neoechinulin-a and 1-1-diphenyl-2-picrylhydrazyl

Twelve new compounds, variecolorins A-L ( 1- 12), together with eleven known analogues ( 13- 23) were isolated from the broth of a halotolerant fungus, Aspergillus variecolor. The structures of compounds 1- 12 were determined by chemical and spectroscopic methods. Compounds 1- 11, 13- 15, and 20- 23 exhibited weak radical scavenging activity against DPPH, with IC 50 values from 43 to 103 microM. The new compounds 1- 12 all were essentially nontoxic against the P388, HL-60, BEL-7402, and A-549 cell lines with IC 50 values from 70 to 260 microM.

Topics: Alkaloids; Animals; Aspergillus; Biphenyl Compounds; China; Drug Screening Assays, Antitumor; Free Radical Scavengers; Inhibitory Concentration 50; Molecular Structure; Picrates; Salinity

A new diketopiperazine alkaloid, golmaenone (1). and related alkaloids, neoechinulin A (2). and L-alanyl-L-tryptophan anhydride (3). have been isolated from the culture broth of the marine-derived fungus Aspergillus sp. The structure and absolute stereochemistry of the new compound (1). was assigned by spectroscopic methods and the advanced Marfey's method. Compounds 1 and 2 exhibited a significant radical scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH) with IC(50) values of 20 and 24 microM, respectively, which are similar to the positive control, ascorbic acid (IC(50), 20 microM). Compounds 1 and 2 also showed an ultraviolet-A (UV-A) (320--390 nm) protecting activity with ED(50) values of 90 and 170 microM, respectively, which are more active than oxybenzone (ED(50), 350 microM) currently being used as sunscreen.

Topics: Ascorbic Acid; Aspergillus; Benzophenones; Biphenyl Compounds; Dipeptides; Free Radical Scavengers; Indole Alkaloids; Inhibitory Concentration 50; Molecular Structure; Nuclear Magnetic Resonance, Biomolecular; Peptides, Cyclic; Picrates; Piperazines; Sunscreening Agents; Ultraviolet Rays