Matural curcuminoids, curcumin, I, II and III isolated from turmeric (
Curcuma longa) were compared for their cytotoxic, tumour reducing and
antioxidant activities, Curcumin III was found to be more active than
the other two as a cytotoxic agent and in the inhibition of Ehrlich as
cites tumour in mice (ILS 74.1%), These compounds were also checked fo
r their antioxidant activity which possibly indicates their potential
use as anti-promoters. The amount of curcuminoids (I, II and III) need
ed for 50% inhibition of lipid peroxidation was 20, 14 and 11 g/ml. Co
ncentrations needed for 50% inhibition of superoxides were 6.25, 4.25
and 1.9 mu g/ml and those for hydroxyl radical were 2.3, 1.8 and 1.8 m
u g/ml, respectively. The ability of these compounds to suppress the s
uperoxide production by macrophages activated with phorbol-12-myristat
e-13-acetate (PMA) indicated that all the three curcuminoids inhibited
superoxide production and curcumin III produced maximum effect. These
results indicate that curcumin III is the most active of the curcumin
oids present in turmeric. Synthetic curcumin I and III had similar act
ivity to natural curcumins.