Bidysoxyphenols A-C, dimeric sesquiterpene phenols from the leaves of Dysoxylum parasiticum (Osbeck) Kosterm.

Three new sesquiterpene phenol dimers, bidysoxyphenols A-C (2-4), along with two known compounds, namely sesquiterpene phenol (1) and ionone derivatives (5), were isolated from the leaves of Dysoxylum parasiticum (Osbeck) Kosterm. The structures of these new compounds, including their absolute configurations, were elucidated by nuclear magnetic resonance spectroscopy, ultraviolet spectroscopy, infrared spectroscopy, high-resolution electrospray ionization time-of-flight mass spectrometry, and electronic circular dichroism. Compounds 1 and 2 showed cytotoxicity against human promyelocytic leukemia cells, with IC50 values of 18.25 ± 1.52 and 39.04 ± 3.12 µM, respectively.

Petasin is the main component responsible for the anti-adipogenic effect of Petasites japonicus.

Petasites japonicus is one of the most popular edible wild plants in Japan. Many biological effects of P. japonicus have been reported, including anti-allergy, anti-inflammation, and anticancer effects. Although its anti-obesity effect has been reported in several studies, the most important component responsible for this activity has not been fully elucidated. On screening the components that suppress adipocyte differentiation in 3T3-F442A cells, we found that the extract of the flower buds of P. japonicus has anti-adipogenic effect. Among the known major components of P. japonicus, petasin exhibited a potent anti-adipogenic effect at an IC50 value of 0.95 µM. Quantitative analysis revealed that the active component responsible for most of the anti-adipogenic effects of P. japonicus extract is petasin. Petasin suppressed the expression of markers of mature adipocytes (PPARγ, C/EBPα, and aP2). However, as isopetasin and petasol, analogs of petasin, did not exhibit these effects, it indicates that a double bond at the C11-C12 position and an angeloyl ester moiety were essential for the activity. Petasin affected the late stage of adipocyte differentiation and inhibited the expression of lipid synthesis factors (ACC1, FAS, and SCD1). Additionally, it was revealed that petasin could be efficiently extracted using hexane with minimal amount of pyrrolizidine alkaloids, the toxic components. These findings indicate that P. japonicus extract containing petasin could be a promising food material for the prevention of obesity.

Cochlioquinone derivatives produced by coculture of endophytes, Clonostachys rosea and Nectria pseudotrichia.

Three new meroterpenoid derivatives, furanocochlioquinol (1) and furanocochlioquinone (2), as well as nectrianolin D (3), together with two known biogenetically related compounds 4 and 5 were isolated from a mixed culture of two mangrove-derived fungi, Clonostachys rosea B5-2 and Nectria pseudotrichia B69-1. The structures of 1-3 were deduced based on the interpretation of HRMS and NMR data. Compounds 1-5 exhibited cytotoxicity against human promyelocytic leukemia (HL60) cells with IC50 values ranging from 0.47 to 10.16 µM.

Triterpene saponins from the roots of Acacia senegal (L.) Willd.

Six new triterpenoid saponins, named senegalosides A-F (1-6) were isolated from the seedpods and roots of Acacia senegal (Mimosaceae). Their structures were elucidated using 1D and 2D-NMR spectroscopic analysis and mass spectrometry. Compound 1 possesses an unusual sapogenin, 3ß-hydroxy-21-oxo-olean-12-en-28-oic acid (machaeric acid), and was reported here in its natural form for the first time within the genus Acacia. Senegaloside A is the first example of a machaeric-type triterpenoid glycoside in the plant kingdom. The cytotoxic effect of isolated saponins was evaluated on the H4IIE rat hepatoma cell line. As a result, compounds 1, 3-6 were not significantly cytotoxic to H4IIE cells even at 200 µM. Compound 2 was suppressed cell viability at 50-200 µM.

Antibacterial and herbicidal properties of secondary metabolites from fungi.

Twenty-eight compounds were isolated from endophytic, soil and marine fungi and their structures were elucidated through spectroscopic methods. The isolated compounds were tested for their antibacterial and herbicidal activities against phytopathogenic bacteria and barnyard grass weed for the first time. Methyleurotinone (14) was the most potent compound against Pectobacterium carotovorum subsp. carotovorum, Pseudomonas syringae pv. syringae, Rhizobium radiobacter and Ralstonia solanacearum with minimum inhibitory concentration (MIC) values of 31.3, 125, 31.3 and 125 mg/L, respectively. Compounds 13-15 were highly effective in reducing the development of potato tuber soft rot disease caused by P. carotovorum subsp. carotovorum. Furthermore, twelve of the tested compounds induced a significant reduction in seed germination of Echinochloa crus-galli at 2 mM with compounds 8 and 26 causing complete inhibition of seed germination. Also, compounds 4, 22, 5, 8, 18 and 25-27 induced remarkable reduction of root and shoot growth of E. crus-galli at 2 mM.

New polyketides, paralactonic acids A-E produced by Paraconiothyrium sp. SW-B-1, an endophytic fungus associated with a seaweed, Chondrus ocellatus Holmes.

Five polyketides, paralactonic acids A-E (1-5) were isolated from Paraconiothyrium sp. SW-B-1, an endophytic fungus isolated from the seaweed, Chondrus ocellatus Holmes. Their structures were determined by various spectroscopic methods, predominantly by 2D NMR spectroscopic analyses. The absolute configurations of compounds 1-5 were determined by comparison of the experimental and calculated ECD spectra. Compound 5 showed moderate antibacterial activity and restored the growth of a mutant yeast strain inhibited by hyperactivated Ca2+-signaling.

New isocoumarins, naphthoquinones, and a cleistanthane-type diterpene from Nectria pseudotrichia 120-1NP.

Four new compounds, namely, nectriapyrones A (2) and B (3), nectriaquinone B (5), and zythiostromic acid C (8), were isolated from the brown rice culture of Nectria pseudotrichia 120-1NP together with four known compounds (1, 4, 6, and 7). To the best of our knowledge, this is the first report of 4 from a natural source. Their structures were determined on the basis of 1D/2D-NMR spectroscopy and HRESITOFMS data. In addition, the absolute configuration of secondary alcohols in 8 were determined using modified Mosher's ester method. All isolated compounds were evaluated for their antimicrobials activity, phytotoxicity, and cytotoxicity.

A new limonoid from stem bark of Chisocheton pentandrus (Meliaceae).

A new limonoid, pentandricine (1), along with three known limonoids, ceramicine B (2), 6-de(acetyloxy)-23-oxochisocheton (3), 6-de(acetyloxy)-23-oxo-7-O-deacetylchisocheton (4), have been isolated from the stembark of Chisocheton pentandrus. The chemical structures of the new compound were elucidated on the basis of spectroscopic evidence. All of the compounds were tested for their cytotoxic effects against MCF-7 breast cancer cells. Compounds 1-4 showed weak and no cytotoxicity against MCF-7 breast cancer cells with IC50 values of 369.84, 150.86, 208.93 and 120.09 µM, respectively.

A new depsidone derivative from the leaves of Garcinia polyantha.

One new depsidone, polyanthadepsidone A (1), together with four known compounds were isolated from the dichloromethane extract of the leaves of Garcinia polyantha. The structures of all compounds were determined by comprehensive analyses of their 1D and 2D NMR and EI mass spectral data. All the isolates exhibited suppressive effect on phagocytosis response upon activation with serum opsonised zymosan in the IC50 range of 4.5-23.80 µM, tested in vitro for oxidative burst studies of whole blood.

A phytotoxic bicyclic lactone and other compounds from endophyte Xylaria curta.

A new compound, (3aS,6aR)-4,5-dimethyl-3,3a,6,6a-tetrahydro-2H-cyclopenta [b]furan-2-one (2), along with two known metabolites, myrotheciumone A (1) and 4-oxo-4H-pyron-3-acetic acid (3) was isolated from the ethyl acetate extract of fermentation broth of Xylaria curta 92092022. The structures of these compounds were elucidated on the basis of spectroscopic methods (UV, IR, HRESITOFMS, 1D NMR, and 2D NMR). Compounds 1 and 2 showed moderate antibacterial and phytotoxic activities.

Two new 5-deoxyflavan-3,4-diol glucosides from roots of Albizia chevalieri.

Phytochemical investigation of the roots of Albizia chevalieri led to the isolation of two new 5-deoxyflavan-3,4-diol glucosides from roots of A. chevalieri, Chevalieriflavanosides A and B. Their structures were established by 2D NMR techniques, UV, IR, CD, and mass spectrometry. Cytotoxicity of the two compounds was evaluated against acute promyelocytic leukemia HL60 cells. The antibacterial activities of 1 and 2 also were evaluated against Pseudomonas aeruginosa and Staphylococcus aureus using the agar diffusion test. Copyright © 2016 John Wiley & Sons, Ltd.

Antibacterial triterpenoids from the bark of Sonneratia alba (Lythraceae).

The new lupane-type triterpenoid, 3ß-hydroxy-lup-9(11),12-diene, 28-oic acid (1), along with two known lupane-type triterpenoids, lupeol (2) and lupan-3ß-ol (3), were isolated from the bark of Sonnetaria alba. The structure of the new compound was elucidated on the basis of spectroscopic and mass spectrometric data analysis. Using the broth microdilution method, all compounds exhibited antibacterial activity against the Gram-positive bacteria Staphylococcus aureus ATCC 6538 and Streptococcus mutans ATCC 25175, with minimum inhibitory concentrations ranging from 15-33 to 35-55 µg/mL, respectively.

A new cytosporone derivative from the endophytic fungus Cytospora sp.

Japanese oak wilt (JOW) is a tree disease caused by the fungus Raffaelea quercivora, which is vectored by the ambrosia beetle, Platypus quercivorus. In a screening study of the inhibitory active compounds from fungi, a new cytosporone analogue, compound 1, was isolated from the endophytic fungus Cytospora sp. TT-10 isolated from Japanese oak, together with the known compounds, integracin A (2), cytosporones N (3) and A (4). Their structures were determined by extensive 1D- and 2D-NMR spectroscopic and mass spectral analyses. Compound 1 was identified as 4,5-dihydroxy-3-heptylphthalide and named cytosporone E. Compounds 2 and 3 showed antimicrobial activity against Raffaelea quercivora.

Isolation of a phomoxanthone A derivative, a new metabolite of tetrahydroxanthone, from a Phomopsis sp. isolated from the mangrove, Rhizhopora mucronata.

From the rice culture of Phomopsis sp. IM 41-1, isolated from the mangrove plant, Rhizhopora mucronata, two dimeric tetrahydroxanthones, phomoxanthone A (1) and 12-O-deacetyl-phomoxanthone A (2) were obtained. Their structures were determined by spectroscopic and spectrometric methods. Both compounds exhibited antimicrobial activities.

Polyketide metabolites from the endophytic fungus Microdiplodia sp. KS 75-1.

Through our screening for new natural compounds, four new polyketide metabolites, 7,8-dihydonivefuranone A (1), 6(7)-dehydro-8-hydroxyterrefuranone (2), 8-hydroxyterrefuranone (3), and 6-hydroxyterrefuranone (4) were isolated from the fermentation extract of Microdiplodia sp. KS 75-1, together with the known compounds nivefuranones A (5) and B (6); their structures were determined by spectroscopic (NMR, UV and IR) and MS analysis. Compounds 1, 2, 4 and 5 showed antimicrobial activity against Candida albicans and Staphylococcus aureus.

Effects of polyphenolic anthrone derivatives, resistomycin and hypercin, on apoptosis in human megakaryoblastic leukemia CMK-7 cell line.

A tetrahydroxyanthrone derivative, resistomycin, was isolated from the culture broth of Streptomyces sulphureus and a similar polyphenolic dianthraquinone, hypericin, was isolated from an extract of Hypericum perforatum L. as modulators for apoptosis. Resistomycin inhibited apoptosis induced by actinomycin D (AD) with or without acceleration by colcemid (CL) in human megakaryoblastic leukemia CMK-7 cells, IC50 for inhibition against AD-induced apoptosis was about 0.5 microM and IC50 for inhibition against AD plus CL-induced apoptosis was about 1 microM. CL alone induced weak apoptosis in cells, which was enhanced by resistomycin. Hypericin did not inhibit AD-induced apoptosis and slightly enhanced CL-induced apoptosis. Emodin, corresponding to 1 of 2 anthraquinone units in hypericin, did not show any effect on this apoptotic system. AD-induced apoptosis was inhibited by the antioxidative flavonoid, luteolin (IC50 45 microM), and a protein kinase C (PKC) inhibitor, staurosporine (IC50 1.5 microM), but these compounds did not affect the CL-induced apoptosis. Hypericin and resistomycin scavenged superoxide anion radicals at the same rate as luteolin. PKC in CMK-7 cells was inhibited by hypericin and luteolin, but not significantly inhibited by resistomycin. This result suggests that the inhibition of AD-induced apoptosis by resistomycin is at least partly correlated with its antioxidative activity, and that the enhancement of CL-induced apoptosis by this compound depends upon the lack of PKC inhibitory activity. Though the mechanism is not clear, the enhancement of the CL-induced apoptosis might be hindered by PKC inhibition in the case of hypericin and luteolin.