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The polyene macrolide antibiotic filipin is widely used as a probe for cholesterol and a diagnostic tool for type C Niemann-Pick disease. Two position-specific P450 enzymes are involved in the post-polyketide modification of filipin during its biosynthesis, thereby providing molecular diversity to the "filipin complex." CYP105P1 and CYP105D6 from(More)
Pure natural products isolated from marine sponges, algae, and cyanobacteria were examined for antioxidant activity using a 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) solution-based chemical assay and a 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA) cellular-based assay. The DCFH system detects only antioxidants that penetrate cellular membranes.(More)
Pentalenic acid (1) has been isolated from many Streptomyces sp. as a co-metabolite of the sesquiterpenoid antibiotic pentalenolactone and related natural products. We have previously reported the identification of a 13.4-kb gene cluster in the genome of Streptomyces avermitilis implicated in the biosynthesis of the pentalenolactone family of metabolites(More)
A new arylbenzofuran, 3',5'-dihydroxy-6-methoxy-7-prenyl-2-arylbenzofuran (1), and 25 known compounds, including moracin R (2), moracin C (3), moracin O (4), moracin P (5), artoindonesianin O (6), moracin D (7), alabafuran A (8), mulberrofuran L (9), mulberrofuran Y (10), kuwanon A (11), kuwanon C (12), kuwanon T (13), morusin (14), kuwanon E (15),(More)
A new antimalarial quassinoid, namely, orinocinolide (1), was isolated from the root bark of Simaba orinocensis, together with the previously reported simalikalactone D (2). The structure of 1 was determined primarily from 1D and 2D NMR analysis, as well as by chemical derivatization. Compound 1 was found to be as equally potent as 2 against Plasmodium(More)
The aerial parts of Centaurothamnus maximus yielded three cytotoxic guaianolides, chlorojanerin (1), cynaropicrin (2) and janerin (3). The structure elucidation of 1-3 was based on (1)H and (13)C NMR data, mainly 2D-NMR (1)H-(1)H COSY and (1)H-(13)C HETCOR experiments. Compounds 1-3 showed in vitro cytotoxic activity against human cancer cell lines of(More)
The fermentation and isolation of 1 were carried out in the same way as reported previously1}. Astock culture of the producing organism was inoculated into a test tube (i.d. 2x20cm) containing 10ml of seed medium consisting of2% glucose, 0.5% peptone, 0.3% dry yeast, 0.5% meat extract, 0.5% NaCl and 0.3% CaCO3 (pH 7.0 before sterilization). The tube was(More)
Free radical scavenging and cell aggregation inhibitory activities of 36 secondary metabolites isolated from the methanolic extracts of Verbascum cilicicum Boiss., V. lasianthum Boiss. ex Bentham, V pterocalycinum var. mutense Hub.-Mor., and V. salviifolium Boiss. (Scrophulariaceae) were investigated. The isolated compounds, 6-O-vaniloyl ajugol (1),(More)
New melanin synthesis inhibitors, OH-3984 K1 and K2, were isolated from the fermentation broth of Streptomyces sp. OH-3984, and their structures were elucidated by spectroscopic methods and by chemical transformations. OH-3984 K1 (M.W.: 306; C18H26O4) and K2 (M.W.: 308; C18H28O4) have unique gamma-lactone rings, both of which correspond to oxidative(More)
A new melanogenesis inhibitor, named amphistin, was isolated from the fermentation broth of an actinomycete strain KP-3052. Amphistin was purified from the culture filtrate by the combination of cation exchange, gel filtration, and aminosilyl silica gel chromatographic methods. The structure of amphistin was elucidated as(More)