Novel DPPH Radical Scavengers, Demethylbisorbibutenolide and Trichopyrone, from a Fungus

Abstract

In our screening program for antioxidants with 1,1-diphenyl-2-picrylhydrazyl (DPPH)-radical scavenging activity, two novel compounds, demethylbisorbibutenolide (1) and trichopyrone (2), were isolated from the fermentation broth of the fungus of USF-4860 strain isolated from a soil sample. The structures of these compounds were determined from spectroscopic evidence. The biosynthetic origin of the carbon atoms of 2 was unambiguously determined by feeding experiments using (13)C-labeled precursors and elucidation of the (13)C-NMR spectrum of (13)C-labeled 2. These studies showed that 2 was derived from five acetates and a methyl group of methionine. In the DPPH-radical scavenging assay, 1 and 2 gave ED(50) values of 149 and 167 muM after standing for 2.0 hr. Compound 2 reacted with the DPPH radical to form reaction product 3 which was determined to be 1-[4-(3,4-dihydro-3-methyl-6-{1,3-pentadienyl}-2,4-dioxo-2H-pyran-3-yl)-phenyl]-1-phenyl-2-picrylhydrazine from spectroscopic evidence.

Surugapyrone A from Streptomyces coelicoflavus strain USF-6280 as a new DPPH radical-scavenger

“…The mild activity of surugapyrone A is similar to that of the two 4-hydroxy-2-pyrones previously isolated from fungi by our research group. 4,11 Accordingly, the mechanism of the DPPH radical-scavenging of 1 was expected to proceed through formation of an adduct with the DPPH radical. 4,11 Recently, the biosynthesis of similar 2-pyrone derivatives isolated from Streptomyces coelicolor was studied mainly by means of LC/MS analysis.…”

“…4,11 Accordingly, the mechanism of the DPPH radical-scavenging of 1 was expected to proceed through formation of an adduct with the DPPH radical. 4,11 Recently, the biosynthesis of similar 2-pyrone derivatives isolated from Streptomyces coelicolor was studied mainly by means of LC/MS analysis. 12 Our results indicated precise regiospecific incorporation of precursors, suggesting that surugapyrone A (1) was biosynthesized by type III polyketide synthase.…”

“…[1][2][3][4][5][6] Recently, we found that Streptomyces sp. strain USF-6280 obtained from a soil sample collected in Suruga-ku, Shizuoka-city, Japan, produced two new DPPH radical-scavenging N-hydroxypyrrole compounds-surugapyrroles A and B.…”

12T061A and 12T061C, two new julichrome family compounds, as radical scavengers from <i>Streptomyces</i> sp.

“…Measurement of DPPH radical-scavenging activity. This assay was performed by a previously reported spectroscopic method (Chen et al, 2005;Washida et al, 2007). An MeOH solution (2 mL) of each sample was mixed with a 0.5 mM DPPH MeOH solution (1 mL) in 0.1 M acetate buffer (pH 5.5, 2 mL).…”

6'-Hydroxyoxosorbicillinol, a New Lipoxygenase Inhibitor and PGD2/LTB4Release Suppressor fromPenicilliumsp.

“…The polarity of the optical rotation values for 1 and 2, both of which were negative, suggests that the stereochemistry of C-6 in 1 is the same as that in 2, an R configuration. Abe et al [6][7][8][9] have reported the isolation of sorbicillin compounds, including oxosorbicillinol (2), from the fungus Trichoderma sp. They also isolated various dimeric compounds and discussed their biosynthetic pathways.…”