A new alkylbenzoquinone from Embelia rowlandii Gilg. (Myrsinaceae)

A new alkylbenzoquinone named embeliquinone (1) together with five known compounds, lupeol (2), 3-O-[6′-O-palmitoyl-β-d-glucosyl]-spinasta-7,22(23)-diene (3), quercetin (4), (2S,3S,4R,8E)-2-[(2′R)-2′-hydroxy-heneicosanoylamino]-heneicosane-1,3,4-triol-8-ene (5), and β-sitosterol-3-O-β-d-glucopyranoside (6) were isolated from the MeOH leaf extract of Embelia rowlandii by using repeated open column chromatography techniques. The structure of the new compound was characterized by analyses of 1D- and 2D-NMR, and MS data. Embeliquinone (1) had moderate anti-cell proliferation activity against A549 cell line with the IC₅₀ value of 21.8 μM. In addition, 1 exhibited weak antibacterial activities against Klebsiella pneumoniae and Staphylococcus aureus with an MIC value of 206.0 μM in both cases.     

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.     

A new benzopyrans derivatives from a mangrove-derived fungus Penicillium citrinum from the South China Sea

One new benzopyran derivative (2R^*,4R^*)-3,4-dihydro-5-methoxy-2-methyl-2H-1-benzopyran-4-ol (1), together with five known compounds (2?6), were obtained from the EtOAc extract of the endophytic fungus Penicillium citrinum HL-5126 isolated from the mangrove Brguiera sexangula var. rhynchopetala collected in the South China Sea. Their structures were elucidated by the detailed analysis of comprehensive spectroscopic data. All compounds were evaluated for their antibacterial activities. Compound 6 exhibited potent inhibitory activity against Bacillus subtilis, Bacillus cereus and Micrococcus tetragenus with the same MIC values of 6.94 μM.     

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.     

Terrenolide S,a new antileishmanial butenolide from the endophytic fungus Aspergillus terreus

Terrenolide S, a new butenolide derivative (6), together with six known compounds: (22E,24R)-stigmasta-5,7,22-trien-3-β-ol (1), stigmast-4-ene-3-one (2), stigmasta-4,6,8(14),22-tetraen-3-one (3), terretonin A (4), terretonin (5) and butyrolactone VI (7) have been isolated from the endophytic fungus Aspergillus terreus isolated from the roots of Carthamus lanatus (Asteraceae). Their structures were established by extensive spectroscopic analyses (1D, 2D NMR and HRESIMS), as well as optical rotation measurement and comparison with literature data. Compound 1 displayed a potent activity towards methicillin-resistant Staphylococcus aureus (MRSA) and Cryptococcus neoformans with IC₅₀ values of 2.29 and 10.68 µM, respectively. Moreover, 1, 2 and 6 exhibited antileishmanial activity towards Leishmania donovani with IC₅₀ values of 11.24, 15.32 and 27.27 µM, respectively and IC₉₀ values of 14.68, 40.56 and 167.03 µM, respectively.     

Acetylcholinesterase inhibitory active metabolites from the endophytic fungus Colletotrichum sp. YMF432

An endophytic fungus, Chaetomium sp. YMF432, was isolated from Huperzia serrata (Thunb. ex Murray) Trev. and subjected to phytochemical investigation based on its special environment. From the extracts of fermentation solid of strain YMF 432, eight compounds including 1-O-methylemodin (1), 5-methoxy-2-methyl-3-tricosyl-1,4-benzoquinone (2), 4,8-dihydroxy-1-tetralone (3), (3β,5α,6α, 22E)-3-hydroxy-5,6-epoxy-7-one-8(14),22-dien-ergosta (4), ergosta-4,6,8(14),22-tetraen-3-one (5), β-sitostenone (6), β-sitosterol (7) and (22E,24R)-ergosta-5,7,22 -trien-3β-ol (8) were obtained. Their structures were elucidated on the basis of their spectroscopic data. These compounds were evaluated for acetylcholinesterase inhibitory activities in vitro. Compounds 1, 2, and 4 showed moderate acetylcholinesterase inhibitory activities (IC₅₀ from 37.7 ± 1.5 to 370.0 ± 2.9 μM).     

Chemical and biological studies on Bridelia ferruginea grown in Nigeria

Phytochemical investigation of the methanolic extract of dried leaves of Bridelia ferruginea led to the isolation and identification of fourteen compounds (1–14): compound 1 [mixture of palmitic, stearic and oleic acids], stearyl monoester of 2-O-β-?-glucosylglycerol (2), 6β-hydroxy-(20R)-24-ethylcholest-4-en-3-one (3a), 6β-hydroxy-(20R)-24-ethylcholest-4,22-dien-3-one (3b), lutein (4), vomifoliol (5), corilagin (6), kaempferide-3-O-β-?-glucoside (7), myricetin (8), isomericitrin (9), isoquercetin (10), myricitrin (11), quercitrin (12), rutin (13), and β-sitosterol glucoside (14). The total extract exhibited moderate activity towards CB2 receptor and 90% inhibition against leishmanial pathogen Trypanosoma brucei. Compound 4 exhibited 73% displacement in CB2 receptor with IC₅₀ 56.47 μM, and 93% inhibition towards T. brucei with IC₅₀ 4.16 μM. Compound 11 showed 99% inhibition towards Escherichia coli with IC₅₀ 1.123 μM.     

Spectroscopic characterisation of two polyketide metabolites from Cylindrocarpon sp. from driftwood

Two new polyketides, (5R,7R,9R)-7,9-dihydroxy-5-decanolide and (4E,6R,9R)- 6,9-dihydroxydec-4-enoic acid (2), were isolated from rice cultures of Cylindrocarpon sp. SY-39 discovered during screening of driftwood at a Shonai coast area in Yamagata, Japan. The structures of 1 and 2 were determined using a variety of spectroscopic methods. Compound 2 exhibited moderate antimicrobial activity against Staphylococcus aureus NBRC 13276 and Aspergillus clavatus F 318a at a concentration of 50 μg per disk.     

Uncommon secondary metabolites from Etlingera pavieana rhizomes

From the rhizomes of Etlingera pavieana (Pierre ex Gagnep.) R.M. Sm., four phenylpropens, (E)-3-(4-methoxyphenyl)prop-2-en-1-amine (1), (E)-4-methoxycinamaldehyde (2), (E)-4-methoxycinamic acid (3) and (E)-1-methoxy-4-(3-methoxyprop-1-enyl)benzene (4), together with two other compounds, (E)-((E)-3-(4-methoxyphenyl)allyl)3-(4-hydroxyphenyl)acrylate (5) and 4-methoxybenzoic acid (6) were isolated. This is the first report on the presence of all compounds in Etlingera. Compounds 1 and 5 have been previously synthesised, but this is the first report of their isolation from a natural source. Compound 5 exhibited weak activity against Mycobacterium tuberculosis with MIC 50.00 μg/mL and cytotoxic activity against the KB, MCF7 and NCI-H187 cells with IC₅₀ values of 25.11, 20.16 and 34.83 μg/mL, respectively.     

Two new isochromane derivatives penisochromanes A and B from ascidian-derived fungus Penicillium sp. 4829

Seven polyketides, including two new isochromanes, penisochromanes A and B (1 and 2), as well as five known compounds were obtained from an ascidian-derived fungus Penicillium sp. 4829. Their structures were identified by extensive spectroscopic analyses. The structures of compounds 1 and 3 were further determined by the X-ray crystallography. Compounds 1 and 2 were the first example of isochromane with three adjacent oxy substituents in natural source. Compound 4 exhibited selective activities against two Gram-positive bacteria Staphylococcus aureus and Bacillus subtilis, with MIC values 6.25 and 12.5 μM, respectively.     

Two new steroids with cytotoxicity from the marine sponge Dactylospongia elegans collected from the South China Sea

A new steroid, (3S,5R,9R,10S,13R,17R,20R,24S,22E)-ergosta-6,8,22-triene-3,25-diol (1), and its sulfonated analogue (2) together with a known one, 5α,8α-epidioxy-cholest-6-en-3β-ol (3) were isolated from the marine sponge Dactylospongia elegans collected from the South China Sea. The new structures including absolute configurations were established by the HRESIMS and 1D and 2D NMR analysis coupled with the X-ray crystal analysis. Both of 1 and 2 exhibited cytotoxicity against cancer cell line MCF-7 with IC₅₀ values of 9.7 and 8.5 μM, respectively.     

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.     

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 natural nucleotide and other antibacterial metabolites from an endophytic Nocardia sp.

Nine compounds were isolated from Nocardia sp. YIM 64630, and their structures were elucidated as 5′-O-acetyl-2′-deoxyuridine (1), 22E,24R-5α,6α-epoxyergosta-8(14),22-diene-3β,7α-diol (2), 22E,24R-5α,6α-epoxyergosta-8,22-diene-3β,7α-diol (3), 22E,24R-ergosta-7,22-diene-3β,5α,6β-triol (4), 5α,8α-epidioxyergosta-6,22-dien-3β-ol (5), 4′,5,6-trihydroxy-7-methoxyisoflavone (6), 2,4,4′-trihydroxy-deoxybenzoin (7), methyl [4-hydroxyphenyl]acetate (8) and daidzein by extensive spectroscopic analyses. Compound 1 was isolated from natural resources for the first time. The antimicrobial and antioxidant activities of compounds 1–8 were investigated.     

Polar steroid derivatives from the Vietnamese starfish Astropecten polyacanthus

Five polar steroid derivatives, including one new glycosylated polyhydroxysteroid namely polyacanthoside A (1), were isolated from the water-soluble materials from the MeOH extract of the Vietnamese starfish Astropecten polyacanthus using various chromatographic separations. The structure elucidation was confirmed by spectroscopic experiments such as HR-ESI-MS, 1D and 2D NMR. Among the isolated compounds, (20R,24S)-3β,6α,8,15β,24-pentahydroxy-5α-cholestane (3) showed significant cytotoxic effect against five human cancer cell lines as HepG2, KB, LNCaP, MCF7 and SK-Mel2 with the IC₅₀ values from 18.03 ± 2.63 to 21.59 ± 3.23 μM.     

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.     

Insecticidal and α-glucosidase inhibitory activities of chemical constituents from Viburnum fordiae Hance

The ethanolic extract of the stems of Viburnum fordiae Hance showed insecticidal and α-glucosidase inhibitory activities and then was fractionated by bioactivity-guided fractionation to obtain a rare C₁₃-norisoprenoid (1), together with a new phenolic glycoside (2), and seven known compounds, alangionoside C (3), pisumionoside (4), koaburaside (5), 3,5-dimethoxy-benzyl alcohol 4-O-β-d-glucopyranoside (6), 3,4,5-trimethoxybenzyl-β-d-glucopyranoside (7), arbutin (8), and salidroside (9). The previously undescribed compounds were elucidated as (3R,9R)-3-hydroxy-7,8-didehydro-β-ionyl 9-O-α-d-arabinopyranosyl-(1→6)-β-d-glucopyranoside (1) and 2-(4-O-β-d-glucopyranosyl)syringylpropane-1,3-diol (2) by spectroscopic data (¹H and ¹³C NMR, HSQC, HMBC, ¹H-¹H COSY, HSQC-TOCSY, HRESIMS, IR and ORD) and chemical methods. Compound 1 showed potent insecticidal effect against Mythimna separata with LD₅₀ value of 140 μg g^?1. Compounds 2, 5, 6, 8 and 9 showed varying α-glucosidase inhibitory activity with IC₅₀ values ranging from 148.2 to 230.9 μM.     

Microporotriol,a new cadinane-type sesquiterpenoid from the cultures of the wood-decay fungus Microporus affinis HFG829

Abstract

A new cadinane-type sesquiterpenoid, microporotriol (1), together with four known compound, 5-methylresorcinol (2), (22E,24R)-ergosta-4,6,8(14),22-tetraen-3-one (3), (22E,24R)-ergosta-5,7,22-trien-3β-ol (4), (22E,24R)-5α,8α-epidioxy-ergosta-6,22-dien-3β-ol (5), were isolated from the fermentation broth of the wood decaying fungus Microporus affinis HFG829. The structures of the compounds were established by extensive spectroscopic methods, including 1D & 2D NMR, along with HRMS spectroscopic analysis. The relative configuration of 1 was confirmed by NMR calculation. Compound 1 was evaluated for the cytotoxicity against five human cancer cell lines.     

New lipoxygenase and cholinesterase inhibitory sphingolipids from Carthamus oxyacantha

Two new sphingolipids: oxyacanthin A [(2S,3S,4R)-2-{[(2R,5E)-2-hydroxyoctadec-5-enoyl]amino}hexaeicosane-1,3,4-triol; 1] and B [(2S,3S,4R)-2-{[(2R,5E)-2-hydroxyoctadec-5-enoyl]amino}hexaeicosane-1,3,4-triol-1-O-β-D-glucopyranoside; 2], together with 1-octacosanol, β-sitosterol, β-sitosterol 3-O-β-D-glucopyranoside and luteolin 7-O-β-glucopyranoside were isolated from the methanolic extract of the whole plant of Carthamus oxyacantha. Their structures were elucidated using ¹H and ¹³C NMR spectra and 2D NMR analyses (HMQC, HMBC and COSY) in combination with mass spectrometry (EI-MS, HR-EI-MS, FAB-MS and HR-FAB-MS) experiments and in comparison with the literature data of the related compounds. Both the compounds 1 and 2 showed inhibitory potential against lipoxygenase (LOX) in a concentration-dependent manner with IC₅₀ values 83.3 ± 1.3 and 245.7 ± 1.1 µM, whereas compound 2 showed inhibition against enzymes acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) with IC₅₀ values 65.3 ± 0.1 and 93.6 ± 0.1 µM, respectively.     

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).