A new antimicrobial and radical-scavenging glycoside from Paullinia pinnata var. cameroonensis

A new glycoside, pinnatoside A (1), together with two known compounds (2 and 3), were isolated from the stems of Paullinia pinnata. Their structures were elucidated on the basis of extensive spectroscopic analysis and chemical methods. Compound 1 showed significant antibacterial activity with a minimum inhibitory concentration (MIC) value of 1.56 μg/mL against Escherichia coli, and 2 displayed significant antibacterial activity with a MIC value of 1.56 μg/mL against Enterobacter aerogenes and E. coli. Equally, compound 1 exhibited the best radical-scavenging activity (RSa₅₀ = 25.07 ± 0.49 μg/mL).     

Antimicrobial compounds from root,stem bark and seeds of Melia volkensii

Three compounds, toosendanin (1), kulactone (2) and scopoletin (3), were isolated from either the root bark and/or the stem bark of Melia volkensii. Their structures were determined on the basis of spectroscopic data generated and by comparison with data from the literature. 1 and 2, isolated for the first time from M. volkensii, exhibited significant (p < 0.05) activity against Escherichia coli with minimum inhibitory concentration of 12.5 μg/mL, close to that of neomycin (6.25 μg/mL). The compounds also exhibited high activity against Aspergillus niger (MIC 6.25 μg/mL compared to 2.5 μg/mL for clotrimazole). Dichloromethane and methanol seed, hexane stem bark and methanol root bark extracts exhibited activities towards Escherichia coli, Staphylococcus aureus, Aspergillus niger and Plasmodium falciparum, respectively. Antimicrobial activity of the plant towards A. niger, P. falciparum and S. aureus is reported for the first time in the current work.     

Two new benzophenones and one new natural amide alkaloid isolated from a mangrove-derived Fungus Penicillium citrinum

Two new compounds penibenzophenones A-B (1–2), and the synthetic α,β-unsaturated amide alkaloid (E)-tert-butyl(3-cinnamamidopropyl)carbamate (4), newly identified as a natural product, alone with three known ones (3, 5–6) were isolated from the EtOAc extract of the endophytic fungus Penicillium citrinum HL-5126 isolated from the mangrove Bruguiera sexangula var. rhynchopetala collected in the South China Sea. Compound 1 was a chlorinated benzophenone. The structures of 1–6 were elucidated by extensive NMR spectral interpretation, MS data and X-ray analysis. The new compound 2 displayed cytotoxic activity against human A549 cell lines with an IC₅₀ value of 15.7 μg/mL, and 1 showed antibacterial activity against Staphylococcus aureus with a MIC value of 20 μg/mL.     

Chemical constituents of Genista numidica Spach aerial parts and their antimicrobial,antioxidant and antityrosinase activities

A previously undescribed triterpenoid saponin, 3-O-[α-l-rhamnopyranosyl-(1→2)-{β-d-glucopyranosyl-(1→6)-}β-d-galactopyranosyl-(1→2)-β-d-glucuronopyranosyl]-sophoradiol (1), in addition to twenty-nine known constituents (2–30) were isolated from the aerial parts of Genista numidica Spach. Structures elucidation was performed by comprehensive 1D- and 2D-NMR analyses and HRESIMS. The extracts, fractions and isolated compounds were evaluated for their antibacterial, antioxidant and tyrosinase inhibitory activities. The experimental findings indicated that genistin (16), isosalipurpol (27), and koaburaside (29) have moderate to low antibacterial activity against E. faecalis, S. aureus, S. epidermidis and P. aeruginosa bacteria with MICs ranging from 31.2 to 125 μg/mL. Compounds 19 and 27 exhibited a good antiradical activity potential (IC₅₀ 11.8 and 11.1 μg/mL, respectively). Only compounds 23, 27 and 28 exhibited low inhibitory effect against mushroom tyrosinase (IC₅₀ from 90.2 to 225.6 μg/mL).     

Guttiferone BL with antibacterial activity from the fruits of Allanblackia gabonensis

Allanblackia genus, an endless source of bioactive compounds, was investigated for its antibacterial properties. The chemical study of the methanol extract from the fruits of Allanblackia gabonensis resulted in the isolation of the undescribed guttiferone BL (1) along with the known kaempferol (2), morelloflavone (3), morelloflavone 7″-O-β-D-glucopyranoside (4), β-sitosterol 3-O-β-D-glucopyranoside and β-sitosterol. Their structures were determined using spectrometry and spectroscopic techniques. The antibacterial activity was evaluated against five Gram-negative and two Gram-positive strains using a broth micro-dilution method. Compounds displayed low to significant activity against the tested bacterial strains with MICs ranging from 8 to 512 μg/mL. Morelloflavone (3) presented significant activity against E. coli ATCC8739 (MIC = 8 μg/mL) while guttiferone BL (1) exhibited low activity (MICs = 256–512 μg/mL) against all the tested strains. The crude extract also had moderate to significant activity against the tested bacterial strains.     

A new naphthoquinone and other antibacterial constituents from the roots of Xanthium sibiricum

Reinvestigating the chemical constituents of the roots of Xanthium sibiricum led to the isolation of a new naphthoquinone (1), together with 13 known compounds (2–14). Their structures were elucidated by using spectroscopic analyses, including HR-ESI-MS, 1D and 2D NMR, and by comparing their NMR data with those of related compounds. Compound 1 showed moderate antibacterial activity against Escherichia coli, Bacillus subtilis, Micrococcus tetragenus and Staphylococcus aureus, while 6 and 12 showed stronger antibacterial activity than the positive control ciprofloxacin against E. coli, with minimum inhibitory concentration values of 0.17 and 0.35 μg/mL, respectively.     

A new sesquiterpene from the entomogenous fungus Phomopsis amygdali

A new sesquiterpene, (+)-S-1-methyl-abscisic-6-acid (1), together with five known compounds, (+)-S-abscisic acid (2), fusicoccin J (3), 3α-hydroxyfusicoccin J (4), (R)-5-hydroxymethylmellein (5) and 4-hydroxyphenethyl acetate (6) was isolated from the fermentation extract of Phomopsis amygdali, an entomogenous fungus isolated from Call midge. Their structures were determined mainly by analysis of MS and NMR spectroscopic data. Compounds 1–6 were tested for antimicrobial activity against three plant pathogenic fungi: Gibberella zeae, Verticillium albo-atrum, and Fusarium nivale, and two bacteria: Escherichia coli and Pseudomonas aeruginosa 2033E. As a result, compounds 1–4 displayed antibacterial activity against Gram-negative P. aeruginosa 2033E, and the minimum inhibition concentration (MIC value) of 1–4 is 30 μg/mL, 58 μg/mL, 26 μg/mL, and 26 μg/mL, respectively.     

One new flavonoid from Oroxylum indicum

One new flavonoid, 5,6,7-trimethoxyflavone-8-O-β-d-glucopyranoside (1), along with six known compounds 2–7, was isolated from Oroxylum indicum. Their structures were determined on the basis of spectral data. The antibacterial activities of compounds 1–4 were studied. Compounds 1 and 3 showed medium antibacterial activity against Staphylococcus aureus with MIC/MBC at 32–128 μg/ml.     

A novel xanthone dimer derivative with antibacterial activity isolated from the bark of Garcinia mangostana

A novel xanthone dimer derivative, garmoxanthone (1), together with 10 known compounds (2–11), were isolated from bark of Garcinia mangostana. Their structures were established through spectroscopic methods. Garmoxanthone exhibited strong inhibitory activities against MRSA ATCC 43300 and MRSA CGMCC 1.12409 (with MIC values of both 3.9 μg/mL) and moderate activities against tested strains of Vibrio (with MIC values ranging from 15.6 to 31.2 μg/mL). Garmoxanthone is a unique xanthone dimer with linkage of a fused 5/6 ring system and its absolute configuration was elucidated on the basis of experimental and calculated electronic circular dichroism. Garmoxanthone exhibited strong antibacterial activity which partially validated the ethnobotanical use of G. mangostana in the treatment of infections.     

Chemical composition,antioxidant and antibacterial properties of Pteranthus dichotomus from Algerian Sahara

The phytochemical study of ethyl acetate and n-butanol extracts of Pteranthus dichotomus Forssk. led to the isolation and identification of 11 compounds, including three glycolipids 1–3, one lignan 4, three flavonoids 5–7 and four phytosterols 8–11. Structures of the isolated compounds have been elucidated by analysis of 1D and 2D NMR data, and mass spectrometry EI-MS and ESI-MS and by comparison with literature data. Furthermore, the ethyl acetate and n-butanol extracts were examined for their antioxidant and antibacterial activities. The results showed that both extracts (PDAC and PDBU) had a moderate antioxidant activity (IC50 = 375.514 μg/mL and 691.333 μg/mL) respectively.     

Two thymol derivatives from the flower buds of Lonicera japonica and their antibacterial activity

A new monoterpenoid, 7-acetyl-8,9-dihydroxy thymol (1), together with a known one 7,8-dihydroxy-9-buyryl thymol (2), were isolated from the dried flower buds of Lonicera japonica Thunb. Their structures were elucidated on the basis of extensive 1D and 2D NMR spectroscopic data analyses. The potential antibacterial effects of these compounds on Staphylococcus aureus, Escherichia coli, Micrococcus luteus, and Bacillus cereus were evaluated. Interestingly, both compounds 1 and 2 exhibited significant antibacterial activities with IC₅₀ values range from 27.64 ± 2.26 to 128.58 ± 13.26 μg/mL.     

A new butenolide cinnamate and other biological active chemical constituents from Polygonum glabrum

Phytochemical investigation of the methanol extract of the aerial parts of Polygonum glabrum afforded one new natural product ( ? )-2-methoxy-2-butenolide-3-cinnamate (1) along with six known compounds, β-hydroxyfriedalanol (2), 3-hydroxy-5-methoxystilbene (3), ( ? ) pinocembrin (4), sitosterol-(6′-O-palmitoyl)-3-O-β-d-glucopyranoside (5), ( ? ) pinocembrin-5-methyl ether (6) and sitosterol-3-O-β-d-glucopyranoside (7). Compound 1 showed promising in vitro anti-HIV-1 activity against primary isolates HIV-1_UG070 (X4, subtype D) and HIV-1_VB59 (R5, subtype C) assayed using TZM-bl cell line with IC₅₀ in the range of 15.68–22.43 μg/mL. The extract showed TI in the range of 19.19–27.37 with IC₅₀ in the range of 10.90–15.55 μg/mL. Compounds 1, 3 and 4 exhibited in vitro anti-mycobacterium activity against Mycobacterium tuberculosis H37Ra with IC₅₀ values of 1.43, 3.33 and 1.11 μg/mL in dormant phase and 2.27, 3.33 and 1.21 μg/mL in active phase, respectively. Compound 4 was found to be the most active antiproliferative with IC₅₀ values of 1.88–11.00 μg/mL against THP-1, A549, Panc-1, HeLa and MCF7 cell lines.     

A new phthalide from the endophytic fungus Xylaria sp. GDG-102

A new phthalide derivative, xylarphthalide A (1), along with two known compounds (-)-5-carboxylmellein (2) and (-)-5-methylmellein (3), were isolated from the endophytic fungus Xylaria sp. GDG-102 cultured from the Chinese medicinal plant Sophora tonkinensis. Their structures were identified by MS and NMR experiments, and the absolute configuration of 1 was further confirmed by single-crystal X-ray diffraction analysis. Compound 1–3 showed antibacterial activities against Bacillus megaterium, Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Shigella dysenteriae with MIC values of 12.5–25 μg/mL.     

Hypocrol A,a new tyrosol derivative from a sponge-derived strain of the fungus Hypocrea koningii

In continuation of our search for new antibacterial and antioxidant metabolites from sponge-derived fungi, one new tyrosol derivative, hypocrol A (1), together with four known congeners, trichodenol B (2), 4-hydroxyphenethyl acetate (3), 4-hydroxyphenethyl tetradecanoate (4) and 1-oleyltyrosol (5), was isolated from the strain Hypocrea koningii PF04. Their planar structures were unequivocally elucidated by spectroscopic methods and comparison with the literature data. All the compounds displayed weak antibacterial activities against Staphylococcus aureus, methicillin-resistant S. aureus and Escherichia coli, whereas compounds 1 and 2 exhibited a moderate antioxidant efficacy in the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging assay with IC₅₀ values of 48.5 and 97.4 μg/mL, respectively.     

In vitro pharmacological screening of three newly synthesised pyrimidine derivatives

The antibacterial and antifungal activities of three new pyrimidine derivatives, namely, 2,6-bis(4,6-dimethylpyrimidin-2-ylthio)benzene-1,4-diol (1),3,5-bis(4,6-dimethylpyrimidin-2-ylthio)-2-methylbenzene-1,4-diol (2) and 3,5-bis(4,6-dimethylpyrimidin-2-ylthio)-2-methoxybenzene-1,4-diol (3), synthesised by electrochemical method are presented here. The compounds were screened for their activities against Gram-positive and Gram-negative bacteria, Bacillus subtilis, Staphylococcusaureus, Escherichia coli and a pathogenic fungus Aspergillus niger. The results show that these compounds have significant activity against these bacteria and fungus. The minimum inhibitory concentration of compound 1 was determined as 62.5 μg/mL against B. subtilis, 125 μg/mL against E. coli and 250 μg/mL against S. aureus establishing its promising activities higher than susceptible ranges.     

Antimicrobial activity and molecular docking studies of a novel anthraquinone from a marine-derived fungus Aspergillus versicolor

A novel anthraquinone, 2-(dimethoxymethyl)-1-hydroxyanthracene-9,10-dione (1), together with nine known compounds (2–10), were isolated from the fermentation of Aspergillus versicolor derived from deep sea sediment. Their structures were established through spectroscopic methods. Compound 1 exhibited strong inhibitory activities against MRSA ATCC 43300 and MRSA CGMCC 1.12409 (with MIC values of 3.9 and 7.8 μg/mL respectively) and moderate activities against tested strains of Vibrio (with MIC values ranging from 15.6 to 62.5 μg/mL). Compound 1 was subjected to molecular docking studies for inhibition of topoisomerase IV and AmpC β-lactamase enzymes indicating its usefulness as antimicrobial agent.     

Antibacterial triterpenoids from the leaves of Ilex hainanensis Merr.

One new triterpenoid (1) and seven known analogues (2–8) were isolated from the leaves of Ilex hainanensis Merr.. Their structures were established by analysis of their MS, 1D and 2D NMR spectroscopic data and comparison with those in the literature. The antibacterial activity of compounds 1–8 were evaluated by determination of minimum inhibitory concentration using twofold microdilution broth method against Streptococcus mutans ATCC 25175 (Gram-positive) and Fusobacterium nucleatum ATCC 10953 (Gram-negative). Compounds 3 and 5 showed significant antibacterial activity against S. mutans in concentration of 9.7 μg/mL, while showed little antibacterial activity against F. nucleatum. On the contrary, the inhibitory activity of compounds 1, 2 and 6 against F. nucleatum were higher than them against S. mutans.     

Structure activity relationship of bergenin,p-hydroxybenzoyl bergenin, 11-O-galloylbergenin as potent antioxidant and urease inhibitor isolated from Bergenia ligulata

Ethanol extract of the aerial parts of Bergenia ligulata was subjected to solvent–solvent separation followed by various chromatographic techniques that lead to isolation of bergenine (1), p-hydroxybenzoyl bergenin (2), 11-O-galloylbergenin (3) and methyl gallate (4) as major constituents. Ethyl acetate fraction showed a dose-dependent urease inhibitory pattern with IC₅₀ value of 54μg/mL. Structures of compounds 1 and 3 were established by XRD and 2, 4 by NMR. All these compounds were subjected to DPPH scavenging activity, reducing power assay and urease inhibitory activity. The EC₅₀ 7.45 ± 0.2 μg/mL and 5.39 ± 0.28 μg/mL values in terms of antioxidant and reducing power, respectively, were less for 3. Compounds 1–3 showed moderate to significant urease inhibitory potential with IC₅₀ 57.1 ± 0.7, IC₅₀ 48.4 ± 0.3 and 38.6 ± 1.5. Antioxidant activities and urease inhibitory potential were investigated and compound 3 was found to be the most active.     

Two new aromatic polyketides from a deep-sea fungus Penicillium sp. SCSIO 06720

Abstract

Two new compounds, 5-[2-hydroxypropane-1-yl]-2,6-dimethlbenzene-1,3-diol (1) and coniochaetone L (2), together with 19 known compounds (3–21), were isolated from a deep-sea fungus, Penicillium sp. SCSIO 06720. Their structures and absolute configurations were elucidated by detailed NMR, MS spectroscopic analyses, chiral-phase HPLC analysis, and electronic circular dichroism spectra. All the isolated compounds (1–21) were tested for their antibacterial and HIV latency-reversal activities. Among these compounds, compound 16 showed moderate antibacterial activities against Staphylococcus aureus ATCC 29213 and Methicillin-Resistant Staphylococcus Aureus-shh-1 with MIC values of 10.4?±?3.7?μg/mL and 46.9?±?29.7?μg/mL, respectively, which were comparable to that of the positive control ampicillin with MIC values of 0.5?±?0.4?μg/mL and 2.7?±?0.9?μg/mL, respectively.     

Penicillilactone A,a novel antibacterial 7-membered lactone derivative from the sponge-associated fungus Penicillium sp. LS54

One novel 7-membered lactone derivative, penicillilactone A (1), together with two known compounds, rugulosin A (2) and rugulosin (3) were isolated from the sponge-derived fungus Penicillium sp. LS54. Their structures were elucidated on the basis of spectroscopic analysis and comparison with literature data. Remarkably, penicillilactone A (1) is the first natural product containing a 7-membered lactone ring fused with a furan core. Penicillilactone A (1) exhibited moderate antibacterial activity against aquatic pathogen Vibrio harveyi with an MIC value of 8 μg/mL.