Protective and antioxidative effect of rubropunctatin against oxidative protein damage induced by metal catalyzed reaction.

Monascus purpureus is known to produce several coloured secondary metabolites. In this
study, M. purpureus CFR 410-11 mutant fermented with rice was dried and extracted in hexane
for purification of pigment. The purity of the isolated pigment was confirmed by different
chromatography techniques. The spectroscopic analysis revealed its structural identity as
rubropunctatin. The antioxidant potencies of isolated rubropunctatin were evaluated.
Rubropunctatin scavenged 16% 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical and inhibited
20% superoxide generation at 8 μg/ml concentration. The multiple antioxidant abilities of
rubropunctatin were evidenced by its ferric reducing capacity also. The oxidative damage of
BSA protein was induced by the metal catalyzed oxidation (MCO) by Fe2+/H2O2. The protective
effects of rubropunctatin and M. purpureus (MTCC-410 and CFR 410-11) extracts were
compared with glutathione and ascorbic acid. The M. purpureus extracts and rubropunctatin
inhibited the formation of carbonyl content and protein oxidation assayed by SDS-PAGE.
Rubropunctatin (42-169 μM) efficiently inhibited the protein oxidation compared to glutathione
(48-195 μM) and ascorbic acid (85-340 μM) by scavenging the superoxide and hydroxyl radical
generated in the system.