Neuroprotective potential of new chromones isolated from the soil actinomycete Microbispora sp. TBRC6027.

Nine new chromone analogs (1-9) were isolated from the soil actinomycete Microbispora sp. TBRC6027. The chemical structures were determined based upon NMR spectroscopic methods. These compounds were evaluated in vitro by using P19-derived neurons for neuroprotective activity against oxidative stress induced by serum deprivation and showed % viability of neurons at the concentration of 1 ng/mL varied from 43.51% to 52.99% without significant neurotoxicity for P19-derived neurons at the same concentration. Moreover, all tested compounds were inactive for antibacterial activity against both Gram-positive and Gram-negative bacteria and for cytotoxicity against MCF-7 (human breast cancer) and Vero cells at maximum tested concentration 50 µg/mL. However, compounds 4, 6, and 7 displayed weak cytotoxicity against NCI-H187 (human small-cell lung cancer) cells with IC50 in a range of 87.99-91.57 µM.

Semisynthesis and antibacterial activities of nidulin derivatives.

Derivatives of the fungal depsidone, nidulin, have been synthesized in order to evaluate the potential of the chemical skeleton as antibacterial agents. Alkylation, acylation, and arylation reactions of nornidulin underwent in a regioselective manner to predominantly produce 8-O-substituted derivatives. Many of the semisynthetic derivatives showed more potent antibacterial activities than nidulin, In particular, 8-O-aryl ether derivatives displayed significant activities against Gram-positive bacteria, including Methicillin-resistant Staphylococcus aureus.

Salicylaldehyde and dihydroisobenzofuran derivatives from the marine fungus Zopfiella marina.

Two salicylaldehyde derivatives (1 and 2), a hydroxymethylphenol (3), five dihydroisobenzofuran (4-8) derivatives, and a 5-chloro-3-deoxyisoochracinic acid (9), together with a known 3-deoxyisoochracinic acid (10) were isolated from the marine fungus Zopfiella marina BCC 18240 (or NBRC 30420). The structures of these compounds were elucidated by extensive spectroscopic analysis. Compound 1 showed weak antituberculous activity against Mycobacterium tuberculosis H37Ra, and antibacterial activity against Bacillus cereus with MIC values of 25 and 12.5 µg/mL, respectively.

Alliacane sesquiterpenoids from submerged cultures of the basidiomycete Inonotus sp. BCC 22670.

Nine alliacane sesquiterpenoids, inonoalliacanes A-I, were isolated from culture broth of the basidiomycete Inonotus sp. BCC 22670. The structures were elucidated on the basis of NMR spectroscopic and mass spectrometry data. The absolute configuration of inonoalliacane F was determined by application of the modified Mosher's method. Inonoalliacane A, the most abundant sesquiterpene constituent, exhibited moderate antibacterial activity against Bacillus cereus, whereas inonoalliacane B showed antiviral activity against herpes simplex virus type 1.

Cadinane sesquiterpenoids from the basidiomycete Stereum cf. sanguinolentum BCC 22926.

Stereumins Q-U, together with known stereumins A, B, K, L, and N, as well as ent-strobilols E and G were isolated from the culture of Stereum cf. sanguinolentum BCC 22926. Their structures were elucidated by extensive spectroscopic analyses. The absolute configurations of stereumins A and Q, as well as ent-strobilol E were established by application of the modified Mosher's method. Stereumin T displayed antibacterial activity against Bacilluscereus with a MIC value of 3.97µM.

Bioactive compounds from the scale insect pathogenic fungus Conoideocrella tenuis BCC 18627.

A new cyclohexadepsipeptide, conoideocrellide A (1), its linear derivatives, conoideocrellides B-D (2-4), three new hopane triterpenoids (5-7), two new bioxanthracenes (9 and 10), and a new isocoumarin glycoside (13) were isolated from the scale insect pathogenic fungus Conoideocrella tenuis BCC 18627. Biological activities of the new compounds were evaluated.

Hopane-type triterpenes and binaphthopyrones from the scale insect pathogenic fungus Aschersonia paraphysata BCC 11964.

Two new triterpenes, 17(21)-hopene-6alpha,12beta-diol (1) and 17(21)-hopen-12beta-ol (2), the known 17(21)-hopen-6alpha-ol (zeorinin, 3), and two new biarylic dihydronaphthopyrones, aschernaphthopyrones A (4) and B (5), were isolated from the scale insect pathogenic fungus Aschersonia paraphysata BCC 11964. Hopene 1 and aschernaphthopyrone A (4) exhibited antimalarial activity with IC(50) values of 15 and 7.3 microM, respectively.

Phenolic glycosides from the filamentous fungus Acremonium sp. BCC 14080.

New phenolic mono- and digalactopyranosides (1 and 2), their aglycone KS-501a (3), and a new phenolic 4-O-methylglucopyranoside (4) were isolated from the filamentous fungus Acremonium sp. BCC 14080. Structures of these compounds were elucidated by extensive MS and NMR spectroscopic analyses. Compound 1 displayed anti-HSV-1 activity with an IC(50) value of 7.2 microM. Compound 3 exhibited activity against Plasmodium falciparum K1 with an IC(50) value of 9.9 microM.