Peroxynitrite scavengers from Phellinus linteus

Peroxynitrite (ONOO^-) is a cytotoxic species formed from nitric oxide and superoxide anion, which are highly implicated in the pathogenesis of oxidative stress-mediated diseases. The aim of this study was to investigate the scavenging effects of Phellinus linteus on authentic ONOO^-, and further phytochemical studies are planned that will attempt to identify the active principles. From the active EtOAc fraction, a mixture of fungisterol and 5-dihydroergosterol (1), a mixture of betulin and 1,2-benzenedicarboxylic acid bis (2-methyl heptyl) ester (2), protocatechualdehyde (3), protocatechuic acid (4), cirsiumaldehyde (5), hispidin (6), caffeic acid (7), phelligridin D (8), uracil (9), gallic acid (10), 2,5-dihydroxybenzoic acid (11), ferulic acid (12), 2,3-dihydroxybenzaldehyde (13), arbutin (14), isoferulic acid (15), guanosine (16), and ellagic acid (17) were isolated, and their structures were characterized based on spectroscopic data. All compounds except 3, 6, 7 and 16 were isolated for the first time from P. linteus. Compounds 3, 4, 6-8, 10-15, and 17 showed potent scavenging activity on ONOO^-, with IC ₅₀ values of 2.06 ± 0.10, 3.45 ± 0.57, 0.71 ± 0.05, 2.78 ± 0.36, 5.42 ± 0.26, 1.13 ± 0.02, 1.82 ± 0.17, 0.91 ± 0.19, 1.59 ± 0.09, 1.88 ± 0.07, 1.22 ± 0.37, and 2.01 ± 0.02 μM, respectively, as compared to the positive control, DL-penicillamine, with an IC₅₀ value of 5.04 ± 0.06 μM.