One new α-pyrone and one new fatty acid derivative from mangrove-derived fungus Phomopsis sp. HYP11

One new α-pyrone derivative (S)-3-(4-methoxy-3-methyl-2-oxo-2H-pyran-6-yl)butyl acetate (1) and one new fatty acid derivative (4S,5S)-5-acetoxy-4-hydroxyhexanoic acid (2), along with six known compounds (3–8) were obtained from the mangrove-derived fungus Phomopsis sp. HYP11. Their structures and absolute configurations were determined by detailed 1D and ²D NMR, HR-ESI-MS spectral, and quantum chemical electronic circular dichroism (ECD) calculations. Compounds 2, 3, 5, 6 and 8 showed antioxidant activity with the IC₅₀ values range of 0.09–0.67 mM, especially compounds 5 and 6 showed stronger antioxidant activity than the positive control trolox (IC₅₀ = 0.29 mM). Compound 8 showed weak antagonistic effect on Ralstonia solanacearum with the MIC value of 50 μg/mL.     

Two new polyhydroxylated steroidal glycosides from Paris polyphylla var. yunnanensis

Chemical investigation of Paris polyphylla smith var. yunnanensis afforded two new polyhydroxylated steroidal glycosides, named Parisyunnanosides K and L (1–2), together with nine known ones. The chemical structures of the new compounds were elucidated by 1D, 2D NMR and HR-ESI-MS techniques, together with chemical methods. Parisyunnanosides K and L (1–2) are rare C₂₇ steroidal glycosides with two double bonds located at C-5, 6 and C-25, 26 of the aglycone, respectively. The cytotoxic activities of the isolated compounds were evaluated against Caco-2 cells by CCK-8 assay. Among them, compounds 5–11 exhibited potent cytotoxic activity with IC₅₀ values ranging from 1.10 to 14.14 μM compared with the positive control oxaliplatin (1.38 μM).     

Antioxidant metabolites from marine alga-derived fungus Aspergillus wentii EN-48

Eight secondary metabolites (1–8) including a new seco-anthraquinone (wentiquinone C, 1) and a new benzamide derivative (methyl 4-(3,4-dihydroxybenzamido)butanoate, 2), as well as three other derivatives (4, 7, and 8) that were isolated from natural source for the first time, were characterized from the EtOAc extracts of the marine alga-derived endophytic fungus Aspergillus wentii EN-48. The structures of the isolated compounds were elucidated on the basis of 1D and 2D NMR experiments. Each of the isolated compounds was evaluated for α,α-diphenyl-picrylhydrazyl (DPPH) radical scavenging activity, and some of them showed potent activities with IC₅₀ values ranging from 5.2 to 99.4 μg/mL, compared to the positive control, butylated hydroxytoluene (BHT), with an IC₅₀ of 36.9 μg/mL.     

Antiplasmodial β-triketones from the flowers of the Australian tree Angophora woodsiana

Chemical investigations of the MeOH extract of air dried flowers of the Australian tree Angophora woodsiana (Myrtaceae) yielded two new β-triketones, woodsianones A and B (1, 2) and nine known β-triketones (3–11). Woodsianone A is a β-triketone-sesquiterpene adduct and woodsianone B is a β-triketone epoxide derivative. The structures of the new and known compounds were elucidated from the analysis of 1D/2D NMR and MS data. The relative configurations of the compounds were determined from analysis of ¹H–¹H coupling constants and ROESY correlations. All compounds (1–11) had antiplasmodial activity against the chloroquine sensitive strain 3D7. The known compound rhodomyrtone (5) and new compound woodsianone B (2) showed moderate antiplasmodial activities against the 3D7 strain (1.84 µM and 3.00 µM, respectively) and chloroquine resistant strain Dd2 (4.00 µM and 2.53 µM, respectively).     

New bioactive natural products from Launaea nudicaulis

Ethyl acetate soluble fraction of methanolic extract of Launaea nudicaulis was subjected to chromatographic purification to get four new compounds including a quinic acid derivative (1), a pentahydroxy acetylene analog: trideca-12-ene-4,6-diyne-2,8,9,10,11-pentaol (2), a flavone glycoside (3) and a sesquiterpene lactone (4) together with 10 known compounds. The structures of the new isolates were established by using 1D, 2D NMR techniques and high-resolution mass spectrometry, whereas, the known isolates were identified based on 1D NMR and mass spectrometric information and in comparison with the reported data in the literature. The structure of 4 was also confirmed through single X-ray crystallographic analysis. Cholistaquinate (1) exhibited significant activity in DPPH free radical scavenging assay with an IC₅₀ value of 60.7 μM, whereas, nudicholoid (4) exhibited a moderate inhibitory activity against the enzyme butyrylcholinesterase with an IC₅₀ value of 88.3 μM.     

Tanzawaic acid derivatives from a marine isolate of Penicillium sp. (SF-6013) with anti-inflammatory and PTP1B inhibitory activities

Chemical investigation of a marine-derived fungus Penicillium sp. SF-6013 resulted in the discovery of a new tanzawaic acid derivative, 2E,4Z-tanzawaic acid D (1), together with four known analogues, tanzawaic acids A (2) and D (3), a salt form of tanzawaic acid E (4), and tanzawaic acid B (5). Their structures were mainly determined by analysis of NMR and MS data, along with chemical methods. Preliminary screening for anti-inflammatory effects in lipopolysaccharide (LPS)-activated microglial BV-2 cells showed that compounds 1, 2, and 5 inhibited the production of nitric oxide (NO) with IC₅₀ values of 37.8, 7.1, and 42.5 μM, respectively. Compound 2 also inhibited NO production in LPS-stimulated RAW264.7 murine macrophages with an IC₅₀ value of 27.0 μM. Moreover, these inhibitory effects correlated with the suppressive effect of compound 2 on inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression in LPS-stimulated RAW264.7 and BV2 cells. In addition, compounds 2 and 5 significantly inhibited the activity of protein tyrosine phosphatase 1B (PTP1B) with the same IC₅₀ value (8.2 μM).     

Norlignan glycosides from the leaves of Molineria latifolia

Two new norlignan glycosides, molinerioside D (5) and molinerioside E (9), were isolated from the methanol extract of fresh leaves of Molineria latifolia. Their structures were determined using spectroscopic evidence, such as 1D and 2D NMR and HR-ESI-MS studies. The structure of molinerioside D (5) was determined to be a norlignan glycoside with a C6-C5-C6 skeleton, while the structure of molinerioside E (9) was determined to be a glucosyl-fused norlignan derivative. In addition to the new compounds, twenty known compounds were found in the extract of M. latifolia fresh leaves.     

Formyleleganolone and bibifuran,two metabolites from the brown alga Bifurcaria bifurcata

Two new diterpenoids formyleleganolone (1) and bibifuran (2) were isolated from a sample of the brown alga Bifurcaria bifurcata collected near Roscoff (Brittany, France). The structures of the new compounds were established on the basis of 1D and 2D NMR spectroscopic and mass spectrometric (ESI and EI) analyses. Formyleleganolone (1) is derived from eleganolone (4) by formylation of the hydroxy group. Bibifuran (2) has been identified as a new furan derivative of 4. Additionally, the diterpenoid 16-hydroxygeranylgeraniol (3) is reported for the first time from this species.     

Chemical constituents from the stems of Alyxia schlechteri

The extraction of the stems of Alyxia schlechteri and then using chromatographic separation and recrystallization afforded 2 new compounds, a benzyl coumarin derivative named alyterinin (1) and a germacrane sesquiterpene named alyterinone (2). In addition, 20 known compounds were discovered from the stems of this plant. Mosher's method was used to identify the absolute configuration of 2. Ficusequilignan A (12) showed strong antifungal activity against Pythium insidiosum. Structural determination of all compounds was accomplished by 1D and 2D NMR, IR and MS spectrometry.     

Polyoxygenated seco-cyclohexenes and other constituents from Uvaria valderramensis

Phytochemical study on the Philippine endemic Annonaceae plant Uvaria valderramensis afforded a new highly oxygenated seco-cyclohexene derivative, valderepoxide (1), along with the six known compounds uvamalols D (2) and G (3), grandiuvarone (4), 2′-hydroxy-3′,4′,6′-trimethoxychalcone (5), valderramenol B (6) and benzoic acid. The structure of 1 was determined through extensive spectroscopic analyses including 1D, 2D NMR and HRESIMS. Its relative stereochemistry was established using 2D-NOESY. This is the first report on the isolation of polyoxygenated compounds 1–3 and chalcone 5 from U. valderramensis.     

Secondary metabolites produced by the fungus Monascus pilosus and their anti-inflammatory activity

A detailed phytochemical study of the n-BuOH-soluble fraction of the 95% EtOH extract of red yeast rice fermented with the fungus Monascus pilosus BCRC 38072 (Eurotiaceae) revealed a new azaphilone derivative, namely monascusazaphilol (1) (rel-(3S,3aR,9aR)-3-(1-hydroxydecyl)-9a-methyl-6-((E)-propenyl)-3a,4,8,9a-tetrahydro-3H-furo[3,2-g]isochromene-2,9-dione), along with ten known compounds (2–11). Their structures were established by direct interpretation of their spectral data, mainly high resolution electrospray ionization mass spectrometry (HR-ESI-MS), 1D and 2D NMR (COSY, ROESY, HSQC and HMBC), and comparison of the spectroscopic data with those reported for structurally related compounds. We also evaluated the inhibitory effects of some isolates on the production of tumor necrosis factor (TNF-α) induced by lipopolysaccharide (LPS). Among the isolates, compounds 1–3 inhibited TNF-α production in U937 cells in vitro, and the IC₅₀ values were 1.24, 2.35 and 3.75 μg/ml, respectively.     

Stigmastane derivatives from the roots of Vernonia guineensis and their antimicrobial activity

Chemical investigation of the roots of Vernonia guineensis (Asteraceae) afforded a new stigmastane derivative, vernoguinoside A (1) and the known vernoguinoside (2), stigmasterol 3-O-β-d-glucoside (3) and sitosterol 3-O-β-d-glucoside (4). Their structures were elucidated by spectroscopic analysis. Antimicrobial activities of 1–3 and CH₂Cl₂–MeOH (1:1) extract were evaluated against three bacteria species (Salmonella typhi, Staphylococcus aureus and Shigella flexneri) and three yeasts species (Candida albicans, Candida parapsilosis and Cryptococcus neoformans). Compounds 1 and 2 exhibited both antibacterial and antifungal activities that varied between the microbial species (MIC = 7.81–125 μg/mL) while S. flexneri and C. albicans were sensitive to all the tested compounds.     

Isochroman and isocoumarin derivatives from hypersaline lake sediment-derived fungus Penicillium sp.

Chromatographic analysis of the ethyl acetate extract of the fungus Penicillium sp., which was isolated from the sediment of the hyper saline lake Wadi El-Natrun in Egypt, afforded two new isochromans (1 and 2) and a new isocoumarin derivative (3), along with six known compounds (4–9). The planar structures of new compounds were unequivocally elucidated on the basis of extensive 1D- and 2D-NMR spectroscopy as well as HRESIMS. The relative configurations of the new compounds were established by analysis of the coupling constants as well as through ROESY experiments, while the absolute configurations were determined by comparison of the [α]_D values and by plausible biosynthetic considerations. Compounds (1–6) were found to share (3S) configuration. All compounds demonstrated a weak to moderate cytotoxic activity against the murine lymphoma L5178Y cell line.     

Nitric oxide inhibitory constituents from Siegesbeckia pubescens

Two new sesquiterpenoids (1 and 2) and a new ent-pimarane type diterpenoid (3), together with eighteen known compounds (4–21), were isolated from the whole plants of Siegesbeckia pubescens. The structures of the new compounds were determined on the basis of 1D-, 2D NMR and HRESIMS data. All compounds were evaluated for their inhibitory effects on LPS-induced nitric oxide production in RAW 264.7 macrophages. Of these, highly oxygenated germacrane type sesquiterpenoids (1–2 and 13–14) showed significant inhibitory effects with IC₅₀ values ranging from 3.9 to 16.8 μM.     

Anti-inflammatory activity of flavonoids from Chrozophora tinctoria

Chemical investigation of Chrozophora tinctoria (L.) A. Juss. growing in Saudi Arabia revealed the isolation of two new acylated flavonoids identified as acacetin-7-O-β-d-[α-l-rhamnosyl(1 → 6)]3″-E-p-coumaroyl glucopyranoside (4) and apigenin-7-O-(6″-Z-p-coumaroyl)-β-d-glucopyranoside (5), in addition to amentoflavone (1), apigenin-7-O-β-d-glucopyranoside (2), apigenin-7-O-6″-E-p-coumaroyl-β-d-glucopyranoside (3) and rutin (6). The structures of isolated compounds were established by 1D, 2D NMR and HRESIMS spectral data, in addition to comparison with literature data. The anti-inflammatory activities of isolated compounds were assessed by measuring the levels of IL-1β, IL-6, TNF-α and PGE₂ in the supernatant media of human peripheral blood mononuclear cells (PBMCs) stimulated by phytohaemagglutinin (PHA). At a concentration of 100 μM, compounds 1, 2, 4 and 6 significantly decreased Il-1β, Il-6 and PGE₂ to nearly normal values. All tested compounds caused a dose-dependent decrease in TNF-α level but failed to reach that of the control values.     

Two new butanolides from the roots of Litsea acuminata

Two new butanolides, licunolides A (1) and B (2), were isolated from the roots of Litsea acuminata, together with three known compounds: isolancifolide (3), longifolin (4), and sesquirose furan (5). The structures of compounds 1 and 2 were determined by spectroscopic studies (IR, MS, 1D and 2D NMR) and chemical evidence. This is the first report of 4-hydroxy-5-methylbutanolides with a C₁₀-side chain from a natural source. Longifolin (4) and sesquirose furan (5) showed a significant cytotoxicity against HeLa cell lines in vitro.     

Eight new monoterpene acylglucosides from Sibiraea angustata

Chemical investigation of the aqueous extract of the aerial portion of Sibiraea angustata led to the isolation of eight new monoterpene acylglucosides named sibiraglucoside A–H (1–8) and two known monoterpenes, sibiraic acid (9) and sibiskoside (10). Their structures were elucidated through extensive spectroscopic data analysis (including 1D and 2D NMR and HRESIMS experiments) and compared to literature data. In the in vitro bioassay, all of the compounds showed moderate hypolipidemic effects.     

Novel tetrahydrofuran derivatives from Trigonostemon howii with their potential anti-HIV-1 activities

A novel tetrahydrofuran derivative, trigonohowine (1), together with five known tetrahydrofuran derivatives (2–6), were isolated from the stems and leaves of Trigonostemon howii. The structure of 1 was elucidated by extensive spectroscopic methods and the known compounds were identified by comparisons with the data reported in literature. Among them, trigonohowine (1) represents the first example of a new type of tetrahydrofuran derivative, possessing an unprecedented carbon skeleton containing 23 carbon atoms on the carbon skeleton and the known compouds (2–6) are rare tetrahydrofuran derivatives in the plant kingdom with various carbon skeletons. All isolated compounds were evaluated for their anti-HIV-1 activities. Compounds 1–6 showed significant anti-HIV-1 activities with EC₅₀ ranged from 0.08 to 1.03 µM. These findings suggest that the discoveries of these tetrahydrofuran derivatives with significant anti-HIV-1 activities isolated from T. howii could be of great importance to the development of new anti-HIV agents.     

Aegyptolidines A and B: New pyrrolidine alkaloids from the fungus Aspergillus aegyptiacus

Chemical examination of the fungus Aspergillus aegyptiacus isolated from cotton textile yielded two new pyrrolidine alkaloids: aegyptolidine A (3) and aegyptolidine B (4), together with two known ophiobolin sesterterpenoids: (±)-5-deoxovariecolin (1) and variculanol (2). Compound 1 is reported for the first time from a natural source. The structures of the isolated compounds were unambiguously elucidated on the basis of extensive spectroscopic data analysis (1D (¹H and ¹³C) and 2D (¹H–¹H COSY, HMQC, HMBC, and NOESY) NMR, MS, IR, and UV) and comparison with literature data. Compounds 1 and 2 showed moderate cytotoxic activity against murine lymphoma cancer cell line L5178Y with ED₅₀ 7.6 and 8.1 μg/mL, respectively.     

Ulmosides A and B: Flavonoid 6-C-glycosides from Ulmus wallichiana,stimulating osteoblast differentiation assessed by alkaline phosphatase

Chemical investigation of Ulmus wallichiana stem bark resulted in isolation and identification of three new compounds (2S,3S)-(+)-3′,4′,5,7-tetrahydroxydihydroflavonol-6-C-β-d-glucopyranoside (1), (2S,3S)-(+)-4′,5,7-trihydroxydihydroflavonol-6-C-β-d-glucopyranoside (3) and 3-C-β-d-glucopyranoside-2,4,6-trihydroxymethylbenzoate (8), together with five known flavonoid-6-C-glucosides (2, 4–7). Their structures were elucidated using 1D and 2D NMR spectroscopic analysis. The absolute stereochemistry in compounds 1 and 3 were established with the help of CD data analysis and comparison with the literature data analysis. All the isolated compounds (1–8) were assessed for promoting the osteoblast differentiation using primary culture of rat osteoblast as an in vitro system. Compounds 1–3 and 5 significantly increased osteoblast differentiation as assessed by alkaline phosphatase activity.