Daldinans D‒G, new isoindolinone antioxidants isolated from the ascomycete Daldinia concentrica.

Four new isoindolinone derivatives, daldinans D‒G (3‒6), together with two known compounds, daldinans A and B (1 and 2), were isolated from the stroma of the ascomycete Daldinia concentrica. Chemical structures of the isolated compounds were determined by spectroscopic methods. All of these compounds exhibited antioxidant activities with IC50 values of 3.21 to 39.67 µM in the 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay.

Screening, isolation and evaluation of a nematicidal compound from actinomycetes against the pine wood nematode, Bursaphelenchus xylophilus.

BACKGROUND: Bursaphelenchus xylophilus is a migratory endoparasitic nematode known to cause severe environmental damage and economic losses in pine forest ecosystems. This present study investigated the nematicidal metabolites of actinomycetes in vitro and evaluated the disease control efficacy of the active compound and metabolites under greenhouse and field conditions. RESULTS: Five thousand types of actinobacteria from Korean forest soil samples were screened to identify novel nematicidal agents against the pine wood nematode. Streptomyces sp. AN091965 showed the strongest nematicidal activity. One active compound, spectinabilin, was obtained by nematicidal asssy-directed fractionation, and it showed significant nematicidal activity against B. xylophilus, with an LC50 value of 0.84 µg mL-1 . Spectinabilin effectively suppressed the development of pine wilt disease in 5-year-old Pinus densiflora trees, even at 0.9 mg per tree under greenhouse conditions. Moreover, the acetone extract of the active strain's mycelia efficiently suppressed the development of pine wilt disease under field conditions. CONCLUSION: To the best of our knowledge, this the first report to describe the nematicidal activity of spectinabilin against B. xylophilus. The cell extracts described herein merit further field studies as potential nematicides against the pine wood nematode. © 2018 Society of Chemical Industry.

Statistical optimization of culture medium for improved production of antimicrobial compound by Streptomyces rimosus AG-P1441.

The nutritional requirements for antimicrobial activity of Streptomyces rimosus AG-P1441 were optimized using statistically-based experimental designs at a flask level. Based on a one-factor-at-a-time (OFAT) approach, glucose, corn starch and soybean meal were identified as the carbon and nitrogen sources having a significant effect on antimicrobial productivity. As a result of investigating the effect of glucose concentration, the highest antimicrobial activity was observed at 3% concentration. Response surface methodology (RSM) was then applied to optimize the growth medium components (corn starch, soybean meal, MgCl2 and glutamate). Antimicrobial productivity increased sharply when the medium consisted of 3% glucose, 3.5% corn starch, 2.5% soybean meal, 1.2 mM MgCl2 and 5.9 mM glutamate. The fermentation using optimized culture medium in a 5-L bioreactor allowed a significant increase in antimicrobial activity, evaluated by the paper disc assay, revealed a 29 mm inhibition zone diameter against Phytophthora capsici.

Neuraminidase Inhibitors from the Fruiting Body of Phellinus igniarius.

During our ongoing investigation of neuraminidase inhibitors from medicinal fungi, we found that the fruiting bodies of Phellinus igniarius exhibited significant inhibitory activity against neuraminidase from recombinant H3N2 influenza viruses. Two active compounds were isolated from the methanolic extract of P. igniarius through solvent partitioning and Sephadex LH-20 column chromatography. The active compounds were identified as phelligridins E and G on proton nuclear magnetic resonance ((1)H NMR) and electrospray ionization mass measurements. These compounds inhibited neuraminidases from recombinant rvH1N1, H3N2, and H5N1 influenza viruses, with IC50 values in the range of 0.7~8.1 µM.

Characterization of Neuraminidase Inhibitors in Korean Papaver rhoeas Bee Pollen Contributing to Anti-Influenza Activities In Vitro.

The active constituents of Korean Papaver rhoeas bee pollen conferring neuraminidase inhibitory activities (H1N1, H3N2, and H5N1) were investigated. Six flavonoids and one alkaloid were isolated and characterized by nuclear magnetic resonance and mass spectrometry data. These included kaempferol-3-sophoroside (1), kaempferol-3-neohesperidoside (2), kaempferol-3-sambubioside (3), kaempferol-3-glucoside (4), quercetin-3-sophoroside (5), luteolin (6), and chelianthifoline (7). All compounds showed neuraminidase inhibitory activities with IC50 values ranging from 10.7 to 151.1 µM. The most potent neuraminidase inhibitor was luteolin, which was the dominant content in the ethyl acetate fraction. All tested compounds displayed noncompetitive inhibition of H3N2 neuraminidase. Furthermore, compounds 1-7 all reduced the severity of virally induced cytopathic effects as determined by the Madin-Darby canine kidney cell-based assay showing antiviral activity with IC50 values ranging from 10.7 to 33.4 µM (zanamivir: 58.3 µM). The active compounds were quantified by high-performance liquid chromatography, and the total amount of compounds 1-7 made up about 0.592 g/100 g bee pollen, contributing a rich resource of a natural antiviral product.

Antifungal Substances from Streptomyces sp. A3265 Antagonistic to Plant Pathogenic Fungi.

In a previous study, we identified a Streptomyces sp., A3265, as exhibiting potent antifungal activity against various plant pathogenic fungi, including Botrytis cinerea, Colletotrichum gloeosporioides, and Rhizoctonia solani. This strain also exhibited a biocontrolling effect against ginseng root rot and damping-off disease, common diseases of ginseng and other crops. In this study, we isolated two antifungal substances responsible for this biocontrolling effect via Diaion HP-20 and Sephadex LH-20 column chromatography, medium pressure liquid chromatography, and high-performance liquid chromatography. These compounds were identified as guanidylfungin A and methyl guanidylfungin A by spectroscopic methods. These compounds exhibited potent antimicrobial activity against various plant pathogenic fungi as well as against bacteria.

Anti-influenza activities of polyphenols from the medicinal mushroom Phellinus baumii.

Five polyphenols were isolated from the ethanolic extract of the fruiting bodies of Phellinus baumii. These compounds were identified by various spectroscopic methods as hispidin, hypholomine B, inoscavin A, davallialactone, and phelligridin D. All compounds inhibited noncompetitively H1N1, H5N1, and H3N2 neuraminidase activity and reduced the amount of virally-induced cytopathic effect (CPE) according to an MDCK cell-based assay.

Chemical Constituents of the Culture Broth of Phellinus linteus and Their Antioxidant Activity.

The medicinal fungus Phellinus linteus, in the family Hymenochaetaceae, has been used as a traditional medicine for the treatment of various diseases. In this study, the chemical constituents of the culture broth of P. linteus were investigated. P. linteus was cultured in potato dextrose broth medium, and the culture broth was extracted with ethyl acetate. The ethyl acetate-soluble portion was concentrated and subjected to ODS column chromatography, followed by Sephadex LH-20 column chromatography. Six compounds (1~6) were purified by preparative reversed-phase high-performance liquid chromatography. Spectroscopic methods identified their structures as caffeic acid (1), inotilone (2), 4-(3,4-dihydroxyphenyl)-3-buten-2-one (3), phellilane H (4), (2E,4E)-(+)-4'-hydroxy-γ-ionylideneacetic acid (5), and (2E,4E)-γ-ionylideneacetic acid (6). Compounds 1, 2, and 3 exhibited potent dose-dependent antioxidant activity.

Neuraminidase Inhibitors from the Fermentation Broth of Phellinus linteus.

During a search for neuraminidase inhibitors derived from medicinal fungi, we found that the fermentation broth of Phellinus linteus exhibited potent neuraminidase inhibitory activity. Through bioassay-guided fractionation, two active compounds were purified from the ethyl acetate-soluble portion of the fermentation broth of P. linteus. These structures were identified as inotilone (1) and 4-(3,4-dihydroxyphenyl)-3-buten-2-one (2) by spectroscopic methods. Compounds 1 and 2 inhibited H1N1 neuraminidase activity with IC50 values of 29.1 and 125.6 µM, respectively, in a dose-dependent manner. They also exhibited an antiviral effect in a viral cytopathic effect reduction assay using MDCK cells. These results suggest that compounds 1 and 2 from the culture broth of P. linteus would be good candidates for the prevention and therapeutic strategies towards viral infections.

Lipoxygenase Inhibitory Activity of Korean Indigenous Mushroom Extracts and Isolation of an Active Compound from Phellinus baumii.

We investigated a total of 335 samples of Korean native mushroom extracts as part of our lipoxygenase (LOX) inhibitor screening program. Among the mushroom-methanolic extracts we investigated, 35 exhibited an inhibitory activity greater than 30% against LOX at a concentration of 100 µg/mL. Especially, Collybia maculata, Tylopilus neofelleus, Strobilomyces confusus, Phellinus gilvus, P. linteus, P. baumii, and Inonotus mikadoi exhibited relatively potent LOX inhibitory activities of 73.3%, 51.6%, 52.4%, 66.7%, 59.5%, 100.0%, and 85.2%, respectively. Bioassay-guided fractionation led to the isolation of inoscavin A from the methanolic extract of P. baumii, which showed the most potent activity and was identified by spectroscopic methods. Specifically, inoscavin A exhibited potent LOX inhibitory activity with an IC50 value of 6.8 µM.

Vigna angularis inhibits IL-6-induced cellular signalling and ameliorates collagen-induced arthritis.

OBJECTIVES: The present study was conducted in order to assess whether extracts or isolated compounds from Vigna angularis were able to suppress IL-6 signalling and to show the therapeutic effect on collagen-induced arthritis (CIA) in mice. METHODS: The effect of V. angularis on IL-6 signalling was studied by measuring Stat3-dependent luciferase activity, expression of inflammation-related genes, and phosphorylation of Janus kinase 2 (JAK2), signal transducer and activator of transcription 3 (STAT3) and extracellular signal-regulated kinase (ERK) induced by IL-6. CIA was induced by immunizing with bovine type II collagen. V. angularis extract (VAE) was administrated orally at 50 and 100 mg/kg from day 1 to day 28. Induction of arthritis was evaluated with a visual scoring system and histological analysis. RESULTS: Extracts or two triterpenoid compounds from V. angularis showed potent inhibitory effects on pSTAT3-inducible luciferase activity, STAT3 tyrosine phosphorylation and the expression of inflammation-related genes induced by IL-6. Administration of VAE significantly suppressed the progression of CIA, accompanied by a reduced antibody response to type II collagen and protection from tissue damage in knee joints. CONCLUSION: Administration of VAE has a therapeutic effect on CIA and this effect is associated with the inhibitory activity on IL-6/STAT3 signalling. These results suggest that extracts or compounds from V. angularis could be a useful treatment for diseases related to IL-6, including RA.

New bioactive compounds from korean native mushrooms.

Mushrooms are ubiquitous in nature and have high nutritional attributes. They have demonstrated diverse biological effects and therefore have been used in treatments of various diseases, including cancer, diabetes, bacterial and viral infections, and ulcer. In particular, polysaccharides, including ß-glucan, are considered as the major constituents responsible for the biological activity of mushrooms. Although an overwhelming number of reports have been published on the importance of polysaccharides as immunomodulating agents, not all of the healing properties found in these mushrooms could be fully accounted for. Recently, many research groups have begun investigations on biologically active small-molecular weight compounds in wild mushrooms. In this mini-review, both structural diversity and biological activities of novel bioactive substances from Korean native mushrooms are described.

Inhibition of LFA-1/ICAM-1-mediated cell adhesion by stilbene derivatives from Rheum undulatum.

Six stilbenes were isolated from the methanol extract of Rheum undulatum rhizomes by bioactivity-guided fractionation. The structures of the compounds were determined by spectroscopic analysis ((1)H-, (13)C-NMR and MS), to be desoxyrhapontigenin (1), rhapontigenin (2), trans-resveratrol (3), piceatannol (4), piceatannol-3'-O-ß-D-glucopyranoside (5) and isorhapontin (6). Compounds 1-4 inhibited the direct binding between sICAM-1 and LFA-1 of the THP-1 cells in a dose-dependent manner with IC(50) values of 50.1, 25.4, 33.4 and 45.9 µM, respectively. On the other hand, the other compounds 5 and 6 with a glucose moiety in each molecule did not show any inhibitory activity in the cell adhesion assay (IC(50) values of >100.0 µM). Compounds 2, 3 and 4 also had an inhibitory effect on direct binding between sVCAM-1 and VLA-4 of THP-1 cells. This suggests that the stilbenes from Rheum undulatum rhizomes are good candidates for therapeutic strategies towards inflammation.

Gallic acid inhibits cell viability and induces apoptosis in human monocytic cell line U937.

In the present study, we investigated the effects of gallic acid (GA) (3,4,5-trihydroxybenzoic acid), a polyhydroxyphenolic compound, isolated from Rhus chinensis, on the human monocytic lymphoma cell line U937. In vitro experiments showed that treating U937 cells with various amounts of GA inhibited cell viability and induced apoptosis in a dose-dependent manner. In order to understand the mechanism by which GA induces apoptosis, we examined the gene expression of p53, nuclear factor κB (NF-κB), and inhibitor of NF-κB (I-κB) after treating the cells with GA and found that expression levels of the genes for p53 and NF-κB increased and that for I-κB decreased. The results obtained from western blotting with U937 cells showed up-regulation of NF-κB protein and down-regulation of proliferating cell nuclear antigen and I-κB protein. These results demonstrate that GA efficiently induces apoptosis in U937 cells and that GA is a potential chemotherapeutic agent against lymphoma.

Pharmacological mechanism responsible for the Atractylodes japonica-induced distal colonic contraction in rats.

BACKGROUND AND AIM: Atractylodes japonica Koidz (Compositae) has been commonly used to treat the gastrointestinal (GI) disorders in Korean traditional medicine, but its pharmacological roles in the regulation of GI motility have not been clarified yet. METHODS: Atractylodes japonica was sequentially partitioned with MeOH, n-hexane, CHCl(3), EtOAc and n-BuOH saturated with H(2)O, and the effects of Atractylodes japonica extracts on the spontaneous contractility of GI muscle strips prepared from rats were measured. RESULTS: Among five different fractionations, EtOAc extracts of Atractylodes japonica (AJEA) dose-dependently increased the low frequency contraction of distal colon longitudinal muscles (DCLM), and the ED(50) values were revealed to be 1.71×10(-9) g/ml. Among GI tracts, a prominent contractile response to AJEA was observed only in the DCLM. The contractile patterns produced by AJEA remarkably differed from those caused by acetylcholine and 5-HT. 4-DAMP and methoctramine at 0.5 µM significantly blocked the AJEA (1.0 µg/ml)-induced contraction of DCLM, but ondansetron, GR113808 and methysergide at 1.0 µM in combination did not change the AJEA-induced DCLM contractions. Acetylethylcholine mustard (5.0 µM) significantly diminished the AJEA-induced DCLM contractions, whereas p-chlorophenyl alanine (1.0 µM) did not affect the stimulatory effects of AJEA on the DCLM contractions. CONCLUSION: The present results suggest that AJEA may specifically act on the DCLM among GI smooth muscles, and AJEA-induced DCLM contraction is likely mediated, at least, by activation of ChAT and acetylcholinergic muscarinic receptors.

Acetylene compound isolated from Atractylodes japonica stimulates the contractility of rat distal colon via inhibiting the nitrergic-purinergic relaxation.

AIM OF THE STUDY: Our previous research has showed that rhizome of Atractylodes japonica Koidz (Compositae) exhibits an increase in the spontaneous contractility of distal colon in rats. The aims of this study are to identify the phytochemical(s), which stimulate(s) the colonic contractility, contained in Atractylodes japonica and to evaluate the pharmacological mechanism responsible for the colonic muscle contraction. MATERIALS AND METHODS: Based on the stimulatory activity-guided fractionation on the isometric contraction of rat distal colonic strips, atractylodiol (ATD) and diacetyl-atractylodiol (DATD) were isolated from the CHCl(3) fractions of Atractylodes japonica. RESULTS: ATD and DATD dose-dependently increased both tension and amplitude of distal colon longitudinal muscle (DCLM), but they stimulated only amplitude in the distal colon circular muscle. The ED(50) values of ATD and DATD to stimulate the amplitude of DCLM were revealed as 9.1×10(-9)M and 1.8×10(-8)M, respectively. l-NAME (0.1mM) significantly increased the ADT (1µM)-induced contraction of DCLM, whereas SNAP (0.1mM) markedly reduced the stimulatory effects of ATD on DCLM contractility. The combined effects of SNAP and atropine (0.5µM) on the ATD-induced contraction of DCLM were similar to the inhibitory effects of SNAP alone. Suramin (0.1mM) significantly enhanced the increase of ATD-induced DCLM contraction, whereas ADPßS (0.1mM) markedly abolished the stimulatory effects of ATD on the spontaneous contractility of DCLM. CONCLUSIONS: The present results demonstrate that acetylene compounds, ATD and DATD, are the effective phytochemical of Atractylodes japonica to stimulate the motility of distal colon in rats, and ATD possibly enhances the spontaneous contractility of distal colon through inhibiting the mechanism of nitrergic-purinergic relaxation.

Antibacterial activity of phytochemicals isolated from Atractylodes japonica against methicillin-resistant Staphylococcus aureus.

Methicillin-resistant Staphylococcus aureus (MRSA) has been emerging worldwide as one of the most important problems in communities and hospitals. Therefore, new agents are needed to treat acute oral infections from MRSA. In this study, antibacterial compounds from the roots of Atractylodes japonica (A. japonica) were isolated and characterized. The compounds were isolated from the root extracts using HPLC-piloted activity-guided fractionations. Four A. japonica compounds were isolated and identified as atractylenolide III (1), atractylenolide I (2), diacetylatractylodiol [(6E,12E)-tetradeca-6,12-diene-8,10-diyne-1,3-diol diacetate, TDEYA, 3). and (6E,12E)-tetradecadiene-8,10-diyne-1,3-diol (TDEA, 4), which was obtained by hydrolysis of TDEYA. The minimum inhibitory concentrations (MICs) was determined in the setting of clinical MRSA isolates. Compound 4 showed anti-MRSA activity with a MIC value of 4-32 µg/mL. The overall results provide promising baseline information for the potential use of the extract of A. japonica as well as some of the isolated compounds in the treatment of bacterial infections.