Regulation of secondary metabolites in the endophytic fungus Penicillium sp. KMU18029 by the chemical epigenetic modifier 5-azacitidine.

The chemical epigenetic modifier 5-azacitidine (5-Aza C), a DNA methyltransferase inhibitor, was used to manipulate the endophytic fungus Penicillium sp. KMU18029. From its rice fermentation extract, a new polyketone compound (3S,4R)-3,4,8-trihydroxy-6-methyl-3,4-dihydronaphthalen-1(2H)-one (1), along with 13 known compounds, 3,4,8-trihydroxy-6-(hydroxymethyl)-3,4-dihydronaphthalen-1(2H)-one (2), decaturin B (3), 15-hydroxydecaturin A (4), oxalicine A (5), pileotin A (6), pyrandecarurin A (7), decaturenol A (8), decaturenoid (9), penisarins A (10), oxaline (11), (4E,8E)-N-D-2'-hydroxyocta-decanoyl-1-O-ß-D-glycopy-ranosyl-9-methyl-4,8-sphingadienine (12), ergosterol (13) and stigma-5-en-3-O-ß-glucoside (14), were separated. Among the known compounds, 2, 7, 12 and 14 were not found in our previous research on this strain. The structure of the new compound was identified by spectroscopic techniques such as HR-ESIMS, 1D NMR, 2D NMR and CD. Furthermore, all the isolated compounds were tested for their antimicrobial activities, and only compounds 1, 2 and 11 showed weak activities against S. aureus, with MICs of 128 µg/mL.

The erythromycin polyketide compound TMC-154 stimulates ROS generation to exert antibacterial effects against Streptococcus pyogenes.

The erythromycin polyketide compound TMC-154 is a secondary metabolite that is isolated from the rhizospheric fungus Clonostachys rogersoniana associated with Panax notoginseng, which possesses antibacterial activity. However, its antibacterial mechanism has not been investigated thus far. In this study, proteomics coupled with bioinformatics approaches was used to explore the antibacterial mechanism of TMC-154. KEGG pathway enrichment analysis indicated that eight signaling pathways were associated with TMC-154, including oxidative phosphorylation, cationic antimicrobial peptide (CAMP) resistance, benzoate degradation, heme acquisition systems, glycine/serine and threonine metabolism, beta-lactam resistance, ascorbate and aldarate metabolism, and phosphotransferase system (PTS). Cell biology experiments confirmed that TMC-154 could induce reactive oxygen species (ROS) generation in Streptococcus pyogenes; moreover, TMC-154-induced antibacterial effects could be blocked by the inhibition of ROS generation with the antioxidant N-acetyl L-cysteine. In addition, TMC-154 combined with ciprofloxacin or chloramphenicol had synergistic antibacterial effects. These findings indicate the potential of TMC-154 as a promising drug to treat S. pyogenes infections. SIGNIFICANCE: Streptococcus pyogenes is a nearly ubiquitous human pathogen that causes a variety of diseases ranging from mild pharyngitis and skin infection to fatal sepsis and toxic heat shock syndrome. With the increasing incidence of known antibiotic resistance, there is an urgent need to find novel drugs with good antibacterial activity against S. pyogenes. In this study, we found that TMC-154, a secondary metabolite from the fungus Clonostachys rogersoniana, inhibited the growth of various bacteria, including Staphylococcus aureus, S. pyogenes, Streptococcus mutans, Pseudomonas aeruginosa and Vibrio parahemolyticus. Proteomic analysis combined with cell biology experiments revealed that TMC-154 stimulated ROS generation to exert antibacterial effects against S. pyogenes. This study provides potential options for the treatment of S. pyogenes infections in the future.

A new C19-diterpenoid alkaloid in Aconitum georgei Comber.

Nine diterpenoid alkaloids were isolated from Aconitum georgei Comber belonging to the genus Aconitum in Ranunculaceae family. Their structures were determinated by using HR-ESI-MS and 1 D/2D NMR spectra as geordine (1), yunaconitine (2), chasmanine (3), crassicauline A (4), forestine (5), pseudaconine (6), 14-acetylalatisamine (7), austroconitine B (8), and talatisamine (9). Among them, compound 1 is a previously undescribed aconitine-type C19-diterpenoid alkaloid, and compounds 3, and 5-9 have not previously been isolated from this species. The results of in vitro experiments indicated that new compound 1 possesses mild anti-inflammatory activity, which inhibited the production of NO in LPS-activated RAW 264.7 cells with an inhibition ratio of 29.75% at 50 µM.

New diterpenoid alkaloids from Delphinium pachycentrum Hemsl.

Six diterpenoid alkaloids, namely, pachycentine (1), deacetylswinanine A (2), siwanine A (3), tatsiensine (4), deacetyltatsiensine (5), and 6-deoxydeltamine (6), were isolated from a China-specific Delphinium plant (family Ranunculaceae), Delphinium pachycentrum Hemsl. Their structures were established via detailed spectroscopic analyses, including IR, HR-ESI-MS, 1D and 2D NMR techniques. Pachycentine (1) is a previously undescribed hetisine-type C20-diterpenoid alkaloid, and compounds 5 and 6 were synthetic intermediates newly identified as natural products. In addition, compounds 2-4 were isolated from this species for the first time. The chemotaxonomic significance of all the isolates was summarized. Moreover, the new compound was evaluated for its potential anti-inflammatory effect using LPS-stimulated RAW 264.7 macrophages.

Penisarins A and B, Sesquiterpene Coumarins Isolated from an Endophytic Penicillium sp.

Penisarins A (1) and B (2), sesquiterpene coumarins with an unusual tricyclic sesquiterpene system, were isolated from endophytic Penicillium sp. KMU18029. Their structures were elucidated on the basis of spectroscopic methods, single-crystal X-ray diffraction, and electronic circular dichroism calculations. Compound 2 showed significant cytotoxicities against two human cancer cell lines, HL-60 and SMMC-7721, with IC50 values of 3.6 ± 0.2 and 3.7 ± 0.2 µM, respectively.

A new diterpenoid alkaloid from Aconitum hemsleyanum.

A new C19-diterpenoid alkaloid named hemsleyaline (1), along with fourteen known alkaloids (2-15), were isolated from the roots of Aconitum hemsleyanum Pritz. (Ranunculaceae), a herbal medicine in southwest China. Their structures were established on the basis of extensive spectroscopic analyses. Compound 1 showed mild cholinesterase inhibitory effect with IC50 value of 471 ± 9 µM.

Rynchopeterine F, unique heterodimer of phenethanol-phenylacetyl linking with lactic acid from the medicinal insect Blaps rynchopetera.

A new heterodimer, rynchopeterine F (1), a new natural product, rynchopeterine G (2), and eleven known phenolics were isolated from Blap rynchopetera Fairmaire, a kind of medicinal insect utilized by the Yi and Bai Nationality in Yunnan Province of China. Their structures were established on the basis of extensive spectroscopic analyses (1D and 2D NMR, HR-MS) along with calculated electronic circular dichroism method. Rynchopeterine F was a unusual heterodimer of a 3,4-dihudroxy phenylethanol unit fused to a 3,4-dihudroxy phenylacetyl group through two ester bonds with lactic acid, and rynchopeterine G was a 3,4-dihudroxy phenylethanyl monoester succinate. Attributed to the adjacent dihydroxyl grops, compounds 1 and 2 exhibited significant anti-radical activity with an IC50 value of 3.52 and 7.83 µg/mL for DPPH radical-scavenging, similar with that of the positive controls, vitamin C, 6.92 µg/mL and rutin, 8.28 µg/mL.

Three new diterpenoid alkaloids isolated from Aconitum brevicalcaratum.

In the present study, three new aconitine-type diterpenoid alkaloids brochyponines A-C (1-3) were isolated from the roots of Aconitum brevicalcaratum. Their structures were established on the basis of extensive spectroscopic analyses (IR, HR-ESI-MS, and 1D and 2D NMR). The NMR data of salt form for compound 1 in CDCl3 were also measured.

New phenylpropanoids from Bulbophyllum retusiusculum.

Two new phenylpropanoids, retusiusines A (1) and B (2), and a pair of new phenylpropyl enantiomers, (±)-retusiusine C (3a and 3b), together with eight known compounds, dihydroconiferyl dihydro-p-coumarate (4), methyl 3-(4-hydroxyphenyl) propionate (5), 3-(4-hydroxyphenyl)-propanoic acid (6), dihydroferulic acid (7), methyl 3-(4-methoxyphenyl) propionate (8), 3-(3,4-dimethoxyphenyl)-2-propenal (9), trans-p-coumaric acid (10) and dihydroconiferyl alcohol (11), were isolated from the tubers of Bulbophyllum retusiusculum. The absolute configurations of the new compounds were determined by calculating their electronic circular dichroism (ECD), spectra and specific optical rotations and comparing the calculated values with the experimental data. Compound 2 exhibited potent antifungal activity against Candida albicans (16 µg/mL). Compound 3 showed moderate antibacterial activity against Bacillus subtilis (64 µg/mL).

Five New Phenolic Compounds with Antioxidant Activities from the Medicinal Insect Blaps rynchopetera.

Five new phenolic compounds rynchopeterines A-E (1-5), in addition to thirteen known phenolics, were isolated from Blaps rynchopetera Fairmaire, a kind of medicinal insect utilized by the Yi Nationality in Yunnan Province of China. Their structures were established on the basis of extensive spectroscopic analyses (1D and 2D NMR, HR-MS, IR) along with calculated electronic circular dichroism method. Rynchopeterines A-E (1-4) exhibited significant antioxidant activities with IC50 values of 7.67-12.3 µg/mL measured by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. Besides, rynchopeterines B (2) and C (3) showed mild cytotoxicity against tumor cell Caco-2 and A549.

A new polyketide glycoside from the rhizospheric Clonostachys rogersoniana associated with Panax notoginseng.

A new polyketide glycoside rogerson A (1), along with two known compounds, rogerson B (2) and (22E)-5α,8α-epidioxyergosta-6,22-dien-3ß-ol (3), was obtained from the solid fermentation of Clonostachys rogersoniana, which was isolated from the rhizosphere soil of Panax notoginseng. Rogerson B (2) was isolated for the first time from a natural source. Their structure was determined by extensive analyses of NMR and MS studies. Compounds 1 and 2 were tested for its cytotoxicity against five human cancer cell lines.

A new C20-diterpenoid alkaloid from the lateral roots of Aconitum carmichaeli.

A new C20-diterpenoid alkaloid carmichaedine (1) and six known alkaloids (2-7) were isolated from the lateral roots of Aconitum carmichaeli. Their structures were established on the basis of extensive spectroscopic analyses. Compound 1 exhibited potent antibacterial activity against Bacillus subtilis with minimum inhibitory concentration of 8 µg/mL.

Improving the antioxidant activity and enriching salvianolic acids by the fermentation of Salvia miltiorrhizae with Geomyces luteus.

The antioxidant activities and total phenolic content of fermented Salvia miltiorrhiza with fungus Geomyces luteus were investigated. The results revealed that G. luteus fermentation could significantly improve the antioxidant activity and total phenolic content of S. miltiorrhiza. The main antioxidant constituents were characterized by spectroscopic analysis as salvianolic acids. High-performance liquid chromatography (HPLC) quantification also showed the enhanced content of salvianolic acid B after fermentation. The present study suggests that G. luteus fermentations are effective in the S. miltiorrhiza salvianolic acids' enrichment process.

A new flavone C-glycoside and a new bibenzyl from Bulbophyllum retusiusculum.

A new flavone C-glycoside, apigenin 6-C-α-arabinofuranosyl 8-C-α-arabinopyranoside (1) and a new bibenzyl, bulbotetusine (2), were isolated from the tubers of Bulbophyllum retusiusculum. Their structures were established on the basis of extensive spectroscopic analyses. The absolute configuration of 2 was determined by the comparison of experimental and calculated electronic circular dichroism. Compounds 1 and 2 showed no obvious cytotoxic activity against any five human tumour cell lines with IC50 values >40 µM.

Alkaloids with antioxidant activities from Aconitum handelianum.

A new C20-diterpenoid alkaloid handelidine (1) and twenty-seven known alkaloids (2-28) were isolated from the roots of Aconitum handelianum. Their structures were established on the basis of extensive spectroscopic analyses. The study indicated that denudatine-type C20-diterpenoid alkaloids with vicinal-triol system and benzyltetrahydroisoquinoline alkaloids exhibited significant antioxidant activities measured by three antioxidant test systems. The aconitine-type C19-diterpenoid alkaloids could serve as potential secondary antioxidants for their strong binding effects to metal ions.

New Alkaloids from Aconitum stapfianum.

Nineteen alkaloids, including a new C19-diterpenoid alkaloid stapfianine A (1) and a new benzamide derivative stapfianine B (2) were isolated from the roots of Aconitum stapfianum. Their structures were established on the basis of extensive spectroscopic analyses (IR, HRESIMS, 1D and 2D NMR).

Diterpenoid alkaloids from Aconitum vilmorinianum.

Diterpenoid alkaloids, named vilmorines A-D, in addition to fifteen known alkaloids, were isolated from roots of Aconitum vilmorinianum. Their structures were established on the basis of extensive spectroscopic analyses. Antibacterial and antioxidant studies on isolated compounds were also carried out.

Tannins and Antioxidant Activities of the Walnut (Juglans regia) Pellicle.

The total phenolic content and antioxidant activities of the acetone extract and derived fractions from the walnut (Juglans regia) pellicle were estimated. The BuOH fraction exhibited the strongest antioxidant activity with the highest phenolic content. A phytochemical investigation of this fraction led to the isolation of three tannins, 2,3-hexahydroxydiphenoylglucose (1), pedunculagin (2) and 2,3,4,6-tetragalloylglucose (3). Pedunculagin showed high content and powerful activity, which implied that this compound plays an important role in the antioxidant activity of the walnut pellicle.

A new C19-diterpenoid alkaloid from the roots of Aconitum duclouxii.

A new C19-diterpenoid alkaloid, ducloudine F (1), was obtained from the roots of Aconitum duclouxii, along with eight known alkaloids (2-9) isolated from this species for the first time. Their structures were established on the basis of extensive spectroscopic analyses. The antimicrobial activities of these compounds were investigated.

Three new diterpenoid alkaloids from the roots of Aconitum duclouxii.

Three new C19-diterpenoid alkaloids, ducloudines C (1), D (2), and E (3), were isolated from the roots of Aconitum duclouxii. Their structures were established on the basis of extensive spectroscopic analyses. Ducloudine C (1) is the first aconitine-type C19-diterpenoid alkaloid with a C=O group at C-3 and a C=C bond between C-1 and C-2. All compounds were tested for their biological activities against one pathogenic fungi and two pathogenic bacteria.