Two new ent-kaurane diterpenes from the stems of Eurya chinensis

Abstract

Two new ent-kaurane diterpenes (1–2), together with five known analogs, were isolated from the stems of Eurya chinensis. The structures of new compounds were established by extensive analysis of mass spectrometric and 1D and 2D NMR spectroscopic data. Compound 3 exhibited noticeable anti-inflammatory activity as denoted by inhibiting LPS-induced nitric oxide (NO) production in RAW264.7 cells with an IC₅₀ value of 7.82 μM. Compound 4 showed potent cytotoxic activity against human cancer cell lines NCI-H46, HepG2 and SW480 with IC₅₀ values ranging from 7.45 to 8.54 μM.     

Rhobupcyanoside B,A new cyanoside from Rhodiola bupleuroides

One new cyanoside, rhobupcyanoside B (1), together with 7 known ones, was isolated from the 70% ethanol extract of the roots and rhizomes of Rhodiola bupleuroides. Their structures were determined by spectroscopic methods, including 2D NMR techniques. Compound 1 was evaluated for its inhibitory activity against α-glucosidase with IC₅₀ value of 278.28 ± 0.55 μM by comparing with the positive control (acarbose) at 210.40 ± 0.32 μM.     

Brominated polyunsaturated lipids with protein tyrosine phosphatase-1B inhibitory activity from Chinese marine sponge Xestospongia testudinaria

A new brominated polyunsaturated lipid, methyl (E,E)-14,14-dibromo-4,6,13-tetradecatrienoate (1), along with three known related analogues (2–4), were isolated from the Et₂O-soluble portion of the acetone extract of Chinese marine sponge Xestospongia testudinaria treated with diazomethane. The structure of the new compound was elucidated by detailed spectroscopic analysis and by comparison with literature data. Compound 3 exhibited significant inhibitory activity against protein tyrosine phosphatase 1B (PTP1B), a key target for the treatment of type II diabetes and obesity, with an IC₅₀ value of 5.30 ± 0.61 μM, when compared to the positive control oleanolic acid (IC₅₀ = 2.39 ± 0.26 μM).     

A novel 3,4-dihydronaphthalen-1(2H)-one with spiro-butyrolactone and a new isocoumarin isolated from the endophytic fungus Phoma sp. YN02-P-3

A novel 3,4-dihydronaphthalen-1(2H)-one with spiro-butyrolactone phomol (1) and a new isocoumarin phomasatin (2), together with two known compounds (3–4) were isolated from the solid culture of the endophytic fungus Phoma sp. YN02-P-3. Their structures including the absolute configurations were characterized on the basis of extensive 1D, 2D NMR (HSQC, HMBC, NOESY), MS, and CD spectral data. Compound 1 showed selective cytotoxic activity against HL-60 cell line with the IC₅₀ value of 29.05 μM.     

Further brominated polyacetylenes with pancreatic lipase inhibitory activity from Chinese marine sponge Xestospongia testudinaria

A new brominated polyacetylene, xestonariene I (1), along with three known related analogues (2–4), was obtained from Chinese marine sponge Xestospongia testudinaria. Its structure was determined on the basis of detailed spectroscopic analysis and by comparison with literature data. Compound 4 exhibited significant inhibitory activity against pancreatic lipase, which plays a key role in preventing obesity, with an IC₅₀ value of 0.61 μM, being comparable to that of the positive control orlistat (IC₅₀ = 0.78 μM).     

Metabolites from endophytic fungus A12 of Dracaena cambodiana

A new drimane sesquiterpene, 1α,7α-dihydroxyconfertifolin (1), along with two known compounds 2 and 3, was isolated from endophytic fungus A12 of Dracaena cambodiana. The new compound was elucidated by HR-ESI-MS and spectroscopic techniques (IR, UV, 1D, and 2D NMR). Compound 2 showed inhibitory bacterial activity against Staphylococcus aureus with diameter of the inhibition zone of 13.5 mm.     

A new labdane-type diterpenoid from Leonurus japonicus

Five fractions prepared from the crude extract of Leonurus japonicus were examined in order to determine their cytotoxic potential. Under the bioassay guidance, a new labdane-type diterpenoid (1), and nine known ones (2–10) along with a seco-labdane (11) were isolated from the aerial parts of Leonurus japonicus. The structure elucidation was primarily based on comprehensive spectroscopic analyses, including HRESIMS, IR, and 1D and 2D NMR methods. Compound 4 (6β-hydroxy-15,16-epoxylabda-8,13(16),14-trien-7-one) exhibited potential cytotoxicity against HeLa cell line (IC₅₀ = 23.75 μM).     

Isolation and structure elucidation of halymeniaol,a new antimalarial sterol derivative from the red alga Halymenia floresii

A new mono-hydroxy acetylated sterol derivative: 12β-hydroxy-3β, 15α, 16β-triacetoxy-cholest-5-en-7-one (halymeniaol) (1), and cholesterol (2) were isolated from the marine red alga Halymenia floresii. The structure of the compound 1 (halymeniaol) was established from its spectral data, derived from HRMS/MS and 2D NMR. Compound 1 exhibited growth inhibitory activity against chloroquine-resistant Plasmodium falciparum 3D7 strain with an IC₅₀ of 3.0 μM.     

Lanostane triterpenoids and ergostane-type steroids from the cultured mycelia of Ganoderma capense

Abstract

Two new lanostane triterpenoids (1 and 2), two new ergostane-type steroids (3 and 4) together with two known lanostane triterpenoids (5 and 6) and one known steroid (7) were isolated from the cultured mycelia of Ganoderma capense (CGMCC 5.71). Their structures were determined on the basis of extensive spectroscopic (HRESIMS, 1D NMR, 2D NMR) data analyses. Compound 1 exhibited moderate cytotoxic activity against the human cancer cell line NCI-H1650 with an IC₅₀ value of 22.3 μM, and 7 displayed cytotoxic activity against the human cancer cell line HCT116 with an IC₅₀ value of 17.4 μM. In addition, compounds 2, 3, 5, and 6 displayed weak anti-HIV activity with IC₅₀ values of 23.5, 46.7, 21.6, and 30.1 μM, respectively.     

Two new 2-(2-Hydroxy-2-phenylethyl)chromens from agarwood originating from Aquilaria crassna

Two new 2-(2-hydroxy-2-phenylethyl)chromones (1?2), along with three known 2-(2-phenylethyl)chromones (3?5), were isolated from the agarwood originating from Aquilaria crassna Pierre ex Lecomte. Their structures were determined by the spectroscopic methods including 1D and 2D NMR analysis and comparison with reported data in the literature. All the compounds were isolated from agarwood of A. crassna for the first time. Compounds 1 and 2 exhibited inhibitory activity against acetylcholinesterase (AChE) with 17.4 ± 0.6 and 15.8 ± 0.7%, respectively, at a concentration of 50 μg/ml. Besides, Compound 3 expressed antibacterial activities against Ralstonia solanacearum with diameter of the inhibition zone of 6.80 ± 0.08 mm at a concentration of 10 mg/ml.     

A new phenolic enamide and a new meroterpenoid from marine alga-derived endophytic fungus Penicillium oxalicum EN-290

Abstract

Ten secondary metabolites (1–10) including a new phenolic enamide, methyl (Z)-3-(3,4-dihydroxyphenyl)-2-formamidoacrylate (1), and a new meroterpenoid, 15-hydroxydecaturin A (2), were characterized from the EtOAc extracts of the marine alga-derived endophytic fungus Penicillium oxalicum EN-290. The structures of these compounds were elucidated on the basis of 1D and 2D NMR experiments and the absolute configuration of compound 2 was confirmed by electronic circular dichroism quantum calculations. Compound 1 showed potent activity against Staphylococcus aureus with an MIC value of 2.0 μg/ml, which is stronger than that of the positive control (chloromycetin, with an MIC 4.0 μg/ml). This compound also showed activity against harmful algal bloom causative species Nitzschia closterium with inhibition zones of 20, 16, and 10 mm at 20, 10, and 5 mg/ml, respectively. Interestingly, so far, this type of anti-HAB metabolites has only been found in the algal-derived isolate of P. oxalicum. It could probably be a defense of this fungus against environmental stress and threat of survival.     

A new schistosomicidal and antioxidative phenylpropanoid from Astragalus englerianus

A new phenylpropanoid, (E)-2,3,4-trimethoxy-5-(1-propenyl)phenol (1), along with five known aromatic compounds (2–6), was isolated from the methanol extract of roots of Astragalus englerianus. Their structures were elucidated based on the analyses of extensive spectroscopic data and comparison of their physicochemical properties. Compounds 1 and 2 were evaluated schistosomicidal activities, and all the isolated compounds were tested for their antioxidant activities in vitro. Compound 1 showed significant schistosomicidal activity with worm mortality rates of 66.7% and 83.3% within 12 and 24 h in a drug-containing (1.16 mM) RPMI 1640 medium, respectively. Also, compound 1 exhibited excellent antioxidant activity (2,2-diphenyl-1-(2,4,6-trinitrophenyl)hydrazyl free radical-scavenging capability) with an IC₅₀ value of 81.3 ± 1.3 μM.     

Three new diphenyl ether derivatives from the fermentation products of an endophytic fungus Phomopsis fukushii

Three new diphenyl ethers (1-3), together with four known isopentylated diphenyl ethers derivatives (4-7), were isolated from the fermentation products of an endophytic fungus Phomopsis fukushii. Their structures were elucidated by spectroscopic methods, including extensive 1D and 2D NMR techniques. Compounds 1-3 were evaluated for their anti-methicillin-resistant Staphylococcus aureus (anti-MRSA) activity. The results revealed that compounds 1 and 2 showed strong inhibitions with inhibition zone diameters (IZD) of 20.2 ± 2.5 mm and 17.9 ± 2.2 mm, respectively. Compound 3 also showed good inhibition with IZD 15.2 ± 1.8 mm. The IZD data of compound 1 is close to that of positive control with IZD 21.9 ± 2.1 mm.     

Two new sesquiterpenoid glycosides from the leaves of Lycium barbarum

Two new sesquiterpenoid glycosides, lyciumionosides A–B (1–2), together with four known compounds (3–6), were isolated from the leaves of Lycium barbarum. Their structures were mainly established on the basis of MS, 1D and 2D NMR spectroscopic techniques. The antiproliferative activities of compounds 1–5 were evaluated. Compound 1 showed highest inhibitory activity against A549 cells with IC₅₀ value of 32.6 ± 2.6 μM, compound 3 showed highest inhibitory activity against PC-3 cells with IC₅₀ value of 36.0 ± 2.9 μM, and compound 5 exhibited highest inhibitory activity against HeLa cells with IC₅₀ value of 32.3 ± 4.2 μM.     

Two new coumarin glycosides from Herpetospermum caudigerum

Phytochemical investigation on the seeds of Herpetospermum caudigerum afforded two new coumarin glycosides A and B (1 and 2), together with a known compound herpetolide A (3). Their structures were determined by spectroscopic methods, including 2D NMR techniques. Compound 3 exhibited cytotoxicity against HepG2 cells with IC₅₀ value of 6.47 μg/ml. Compound 2 showed anti-hepatitis B virus activity with HBsAg secretion by 33.1% at 200 μg/ml.     

New cyclopeptide alkaloid and lignan glycoside from Justicia procumbens

This study reported a new cyclopeptide alkaloid, justicianene A (1), and a new lignan glycoside, procumbenoside H (2), isolated from Justicia procumbens. The structures of the new compounds were elucidated by means of spectroscopic analysis, including extensive 2D NMR studies and mass spectrometry. Cyclopeptide alkaloids were first observed from the genus Justicia. Compound 2 was cytotoxic against human LoVo colon carcinoma cells with an IC₅₀ value of 17.908 ± 1.949 μM.     

Two new morphinane alkaloids from Sinomenium acutum

Two new morphinane alkaloids, 1-hydroxy-10-oxo-sinomenine (1) and 4,5-epoxy-14-hydroxy sinomenine N-oxide (2), have been isolated from the stems of Sinomenium acutum. Their structures were established by various spectral analyses, especially 2D NMR experiments. The structure of 2 was confirmed by single crystal X-ray diffraction. The absolute configurations of 1 and 2 were deduced by comparison of CD spectra with the known alkaloid sinomenine (3). Compound 1 was tested for DPPH inhibition and gave IC₅₀ of 27.9 μM. Compound 2 was tested for neuroprotective effect and showed significant activity against β-amyloid_25–35-induced oxidative injury (*P < 0.05) at 10 μM in PC-12 cells.     

Carbazole alkaloids from the stems of Clausena excavata

A new carbazole alkaloid, sansoakamine (8), together with 11 known compounds, was isolated from the stems of Clausena excavata. All structures were elucidated by spectroscopic methods. Compound 7 showed moderate anti-malarial activity against Plasmodium falciparum with a MIC value of 6.74 μg/ml.     

A new bioactive steroidal ketone from the South China Sea sponge Xestospongia testudinaria

A new steroidal ketone (1), with an ergosta-22,25-diene side chain, was obtained from the South China Sea marine sponge Xestospongia testudinaria. The structure of 1 was determined on the basis of detailed spectroscopic analysis and by comparison with literature. Compound 1 exhibited significant inhibitory activity against protein tyrosine phosphatase 1B (PTP1B), a key target for the treatment of type II diabetes and obesity, with an IC₅₀ value of 4.27 ± 0.55 μM, which is comparable with the positive control oleanolic acid (IC₅₀ = 2.63 ± 0.22 μM).     

Acylphloroglucinol derivatives from Decaspermum gracilentum and their antiradical and cytotoxic activities

Two new acylphloroglucinol derivatives, 1-(hexanoyl)phloroglucinol-α-d-arabinopyranoside (1) and 1-(hexanoyl)phloroglucinol-β-d-glucopyranoside (2), along with two known ones, 1-(acetyl)phloroglucinol-β-d-glucopyranoside (3) and ethyl 2,4,6-trihydroxybenzoate (4), were isolated from the EtOAc soluble fraction of EtOH extract of Decaspermum gracilentum. The structures of the new compounds were determined by extensive spectroscopic analyses including HRESIMS, 1D and 2D NMR data. Interestingly, all of the compounds showed ABTS^·+ radical scavenging activity with the IC₅₀ values less than 10 μM. Furthermore, compounds 3 and 4 displayed moderate cytotoxicity on human non-small-cell lung carcinoma cell line A549 (IC₅₀ = 50.9 μΜ) and human renal carcinoma cell line 786-O (IC₅₀ = 38.6 μΜ), respectively.