S. Kato et al., IN-VITRO AND EX-VIVO FREE-RADICAL SCAVENGING ACTIVITIES OF CARAZOSTATIN, CARBAZOMYCIN B AND THEIR DERIVATIVES, Journal of antibiotics, 46(12), 1993, pp. 1859-1865
Free radical scavenging activities of various carbazole compounds, car
azostatin, carbazomycin B and their chemically modified derivatives we
re studied in vitro and ex vivo. Among these compounds, carazostatin,
which was isolated as a free radical scavenger from the culture of Str
eptomyces chromofuscus, showed the most potent inhibitory activity aga
inst lipid peroxidation of rat brain homogenate in vitro. Carbazomycin
B, a known antimicrobial antibiotic, also exhibited strong activity i
n this system. Although O-modified derivatives of carazostatin and car
bazomycin B retained considerable activity, N,O-dimethyl derivatives d
id not suppress the peroxidation. On the other hand, the results from
the ex vivo evaluation of these carbazoles in the lipid peroxidation s
ystem of mouse blood plasma showed that the original compounds as well
as their O-modified derivatives had a strong inhibitory activity upon
oral administration to mice. These findings suggest that these natura
l carbazoles and their effective derivatives can protect tissues from
the peroxidative damage due to generation of free radicals.