided fractionation from the ethyl acetate of seeds extracts, which was the most autotoxic compared to the other plant parts. Phytochemical investigation of the seeds extracts of C. arabica by spectroscopy analyses has led to identify two new dammarane type triterpenes (4 and 9), with nine known analogues (1???3, 5???8, 10 and 11), a new cucurbitane triterpene (12), acylated dehydrodiconiferyl alcohol (13), and three highly oxygenated flavonols (14?16). The most autotoxic compounds on germination and seedling growth were elucidated as dammarane type triterpenes. However, less autotoxic effect was recorded by an inhibition under 50% for most of the identified flavonoids. These results suggest that those autotoxic substances may be used as a new bio-herbicide that may contribute to manage the distribution of C. arabica in agronomic field.