Phosphodiesterase 5 and Arginase Inhibitory Activities of the Extracts from Some Members of Nelumbonaceae and Nymphaeaceae Families.

The objectives of this study were (1) to investigate the effect of extracts from some plants in the families Nelumbonaceae and Nymphaeaceae on phosphodiesterase 5 (PDE5) and arginase, which have been used in erectile dysfunction treatment, and (2) to isolate and identify the compounds responsible for such activities. The characterization and quantitative analysis of flavonoid constituents in the active extracts were performed by HPLC. Thirty-seven ethanolic extracts from different parts of plants in the genus Nymphaea and Victoria of Nymphaeaceae and genus Nelumbo of Nelumbonaceae were screened for PDE5 and arginase inhibitory activities. The ethanolic extracts of the receptacles and pollens of Nelumbo nucifera Gaertn., petals of Nymphaea cyanea Roxb. ex G.Don, Nymphaea stellata Willd., and Victoria amazonica (Poepp.) Sowerby and the petals and receptacles of Nymphaea pubescens Willd. showed IC50 values on PDE5 of less than 25 µg/mL while none of the extracts showed effects on arginase. The most active extract, N. pubescens petal extract, was fractionated to isolate and identify the PDE5 inhibitors. The results showed that six flavonoid constituents including quercetin 3'-O-ß-xylopyranoside (1), quercetin 3-methyl ether 3'-O-ß-xylopyranoside (2), quercetin (3), 3-O-methylquercetin (4), kaempferol (5) and 3-O-methylkaempferol (6) inhibited PDE5 with IC50 values at the micromolar level.

New antibacterial depsidones from an ant-derived fungus Spiromastix sp. MY-1.

Six new (1-6) and seven known depsidones (7-13) were isolated from the culture of an ant (Monomorium chinensis)-derived fungus Spiromastix sp. MY-1. Their structures were elucidated by extensive spectroscopic analysis including high resolution MS, 1D and 2D NMR data. The new bromide depsidones were obtained through supplementing potassium bromide in the fermentation medium of Spiromastix sp. MY-1. All isolated compounds showed various bioactivities against the tested phytopathogenic bacteria. Particularly, new bromide compound 4, named spiromastixone S, exhibited the strongest activity against Xanthomonas oryzae pv. oryzae with a MIC value of 5.2 µmol·-1.

Study on the secondary metabolites of grasshopper-derived fungi Arthrinium sp. NF2410.

Two new 2-carboxymethyl-3-hexyl-maleic anhydride derivatives, arthrianhydride A (1) and B (2), along with three known compounds 3-5, were isolated from the fermentation broth of a grasshopper-associated fungus Arthrinium sp. NF2410. The structures of new compounds 1 and 2 were determined based on the analysis of the HR-ESI-MS and NMR spectroscopic data. Furthermore, compounds 1 and 2 were evaluated on inhibitory activity against the enzyme SHP2 and both of them showed moderate inhibitory activity against SHP2.

Bioactive phenazines from an earwig-associated Streptomyces sp.

Three new phenazine-type compounds, named phenazines SA-SC (1-3), together with four new natural products (4-7), were isolated from the fermentation broth of an earwig-associated Streptomyces sp. NA04227. The structures of these compounds were determined by extensive analyses of NMR, high resolution mass spectroscopic data, as well as single-crystal X-ray diffraction measurement. Sequencing and analysis of the genome data allowed us to identify the gene cluster (spz) and propose a biosynthetic pathway for these phenazine-type compounds. Additionally, compounds 1-5 exhibited moderate inhibitory activity against acetylcholinesterase (AChE), and compound 3 showed antimicrobial activities against Micrococcus luteus.

Dalestones A and B, two anti-inflammatory cyclopentenones from Daldinia eschscholzii with an edited strong promoter for the global regulator LaeA-like gene.

Replacement of the native promoter of theglobal regulator LaeA-like gene of Daldinia eschscholzii by a strong gpdA promoter led to the generation of two novel cyclopentenone metabolites, named dalestones A and B, whose structures were assigned by a combination of spectroscopic analysis, modified Mosher's reaction, and electronic circular dichroism (ECD). Dalestones A and B inhibit the gene expression of TNF-α and IL-6 in LPS-induced RAW264.7 macrophages.

Anti-hyperuricemic and anti-inflammatory actions of vaticaffinol isolated from Dipterocarpus alatus in hyperuricemic mice.

The present study was designed to examine the anti-hyperuricemic and anti-inflammatory effects and possible mechanisms of vaticaffinol, a resveratrol tetramer isolated from ethanol extracts of Dipterocarpus alatus, in oxonate-induced hyperuricemic mice. At 1 h after 250 mg·kg-1 potassium oxonate was given, vaticaffinol at 20, 40, and 60 mg·kg-1 was intragastrically administered to hyperuricemic mice once daily for seven consecutive days. Vaticaffinol significantly decreased serum uric acid levels and improved kidney function in hyperuricemic mice. It inhibited hepatic activity of xanthine dehydrogenase (XDH) and xanthine oxidase (XOD), regulated renal mRNA and protein levels of urate transporter 1 (URAT1), glucose transporter 9 (GLUT9), organic anion transporter 1 (OAT1), organic cation transporter 1 (OCT1), OCT2, organic cation/carnitine transporter 1 (OCTN1), and OCTN2 in hyperuricemic mice. Moreover, vaticaffinol markedly down-regulated renal protein levels of NOD-like receptor 3 (NLRP3), apoptosis-associated speck-like (ASC), and Caspase-1, resulting in the reduction of interleukin (IL)-1ß, IL-18, IL-6 and tumor necrosis factor-α (TNF-α) levels in this animal model. Additionally, HPLC and LC-MS analyses clearly testified the presence of vaticaffinol in the crude extract. These results suggest that vaticaffinol may be useful for the prevention and treatment of hyperuricemia with kidney inflammation.

Antiviral activity of Paulownia tomentosa against enterovirus 71 of hand, foot, and mouth disease.

The bark, leaves, and flowers of Paulownia trees have been used in traditional Chinese medicine to treat infectious and inflammatory diseases. We investigated the antiviral effects of Paulownia tomentosa flowers, an herbal medicine used in some provinces of P. R. China for the treatment of skin rashes and blisters. Dried flowers of P. tomentosa were extracted with methanol and tested for antiviral activity against enterovirus 71 (EV71) and coxsackievirus A16 (CAV16), the predominant etiologic agents of hand, foot, and mouth disease in P. R. China. The extract inhibited EV71 infection, although no effect was detected against CAV16 infection. Bioactivity-guided fractionation was performed to identify apigenin as an active component of the flowers. The EC50 value for apigenin to block EV71 infection was 11.0 µM, with a selectivity index of approximately 9.3. Although it is a common dietary flavonoid, only apigenin, and not similar compounds like naringenin and quercetin, were active against EV71 infection. As an RNA virus, the genome of EV71 has an internal ribosome entry site that interacts with heterogeneous nuclear ribonucleoproteins (hnRNPs) and regulates viral translation. Cross-linking followed by immunoprecipitation and reverse transcription-polymerase chain reaction (RT-PCR) analysis showed that EV71 RNA was associated with hnRNPs A1 and A2. Apigenin treatment disrupted this association, indicating that apigenin suppressed EV71 replication through a novel mechanism by targeting the trans-acting factors. This study therefore validates the effects of Paulownia against EV71 infection. It also yielded mechanistic insights on apigenin as an active compound for the antiviral activity of P. tomentosa against EV71 infection.

Oligostilbenoids with acetylcholinesterase inhibitory activity from Dipterocarpus alatus.

Phytochemical investigation of the stem wood of Dipterocarpus alatus led to the isolation and characterization of four new oligostilbenoids, dipterocarpols A-D (1-4), together with two known resveratrol oligomers, hopeahainol (5) and hopeafuran (6). The structures of the new compounds were determined by comprehensive spectral analysis including 1D and 2D NMR, and high-resolution MS. The absolute configurations were determined by NOESY and CD spectra. Dipterocarpol A (1) and hopeahainol A (5) showed moderate acetylcholinesterase inhibitory activity with IC50 values of 8.28 µM and 11.28 µM, respectively. Furthermore, the discovery of compound 3 gave the first evidence that the biosynthetic origin of resveratrol aneuploids is related to the loss of a half resveratrol unit by oxidative cleavage.

Cytotoxic and antimicrobial flavonoids from Cryptocarya concinna.

Five new flavonoids, cryptoconones A-E (1-5), along with six known compounds (6-11), were isolated from the stems of Cryptocarya concinna. The structures of these compounds were elucidated on the basis of spectroscopic data interpretation, and the absolute configurations were determined via circular dichroism spectra and X-ray crystal analysis. The cytotoxic and antimicrobial activities of these compounds were also evaluated. Compounds 9 and 10 exhibited moderate cytotoxic activities against HCT116, HT-29, SW480, and MDA-MB-231 cell lines with IC50 values ranging from 6.25 to 9.35 µM. Compounds 8 and 11 exhibited antimicrobial activity against Fusarium moniliforme and Botrytis cinerea, respectively, with the same minimum inhibitory concentration of 5 µg/mL.

New flavonol and diterpenoids from the endophytic fungus Aspergillus sp. YXf3.

One new flavonol, chlorflavonin A (1), four new diterpenoids, aspergiloids E-H (3, 5-7), together with eight known compounds (2, 4, 8-13) were isolated from solid fermentation of Aspergillus sp. (strain no. YXf3), an endophytic fungus from Ginkgo biloba. Their structures were determined through detailed spectroscopic analysis combined with comparison of NMR spectra data with reported ones. All of them were screened on cytotoxicity against KB, SGC-7901, SW1116, and A549 cell lines; compounds 4, 9-11 exhibited moderate activities with IC50 values ranging from 6.74 to 46.64 µM.

Glycyrrhizic acid as the antiviral component of Glycyrrhiza uralensis Fisch. against coxsackievirus A16 and enterovirus 71 of hand foot and mouth disease.

ETHNOPHARMACOLOGICAL RELEVANCE: The radices of Glycyrrhiza uralensis Fisch. and herbal preparations containing Glycyrrhiza spp. have been used for thousands of years as an herbal medicine for the treatment of viral induced cough, viral hepatitis, and viral skin diseases like ulcers in China. Glycyrrhizic acid (GA) is considered the principal component in Glycyrrhiza spp. with a wide spectrum of antiviral activity. AIM: The present study attempt to validate the medicinal use of Glycyrrhiza uralensis for hand, foot and mouth disease (HFMD) and further to verify whether GA is an active antiviral component in the water extract of Glycyrrhiza uralensis. MATERIALS AND METHODS: Radices of Glycyrrhiza uralensis Fisch. were extracted with hot water. The chemical contents of the extract were profiled with HPLC analysis. The antiviral activity of the extract and the major components was evaluated against infection of enterovirus 71 (EV71) and coxsackievirus A16 (CVA16) on Vero cells. The cytopathic effect caused by the infection was measured with MTT assay. Infectious virion production was determined using secondary infection assays and viral protein expression by immunoblotting analysis. RESULTS: The extract at 1000 µg/ml suppressed EV71 replication by 1.0 log and CVA16 by 1.5 logs. The antiviral activity was associated with the content of GA in the extract since selective depletion of GA from the extract by acid precipitation resulted in loss of antiviral activity. In contrast, the acid precipitant retained antiviral activity. The precipitant at a concentration of 200 µg/ml inhibited EV71 and CVA16 replication by 1.7 and 2.2 logs, respectively. Furthermore, GA dose-dependently blocked viral replication of EV71 and CVA16. At 3 mM, GA reduced infectious CVA16 and EV71 production by 3.5 and 2.2 logs, respectively. At 5mM, CVA16 production was reduced by 6.0 logs and EV71 by 4.0 logs. Both EV71 and CVA16 are members of Enterovirus genus, time-of-drug addition studies however showed that GA directly inactivated CVA16, while GA anti-EV71 effect was associated with an event(s) post virus cell entry. CONCLUSIONS: This study validated the medicinal usefulness of radices Glycyrrhiza uralensis against the etiological agents of HFMD. In addition to the identification of GA as the antiviral component of Glycyrrhiza uralensis against EV71 and CVA16 infection, this study also reveals that GA inhibits EV71 and CVA16 with distinct mechanisms.

Thaxtomin A-deficient endophytic Streptomyces sp. enhances plant disease resistance to pathogenic Streptomyces scabies.

Each plant species in nature harbors endophytes, a community of microbes living within host plants without causing any disease symptom. However, the exploitation of endophyte-based phytoprotectants is hampered by the paucity of mechanistic understandings of endophyte-plant interaction. We here reported two endophytic Streptomyces isolates IFB-A02 and IFB-A03 recovered from a stress-tolerant dicotyledonous plant Artemisia annua L. After the determination of their non-pathogenicity at the genomic level and from the toxin (thaxtomin A, TXT) level, the endophytism of both isolates was supported by their successful colonization in planta. Of the two endophytes, IFB-A03 was further studied for the mechanism of endophyte-conferred phytoprotection owing to its plant growth promotion in model eudicot Arabidopsis thaliana. Using the endophyte-Arabidopsis co-cultivation system into which pathogenic Streptomyces scabies was introduced, we demonstrated that IFB-A03 pre-inoculation could activate the salicylic acid (SA)-mediated plant defense responses upon pathogen challenge. Moreover, IFB-A03 was shown to partially rescue the defense deficiency in eds5 (enhanced disease susceptibility 5) Arabidopsis mutants, putatively acting at the upstream of SA accumulation in the defense signaling pathway associated with the systemic acquired resistance (SAR). These data suggest that endophytic Streptomyces sp. IFB-A03 could be a promising candidate for biocontrol agents against S. scabies--a causative pathogen of common scab diseases prevailing in agronomic systems.

Actinotetraoses A-H: tetrasaccharide derivatives from a grasshopper-associated Amycolatopsis sp. HCa1.

Chemical investigation of the insect-derived actinomycete Amycolatopsis sp. HCa1 with NMR-guided fractionation led to the isolation of eight new tetrasaccharide derivatives containing an unusual nonreducing glucotetraose skeleton, named actinotetraoses A-H (1-8), and one known compound, tigloside (9). The structures of these compounds were determined on the basis of analyses of their spectroscopic data. The in vitro immunosuppressive activity and cytotoxicity of these compounds were evaluated by T cell viability and MTT assays, respectively. Only actinotetraose E (5) displayed weak immunosuppressive activity.

Polyphenolic acetylcholinesterase inhibitors from Hopea chinensis.

Bioassay-guided investigation of the stem bark of Hopea chinensis led to the isolation of two new polyphenols, hopeachinols C(1) and D(2), together with ten known compounds (3-12). Compounds 1 and 2 were determined by extensive analysis of spectroscopic data and computational methods. All of these phytochemicals were tested for acetylcholinesterase inhibitory activity, and five resveratrol-derived compounds (1 and 7-10) exhibited significant activity with their IC50 values ranging from 4.81 to 11.71 µM.

Neuraminidase inhibitory polyketides from the marine-derived fungus Phoma herbarum.

Two new polyketides, arthropsadiol C (1) and massarilactone H (2), together with six known derivatives (3-8) were isolated from the culture broth of the marine-derived fungus Phoma herbarum. Their structures were elucidated on the basis of spectroscopic methods, including 2D NMR techniques. Compounds 2, 4, 5, and 8 showed moderate neuraminidase inhibitory activity with IC(50) values ranging from 4.15 to 9.16 µM.

Cytotoxic angucyclines from Amycolatopsis sp. HCa1, a rare actinobacteria derived from Oxya chinensis.

Two new angucyclines, named (2R,3R)-2-hydroxy-8- O-methyltetrangomycin (1) and (2R,3R)-2-hydroxy-5-O-methyltetrangomycin (2), together with eight known compounds (3-10), were isolated from the culture of Amycolatopsis sp. HCa1, a rare actinobacteria isolated from the gut of Oxya chinensis. The new structures were elucidated through extensive spectroscopic data analysis, and their absolute configurations were assigned by application of the modified Mosher's method and CD spectrum comparison. Their IN VITRO cytotoxic activities against four cell lines including human cervical cancer cell line (HeLa), human gastric adenocarcinoma cell line (SGC-7901), human lung adenocarcinoma cell line (SPC-A-1), and mouse macrophage cell line (RAW264.7) were then investigated. Compounds 3, 4, 9, and 10 showed potent cytotoxic activities towards the HeLa cells with IC (50) values of 0.27, 0.11, 0.56, and 0.39 µM, respectively.

New acrylamide and oxazolidin derivatives from a termite-associated Streptomyces sp.

Two new compounds, named 2-formylpyrrole-4-acrylamide (1) and dihydrostreptazolin (2) were isolated from the fermentation broth of BY-4, an actinomycetes residing in the gut of Odontotermes formosanus. The structures of 1 and 2 were elucidated by extensive spectral analysis (1H, 13C, 2D NMR, and HR-ESIMS). The isolated compounds were assayed for cytotoxic and antimicrobial activities.

Chaetoglocins A-D, four new metabolites from the endophytic fungus Chaetomium globosum.

Chaetoglocins A-D (1- 4), four new secondary metabolites, were isolated from the solid-fermentation culture of Chaetomium globosum (strain no. IFB-E036), an endophytic fungus residing inside the root of Cynodon dactylon. The structures of these compounds were elucidated on the basis of detailed spectroscopic evidence and by comparing spectroscopic data with those in the literature. Compounds 1 and 2 displayed antimicrobial activity against the gram-positive bacteria with minimum inhibitory concentrations (MIC) between 8 and 32 µg/mL.

Cytotoxic chaetoglobosins from the endophyte Chaetomium globosum.

Two new alkaloids chaetoglobosins V (1) and W (2), together with the six known congeners 3-8, were isolated through bioassay-guided fractionations from the EtOAc extract of a solid culture of Chaetomium globosum IFB-E041. The structures were elucidated by spectroscopic methods including mainly 1D and 2D NMR techniques. Chaetoglobosin W (2) was unique in its possession of an oxolane ring formed via an oxygen bridge between C-3 and C-6. The isolated fungal metabolites exhibited moderate cytotoxic activities against four human cancer cell lines (KB, K562, MCF-7, and HepG2) with their IC(50) values in a range of 18-30 µg/mL.

Bioactive alkaloids from the plant endophytic fungus Aspergillus terreus.

One new alkaloid, named 16 alpha-hydroxy-5 N-acetylardeemin ( 1), along with seven known metabolites ( 2- 8) was isolated from the fermentation broth of an endophytic fungus, ASPERGILLUS TERREUS. The structures of these metabolites were assigned on the basis of detailed spectroscopic analysis and by comparing spectroscopic data with those in the literature. Compound 1 displayed an inhibitory effect against acetylcholinesterase. Compounds 1- 8 also showed moderate or weak cytotoxic activity against KB and HSC-T6 cell lines.