Streptomyces aureofaciens CMUAc130 was isolated from the root tissue of Zingiber officinale Rosc. (Zingiberaceae). It was an antagonist of Colletotrichum musae and Fusarium oxysporum, the causative agents of anthracnose of banana and wilt of wheat, respectively. Evidence for the in vitro antibiosis of S. aureofaciens CMUAc130 was demonstrated by the zone of fungal-growth inhibition. Microscopic observations showed thickness and bulbous structures at the edges of the inhibited fungal hyphae. The culture filtrate and crude extract from this strain were all inhibitory to tested phytopathogenic fungi. The major active ingredients from the culture filtrate of S. aureofaciens CMUAc130 were purified by silica gel-column chromatography and identified to be (i) 5,7-dimethoxy-4-p-methoxylphenylcoumarin and (ii) 5,7-dimethoxy-4-phenylcoumarin by NMR and mass-spectral data, respectively. Bioassay studies showed that compounds (i) and (ii) had antifungal activities against tested fungi, and their MICs were found to be 120 and 150 mg ml "1 , respectively. This is the first report of compounds (i) and (ii) from micro-organisms as active ingredients for the control of phytopathogenic fungi.

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In a search for antitumor agents, we carried out a screening of 4-arylcoumarins isolated from endophytic Streptomyces aureofaciens CMUAc130, by examining their possible inhibitory effect on the growth of s.c. transplanted Lewis lung carcinoma (LLC) in BDF-1 mice by intraperitoneal (i.p.) administration. The 4-arylcoumarins showed antitumor activity with T/C values of 80.8 and 50.0% at doses of 1 and 10 mg/kg of 5,7-dimethoxy-4-p-methoxylphenylcoumarin treatment, respectively and 81.5 and 44.9% at doses of 1 and 10 mg/kg of 5,7-dimethoxy-4-phenylcoumarin treatment, respectively, compared to adriamycin, which was used a positive control, with T/C value of 55.9% at 2 mg/kg. Furthermore, we investigated the possible effects of these compounds on expression of the bcl-2 and Bax oncoproteins in A427, a human lung cancer cell lines. The cells were cultured in vitro for 24 h in RPMI 1640 with 1.5% (v/v) ethanol, 100 microg/ml 5,7-dimethoxy-4-p-methoxylphenylcoumarin or 5,7-dimethoxy-4-phenylcoumarin. Viability was determined by an MTT assay. Total protein was extracted from cell lysates and the bcl-2 and Bax oncoproteins were identified. Western blotting showed a decrease in bcl-2 and an increase in Bax in A427 cell cultured with 5,7-dimethoxy-4-p-methoxylphenylcoumarin or 5,7-dimethoxy-4-phenylcoumarin. We conclude that 5,7-dimethoxy-4-phenylcoumarin is a more potent inhibitor of cell proliferation than 5,7-dimethoxy-4-p-methoxylphenylcoumarin and has more marked effects on oncoprotein expression.

Strain BO-07 was isolated from the root tissue of Boesenbergia rotunda (L.) Mansf A. and identified as Streptomyces sp. on the basis of morphology, chemotaxonomy and 16S rDNA sequencing. The fractionation of the crude extract from strain BO-07 cultures led to the isolation of two biphenyls: 3 ′-hydroxy-5-methoxy-3,4methylenedioxybiphenyl (1) and 3 ′-hydroxy-5,5 ′-dimethoxy-3,4methylenedioxybiphenyl (2); these compounds and the crude extract had potent antibacterial activity against Gram-positive bacteria, and antioxidant and anticancer activities. These compounds showed the highest activity against Staphylococcus aureus ATCC25932, Bacillus cereus ATCC7064 and Bacillus subtilis ATCC6633 with a minimum inhibitory concentration value of 0.5 µg/ml and minimum bactericidal concentration of 2-8 µg/ml. Compounds 1 and 2 showed the highest (1, 1diphenyl-2-picryl hydrazyl) DPPH antioxidant activity with a scavenging concentration (SC 50) value of 85.84 and 88.26 µg/ml, respectively, and also showed strong cytotoxicity against all the three cancer cell lines (HeLa, HepG2 and Huh7) at an IC 50 value of 3.04-20.30 μg/ml. Both the compounds were less toxic on normal cells (L929) than on the investigated cancer cell lines.

Streptomyces zerumbet W14, a novel species of the endophyte genus Streptomyces was isolated from the rhizome tissue of Zingiber zerumbet (L.) Smith. Identification of strain W14 was based on its morphology, chemotaxonomy and phylogenetic analysis using 16S rDNA sequence. It was classified as the secondary meabolites of the culture extract were studied. The major active ingredients from the crude extract were purified by silica gel column chromatography and identified by spectroscopic data. The crude extract and purified compounds were tested for their biological activities on antibacterial and anti-inflammatory properties. The crude extract showed inhibition on the growth of Gram-positive bacteria with the MIC and MBC values of 8-32 µg/ml and 32-128 µg/ml, respectively. The isolated compounds were identified to be methyl 5-(hydroxymethyl)furan-2-carboxylate (1) and geldanamycin (2). Bioassay studies showed that compound 1 had antibacterial activity against Staphylococus aureus ATCC 25923 and Methicillin Resistant S. aureus strain Sp6 (clinical isolate) with the MIC and MBC values of 1 µg/ml and 16-64 µg/ml, respectively, and also showed activity against Bacillus Calmette-Guérin (vaccine strain) with MIC and MBC values of 128.00 µg/ml and 128.00 µg/ml, respectively. The compound 2 at the concentration of 1-5 µg/ml had in vitro anti-inflammatory activity on LPS-induced RAW 264.7 cells by inhibition of mRNA expression and production of inducible NO synthase (iNOS), tumor necrosis factor-alpha (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6). These results suggest that compounds 1 and 2 produced by S. zerumbet W14 (an endophyte of Z. Zerumbet) have antibacterial and anti-inflammatory activities, respectively. Therefore, the future studies on these compounds could be useful for the management of bacterial infections and inflammatory diseases.

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